Bon S

General

Full name : Bon Suzanne

First name : Suzanne

Mail : Neurobiologie\; CNRS UMR8544\; Ecole Normale Superieure\; 46 rue d'Ulm\; 75005 Paris

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Country : France

Email : subon@orange.fr

Phone : +33144323891

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References (104)

Title : Altered GPI modification of insect AChE improves tolerance to organophosphate insecticides. - Kakani_2011_Insect.Biochem.Mol.Biol_41_150
Author(s) : Kakani EG , Bon S , Massoulie J , Mathiopoulos KD
Ref : Insect Biochemistry & Molecular Biology , 41 :150 , 2011
Abstract : The olive fruit fly Bactrocera oleae is the most destructive and intractable pest of olives. The management of B. oleae has been based on the use of organophosphate (OP) insecticides, a practice that induced resistance. OP-resistance in the olive fly was previously shown to be associated with two mutations in the acetylcholinesterase (AChE) enzyme that, apparently, hinder the entrance of the OP into the active site. The search for additional mutations in the ace gene that encodes AChE revealed a short deletion of three glutamines (3Q) from a stretch of five glutamines, in the C-terminal peptide that is normally cleaved and substituted by a GPI anchor. We verified that AChEs from B. oleae and other Dipterans are actually GPI-anchored, although this is not predicted by the "big-PI" algorithm. The 3Q mutation shortens the unusually long hydrophilic spacer that follows the predicted GPI attachment site and may thus improve the efficiency of GPI anchor addition. We expressed the wild type B. oleae AChE, the natural mutant 3Q and a constructed mutant lacking all 5 consecutive glutamines (5Q) in COS cells and compared their kinetic properties. All constructs presented identical K(m) and k(cat) values, in agreement with the fact that the mutations did not affect the catalytic domain of the enzyme. In contrast, the mutants produced higher AChE activity, suggesting that a higher proportion of the precursor protein becomes GPI-anchored. An increase in the number of GPI-anchored molecules in the synaptic cleft may reduce the sensitivity to insecticides.
ESTHER : Kakani_2011_Insect.Biochem.Mol.Biol_41_150
PubMedSearch : Kakani_2011_Insect.Biochem.Mol.Biol_41_150
PubMedID: 21112395

Title : The PRiMA-linked cholinesterase tetramers are assembled from homodimers: hybrid molecules composed of acetylcholinesterase and butyrylcholinesterase dimers are up-regulated during development of chicken brain - Chen_2010_J.Biol.Chem_285_27265
Author(s) : Chen VP , Xie HQ , Chan WK , Leung KW , Chan GK , Choi RC , Bon S , Massoulie J , Tsim KWK
Ref : Journal of Biological Chemistry , 285 :27265 , 2010
Abstract : Acetylcholinesterase (AChE) is anchored onto cell membranes by the transmembrane protein PRiMA (proline-rich membrane anchor) as a tetrameric globular form that is prominently expressed in vertebrate brain. In parallel, the PRiMA-linked tetrameric butyrylcholinesterase (BChE) is also found in the brain. A single type of AChE-BChE hybrid tetramer was formed in cell cultures by co-transfection of cDNAs encoding AChE(T) and BChE(T) with proline-rich attachment domain-containing proteins, PRiMA I, PRiMA II, or a fragment of ColQ having a C-terminal GPI addition signal (Q(N-GPI)). Using AChE and BChE mutants, we showed that AChE-BChE hybrids linked with PRiMA or Q(N-GPI) always consist of AChE(T) and BChE(T) homodimers. The dimer formation of AChE(T) and BChE(T) depends on the catalytic domains, and the assembly of tetramers with a proline-rich attachment domain-containing protein requires the presence of C-terminal "t-peptides" in cholinesterase subunits. Our results indicate that PRiMA- or ColQ-linked cholinesterase tetramers are assembled from AChE(T) or BChE(T) homodimers. Moreover, the PRiMA-linked AChE-BChE hybrids occur naturally in chicken brain, and their expression increases during development, suggesting that they might play a role in cholinergic neurotransmission.
ESTHER : Chen_2010_J.Biol.Chem_285_27265
PubMedSearch : Chen_2010_J.Biol.Chem_285_27265
PubMedID: 20566626

Title : Respective roles of the catalytic domains and C-terminal tail peptides in the oligomerization and secretory trafficking of human acetylcholinesterase and butyrylcholinesterase - Liang_2009_FEBS.J_276_94
Author(s) : Liang D , Blouet JP , Borrega F , Bon S , Massoulie J
Ref : Febs J , 276 :94 , 2009
Abstract : Butyrylcholinesterase (BChE) and the T splice variant of acetylcholinesterase that is predominant in mammalian brain and muscles (AChE(T)) possess a characteristic C-terminal tail (t) peptide. This t peptide allows their assembly into tetramers associated with the anchoring proteins ColQ and PRiMA. Although the t peptides of all vertebrate cholinesterases are remarkably similar and, in particular, contain seven strictly conserved aromatic residues, these enzymes differ in some of their oligomerization properties. To explore these differences, we studied human AChE (Aa) and BChE (Bb), and chimeras in which the t peptides (a and b) were exchanged (Ab and Ba). We found that secretion was increased by deletion of the t peptides, and that it was more efficient with a than with b. The patterns of oligomers were similar for Aa and Ab, as well as for Ba and Bb, indicating a predominant influence of the catalytic domains. However, addition of a cysteine within the aromatic-rich segment of the t peptides modified the oligomeric patterns: with a cysteine at position 19, the proportion of tetramers was markedly increased for Aa(S19C) and Ba(S19C), and to a lesser extent for Bb(N19C); the Ab(N19C) mutant produced all oligomeric forms, from monomers to hexamers. These results indicate that both the catalytic domains and the C-terminal t peptides contribute to the capacity of cholinesterases to form and secrete various oligomers. Sequence comparisons show that the differences between the t peptides of AChE and BChE are remarkably conserved among all vertebrates, suggesting that they reflect distinct functional adaptations.
ESTHER : Liang_2009_FEBS.J_276_94
PubMedSearch : Liang_2009_FEBS.J_276_94
PubMedID: 19019080

Title : Protein CutA undergoes an unusual transfer into the secretory pathway and affects the folding, oligomerization, and secretion of acetylcholinesterase - Liang_2009_J.Biol.Chem_284_5195
Author(s) : Liang D , Nunes-Tavares N , Xie HQ , Carvalho S , Bon S , Massoulie J
Ref : Journal of Biological Chemistry , 284 :5195 , 2009
Abstract : The mammalian protein CutA was first discovered in a search for the membrane anchor of mammalian brain acetylcholinesterase (AChE). It was co-purified with AChE, but it is distinct from the real transmembrane anchor protein, PRiMA. CutA is a ubiquitous trimeric protein, homologous to the bacterial CutA1 protein that belongs to an operon involved in resistance to divalent ions ("copper tolerance A"). The function of this protein in plants and animals is unknown, and several hypotheses concerning its subcellular localization have been proposed. We analyzed the expression and the subcellular localization of mouse CutA variants, starting at three in-frame ATG codons, in transfected COS cells. We show that CutA produces 20-kDa (H) and 15-kDa (L) components. The H component is transferred into the secretory pathway and secreted, without cleavage of a signal peptide, whereas the L component is mostly cytosolic. We show that expression of the longer CutA variant reduces the level of AChE, that this effect depends on the AChE C-terminal peptides, and probably results from misfolding. Surprisingly, CutA increased the secretion of a mutant possessing a KDEL motif at its C terminus; it also increased the formation of AChE homotetramers. We found no evidence for a direct interaction between CutA and AChE. The longer CutA variant seems to affect the processing and trafficking of secretory proteins, whereas the shorter one may have a distinct function in the cytoplasm.
ESTHER : Liang_2009_J.Biol.Chem_284_5195
PubMedSearch : Liang_2009_J.Biol.Chem_284_5195
PubMedID: 19049969

Title : Old and new questions about cholinesterases - Massoulie_2008_Chem.Biol.Interact_175_30
Author(s) : Massoulie J , Perrier N , Noureddine H , Liang D , Bon S
Ref : Chemico-Biological Interactions , 175 :30 , 2008
Abstract : Cholinesterases have been intensively studied for a long time, but still offer many fascinating and fundamental questions regarding their evolution, activity, biosynthesis, folding, post-translational modifications, association with structural proteins (ColQ, PRiMA and maybe others), export or degradation. They constitute an excellent model to study these processes, particularly because of the sensitivity and specificity of enzymic assays. In addition, a number of provocative ideas concerning their proposed non-conventional, or non-catalytic functions deserve to be further documented.
ESTHER : Massoulie_2008_Chem.Biol.Interact_175_30
PubMedSearch : Massoulie_2008_Chem.Biol.Interact_175_30
PubMedID: 18541228

Title : Acetylcholinesterase associates differently with its anchoring proteins ColQ and PRiMA - Noureddine_2008_J.Biol.Chem_283_20722
Author(s) : Noureddine H , Carvalho S , Schmitt C , Massoulie J , Bon S
Ref : Journal of Biological Chemistry , 283 :20722 , 2008
Abstract : Acetylcholinesterase tetramers are inserted in the basal lamina of neuromuscular junctions or anchored in cell membranes through the interaction of four C-terminal t peptides with proline-rich attachment domains (PRADs) of cholinesterase-associated collagen Q (ColQ) or of the transmembrane protein PRiMA (proline-rich membrane anchor). ColQ and PRiMA differ in the length of their proline-rich motifs (10 and 15 residues, respectively). ColQ has two cysteines upstream of the PRAD, which are disulfide-linked to two AChE(T) subunits ("heavy" dimer), and the other two subunits are disulfide-linked together ("light" dimer). In contrast, PRiMA has four cysteines upstream of the PRAD. We examined whether these cysteines could be linked to AChE(T) subunits in complexes formed with PRiMA in transfected COS cells and in the mammalian brain. For comparison, we studied complexes formed with N-terminal fragments of ColQ, N-terminal fragments of PRiMA, and chimeras in which the upstream regions containing the cysteines were exchanged. We also compared the effect of mutations in the t peptides on their association with the two PRADs. We report that the two PRADs differ in their interaction with AChE(T) subunits; in complexes formed with the PRAD of PRiMA, we observed light dimers, but very few heavy dimers, even though such dimers were formed with the PQ chimera in which the N-terminal region of PRiMA was associated with the PRAD of ColQ. Complexes with PQ or with PRiMA contained heavy components, which migrated abnormally in SDS-PAGE but probably resulted from disulfide bonding of four AChE(T) subunits with the four upstream cysteines of the associated protein.
ESTHER : Noureddine_2008_J.Biol.Chem_283_20722
PubMedSearch : Noureddine_2008_J.Biol.Chem_283_20722
PubMedID: 18511416

Title : Assembly of acetylcholinesterase tetramers by peptidic motifs from the proline-rich membrane anchor, PRiMA: competition between degradation and secretion pathways of heteromeric complexes - Noureddine_2007_J.Biol.Chem_282_3487
Author(s) : Noureddine H , Schmitt C , Liu W , Garbay C , Massoulie J , Bon S
Ref : Journal of Biological Chemistry , 282 :3487 , 2007
Abstract : The membrane-bound form of acetylcholinesterase (AChE) constitutes the major component of this enzyme in the mammalian brain. These molecules are hetero-oligomers, composed of four AChE catalytic subunits of type T (AChE(T)), associated with a transmembrane protein of type 1, called PRiMA (proline-rich membrane anchor). PRiMA consists of a signal peptide, an extracellular domain that contains a proline-rich motif (14 prolines with an intervening leucine, P4LP10), a transmembrane domain, and a cytoplasmic domain. Expression of AChE(T) subunits in transfected COS cells with a truncated PRiMA, without its transmembrane and cytoplasmic domains (P(stp54) mutant), produced secreted heteromeric complexes (T4-P(stp54)), instead of membrane-bound tetramers. In this study, we used a series of deletions and point mutations to analyze the interaction between the extracellular domain of PRiMA and AChE(T) subunits. We confirmed the importance of the polyproline stretches and defined a peptidic motif (RP4LP10RL), which induces the assembly and secretion of a heteromeric complex with four AChE(T) subunits, nearly as efficiently as the entire extracellular domain of PRiMA. It is noteworthy that deletion of the N-terminal segment preceding the prolines had little effect. Interestingly, short PRiMA mutants, truncated within the proline-rich motif, reduced both cellular and secreted AChE activity, suggesting that their interaction with AChE(T) subunits induces their intracellular degradation.
ESTHER : Noureddine_2007_J.Biol.Chem_282_3487
PubMedSearch : Noureddine_2007_J.Biol.Chem_282_3487
PubMedID: 17158452

Title : The C-terminal T peptide of cholinesterases: structure, interactions, and influence on protein folding and secretion - Massoulie_2006_J.Mol.Neurosci_30_233
Author(s) : Massoulie J , Bon S
Ref : Journal of Molecular Neuroscience , 30 :233 , 2006
Abstract : Mammalian cholinergic tissues mostly express the T splice variant of acetylcholinesterase, in which the catalytic domain is associated with a C-terminal peptide of 40 residues, called the t peptide (Massoulie, 2002). Homologous t peptides exist in all vertebrate cholinesterases, acetylcholinesterases (AChEs), and butyrylcholinesterases (BChEs): they contain a series of seven conserved aromatic residues, including three tryptophans, and a cysteine at position-4 of their C-terminus. The major AChE isozyme of the nematode Caenorhabditis elegans also contains a similar peptide. Although the C-terminal t peptides do not seem to affect the catalytic activity of cholinesterases, they determine their physiological function, because they allow cholinesterase subunits of type T to form oligomers and to associate with structural anchoring proteins. When reduced to their catalytic domain, AChE subunits without a t peptide are active but remain monomeric and soluble.
ESTHER : Massoulie_2006_J.Mol.Neurosci_30_233
PubMedSearch : Massoulie_2006_J.Mol.Neurosci_30_233
PubMedID: 17192683

Title : Readthrough acetylcholinesterase expression remains minor after stress or exposure to inhibitors - Perrier_2006_J.Mol.Neurosci_30_75
Author(s) : Perrier NA , Salani M , Falasca C , Bon S , Augusti-Tocco G , Massoulie J
Ref : Journal of Molecular Neuroscience , 30 :75 , 2006
Abstract : The gene of mammalian acetylcholinesterase (AChE) generates multiple molecular forms, by alternative splicing of its transcripts and association of the tailed variant (AChET) with structural proteins. In the mammalian brain, the major AChE species consists of AChET tetramers anchored to the cell membrane of neurons by the PRiMA protein (Perrier et al., 2002). Stress and anticholinesterase inhibitors have been reported to induce rapid and long-lasting expression of the readthrough variant (AChER) in the mouse brain (Kaufer et al., 1998). In the readthrough transcript, there is no splicing after the last exon encoding the catalytic domain, so that the entire alternatively spliced 3' region is maintained. It encodes a C-terminal peptide with no specific interaction properties: COS cells transfected with AChER produce a soluble, nonamphiphilic monomeric form. We quantified AChER and total AChE expression in the mouse brain after an immobilization stress and after heat shock in neuroblastoma cells, and compared the observed effects with those induced by irreversible AChE inhibition (Perrier et al., 2005).
ESTHER : Perrier_2006_J.Mol.Neurosci_30_75
PubMedSearch : Perrier_2006_J.Mol.Neurosci_30_75
PubMedID: 17192635

Title : Determinants of the t peptide involved in folding, degradation, and secretion of acetylcholinesterase - Falasca_2005_J.Biol.Chem_280_878
Author(s) : Falasca C , Perrier NA , Massoulie J , Bon S
Ref : Journal of Biological Chemistry , 280 :878 , 2005
Abstract : The C-terminal 40-residue t peptide of acetylcholinesterase (AChE) forms an amphiphilic alpha helix with a cluster of seven aromatic residues. It allows oligomerization and induces a partial degradation of AChE subunits through the endoplasmic reticulum-associated degradation pathway. We show that the t peptide induces the misfolding of a fraction of AChE subunits, even when mutations disorganized the cluster of aromatic residues or when these residues were replaced by leucines, indicating that this effect is due to hydrophobic residues. Mutations in the aromatic-rich region affected the cellular fate of AChE in a similar manner, with or without mutations that prevented dimerization. Degradation was decreased and secretion was increased when aromatic residues were replaced by leucines, and the opposite occurred when the amphiphilic alpha helix was disorganized. The last two residues (Asp-Leu) somewhat resembled an endoplasmic reticulum retention signal and caused a partial retention but only in mutants possessing aromatic residues in their t peptide. Our results suggested that several "signals" in the catalytic domain and in the t peptide act cooperatively for AChE quality control.
ESTHER : Falasca_2005_J.Biol.Chem_280_878
PubMedSearch : Falasca_2005_J.Biol.Chem_280_878
PubMedID: 15452125

Title : The readthrough variant of acetylcholinesterase remains very minor after heat shock, organophosphate inhibition and stress, in cell culture and in vivo - Perrier_2005_J.Neurochem_94_629
Author(s) : Perrier NA , Salani M , Falasca C , Bon S , Augusti-Tocco G , Massoulie J
Ref : Journal of Neurochemistry , 94 :629 , 2005
Abstract : Acetylcholinesterase (AChE) exists in various molecular forms, depending on alternative splicing of its transcripts and association with structural proteins. Tetramers of the 'tailed' variant (AChE(T)), which are anchored in the cell membrane of neurons by the PRiMA (Proline Rich Membrane Anchor) protein, constitute the main form of AChE in the mammalian brain. In the mouse brain, stress and anticholinesterase inhibitors have been reported to induce expression of the unspliced 'readthrough' variant (AChE(R)) mRNA which produces a monomeric form. To generalize this observation, we attempted to quantify AChE(R) and AChE(T) after organophosphate intoxication in the mouse brain and compared the observed effects with those of stress induced by swimming or immobilization; we also analyzed the effects of heat shock and AChE inhibition on neuroblastoma cells. Active AChE molecular forms were characterized by sedimentation and non-denaturing electrophoresis, and AChE transcripts were quantified by real-time PCR. We observed a moderate increase of the AChE(R) transcript in some cases, both in the mouse brain and in neuroblastoma cultures, but we did not detect any increase of the corresponding active enzyme.
ESTHER : Perrier_2005_J.Neurochem_94_629
PubMedSearch : Perrier_2005_J.Neurochem_94_629
PubMedID: 16001972

Title : The C-terminal peptides of acetylcholinesterase: cellular trafficking, oligomerization and functional anchoring - Massoulie_2005_Chem.Biol.Interact_157-158_3
Author(s) : Massoulie J , Bon S , Perrier N , Falasca C
Ref : Chemico-Biological Interactions , 157-158 :3 , 2005
Abstract : In vertebrates, the catalytic domain of acetylcholinesterase (AChE) may be associated with several C-terminal peptides generated by alternative splicing in the 3' region of transcripts. The "readthrough" (R) variant results from a lack of splicing after the last exon encoding the catalytic domain. Such a variant has been observed in Torpedo and in mammals; its C-terminal r peptide, also called "AChE Related Peptide" (ARP), is poorly conserved between rodents and humans. In rodents, it is significantly expressed in embryonic tissues and at a very low level in the brain of adult mice; it may be increased under various stress conditions, but remains very low. The "hydrophobic" (H) variant generates glycolipid (GPI)-anchored dimers, which are expressed in muscles of Torpedo, and in blood cells of mammals; H variants exist in Torpedo and in mammals, but apparently not in other vertebrate classes, suggesting that they were lost during evolution of early vertebrates and re-appeared independently in mammals. The "tailed" (T) variant exists in all vertebrate cholinesterases and their C-terminal t peptides are strongly conserved; in mammals, AChE(T) subunits represent the major type of acetylcholinesterase in cholinergic tissues. They produce a wide variety of oligomeric forms, ranging from monomers to heteromeric assemblies containing the anchoring proteins ColQ (collagen-tailed forms) and PRiMA (membrane-bound tetramers), which constitute the major functional enzyme species in mammalian muscles and brain, respectively. The oligomerization of AChE(T) subunits depends largely on the properties of their C-terminal t peptide. These peptides contain seven conserved aromatic residues, including three tryptophans, and are organized in an amphiphilic alpha helix in which these residues form a hydrophobic cluster. The presence of a cysteine is required for dimerization, while aromatic residues are necessary for tetramerization. In the collagen-tailed molecules, four t peptides form a coiled coil around a proline-rich motif (PRAD) located in the N-terminal region of ColQ. The t peptide also strongly influences the folding and cellular trafficking of AChE(T) subunits: the presence of hydrophobic residues induces partial misfolding leading to inactive protein, while aromatic residues, organized or not in an amphiphilic helix, induce intracellular degradation through the "Endoplasmic Reticulum Associated Degradation" (ERAD) pathway, rather than secretion. It has been proposed that the r and t C-terminal peptides, or fragments of these peptides, may exert independent, non cholinergic biological functions: this interesting possibility still needs to be documented, especially in view of their various degrees of evolutionary conservation.
ESTHER : Massoulie_2005_Chem.Biol.Interact_157-158_3
PubMedSearch : Massoulie_2005_Chem.Biol.Interact_157-158_3
PubMedID: 16257397

Title : Elements of the C-terminal t peptide of acetylcholinesterase that determine amphiphilicity, homomeric and heteromeric associations, secretion and degradation - Belbeoc'h_2004_Eur.J.Biochem_271_1476
Author(s) : Belbeoc'h S , Falasca C , Leroy J , Ayon A , Massoulie J , Bon S
Ref : European Journal of Biochemistry , 271 :1476 , 2004
Abstract : The C-terminal t peptide (40 residues) of vertebrate acetylcholinesterase (AChE) T subunits possesses a series of seven conserved aromatic residues and forms an amphiphilic alpha-helix; it allows the formation of homo-oligomers (monomers, dimers and tetramers) and heteromeric associations with the anchoring proteins, ColQ and PRiMA, which contain a proline-rich motif (PRAD). We analyzed the influence of mutations in the t peptide of Torpedo AChE(T) on oligomerization and secretion. Charged residues influenced the distribution of homo-oligomers but had little effect on the heteromeric association with Q(N), a PRAD-containing N-terminal fragment of ColQ. The formation of homo-tetramers and Q(N)-linked tetramers required a central core of four aromatic residues and a peptide segment extending to residue 31; the last nine residues (32-40) were not necessary, although the formation of disulfide bonds by cysteine C37 stabilized T(4) and T(4)-Q(N) tetramers. The last two residues of the t peptide (EL) induced a partial intracellular retention; replacement of the C-terminal CAEL tetrapeptide by KDEL did not prevent tetramerization and heteromeric association with Q(N), indicating that these associations take place in the endoplasmic reticulum. Mutations that disorganize the alpha-helical structure of the t peptide were found to enhance degradation. Co-expression with Q(N) generally increased secretion, mostly as T(4)-Q(N) complexes, but reduced it for some mutants. Thus, mutations in this small, autonomous interaction domain bring information on the features that determine oligomeric associations of AChE(T) subunits and the choice between secretion and degradation.
ESTHER : Belbeoc'h_2004_Eur.J.Biochem_271_1476
PubMedSearch : Belbeoc'h_2004_Eur.J.Biochem_271_1476
PubMedID: 15066173

Title : Poster (48) Crystal structure of the tetramerization domain of acetylcholinesterase reveals a model of the AChE tetramer -
Author(s) : Harel M , Dvir H , Bon S , Liu WQ , Garbay C , Sussman JL , Massoulie J , Silman I
Ref : In: Cholinesterases in the Second Millennium: Biomolecular and Pathological Aspects , (Inestrosa NC, Campos EO) P. Universidad Catolica de Chile-FONDAP Biomedicina :347 , 2004
PubMedID:

Title : The synaptic acetylcholinesterase tetramer assembles around a polyproline II helix - Dvir_2004_EMBO.J_23_4394
Author(s) : Dvir H , Harel M , Bon S , Liu WQ , Vidal M , Garbay C , Sussman JL , Massoulie J , Silman I
Ref : EMBO Journal , 23 :4394 , 2004
Abstract : Functional localization of acetylcholinesterase (AChE) in vertebrate muscle and brain depends on interaction of the tryptophan amphiphilic tetramerization (WAT) sequence, at the C-terminus of its major splice variant (T), with a proline-rich attachment domain (PRAD), of the anchoring proteins, collagenous (ColQ) and proline-rich membrane anchor. The crystal structure of the WAT/PRAD complex reveals a novel supercoil structure in which four parallel WAT chains form a left-handed superhelix around an antiparallel left-handed PRAD helix resembling polyproline II. The WAT coiled coils possess a WWW motif making repetitive hydrophobic stacking and hydrogen-bond interactions with the PRAD. The WAT chains are related by an approximately 4-fold screw axis around the PRAD. Each WAT makes similar but unique interactions, consistent with an asymmetric pattern of disulfide linkages between the AChE tetramer subunits and ColQ. The P59Q mutation in ColQ, which causes congenital endplate AChE deficiency, and is located within the PRAD, disrupts crucial WAT-WAT and WAT-PRAD interactions. A model is proposed for the synaptic AChE(T) tetramer.
ESTHER : Dvir_2004_EMBO.J_23_4394
PubMedSearch : Dvir_2004_EMBO.J_23_4394
PubMedID: 15526038
Gene_locus related to this paper: torca-ACHE

Title : Poster (68) Oligomerization of acetylcholinesterase T blocks its degradation via the ubiquitin-proteasome pathway, by masking the c-terminal hydrophobic peptide. -
Author(s) : Belbeoc'h S , Bon S , Massoulie J
Ref : In: Cholinesterases in the Second Millennium: Biomolecular and Pathological Aspects , (Inestrosa NC, Campos EO) P. Universidad Catolica de Chile-FONDAP Biomedicina :356 , 2004
PubMedID:

Title : The C-terminal t peptide of acetylcholinesterase forms an alpha helix that supports homomeric and heteromeric interactions - Bon_2004_Eur.J.Biochem_271_33
Author(s) : Bon S , Dufourcq J , Leroy J , Cornut I , Massoulie J
Ref : European Journal of Biochemistry , 271 :33 , 2004
Abstract : Acetylcholinesterase subunits of type T (AChET) possess an alternatively spliced C-terminal peptide (t peptide) which endows them with amphiphilic properties, the capacity to form various homo-oligomers and to associate, as a tetramer, with anchoring proteins containing a proline rich attachment domain (PRAD). The t peptide contains seven conserved aromatic residues. By spectroscopic analyses of the synthetic peptides covering part or all of the t peptide of Torpedo AChET, we show that the region containing the aromatic residues adopts an alpha helical structure, which is favored in the presence of lipids and detergent micelles: these residues therefore form a hydrophobic cluster in a sector of the helix. We also analyzed the formation of disulfide bonds between two different AChET subunits, and between AChET subunits and a PRAD-containing protein [the N-terminal fragment of the ColQ protein (QN)] possessing two cysteines upstream or downstream of the PRAD. This shows that, in the complex formed by four T subunits with QN (T4-QN), the t peptides are not folded on themselves as hairpins but instead are all oriented in the same direction, antiparallel to that of the PRAD. The formation of disulfide bonds between various pairs of cysteines, introduced by mutagenesis at various positions in the t peptides, indicates that this complex possesses a surprising flexibility.
ESTHER : Bon_2004_Eur.J.Biochem_271_33
PubMedSearch : Bon_2004_Eur.J.Biochem_271_33
PubMedID: 14686917

Title : Molecular organization and functional localization of acetylcholinesterase -
Author(s) : Massoulie J , Belbeoc'h S , Perrier NA , Bon S
Ref : In: Cholinesterases in the Second Millennium: Biomolecular and Pathological Aspects , (Inestrosa NC, Campos EO) P. Universidad Catolica de Chile-FONDAP Biomedicina :1 , 2004
PubMedID:

Title : Crystal structure of the tetramerization domain of acetylcholinesterase at 2. -
Author(s) : Harel M , Dvir H , Bon S , Liu WQ , Garbay C , Sussman JL , Massoulie J , Silman I
Ref : Cholinergic Mechanisms, CRC Press :183 , 2004
PubMedID:

Title : Processing and anchoring of cholinesterases in muscle and brain. -
Author(s) : Massoulie J , Bon S
Ref : Cholinergic Mechanisms, CRC Press :155 , 2004
PubMedID:

Title : Poster (106) Organization and properties of the C-terminal T (WAT) peptide of acetylcholinesterase C-terminal trimerisation domain (CDT) of collagen ColQ -
Author(s) : Bon S , Belbeoc'h S , Massoulie J
Ref : In: Cholinesterases in the Second Millennium: Biomolecular and Pathological Aspects , (Inestrosa NC, Campos EO) P. Universidad Catolica de Chile-FONDAP Biomedicina :376 , 2004
PubMedID:

Title : The C-terminal T peptide of acetylcholinesterase enhances degradation of unassembled active subunits through the ERAD pathway - Belbeoc'h_2003_EMBO.J_22_3536
Author(s) : Belbeoc'h S , Massoulie J , Bon S
Ref : EMBO Journal , 22 :3536 , 2003
Abstract : The catalytic domain of acetylcholinesterase AChE(T) subunits is followed by a C-terminal T peptide which mediates their association with the proline-rich attachment domain (PRAD) of anchoring proteins. Addition of the T peptide induced intracellular degradation and concomitantly reduced to variable degrees the secretion of AChE species differing in their oligomerization capacity and of human alkaline phosphatase. The T peptide forms an amphiphilic alpha-helix, containing a series of conserved aromatic residues. Replacement of two, four or five aromatic residues gradually suppressed degradation and increased secretion. Co-expression with a PRAD- containing protein induced the assembly of PRAD-linked tetramers in the endoplasmic reticulum (ER) and allowed partial secretion of a dimerization- defective mutant; by masking the aromatic side chains, hetero-oligomerization rescued this enzyme from degradation. Degradation was due to ERAD, since it was not blocked by brefeldin A but was sensitive to proteasome inhibitors. Kifunensine reduced degradation, suggesting a cooperativity between the glycosylated catalytic domain and the non-glycosylated T peptide. This system appears particularly well suited to analyze the mechanisms which determine the degradation of correctly folded multidomain proteins in the ER.
ESTHER : Belbeoc'h_2003_EMBO.J_22_3536
PubMedSearch : Belbeoc'h_2003_EMBO.J_22_3536
PubMedID: 12853469

Title : Trimerization domain of the collagen tail of acetylcholinesterase - Bon_2003_Neurochem.Res_28_523
Author(s) : Bon S , Ayon A , Leroy J , Massoulie J
Ref : Neurochem Res , 28 :523 , 2003
Abstract : In the collagen-tailed forms of cholinesterases, each subunit of a specific triple helical collagen, ColQ, may be attached through a proline-rich domain (PRAD) situated in its N-terminal noncollagenous region, to tetramers of acetylcholinesterase (AChE) or butyrylcholinesterase (BChE). This heteromeric assembly ensures the functional anchoring of AChE in extracellulare matrices, for example, at the neuromuscular junction. In this study, we analyzed the influence of deletions in the noncollagenous C-terminal region of ColQ on its capacity to form a triple helix. We show that an 80-residue segment located downstream of the collagenous regions contains the trimerization domain, that it can form trimers without the collagenous regions, and that a pair of cysteines located at the N-boundary of this domain facilitates oligomerization, although it is not absolutely required. We further show that AChE subunits can associate with nonhelical collagen ColQ monomers, forming ColQ-associated tetramers (G4-Q), which are secreted or are anchored at the cell surface when the C-terminal domain of ColQ is replaced by a GPI-addition signal.
ESTHER : Bon_2003_Neurochem.Res_28_523
PubMedSearch : Bon_2003_Neurochem.Res_28_523
PubMedID: 12675141

Title : Photoreversible inhibition of cholinesterases: catalytic serine-labeled caged butyrylcholinesterase - Loudwig_2003_Chembiochem_4_762
Author(s) : Loudwig S , Nicolet Y , Masson P , Fontecilla-Camps JC , Bon S , Nachon F , Goeldner M
Ref : Chembiochem , 4 :762 , 2003
Abstract : The photoregulation of the catalytic activity of butyrylcholinesterase (BChE) was investigated by treating the enzyme with a newly developed carbamylating reagent, N-methyl-N-(2-nitrophenyl)carbamoyl chloride, which has proved to be an efficient photoremovable alcohol-protecting group. BChE was efficiently inhibited in a time- and concentration-dependent manner, and the enzyme could be protected against inhibition by active-site-specific ligands (that is, tacrine). The inactivation kinetics showed a biphasic character, which can be analyzed as the result of the existence of two conformational states in solution. Pseudo-irreversible inactivation of BChE, which results from catalytic serine carbamylation, was suggested by recovery of the enzyme activity after dilution and was demonstrated by X-ray crystallography. Remarkably, the 3D structure of the carbamylated BChE conjugate showed a nonambiguous carbamylation of the catalytic serine residue as the only chemical modification on the protein. The photoreversibility of the enzyme inactivation was analyzed by irradiating the inactivated enzyme at 365 nm and was shown to reach completion in some conditions. The efficient and specific "caging" of BChE, together with the availability of carbamylated BChE crystals, will offer a unique possibility to study the catalytic properties of this enzyme by kinetic crystallography after cryophotolytic uncaging of the enzyme conjugate crystals.
ESTHER : Loudwig_2003_Chembiochem_4_762
PubMedSearch : Loudwig_2003_Chembiochem_4_762
PubMedID: 12898628

Title : Addition of a glycophosphatidylinositol to acetylcholinesterase. processing, degradation, and secretion - Coussen_2001_J.Biol.Chem_276_27881
Author(s) : Coussen F , Ayon A , Le Goff A , Leroy J , Massoulie J , Bon S
Ref : Journal of Biological Chemistry , 276 :27881 , 2001
Abstract : We introduced various mutations and modifications in the GPI anchoring signal of rat acetylcholinesterase (AChE). 1) The resulting mutants, expressed in transiently transfected COS cells, were initially produced at the same rate, in an active form, but the fraction of GPI-anchored AChE and the steady state level of AChE activity varied over a wide range. 2) Productive interaction with the GPI addition machinery led to GPI anchoring, secretion of uncleaved protein, and secretion of a cleaved protein, in variable proportions. Unproductive interaction led to degradation; poorly processed molecules were degraded rather than retained intracellularly or secreted. 3) An efficient glypiation appeared necessary but not sufficient for a high level of secretion; the cleaved, secreted protein was possibly generated as a by-product of transamidation. 4) Glypiation was influenced by a wider context than the triplet omega/omega + 1/omega + 2, particularly omega - 1. 5) Glypiation was not affected by the closeness of the omega site to the alpha(10) helix of the catalytic domain. 6) A cysteine could simultaneously form a disulfide bond and serve as an omega site; however, there was a mutual interference between glypiation and the formation of an intercatenary disulfide bond, at a short distance upstream of omega. 7) Glypiation was not affected by the presence of an N-glycosylation site at omega or in its vicinity or by the addition of a short hydrophilic, highly charged peptide (FLAG; DYKDDDDK) at the C terminus of the hydrophobic region.
ESTHER : Coussen_2001_J.Biol.Chem_276_27881
PubMedSearch : Coussen_2001_J.Biol.Chem_276_27881
PubMedID: 11337488

Title : Acetylcholinesterase H and T dimers are associated through the same contact\; mutations at this interface interfere with the C-terminal T peptide, inducing degradation rather than secretion - Morel_2001_J.Biol.Chem_276_32379
Author(s) : Morel N , Leroy J , Ayon A , Massoulie J , Bon S
Ref : Journal of Biological Chemistry , 276 :32379 , 2001
Abstract : Acetylcholinesterase (AChE) exists as AChE(H) and AChE(T) subunits, which differ by their C-terminal H or T peptides, generating glycophosphatidylinositol-anchored dimers and various oligomers, respectively. We introduced mutations in the four-helix bundle interface of glycophosphatidylinositol-anchored dimers, and analyzed their effect on the production and oligomerization of AChE(H), of AChE(T), and of truncated subunits, AChE(C) (without H or T peptide). Dimerization was reduced for all types of subunits, showing that they interact through the same contact zone; the formation of amphiphilic tetramers (Torpedo AChE(T)) and 13.5 S oligomers (rat AChE(T)) was also suppressed. Oligomerization appeared totally blocked by introduction of an N-linked glycan on the surface of helix alpha(7,8). Other point mutations did not affect the synthesis or the catalytic properties of AChE but reduced or blocked the secretion of AChE(T) subunits. Secretion of AChE(T) was partially restored by co-expression with Q(N), a secretable protein containing a proline-rich attachment domain (PRAD); Q(N) organized PRAD-linked tetramers, except for the N-glycosylated mutants. Thus, the simultaneous presence of an abnormal four-helix bundle zone and an exposed T peptide targeted the enzyme toward degradation, indicating a cross-talk between the catalytic and tetramerization domains.
ESTHER : Morel_2001_J.Biol.Chem_276_32379
PubMedSearch : Morel_2001_J.Biol.Chem_276_32379
PubMedID: 11443120

Title : Two distinct proteins are associated with tetrameric acetylcholinesterase on the cell surface - Perrier_2000_J.Biol.Chem_275_34260
Author(s) : Perrier AL , Cousin X , Boschetti N , Haas R , Chatel JM , Bon S , Roberts WL , Pickett SR , Massoulie J , Rosenberry TL , Krejci E
Ref : Journal of Biological Chemistry , 275 :34260 , 2000
Abstract : In mammalian brain, acetylcholinesterase (AChE) exists mostly as a tetramer of 70-kDa catalytic subunits that are linked through disulfide bonds to a hydrophobic subunit P of approximately 20 kDa. To characterize P, we reduced the disulfide bonds in purified bovine brain AChE and sequenced tryptic fragments from bands in the 20-kDa region. We obtained sequences belonging to at least two distinct proteins: the P protein and another protein that was not disulfide-linked to catalytic subunits. Both proteins were recognized in Western blots by antisera raised against specific peptides. We cloned cDNA encoding the second protein in a cDNA library from bovine substantia nigra and obtained rat and human homologs. We call this protein mCutA because of its homology to a bacterial protein (CutA). We could not demonstrate a direct interaction between mCutA and AChE in vitro in transfected cells. However, in a mouse neuroblastoma cell line that produced membrane-bound AChE as an amphiphilic tetramer, the expression of mCutA antisense mRNA eliminated cell surface AChE and decreased the level of amphiphilic tetramer in cell extracts. mCutA therefore appears necessary for the localization of AChE at the cell surface; it may be part of a multicomponent complex that anchors AChE in membranes, together with the hydrophobic P protein.
ESTHER : Perrier_2000_J.Biol.Chem_275_34260
PubMedSearch : Perrier_2000_J.Biol.Chem_275_34260
PubMedID: 10954708

Title : Effect of mutations within the peripheral anionic site on the stability of acetylcholinesterase - Morel_1999_Mol.Pharmacol_55_982
Author(s) : Morel N , Bon S , Greenblatt HM , Van Belle D , Wodak SJ , Sussman JL , Massoulie J , Silman I
Ref : Molecular Pharmacology , 55 :982 , 1999
Abstract : Torpedo acetylcholinesterase is irreversibly inactivated by modifying a buried free cysteine, Cys231, with sulfhydryl reagents. The stability of the enzyme, as monitored by measuring the rate of inactivation, was reduced by mutating a leucine, Leu282, to a smaller amino acid residue. Leu282 is located within the "peripheral" anionic site, at the entrance to the active-site gorge. Thus, loss of activity was due to the increased reactivity of Cys231. This was paralleled by an increased susceptibility to thermal denaturation, which was shown to be due to a large decrease in the activation enthalpy. Similar results were obtained when either of two other residues in contact with Leu282 in Torpedo acetylcholinesterase, Trp279 and Ser291, was replaced by an amino acid with a smaller side chain. We studied the effects of various ligands specific for either the active or peripheral sites on both thermal inactivation and on inactivation by 4,4'-dithiodipyridine. The wild-type and mutated enzymes could be either protected or sensitized. In some cases, opposite effects of the same ligand were observed for chemical modification and thermal denaturation. The mutated residues are within a conserved loop, W279-S291, at the top of the active-site gorge, that contributes to the peripheral anionic site. Theoretical analysis showed that Torpedo acetylcholinesterase consists of two structural domains, each comprising one contiguous polypeptide segment. The W279-S291 loop, located in the first domain, makes multiple contacts with the second domain across the active-site gorge. We postulate that the mutations to residues with smaller side chains destabilize the conserved loop, thus disrupting cross-gorge interactions and, ultimately, the entire structure.
ESTHER : Morel_1999_Mol.Pharmacol_55_982
PubMedSearch : Morel_1999_Mol.Pharmacol_55_982
PubMedID: 10347238

Title : The polymorphism of acetylcholinesterase: post-translational processing, quaternary associations and localization - Massoulie_1999_Chem.Biol.Interact_119-120_29
Author(s) : Massoulie J , Anselmet A , Bon S , Krejci E , Legay C , Morel N , Simon S
Ref : Chemico-Biological Interactions , 119-120 :29 , 1999
Abstract : The molecular forms of acetylcholinesterase (AChE) correspond to various quaternary structures and modes of anchoring of the enzyme. In vertebrates, these molecules are generated from a single gene: the catalytic domain may be associated with several types of C-terminal peptides, that define distinct types of catalytic subunits (AChE(S), AChE(H), AChE(T)) and determine their post-translational maturation. AChE(S) generates soluble monomers, in the venom of Elapid snakes. AChE(H) generates GPI-anchored dimers, in Torpedo muscles and on mammalian blood cells. AChE(T) is the only type of catalytic subunit that exists in all vertebrate cholinesterases; it produces the major forms in adult brain and muscle. AChE(T) generates multiple structures, ranging from monomers and dimers to collagen-tailed and hydrophobic-tailed forms, in which catalytic tetramers are associated with anchoring proteins that attach them to the basal lamina or to cell membranes. In the collagen-tailed forms, AChE(T) subunits are associated with a specific collagen, ColQ, which is encoded by a single gene in mammals. ColQ contains a short peptidic motif, the proline-rich attachment domain (PRAD), that triggers the formation of AChE(T) tetramers, from monomers and dimers. The critical feature of this motif is the presence of a string of prolines, and in fact synthetic polyproline shows a similar capacity to organize AChE(T) tetramers. Although the COLQ gene produces multiple transcripts, it does not generate the hydrophobic tail. P, which anchors AChE in mammalian brain membranes. The coordinated expression of AChE(T) subunits and anchoring proteins determines the pattern of molecular forms and therefore the localization and functionality of the enzyme.
ESTHER : Massoulie_1999_Chem.Biol.Interact_119-120_29
PubMedSearch : Massoulie_1999_Chem.Biol.Interact_119-120_29
PubMedID: 10421436

Title : Identification of a novel type of alternatively spliced exon from the acetylcholinesterase gene of Bungarus fasciatus. Molecular forms of acetylcholinesterase in the snake liver and muscle - Cousin_1998_J.Biol.Chem_273_9812
Author(s) : Cousin X , Bon S , Massoulie J , Bon C
Ref : Journal of Biological Chemistry , 273 :9812 , 1998
Abstract : The venom of the snake Bungarus fasciatus contains a hydrophilic, monomeric species of acetylcholinesterase (AChE), characterized by a C-terminal region that does not resemble the alternative T- or H-peptides. Here, we show that the snake contains a single gene for AChE, possessing a novel alternative exon (S) that encodes the C-terminal region of the venom enzyme, located downstream of the T exon. Alternative splicing generates S mRNA in the venom gland and S and T mRNAs in muscle and liver. We found no evidence for the presence of an H exon between the last common "catalytic" exon and the T exon, where H exons are located in Torpedo and in mammals. Moreover, COS cells that were transfected with AChE expression vectors containing the T exon with or without the preceding genomic region produced exclusively AChET subunits. In the snake tissues, we could not detect any glycophosphatidylinositol-anchored AChE form that would have derived from H subunits. In the liver, the cholinesterase activity comprises both AChE and butyrylcholinesterase components; butyrylcholinesterase corresponds essentially to nonamphiphilic tetramers and AChE to nonamphiphilic monomers (G1na). In muscle, AChE is largely predominant: it consists of globular forms (G1a and G4a) and trace amounts of asymmetric forms (A8 and A12), which derive from AChET subunits. Thus, the Bungarus AChE gene possesses alternatively spliced T and S exons but no H exon; the absence of an H exon may be a common feature of AChE genes in reptiles and birds.
ESTHER : Cousin_1998_J.Biol.Chem_273_9812
PubMedSearch : Cousin_1998_J.Biol.Chem_273_9812
PubMedID: 9545320

Title : Diversity and Processing of Acetylcholinesterase -
Author(s) : Massoulie J , Anselmet A , Bon S , Krejci E , Legay C , Mayat E
Ref : In: Structure and Function of Cholinesterases and Related Proteins - Proceedings of Sixth International Meeting on Cholinesterases , (Doctor, B.P., Taylor, P., Quinn, D.M., Rotundo, R.L., Gentry, M.K. Eds) Plenum Publishing Corp. :3 , 1998
PubMedID:

Title : Acetylcholinesterase: C-terminal domains, molecular forms and functional localization - Massoulie_1998_J.Physiol.Paris_92_183
Author(s) : Massoulie J , Anselmet A , Bon S , Krejci E , Legay C , Morel N , Simon S
Ref : Journal de Physiologie (Paris) , 92 :183 , 1998
Abstract : Acetylcholinesterase (AChE) possesses short C-terminal peptides that are not necessary for catalytic activity. These peptides belong to different classes (R, H, T, S) and define the post-translational processing and targeting of the enzyme. In vertebrates, subunits of type H (AChEH) and of type T (AChET) are the most important: AChEH subunits produce glycolipid (GPI)-anchored dimers and AChET subunits produce hetero-oligomeric forms such as membrane-bound tetramers in the mammalian brain (containing a 20 kDa hydrophobic protein) and asymmetric collagen-tailed forms in neuromuscular junctions (containing a specific collagen, ColQ). The T peptide allows the formation of tetrameric assemblies with a proline-rich attachment domain (PRAD) of collagen ColQ. These complex molecular structures condition the functional localization of the enzyme in the supramolecular architecture of cholinergic synapses.
ESTHER : Massoulie_1998_J.Physiol.Paris_92_183
PubMedSearch : Massoulie_1998_J.Physiol.Paris_92_183
PubMedID: 9789805

Title : Acetylcholinesterase in Elapid Snakes -
Author(s) : Cousin X , Bon S , Grassi J , Massoulie J , Bon C
Ref : In: Structure and Function of Cholinesterases and Related Proteins - Proceedings of Sixth International Meeting on Cholinesterases , (Doctor, B.P., Taylor, P., Quinn, D.M., Rotundo, R.L., Gentry, M.K. Eds) Plenum Publishing Corp. :99 , 1998
PubMedID:

Title : Surface Residues Near the Peripheral Site Affect the Stability of Torpedo Acetylcholinesterase -
Author(s) : Morel N , Bon S , Sussman JL , Massoulie J , Silman I
Ref : In: Structure and Function of Cholinesterases and Related Proteins - Proceedings of Sixth International Meeting on Cholinesterases , (Doctor, B.P., Taylor, P., Quinn, D.M., Rotundo, R.L., Gentry, M.K. Eds) Plenum Publishing Corp. :435 , 1998
PubMedID:

Title : The Glycolipid-Addition Signal of Acetylcholinesterase -
Author(s) : Bon S , Coussen F , Massoulie J
Ref : In: Structure and Function of Cholinesterases and Related Proteins - Proceedings of Sixth International Meeting on Cholinesterases , (Doctor, B.P., Taylor, P., Quinn, D.M., Rotundo, R.L., Gentry, M.K. Eds) Plenum Publishing Corp. :135 , 1998
PubMedID:

Title : Mutation in the human acetylcholinesterase-associated collagen gene, COLQ, is responsible for congenital myasthenic syndrome with end-plate acetylcholinesterase deficiency (Type Ic) - Donger_1998_Am.J.Hum.Genet_63_967
Author(s) : Donger C , Krejci E , Serradell AP , Eymard B , Bon S , Nicole S , Chateau D , Gary F , Fardeau M , Massoulie J , Guicheney P
Ref : American Journal of Human Genetics , 63 :967 , 1998
Abstract : Congenital myasthenic syndrome (CMS) with end-plate acetylcholinesterase (AChE) deficiency is a rare autosomal recessive disease, recently classified as CMS type Ic (CMS-Ic). It is characterized by onset in childhood, generalized weakness increased by exertion, refractoriness to anticholinesterase drugs, and morphological abnormalities of the neuromuscular junctions (NMJs). The collagen-tailed form of AChE, which is normally concentrated at NMJs, is composed of catalytic tetramers associated with a specific collagen, COLQ. In CMS-Ic patients, these collagen-tailed forms are often absent. We studied a large family comprising 11 siblings, 6 of whom are affected by a mild form of CMS-Ic. The muscles of the patients contained collagen-tailed AChE. We first excluded the ACHE gene (7q22) as potential culprit, by linkage analysis; then we mapped COLQ to chromosome 3p24.2. By analyzing 3p24.2 markers located close to the gene, we found that the six affected patients were homozygous for an interval of 14 cM between D3S1597 and D3S2338. We determined the COLQ coding sequence and found that the patients present a homozygous missense mutation, Y431S, in the conserved C-terminal domain of COLQ. This mutation is thought to disturb the attachment of collagen-tailed AChE to the NMJ, thus constituting the first genetic defect causing CMS-Ic.
ESTHER : Donger_1998_Am.J.Hum.Genet_63_967
PubMedSearch : Donger_1998_Am.J.Hum.Genet_63_967
PubMedID: 9758617

Title : Quaternary associations of acetylcholinesterase. II. The polyproline attachment domain of the collagen tail - Bon_1997_J.Biol.Chem_272_3016
Author(s) : Bon S , Coussen F , Massoulie J
Ref : Journal of Biological Chemistry , 272 :3016 , 1997
Abstract : In transfected COS cells, we analyzed the formation of heteromeric associations between rat acetylcholinesterase of type T (AChET) and various constructions derived from the NH2-terminal region of the collagen tail of asymmetric forms, QN. Using a series of deletions and point mutations in QN, we showed that the binding of AChET to QN does not require the cysteines that normally establish intersubunit disulfide bonds with catalytic subunits and that it essentially relies on the presence of stretches of successive prolines, although adjacent residues also contribute to the interaction. We thus defined a proline-rich attachment domain or PRAD, which recruits AChET subunits to form heteromeric associations. Such molecules, consisting of one PRAD associated with a tetramer of AChET, are exported efficiently by the cells. Using the proportion of AChET subunits engaged in heteromeric tetramers, we ranked the interaction efficiency of various constructions. From these experiments we evaluated the contribution of different elements of the PRAD to the quaternary assembly of AChET subunits in the secretory pathway. The PRAD remained functional when reduced to six residues followed by a string of 10 prolines (Glu-Ser-Thr-Gly3-Pro10). We then showed that synthetic polyproline itself can associate with AChET subunits, producing well defined tetramers, when added to live transfected cells or even to cell extracts. This is the first example of an in vitro assembly of AChE tetramers from monomers and dimers. These results open the way to a chemical-physical exploration of the formation of these quaternary associations, both in the secretory pathway and in vitro.
ESTHER : Bon_1997_J.Biol.Chem_272_3016
PubMedSearch : Bon_1997_J.Biol.Chem_272_3016
PubMedID: 9006950

Title : Acetylcholinesterases from Elapidae snake venoms: biochemical, immunological and enzymatic characterization - Frobert_1997_Biochim.Biophys.Acta_1339_253
Author(s) : Frobert Y , Creminon C , Cousin X , Remy MH , Chatel JM , Bon S , Bon C , Grassi J
Ref : Biochimica & Biophysica Acta , 1339 :253 , 1997
Abstract : We analyzed 45 batches of venom from 20 different species belonging to 11 genera from the 3 main families of venomous snakes (Elapidae, Viperidae and Crotalidae). We found high acetylcholinesterase (AChE) activity in all venoms from Elapidae, except in those from the Dendroaspis genus. AChE was particularly abundant in Bungarus venoms which contain up to 8 mg of enzyme per gram of dried venom. We could not detect acetylcholinesterase activity in any batch of venom from Viperidae or Crotalidae. Titration of active sites with an organophosphorous agent (MPT) revealed that the AChE of all venoms have similar turnovers (6000 to 8000 s(-1)) which are clearly higher than those of Torpedo and mammalian enzymes but lower than that of Electrophorus. AChEs from the venom of elapid snakes of the Bungarus, Naja, Ophiophagus and Haemacatus genera were purified by affinity chromatography. SDS-PAGE analysis and sucrose gradient centrifugation demonstrated that AChE is exclusively present as a nonamphiphilic monomer. These enzymes are true AChEs, hydrolyzing acetylthiocholine faster than propionylthiocholine and butyrylthiocholine and exhibiting excess substrate inhibition. Twenty-seven different monoclonal antibodies directed against AChE from Bungarus fasciatus venom were raised in mice. Half of them recognized exclusively the Bungarus enzyme while the others cross-reacted with AChEs from other venoms. Polyspecific mAbs were used to demonstrate that venoms from Dendroaspis, which contain the AChE inhibitor fasciculin but lack AChE activity, were also devoid of immunoreactive AChE protein. AChE inhibitors acting at the active site (edrophonium, tacrine) and at the peripheral site (propidium, fasciculin), as well as bis-quaternary ligands (BW284C51, decamethonium), were tested against the venom AChEs from 11 different species. All enzymes had a very similar pattern of reactivity with regard to the different inhibitors, with the exception of fasciculin. AChEs from Naja and Haemacatus venoms were relatively insensitive to fasciculin inhibition (IC50 >> 10(-6) M), while Bungarus (IC50 approximately 10(-8) M) and especially Ophiophagus (IC50 < 10(-10) M) AChEs were inhibited very efficiently. Ophiophagus and Bungarus AChEs were also efficiently inhibited by a monoclonal antibody (Elec-410) previously described as a specific ligand for the Electrophorus electricus peripheral site. Taken together, these results show that the venoms of most Elapidae snakes contain large amounts of a highly active non-amphiphilic monomeric AChE. All snake venom AChEs show strong immunological similarities and possess very similar enzymatic properties. However, they present quite different sensitivity to peripheral site inhibitors, fasciculin and the monoclonal antibody Elec-410.
ESTHER : Frobert_1997_Biochim.Biophys.Acta_1339_253
PubMedSearch : Frobert_1997_Biochim.Biophys.Acta_1339_253
PubMedID: 9187246

Title : Quaternary associations of acetylcholinesterase. I. Oligomeric associations of T subunits with and without the amino-terminal domain of the collagen tail - Bon_1997_J.Biol.Chem_272_3007
Author(s) : Bon S , Massoulie J
Ref : Journal of Biological Chemistry , 272 :3007 , 1997
Abstract : We investigated the production of acetylcholinesterase of type T (AChET) in COS cells during transient transfection. When expressed alone, Torpedo AChET remains essentially intracellular, forming dimers and tetramers; in contrast, rat AChET is secreted and produces mostly amphiphilic monomers (G1a) and dimers (G2a), together with smaller proportions of nonamphiphilic (G4na) tetramers, amphiphilic tetramers (G4a), and an unstable higher polymer (13.7 S). The latter two forms have not been described before. We show that secreted G1a and G2a forms differ from their cellular counterparts and that proteolytic cleavage occurs at the COOH terminus of "flagged" subunits. The binding proteins QN/HC and QN/stop are constructed by associating the NH2-terminal domain of the collagen tail (QN) with a functional or truncated signal for addition of a glycolipidic anchor (glycophosphatidylinositol). Coexpression with QN/stop recruits monomers and dimers to form soluble tetramers (G4na), increasing the yield of secreted rat AChE and allowing secretion of Torpedo AChE. Using antibodies against QN or addition of a flag epitope, we showed that the secreted tetramers contain the attachment domain. Coexpression with QN/HC modifies the distribution of AChET in subcellular compartments and allows the externalization of glycophosphatidylinositol-anchored tetramers at the cell surface.
ESTHER : Bon_1997_J.Biol.Chem_272_3007
PubMedSearch : Bon_1997_J.Biol.Chem_272_3007
PubMedID: 9006949

Title : Cloning and expression of acetylcholinesterase from Bungarus fasciatus venom. A new type of cooh-terminal domain\; involvement of a positively charged residue in the peripheral site - Cousin_1996_J.Biol.Chem_271_15099
Author(s) : Cousin X , Bon S , Duval N , Massoulie J , Bon C
Ref : Journal of Biological Chemistry , 271 :15099 , 1996
Abstract : As deduced from cDNA clones, the catalytic domain of Bungarus fasciatus venom acetylcholinesterase (AChE) is highly homologous to those of other AChEs. It is, however, associated with a short hydrophilic carboxyl-terminal region, containing no cysteine, that bears no resemblance to the alternative COOH-terminal peptides of the GPI-anchored molecules (H) or of other homomeric or heteromeric tailed molecules (T). Expression of complete and truncated AChE in COS cells showed that active hydrophilic monomers are produced and secreted in all cases, and that cleavage of a very basic 8-residue carboxyl-terminal fragment occurs upon secretion. The COS cells produced Bungarus AChE about 30 times more efficiently than an equivalent secreted monomeric rat AChE. The recombinant Bungarus AChE, like the natural venom enzyme, showed a distinctive ladder pattern in nondenaturing electrophoresis, probably reflecting a variation in the number of sialic acids. By mutagenesis, we showed that two differences (methionine instead of tyrosine at position 70; lysine instead of aspartate or glutamate at position 285) explain the low sensitivity of Bungarus AChE to peripheral site inhibitors, compared to the Torpedo or mammalian AChEs. These results illustrate the importance of both the aromatic and the charged residues, and the fact that peripheral site ligands (propidium, gallamine, D-tubocurarine, and fasciculin 2) interact with diverse subsets of residues.
ESTHER : Cousin_1996_J.Biol.Chem_271_15099
PubMedSearch : Cousin_1996_J.Biol.Chem_271_15099
PubMedID: 8662867
Gene_locus related to this paper: bunfa-ACHE

Title : Biosynthesis and integration of acetylcholinesterase in the cholinergic synapse -
Author(s) : Massoulie J , Legay C , Anselmet A , Krejci E , Coussen F , Bon S
Ref : Prog Brain Res , 109 :55 , 1996
PubMedID: 9009693

Title : Site-directed mutants designed to test back-door hypotheses of acetylcholinesterase function - Faerman_1996_FEBS.Lett_386_65
Author(s) : Faerman C , Ripoll D , Bon S , Le Feuvre Y , Morel N , Massoulie J , Sussman JL , Silman I
Ref : FEBS Letters , 386 :65 , 1996
Abstract : The location of the active site of the rapid enzyme, acetylcholinesterase, near the bottom of a deep and narrow gorge indicates that alternative routes may exist for traffic of substrate, products or solute into and out of the gorge. Molecular dynamics suggest the existence of a shutter-like back door near Trp84, a key- residue in the binding site for acetylcholine, in the Torpedo californica enzyme. The homology of the omega loop, bearing Trp84, with the lid which sequesters the substrate in neutral lipases displaying structural homology with acetylcholinesterase, suggests a flap-like back door. Both possibilities were examined by site-directed mutagenesis. The shutter-like back door was tested by generating a salt bridge which might impede opening of the shutter. The flap-like back door was tested by de novo insertion of a disulfide bridge which tethered the omega loop to the body of the enzyme. Neither type of mutation produced significant changes in catalytic activity, thus failing to provide experimental support for either back door model. Molecular dynamics revealed, however, substantial mobility of the omega loop in the immediate vicinity of Trp84, even when the loop was tethered, supporting the possibility that access to the active site, involving limited movement of a segment of the loop, is indeed possible.
ESTHER : Faerman_1996_FEBS.Lett_386_65
PubMedSearch : Faerman_1996_FEBS.Lett_386_65
PubMedID: 8635606

Title : The rate of thermal inactivation of Torpedo acetylcholinesterase is not reduced in the C231S mutant - Wilson_1996_FEBS.Lett_379_161
Author(s) : Wilson EJ , Massoulie J , Bon S , Rosenberry TL
Ref : FEBS Letters , 379 :161 , 1996
Abstract : The rate of thermal inactivation of Torpedo AChE at pH 8.5 was increased by the sulfhydryl reagent 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB). At 30 degrees C or 37 degrees C, inactivation rates with 0.3 mM DTNB increased about 5-fold for the wild-type enzyme and for two site-specific mutants, D72S and V129R. The reversible active site inhibitor, ambenonium, completely stabilized the wild type enzyme and partially stabilized the D72S mutant. However, ambenonium did not protect against the destabilization introduced by DTNB, which still accelerated inactivation of D72S 5-fold. When the only free sulfhydryl group in AChE was removed by replacing cysteine 231 with serine, increased rates of thermal inactivation were observed. The inactivation rate increased by a factor of 2 to 3 for the single mutant (C231S) and by a factor of 5 for the double mutant V129R/C231S. Even in the C231S mutants, DTNB still had an additional effect. It increased the inactivation rate for C231S and V129R/C231 by a factor of about 1.5 to 3 beyond the rates seen in the absence of DTNB. Therefore, at least part of the destabilization seen with DTNB in enzymes that retain C231 does not involve reaction of DTNB with C231.
ESTHER : Wilson_1996_FEBS.Lett_379_161
PubMedSearch : Wilson_1996_FEBS.Lett_379_161
PubMedID: 8635584

Title : Acetylcholinesterase from Bungarus venom: a monomeric species - Cousin_1996_FEBS.Lett_387_196
Author(s) : Cousin X , Creminon C , Grassi J , Meflah K , Cornu G , Saliou B , Bon S , Massoulie J , Bon C
Ref : FEBS Letters , 387 :196 , 1996
Abstract : The venom of Bungarus fasciatus, an Elapidae snake, contains a high level of AChE activity. Partial peptide sequences show that it is closely homologous to other AChEs. Bungarus venom AChE is a non-amphiphilic monomeric species, a molecular form of AChE which has not been previously found in significant levels in other tissues. The composition of carbohydrates suggests the presence of N-glycans of the 'complex' and 'hybrid' types. Ion exchange chromatography, isoelectric focusing and electrophoresis in non-denaturing and denaturing conditions reveal a complex microheterogeneity of this enzyme, which is partly related to its glycosylation.
ESTHER : Cousin_1996_FEBS.Lett_387_196
PubMedSearch : Cousin_1996_FEBS.Lett_387_196
PubMedID: 8674549

Title : The C-Terminal Alternative Regions of Acetylcholinesterase -
Author(s) : Massoulie J , Anselmet A , Bon S , Coussen F , Krejci E , Legay C
Ref : In Enzyme of the Cholinesterase Family - Proceedings of Fifth International Meeting on Cholinesterases , (Quinn, D.M., Balasubramanian, A.S., Doctor, B.P., Taylor, P., Eds) Plenum Publishing Corp. :29 , 1995
PubMedID:

Title : Patients with congenital myasthenia associated with end-plate acetylcholinesterase deficiency show normal sequence, mRNA splicing, and assembly of catalytic subunits - Camp_1995_J.Clin.Invest_95_333
Author(s) : Camp S , Bon S , Li Y , Getman DK , Engel AG , Massoulie J , Taylor P
Ref : Journal of Clinical Investigation , 95 :333 , 1995
Abstract : A congenital myasthenic condition has been described in several patients characterized by a deficiency in end-plate acetylcholinesterase (AChE). The characteristic form of AChE in the end-plate basal lamina has the catalytic subunits disulfide linked to a collagen-like tail unit. Southern analysis of the gene encoding the catalytic subunits revealed no differences between patient and control DNA. Genomic DNA clones covering exon 4 and the alternatively spliced exons 5 and 6 were analyzed by nuclease protection and sequencing. Although allelic differences were detected between controls, we found no differences in exonic and intronic areas that might yield distinctive splicing patterns in patients and controls. The ACHE gene was cloned from genomic libraries from a patient and a control. Transfection of the cloned genes revealed identical species of mRNA and expressed AChE. Cotransfection of the genes expressing the catalytic subunits with a cDNA from Torpedo encoding the tail unit yielded asymmetric species that require assembly of catalytic subunits and tail unit. thus the catalytic subunits of AChE expressed in the congenital myasthenic syndrome appear identical in sequence, arise from similar splicing patterns, and assemble normally with a tail unit to form a heteromeric species.
ESTHER : Camp_1995_J.Clin.Invest_95_333
PubMedSearch : Camp_1995_J.Clin.Invest_95_333
PubMedID: 7814634

Title : Mutations in the Catalytic Subunit of Acetylcholinesterase do not Appear Responsible for Congenital Myasthenic Syndrome Associated with End-Plate Acetylcholinesterase Deficiency -
Author(s) : Camp S , Engel AG , Getman DK , Bon S , Massoulie J , Taylor P
Ref : In Enzyme of the Cholinesterase Family - Proceedings of Fifth International Meeting on Cholinesterases , (Quinn, D.M., Balasubramanian, A.S., Doctor, B.P., Taylor, P., Eds) Plenum Publishing Corp. :51 , 1995
PubMedID:

Title : 6-Coumarin diazonium salt: a specific affinity label of the Torpedo acetylcholinesterase peripheral site - Schalk_1995_Mol.Pharmacol_48_1063
Author(s) : Schalk I , Ehret-Sabatier L , Le Feuvre Y , Bon S , Massoulie J , Goeldner M
Ref : Molecular Pharmacology , 48 :1063 , 1995
Abstract : A 6-coumarin diazonium salt was synthesized and tested on Torpedo acetylcholinesterase as a site-directed irreversible probe for quaternary ammonium binding. The rate of the inactivation was examined as a function of time, inhibitor concentration, and pH, which allowed the determination of the dissociation and the rate constants of this efficient affinity labeling process. Protection experiments using tetramethylammonium, edrophonium, and propidium demonstrated that the labeling reaction occurred exclusively at the peripheral quaternary ammonium binding site of the enzyme. This result was confirmed by the modification of propidium binding at the peripheral site after inactivation reaction, as directly determined by fluorescence. Mutations of the likely labeled amino acid residues, Tyr70 and Tyr121, by histidine and phenylalanine indicated a predominant involvement of Tyr70 over Tyr121 in the coupling reaction.
ESTHER : Schalk_1995_Mol.Pharmacol_48_1063
PubMedSearch : Schalk_1995_Mol.Pharmacol_48_1063
PubMedID: 8848006

Title : Two-site immunoradiometric assay of chicken acetylcholinesterase: active and inactive molecular forms in brain and muscle - Chatel_1994_J.Neurochem_63_1111
Author(s) : Chatel JM , Eichler J , Vallette FM , Bon S , Massoulie J , Grassi J
Ref : Journal of Neurochemistry , 63 :1111 , 1994
Abstract : Several monoclonal antibodies were raised against chicken acetylcholinesterase (AChE; EC 3.1.1.7). Some of these antibodies react with quail AChE but not with AChEs from nonavian vertebrates or invertebrates and not with butyrylcholinesterase. They may be classified in several mutually compatible groups, i.e., that can bind simultaneously to the monomeric form of AChE. Most antibodies recognize a peptidic domain that does not exist in mammalian AChE and that may be digested by trypsin without loss of activity or dissociation of quaternary structure. The only exception is the antibody C-131, which is conformation dependent and preferentially recognizes active AChE. We have set up two-site immunoradiometric assays, using an immobilized capture antibody, C-6 or C-131, and a radiolabeled antibody, 125I-C-54. The C-6/C-54 assay quantifies the totality of inactive and active AChE subunits: It detects 10(-3) Ellman unit (approximately 40 pg of protein) and yields a linear response up to at least 25 10(-3) Ellman units. An analysis of gradient fractions, using C-6/C-54 and C-131/C-54 assays as well as activity determination, shows that the A12 and G4 forms are exclusively composed of active subunits, whereas inactive molecules cosediment with the active G2 and G1 forms. Both active and inactive G2 and G1 forms are amphiphilic, as indicated by the influence of detergents on their sedimentation coefficients and Stokes radii. In brain, the proportion of inactive forms decreases from 40% at embryonic day 11 (E11) to 20% at birth [day 1 (D1)]. In muscle, we observed no inactive AChE at E11 and a small proportion of inactive G1 at D1.
ESTHER : Chatel_1994_J.Neurochem_63_1111
PubMedSearch : Chatel_1994_J.Neurochem_63_1111
PubMedID: 8051552

Title : Cloning and expression of a rat acetylcholinesterase subunit: generation of multiple molecular forms and complementarity with a Torpedo collagenic subunit - Legay_1993_J.Neurochem_60_337
Author(s) : Legay C , Bon S , Vernier P , Coussen F , Massoulie J
Ref : Journal of Neurochemistry , 60 :337 , 1993
Abstract : We obtained a cDNA clone encoding one type of catalytic subunit of acetylcholinesterase (AChE) from rat brain (T subunit). The coding sequence shows a high frequency of (G+C) at the third position of the codons (66%), as already noted for several AChEs, in contrast with mammalian butyrylcholinesterase. The predicted primary sequence of rat AChE presents only 11 amino acid differences, including one in the signal peptide, from that of the mouse T subunit. In particular, four alanines in the mouse sequence are replaced by serine or threonine. In northern blots, a rat AChE probe indicates the presence of major 3.2- and 2.4-kb mRNAs, expressed in the CNS as well as in some peripheral tissues, including muscle and spleen. In vivo, we found that the proportions of G1, G2, and G4 forms are highly variable in different brain areas. We did not observe any glycolipid-anchored G2 form, which would be derived from an H subunit. We expressed the cloned rat AChE in COS cells: The transfected cells produce principally an amphiphilic G1a form, together with amphiphilic G2a and G4a forms, and a nonamphiphilic G4na form. The amphiphilic G1a and G2a forms correspond to type II forms, which are predominant in muscle and brain of higher vertebrates. The cells also release G4na, G2a, and G1a in the culture medium. These experiments show that all the forms observed in the CNS in vivo may be obtained from the T subunit. By co-transfecting COS cells with the rat T subunit and the Torpedo collagenic subunit, we obtained chimeric collagen-tailed forms. This cross-species complementarity demonstrates that the interaction domains of the catalytic and structural subunits are highly conserved during evolution.
ESTHER : Legay_1993_J.Neurochem_60_337
PubMedSearch : Legay_1993_J.Neurochem_60_337
PubMedID: 8417155
Gene_locus related to this paper: ratno-ACHE

Title : Molecular and cellular biology of cholinesterases -
Author(s) : Massoulie J , Pezzementi L , Bon S , Krejci E , Vallette FM
Ref : Prog Neurobiol , 41 :31 , 1993
PubMedID: 8321908

Title : Structure and functions of acetylcholinesterase and butyrylcholinesterase -
Author(s) : Massoulie J , Sussman JL , Bon S , Silman I
Ref : Prog Brain Res , 98 :139 , 1993
PubMedID: 8248501

Title : Expression of a cDNA encoding the glycolipid-anchored form of rat acetylcholinesterase - Legay_1993_FEBS.Lett_315_163
Author(s) : Legay C , Bon S , Massoulie J
Ref : FEBS Letters , 315 :163 , 1993
Abstract : We amplified by PCR and characterized a fragment of cDNA from rat spleen, encoding the distinctive C-terminal region of the acetylcholinesterase (AChE) H subunit. A recombinant vector encoding this subunit was constructed and expressed in COS cells: the H subunits produced glycophosphatidylinositol (GPI)-anchored dimers, showing that the spleen cDNA fragment contained a functional GPI cleavage/attachment site. Using PCR, we did not detect mRNAs encoding AChE H in rat muscle or hypothalamus. In the liver of 16-day rat embryos, we found both H and T transcripts, in agreement with the presence of both GPI-anchored dimers and amphiphilic monomers of type II. In addition, we detected 'read-through' (R) transcripts, in which regular introns are spliced, but the intervening sequence between the common exon 4 and the alternative exon 5 (H) is maintained.
ESTHER : Legay_1993_FEBS.Lett_315_163
PubMedSearch : Legay_1993_FEBS.Lett_315_163
PubMedID: 8417973

Title : H and T subunits of acetylcholinesterase from Torpedo, expressed in COS cells, generate all types of globular forms - Duval_1992_J.Cell.Biol_118_641
Author(s) : Duval N , Massoulie J , Bon S
Ref : Journal of Cell Biology , 118 :641 , 1992
Abstract : We analyzed the production of Torpedo marmorata acetylcholinesterase (AChE) in transfected COS cells. We report that the presence of an aspartic acid at position 397, homologous to that observed in other cholinesterases and related enzymes (Krejci, E., N. Duval, A. Chatonnet, P. Vincens, and J. Massouli. 1991. Proc. Natl. Acad. Sci. USA. 88:6647-6651), is necessary for catalytic activity. The presence of an asparagine in the previously reported cDNA sequence (Sikorav, J.L., E. Krejci, and J. Massouli. 1987. EMBO (Eur. Mol. Biol. Organ.) J. 6:1865-1873) was most likely due to a cloning error (codon AAC instead of GAC). We expressed the T and H subunits of Torpedo AChE, which differ in their COOH-terminal region and correspond respectively to the collagen-tailed asymmetric forms and to glycophosphatidylinositol-anchored dimers of Torpedo electric organs, as well as a truncated T subunit (T delta), lacking most of the COOH-terminal peptide. The transfected cells synthesized similar amounts of AChE immunoreactive protein at 37 degrees and 27 degrees C. However AChE activity was only produced at 27 degrees C and, even at this temperature, only a small proportion of the protein was active. We analyzed the molecular forms of active AChE produced at 27 degrees C. The H polypeptides generated glycophosphatidylinositol-anchored dimers, resembling the corresponding natural AChE form. The cells also released non-amphiphilic dimers G2na. The T polypeptides generated a series of active forms which are not produced in Torpedo electric organs: G1a, G2a, G4a, and G4na cellular forms and G2a and G4na secreted forms. The amphiphilic forms appeared to correspond to type II forms (Bon, S., J. P. Toutant, K. Mflah, and J. Massouli. 1988. J. Neurochem. 51:776-785; Bon, S., J. P. Toutant, K. Mflah, and J. Massouli. 1988. J. Neurochem. 51:786-794), which are abundant in the nervous tissue and muscles of higher vertebrates (Bon, S., T. L. Rosenberry, and J. Massouli. 1991. Cell. Mol. Neurobiol. 11:157-172). The H and T catalytic subunits are thus sufficient to account for all types of known AChE forms. The truncated T delta subunit yielded only non-amphiphilic monomers, demonstrating the importance of the T COOH-terminal peptide in the formation of oligomers, and in the hydrophobic character of type II forms.
ESTHER : Duval_1992_J.Cell.Biol_118_641
PubMedSearch : Duval_1992_J.Cell.Biol_118_641
PubMedID: 1639848

Title : Molecular architecture of acetylcholinesterase collagen-tailed forms\; construction of a glycolipid-tailed tetramer - Duval_1992_EMBO.J_11_3255
Author(s) : Duval N , Krejci E , Grassi J , Coussen F , Massoulie J , Bon S
Ref : EMBO Journal , 11 :3255 , 1992
Abstract : Asymmetric forms of Torpedo acetylcholinesterase (AChE) are produced in COS cells by the simultaneous expression of collagenic subunits (Q) and catalytic T subunits (AChET). Truncated AChET delta subunits, from which most of the C-terminal peptide (TC) had been deleted by mutagenesis, did not associate with Q subunits. The TC peptide is therefore necessary for the association of the AChET and Q subunits. In order to determine the orientation of the Q subunit in the collagen-tailed forms, we have developed an antiserum against its non-collagenic C-terminal domain, expressed as a fusion protein in Escherichia coli. This antiserum, which recognized the Q subunit in Western blots, was found to react with intact asymmetric forms, but not with collagenase-treated forms, from which the distal part of the tail had been cleaved, suggesting that the N-terminal non-collogenic domain (QN) is responsible for the interaction with the AChET subunits. This was confirmed by creating a chimeric subunit (QN/HC), in which QN was linked to the C-terminal peptide of the H subunit of Torpedo AChE, which contains the glycophosphatidylinositol (GPI) cleavage/attachment signal: co-expression of AChET and QN/NC produced GPI-anchored tetramers, which were sensitive to PI-PLC and largely exposed to the external surface of the cells. We thus demonstrate that: (i) the HC peptide is sufficient to determine the addition of a glycolipid anchor and (ii) the QN domain is sufficient to bind a catalytic AChET tetramer by interacting with the TC peptide.
ESTHER : Duval_1992_EMBO.J_11_3255
PubMedSearch : Duval_1992_EMBO.J_11_3255
PubMedID: 1380451

Title : Biosynthesis of the Molecular Forms of Acetylcholinesterase -
Author(s) : Massoulie J , Bon S , Anselmet A
Ref : In Multidisciplinary approaches to cholinesterase functions - Proceedings of Fourth International Meeting on Cholinesterases , (Shafferman, A. and Velan, B., Eds) Plenum Press, New York :17 , 1992
PubMedID:

Title : Conversion of acetylcholinesterase to butyrylcholinesterase: modeling and mutagenesis - Harel_1992_Proc.Natl.Acad.Sci.U.S.A_89_10827
Author(s) : Harel M , Sussman JL , Krejci E , Bon S , Chanal P , Massoulie J , Silman I
Ref : Proceedings of the National Academy of Sciences of the United States of America , 89 :10827 , 1992
Abstract : Torpedo acetylcholinesterase (AcChoEase, EC 3.1.1.7) and human butyrylcholinesterase (BtChoEase, EC 3.1.1.8), while clearly differing in substrate specificity and sensitivity to inhibitors, possess 53% sequence homology; this permitted modeling human BtChoEase on the basis of the three-dimensional structure of Torpedo AcChoEase. The modeled BtChoEase structure closely resembled that of AcChoEase in overall features. However, six conserved aromatic residues that line the active-site gorge, which is a prominent feature of the AcChoEase structure, are absent in BtChoEase. Modeling showed that two such residues, Phe-288 and Phe-290, replaced by leucine and valine, respectively, in BtChoEase, may prevent entrance of butyrylcholine into the acyl-binding pocket. Their mutation to leucine and valine in AcChoEase, by site-directed mutagenesis, produced a double mutant that hydrolyzed butyrylthiocholine almost as well as acetylthiocholine. The mutated enzyme was also inhibited well by the bulky, BtChoEase-selective organophosphate inhibitor (tetraisopropylpyrophosphoramide, iso-OMPA). Trp-279, at the entrance of the active-site gorge in AcChoEase, is absent in BtChoEase. Modeling designated it as part of the "peripheral" anionic site, which is lacking in BtChoEase. The mutant W279A displayed strongly reduced inhibition by the peripheral site-specific ligand propidium relative to wild-type Torpedo AcChoEase, whereas inhibition by the catalytic-site inhibitor edrophonium was unaffected.
ESTHER : Harel_1992_Proc.Natl.Acad.Sci.U.S.A_89_10827
PubMedSearch : Harel_1992_Proc.Natl.Acad.Sci.U.S.A_89_10827
PubMedID: 1438284

Title : Site-directed mutagenesis of active-site-related residues in Torpedo acetylcholinesterase. Presence of a glutamic acid in the catalytic triad - Duval_1992_FEBS.Lett_309_421
Author(s) : Duval N , Bon S , Silman I , Sussman JL , Massoulie J
Ref : FEBS Letters , 309 :421 , 1992
Abstract : Site-directed mutagenesis was used to investigate the role of acidic amino acid residues close to the active site of Torpedo acetylcholinesterase. The recently determined atomic structure of this enzyme shows the conserved Glu-327, together with His-440 and Ser-200 as forming a catalytic triad, while the adjacent conserved Asp-326 points away from the active site. Transfection of appropriately mutated DNA into COS cells showed that the mutation of Asp-326----Asn had little effect on catalytic activity or the molecular forms expressed, suggesting no crucial structural or functional role for this residue. Mutation of Glu-327 to Gln or to Asp led to an inactive product. These results support the conclusions of the structural analysis for the two acidic residues.
ESTHER : Duval_1992_FEBS.Lett_309_421
PubMedSearch : Duval_1992_FEBS.Lett_309_421
PubMedID: 1355448

Title : Amphiphilic and nonamphiphilic forms of bovine and human dopamine beta-hydroxylase - Bon_1991_J.Neurochem_57_1100
Author(s) : Bon S , Lamouroux A , Vigny A , Massoulie J , Mallet J , Henry JP
Ref : Journal of Neurochemistry , 57 :1100 , 1991
Abstract : We show that human and bovine dopamine beta-hydroxylases (DBH) exist under three main molecular forms: a soluble nonamphiphilic form and two amphiphilic forms. Sedimentation in sucrose gradients and electrophoresis under nondenaturing conditions, by comparison with acetylcholinesterase (AChE), suggest that the three forms are tetramers of the DBH catalytic subunit and bind either no detergent, one detergent micelle, or two detergent micelles. By analogy with the Gna4 and Ga4 AChE forms, we propose to call the nonamphiphilic tetramer Dna4 and the amphiphilic tetramers Da4I and Da4II. In addition to the major tetrameric forms, DBH dimers occur as very minor species, both amphiphilic and nonamphiphilic. Reduction under nondenaturing conditions leads to a partial dissociation of tetramers into dimers, retaining their amphiphilic character. This suggests that the hydrophobic domain is not linked to the subunits through disulfide bonds. The two amphiphilic tetramers are insensitive to phosphatidylinositol phospholipase C, but may be converted into soluble DBH by proteolysis in a stepwise manner; Da4II----Da4I----Dna4. Incubation of soluble DBH with various phospholipids did not produce any amphiphilic form. Several bands corresponding to the catalytic subunits of bovine DBH were observed in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, but this multiplicity was not simply correlated with the amphiphilic character of the enzyme. In the case of human DBH, we observed two bands of 78 and 84 kDa. As previously reported by others, the presence of the heavy subunit characterizes the amphiphilic forms of the enzyme. We discuss the nature of the hydrophobic domain, which could be an uncleaved signal peptide, and the organization of the different amphiphilic and nonamphiphilic DBH forms. We present two models in which dimers may possess either one hydrophobic domain or two domains belonging to each subunit; in both cases, a single detergent micelle would be bound per dimer.
ESTHER : Bon_1991_J.Neurochem_57_1100
PubMedSearch : Bon_1991_J.Neurochem_57_1100
PubMedID: 1654385

Title : A comparative Raman spectroscopic study of cholinesterases - Aslanian_1991_Biochimie_73_1375
Author(s) : Aslanian D , Grof P , Bon S , Masson P , Negrerie M , Chatel JM , Balkanski M , Taylor P , Massoulie J
Ref : Biochimie , 73 :1375 , 1991
Abstract : We report Raman spectra of various cholinesterases: lytic tetrameric forms (G4) obtained by tryptic digestion of asymmetric acetylcholinesterase (AChE) from Torpedo californica and Electrophorus electricus, a PI-PLC-treated dimeric form (G2) of AChE from T marmorata, and the soluble tetrameric form (G4) of butyrylcholinesterase (BCHE) from human plasma. The contribution of different types of secondary structure was estimated by analyzing the amide I band, using the method of Williams. The spectra of cholinesterases in 10 mM Tris-HCl (pH 7.0) indicate the presence of both alpha-helices (about 50%) and beta-sheets (about 25%), together with 15% turns and 10% undefined structures. In 20 mM phosphate buffer (pH 7.0), the spectra indicated a smaller contribution of alpha-helical structure (about 35%) and an increased beta-sheet content (from 25 to 35%). This shows that the ionic milieu profoundly affects either the conformation of the protein (AChE activity is known to be sensitive to ionic strength), or the evaluation of secondary structure, or both. In addition, we analyzed vibrations corresponding to the side chains of aromatic and aliphatic amino acids. In particular, the analyses of the tyrosine doublet (830-850 cm-1) and of the tryptophan vibration at 880 cm-1 indicated that these residues are predominantly 'exposed' on the surface of the molecules.
ESTHER : Aslanian_1991_Biochimie_73_1375
PubMedSearch : Aslanian_1991_Biochimie_73_1375
PubMedID: 1799630

Title : Amphiphilic, glycophosphatidylinositol-specific phospholipase C (PI-PLC)-insensitive monomers and dimers of acetylcholinesterase - Bon_1991_Cell.Mol.Neurobiol_11_157
Author(s) : Bon S , Rosenberry TL , Massoulie J
Ref : Cellular Molecular Neurobiology , 11 :157 , 1991
Abstract : 1. In a recent study, we distinguished two classes of amphiphilic AChE3 dimers in Torpedo tissues: class I corresponds to glycolipid-anchored dimers and class II molecules are characterized by their lack of sensitivity to PI-PLC and PI-PLD, relatively small shift in sedimentation with detergent, and absence of aggregation without detergent. 2. In the present report, we analyze the amphiphlic or nonamphiphilic properties of globular AChE forms in T28 murine neural cells, rabbit muscle, and chicken muscle. The molecular forms were identified by sucrose gradient sedimentation in the presence and absence of detergent and analyzed by nondenaturing charge-shift electrophoresis. Some amphiphilic forms showed an abnormal electrophoretic migration in the absence of detergent, because of the retention of detergent micelles. 3. We show that the amphiphilic monomers (G1a) from these tissues, as well as the amphiphilic dimers (G2a) from chicken muscle, resemble the class II dimers of Torpedo AChE. We cannot exclude that these molecules possess a glycolipidic anchor but suggest that their hydrophobic domain may be of a different nature. We discuss their relationship with other cholinesterase molecular forms.
ESTHER : Bon_1991_Cell.Mol.Neurobiol_11_157
PubMedSearch : Bon_1991_Cell.Mol.Neurobiol_11_157
PubMedID: 1849452

Title : Poster: A comparative raman spectroscopic study of cholinesterases -
Author(s) : Aslanian D , Grof P , Masson P , Taylor P , Bon S , Chatel JM , Massoulie J
Ref : In: Cholinesterases: Structure, Function, Mechanism, Genetics, and Cell Biology , (Massoulie J, Barnard EA, Chatonnet A, Bacou F, Doctor BP, Quinn DM) American Chemical Society, Washington, DC :56 , 1991
PubMedID:

Title : Primary structure of a collagenic tail peptide of Torpedo acetylcholinesterase: co-expression with catalytic subunit induces the production of collagen-tailed forms in transfected cells - Krejci_1991_EMBO.J_10_1285
Author(s) : Krejci E , Coussen F , Duval N , Chatel JM , Legay C , Puype M , Vandekerckhove J , Cartaud J , Bon S , Massoulie J
Ref : EMBO Journal , 10 :1285 , 1991
Abstract : The asymmetric forms of cholinesterases are synthesized only in differentiated muscular and neural cells of vertebrates. These complex oligomers are characterized by the presence of a collagen-like tail, associated with one, two or three tetramers of catalytic subunits. The collagenic tail is responsible for ionic interactions, explaining the insertion of these molecules in extracellular basal lamina, e.g. at neuromuscular endplates. We report the cloning of a collagenic subunit from Torpedo marmorata acetylcholinesterase (AChE). The predicted primary structure contains a putative signal peptide, a proline-rich domain, a collagenic domain, and a C-terminal domain composed of proline-rich and cysteine-rich regions. Several variants are generated by alternative splicing. Apart from the collagenic domain, the AChE tail subunit does not present any homology with previously known proteins. We show that co-expression of catalytic AChE subunits and collagenic subunits results in the production of asymmetric, collagen-tailed AChE forms in transfected COS cells. Thus, the assembly of these complex forms does not depend on a specific cellular processing, but rather on the expression of the collagenic subunits.
ESTHER : Krejci_1991_EMBO.J_10_1285
PubMedSearch : Krejci_1991_EMBO.J_10_1285
PubMedID: 1840520

Title : The Structure and Significance of Multiple Cholinesterase Forms -
Author(s) : Massoulie J , Bon S , Krejci E , Coussen F , Duval N , Chatel JM , Anselmet A , Legay C , Vallette FM , Grassi J
Ref : In: Cholinesterases: Structure, Function, Mechanism, Genetics, and Cell Biology , (Massoulie J, Barnard EA, Chatonnet A, Bacou F, Doctor BP, Quinn DM) American Chemical Society, Washington, DC :2 , 1991
PubMedID:

Title : Expression and localization in the developing cerebellum of the carbohydrate epitopes revealed by Elec-39, an IgM monoclonal antibody related to HNK-1 - Kuchler_1991_Neurosci_41_551
Author(s) : Kuchler S , Zanetta JP , Bon S , Zaepfel M , Massoulie J , Vincendon G
Ref : Neuroscience , 41 :551 , 1991
Abstract : The immunochemical and immunocytochemical reactivity of an anti-carbohydrate monoclonal antibody (Elec-39), obtained against acetylcholinesterase from Electrophorus electricus electric organ, was followed during the postnatal development of the rat cerebellum. The specificity of this antibody resembles that of a family of anti-carbohydrate antibodies that includes HNK-1, L2, NC-1 and NSP-4, as well as IgMs that occur in some human neuropathies. As revealed by immunoblotting techniques, the reactivity of Elec-39 is maximum around postnatal days 10-12. At this age, the antibody reveals eight major proteins of mol. wt ranging between 14 and 150 kDa. Some of them (with mol. wts of 14, 18, 28 and 31 kDa) are transiently expressed. They correspond to previously identified glycoproteins binding to the plant lectin concanavalin A and binding also to the endogenous mannose-binding lectin CSL and endogenous membrane-bound mannose-binding lectin. In young animals, an important staining with the Elec-39 antibody can be observed on postmitotic precursors of granule cells, on astrocyte processes in the external granular layer, on newly formed parallel fibres and on unmyelinated axons of the white matter. In adult animals, the labelling is localized essentially in myelin and also in the cytoplasm of astrocytes. These results are discussed in relation to ontogenetic phenomena occurring during cerebellar development and the potential role of the carbohydrate epitope revealed with Elec-39 as a determinant in cell adhesion processes.
ESTHER : Kuchler_1991_Neurosci_41_551
PubMedSearch : Kuchler_1991_Neurosci_41_551
PubMedID: 1714552

Title : Subcellular distribution of acetylcholinesterase forms in chromaffin cells. Do chromaffin granules contain a specific secretory acetylcholinesterase? - Bon_1990_Eur.J.Biochem_190_221
Author(s) : Bon S , Bader MF , Aunis D , Massoulie J , Henry JP
Ref : European Journal of Biochemistry , 190 :221 , 1990
Abstract : The presence of acetylcholinesterase (AChE) in chromaffin granules has been controversial for a long time. We therefore undertook a study of AChE molecular forms in chromaffin cells and of their distribution during subcellular fractionation. We characterized four main AChE forms, three amphiphilic forms (Ga1, Ga2 and Ga4), and one non-amphiphilic form (Gna4). Each form shows the same molecular characteristics (sedimentation, electrophoretic migration, lectin interactions) in the different subcellular fractions. All forms are glycosylated and seem to possess both N-linked and O-linked carbohydrate chains. There are differences in the structure of the glycans carried by the different forms, as indicated by their interaction with some lectins. Glycophosphatidylinositol-specific phospholipases C converted the Ga2 form, but not the other amphiphilic forms, into non-amphiphilic derivatives. The distinct patterns of AChE molecular forms observed in various subcellular compartments indicate the existence of an active sorting process. Gna4 was concentrated in fractions of high density, containing chromaffin granules. We obtained evidence for the existence of a lighter fraction also containing chromogranin A, tetrabenazine-binding sites and Gna4 AChE, which may correspond to immature, incompletely loaded granules or to partially emptied granules. The distribution of Gna4 during subcellular fractionation suggested that this form is largely, but not exclusively, contained in chromaffin granules, the membranes of which may contain low levels of the three amphiphilic forms.
ESTHER : Bon_1990_Eur.J.Biochem_190_221
PubMedSearch : Bon_1990_Eur.J.Biochem_190_221
PubMedID: 2364948

Title : Complex alternative splicing of acetylcholinesterase transcripts in Torpedo electric organ\; primary structure of the precursor of the glycolipid-anchored dimeric form - Sikorav_1988_EMBO.J_7_2983
Author(s) : Sikorav JL , Duval N , Anselmet A , Bon S , Krejci E , Legay C , Osterlund M , Reimund B , Massoulie J
Ref : EMBO Journal , 7 :2983 , 1988
Abstract : In this paper, we show the existence of alternative splicing in the 3' region of the coding sequence of Torpedo acetylcholinesterase (AChE). We describe two cDNA structures which both diverge from the previously described coding sequence of the catalytic subunit of asymmetric (A) forms (Schumacher et al., 1986; Sikorav et al., 1987). They both contain a coding sequence followed by a non-coding sequence and a poly(A) stretch. Both of these structures were shown to exist in poly(A)+ RNAs, by S1 mapping experiments. The divergent region encoded by the first sequence corresponds to the precursor of the globular dimeric form (G2a), since it contains the expected C-terminal amino acids, Ala-Cys. These amino acids are followed by a 29 amino acid extension which contains a hydrophobic segment and must be replaced by a glycolipid in the mature protein. Analyses of intact G2a AChE showed that the common domain of the protein contains intersubunit disulphide bonds. The divergent region of the second type of cDNA consists of an adjacent genomic sequence, which is removed as an intron in A and Ga mRNAs, but may encode a distinct, less abundant catalytic subunit. The structures of the cDNA clones indicate that they are derived from minor mRNAs, shorter than the three major transcripts which have been described previously (14.5, 10.5 and 5.5 kb). Oligonucleotide probes specific for the asymmetric and globular terminal regions hybridize with the three major transcripts, indicating that their size is determined by 3'-untranslated regions which are not related to the differential splicing leading to A and Ga forms.
ESTHER : Sikorav_1988_EMBO.J_7_2983
PubMedSearch : Sikorav_1988_EMBO.J_7_2983
PubMedID: 3181125

Title : Amphiphilic and nonamphiphilic forms of Torpedo cholinesterases: I. Solubility and aggregation properties - Bon_1988_J.Neurochem_51_776
Author(s) : Bon S , Toutant JP , Meflah K , Massoulie J
Ref : Journal of Neurochemistry , 51 :776 , 1988
Abstract : We report an analysis of the solubility and hydrophobic properties of the globular forms of acetylcholinesterase (AChE) and butyrylcholinesterase (BCHE) from various Torpedo tissues. We distinguish globular nonamphiphilic forms (Gna) from globular amphiphilic forms (Ga). The Ga forms bind micelles of detergent, as indicated by the following properties. They are converted by mild proteolysis into nonamphiphilic derivatives. Their Stokes radius in the presence of Triton X-100 is approximately 2 nm greater than that of their lytic derivatives. The G2a forms fall in two classes. Class I contains molecules that aggregate in the absence of detergent, when mixed with an AChE-depleted Triton X-100 extract from electric organ. AChE G2a forms from electric organs, nerves, skeletal muscle, and erythrocyte membranes correspond to this type, which is also detectable in detergent-soluble (DS) extracts of electric lobes and spinal cord. Class II forms never aggregate but only present a slight shift in sedimentation coefficient, in the presence or absence of detergent. This class contains the AChE G2a forms of plasma and of the low-salt-soluble (LSS) fractions from spinal cord and electric lobes. The heart possesses a BCHE G2a form of class II in LSS extracts, as well as a similar G1a form. G4a forms of AChE, which are solubilized only in the presence of detergent and aggregate in the absence of detergent, represent a large proportion of cholinesterase in DS extracts of nerves and spinal cord, together with a smaller component of G4a BCHE. These forms may be converted to nonamphiphilic derivatives by Pronase. Nonaggregating G4a forms exist at low levels in the plasma (BCHE) and in LSS extracts of nerves (BCHE) and spinal cord (AChE).
ESTHER : Bon_1988_J.Neurochem_51_776
PubMedSearch : Bon_1988_J.Neurochem_51_776
PubMedID: 3411326

Title : Amphiphilic and nonamphiphilic forms of Torpedo cholinesterases: II. Electrophoretic variants and phosphatidylinositol phospholipase C-sensitive and -insensitive forms - Bon_1988_J.Neurochem_51_786
Author(s) : Bon S , Toutant JP , Meflah K , Massoulie J
Ref : Journal of Neurochemistry , 51 :786 , 1988
Abstract : We report an electrophoretic analysis of the hydrophobic properties of the globular forms of acetylcholinesterase (AChE) and butyrylcholinesterase (BCHE) from various Torpedo tissues. In charge-shift electrophoresis, the rate of electrophoretic migration of globular amphiphilic forms (Ga) is increased at least twofold when the anionic detergent deoxycholate is added to Triton X-100, whereas that of globular nonamphiphilic forms (Gna) is not modified. The G2a forms of the first class, as defined by their aggregation properties, are converted to nonamphiphilic derivatives by phosphatidylinositol phospholipase C (PI-PLC) and human serum phospholipase D (PLD). AChE G2a forms from electric organs, nerves, skeletal muscle, and erythrocyte membranes correspond to this type, which also exists in very small quantities in detergent-solubilized extracts of electric lobes and spinal cord. They present different electrophoretic mobilities, so that each of these tissues contains a distinct "electromorph," or two in the case of electric organs. The G2a forms of the second class (AChE in plasma, BCHE in heart), as well as G4a forms of AChE and BCHE, are insensitive to PI-PLC and PLD but may be converted to nonamphiphilic derivatives by Pronase.
ESTHER : Bon_1988_J.Neurochem_51_786
PubMedSearch : Bon_1988_J.Neurochem_51_786
PubMedID: 3411327

Title : Monoclonal antibodies against acetylcholinesterase from electric organs of Electrophorus and Torpedo - Musset_1987_Biochimie_69_147
Author(s) : Musset F , Frobert Y , Grassi J , Vigny M , Boulla G , Bon S , Massoulie J
Ref : Biochimie , 69 :147 , 1987
Abstract : We studied the reactivity of monoclonal antibodies (mAbs) raised against acetylcholinesterase (AChE) purified from Electrophorus and Torpedo electric organs. We obtained IgG antibodies (Elec-21, Elec-106, Tor-3E5, Tor-ME8, Tor-1A5), all of them directed against the catalytic subunit of the corresponding species, with no significant cross-reactivity. These antibodies do not inhibit the enzyme and recognize all molecular forms, globular (G) and asymmetric (A). Tor-ME8 reacts specifically with the denatured A and G subunits of Torpedo AChE, in immunoblots. Several hybridomas raised against Electrophorus AChE produced IgM antibodies (Elec-39, Elec-118, Elec-121). These antibodies react with the A forms of Electrophorus electric organs and also with a subset of dimers (G2) from Torpedo electric organ. In addition, they react with a number of non-AChE components, in immunoblots. In contrast, they do not recognize AChE from other Electrophorus tissues or A forms from Torpedo electric organs.
ESTHER : Musset_1987_Biochimie_69_147
PubMedSearch : Musset_1987_Biochimie_69_147
PubMedID: 3105603

Title : An immunoglobulin M monoclonal antibody, recognizing a subset of acetylcholinesterase molecules from electric organs of Electrophorus and Torpedo, belongs to the HNK-1 anti-carbohydrate family - Bon_1987_J.Neurochem_49_1720
Author(s) : Bon S , Meflah K , Musset F , Grassi J , Massoulie J
Ref : Journal of Neurochemistry , 49 :1720 , 1987
Abstract : An immunoglobulin M (IgM) monoclonal antibody (mAb Elec-39), obtained against asymmetric acetylcholinesterase (AChE) from Electrophorus electric organs, also reacts with a fraction of globular AChE (amphiphilic G2 form) from Torpedo electric organs. This antibody does not react with asymmetric AChE from Torpedo electric organs or with the enzyme from other tissues of Electrophorus or Torpedo. The corresponding epitope is removed by endoglycosidase F, showing that it is a carbohydrate. The subsets of Torpedo G2 that react or do not react with Elec-39 (Elec-39+ and Elec-39-) differ in their electrophoretic mobility under nondenaturing conditions; the Elec-39+ component also binds the lectins from Pisum sativum and Lens culinaris. Whereas the Elec-39- component is present at the earliest developmental stages examined, an Elec-39+ component becomes distinguishable only around the 70-mm stage. Its proportion increases progressively, but later than the rapid accumulation of the total G2 form. In immunoblots, mAb Elec-39 recognizes a number of proteins other than AChE from various tissues of several species. The specificity of Elec-39 resembles that of a family of anti-carbohydrate antibodies that includes HNK-1, L2, NC-1, NSP-4, as well as IgMs that occur in human neuropathies. Although some human neuropathy IgMs that recognize the myelin-associated glycoprotein did not react with Elec-39+ AChE, mAbs HNK-1, NC-1, and NSP-4 showed the same selectivity as Elec-39 for Torpedo G2 AChE, but differed in the formation of immune complexes.
ESTHER : Bon_1987_J.Neurochem_49_1720
PubMedSearch : Bon_1987_J.Neurochem_49_1720
PubMedID: 2445915

Title : Identical N-terminal peptide sequences of asymmetric forms and of low-salt-soluble and detergent-soluble amphiphilic dimers of Torpedo acetylcholinesterase. Comparison with bovine acetylcholinesterase - Bon_1986_FEBS.Lett_209_206
Author(s) : Bon S , Chang JY , Strosberg AD
Ref : FEBS Letters , 209 :206 , 1986
Abstract : We have determined partial N-terminal sequences of acetylcholinesterase (AChE) catalytic subunits from Torpedo marmorata electric organs and from bovine caudate nucleus. We obtain identical sequences (23 amino acids) for the soluble ('low-salt-soluble' or LSS fraction) and particulate ('detergent-soluble', or DS fraction) amphiphilic dimers (G2 form) and for the asymmetric, collagen-tailed forms ('high-salt-soluble', or HSS fraction, A12 + A8 forms). There are two amino acid differences, at position 3 (Asp/His) and 20 (Ile/Val), with the sequences obtained for T. californica by MacPhee-Quigley et al. [(1985) J. Biol. Chem. 260, 12185-12189] for the soluble G2 form and the lytic G4 form which is derived from asymmetric AChE. The bovine sequence (12 amino acids) presents an identity of 4 amino acids (Glu-Leu-Leu-Val) with that of Torpedo, at positions 5-8 (Torpedo) and 7-10 (bovine). There is also a clear homology with the sequence of human butyrylcholinesterase [(1986) Lockridge et al. J. Biol. Chem., in press] indicating that these enzymes probably derive from a common ancestor.
ESTHER : Bon_1986_FEBS.Lett_209_206
PubMedSearch : Bon_1986_FEBS.Lett_209_206
PubMedID: 3792544

Title : Polymorphism of pseudocholinesterase in Torpedo marmorata tissues: comparative study of the catalytic and molecular properties of this enzyme with acetylcholinesterase - Toutant_1985_J.Neurochem_44_580
Author(s) : Toutant JP , Massoulie J , Bon S
Ref : Journal of Neurochemistry , 44 :580 , 1985
Abstract : We report the existence, in Torpedo marmorata tissues, of a cholinesterase species (sensitive to 10(-5) M eserine) that differs from acetylcholinesterase (AChE, EC 3.1.1.7) in several respects: (a) The enzyme hydrolyzes butyrylthiocholine (BuSCh) at about 30% of the rate at which it hydrolyzes acetylthiocholine (AcSCh), whereas Torpedo AChE does not show any activity on BuSCh. (b) It is not inhibited by 10(-5) M BW 284C51, but rapidly inactivated by 10(-8) M diisopropylfluorophosphonate. (c) It does not exhibit inhibition by excess substrate up to 5 X 10(-3) M AcSCh. (d) It does not cross-react with anti-AChE antibodies raised against purified Torpedo AChE. This enzyme is obviously homologous to the "nonspecific" or pseudocholinesterase (pseudo-ChE, EC 3.1.1.8) that exists in other species, although it is closer to "true" AChE than classic pseudo-ChE in several respects. Thus, it shows the highest Vmax with acetyl-, and not propionyl- or butyrylthiocholine, and it is not specifically sensitive to ethopropazine. Pseudo-ChE is apparently absent from the electric organs, but represents the only cholinesterase species in the heart ventricle. Pseudo-ChE and AChE coexist in the spinal cord and in blood plasma, where they contribute to AcSCh hydrolysis in comparable proportions. Pseudo-ChE exists in several molecular forms, including collagen-tailed forms, which can be considered as homologous to those of AChE. In the heart the major component of pseudo-ChE appears to be a soluble monomeric form (G1). This form is inactivated by Triton X-100 within days.
ESTHER : Toutant_1985_J.Neurochem_44_580
PubMedSearch : Toutant_1985_J.Neurochem_44_580
PubMedID: 2578181

Title : The polymorphism of cholinesterases: classification of molecular forms\; Interactions and solubilization characteristics metabolic relationships and regulations -
Author(s) : Massoulie J , Bon S , Lazar M , Grassi J , Marsh D , Meflah K , Toutant JP , Vallette FM , Vigny M
Ref : In: Cholinesterases, fundamental and applied aspects : proceedings of the Second International Meeting on Cholinesterases , (Brzin M, Barnard EA, Sket D, Eds) De Gruyter :73 , 1984
PubMedID:

Title : Synthesis in vitro of precursors of the catalytic subunits of acetylcholinesterase from Torpedo marmorata and Electrophorus electricus - Sikorav_1984_Eur.J.Biochem_145_519
Author(s) : Sikorav JL , Grassi J , Bon S
Ref : European Journal of Biochemistry , 145 :519 , 1984
Abstract : We translated poly(A-rich messenger RNA prepared from the electric organs of Electrophorus electricus and Torpedo marmorata in a reticulocyte lysate system. In the case of Electrophorus, which appears to contain only one type of acetylcholinesterase catalytic subunit, an anti-(Electrophorus acetylcholinesterase) antiserum precipitated a single 65-kDa polypeptide from the products translation obtained in vitro. In the case of Torpedo, where a number of distinct catalytic subunits corresponding to different fractions of the enzyme have been described, an anti-(Torpedo acetylcholinesterase) antiserum precipitated two main polypeptides, 61 kDa and 65 kDa, both of which could be displaced by unlabelled purified Torpedo acetylcholinesterase. Synthesis in vitro thus appears to produce a single type of precursor of the acetylcholinesterase catalytic subunit for Electrophorus, and at least two distinct precursors for Torpedo, suggesting that several mRNAs code for the catalytic subunits in the latter species.
ESTHER : Sikorav_1984_Eur.J.Biochem_145_519
PubMedSearch : Sikorav_1984_Eur.J.Biochem_145_519
PubMedID: 6150849

Title : Poster 11 Acetylcholinesterase molecular forms in Torpedo marmorata: Tissue specificity and hydrophobic character -
Author(s) : Toutant JP , Bon S
Ref : In: Cholinesterases, fundamental and applied aspects : proceedings of the Second International Meeting on Cholinesterases , (Brzin M, Barnard EA, Sket D, Eds) De Gruyter , 1984
PubMedID:

Title : Poster 28. Evolution of acetylcholinesterase molecular forms in the electric lobes and in the electric organs during development of Torpedo -
Author(s) : Bon S
Ref : In: Cholinesterases, fundamental and applied aspects : proceedings of the Second International Meeting on Cholinesterases , (Brzin M, Barnard EA, Sket D, Eds) De Gruyter , 1984
PubMedID:

Title : The molecular forms of cholinesterase and acetylcholinesterase in vertebrates -
Author(s) : Massoulie J , Bon S
Ref : Annual Review of Neuroscience , 5 :57 , 1982
PubMedID: 6176173

Title : Molecular forms of acetylcholinesterase in developing Torpedo embryos -
Author(s) : Bon S
Ref : Neurochem Int , 4 :577 , 1982
PubMedID: 20487914

Title : The quaternary structure of chicken acetylcholinesterase and butyrylcholinesterase\; effect of collagenase and trypsin - Allemand_1981_J.Neurochem_36_860
Author(s) : Allemand P , Bon S , Massoulie J , Vigny M
Ref : Journal of Neurochemistry , 36 :860 , 1981
Abstract : Acetylcholinesterase (EC 3.1.1.7.; AChE) and butyrylcholinesterase (EC 3.1.1.8.; BCHE) from chicken muscle exist as sets of structurally homologous forms with very similar properties. The collagenase sensitivity and aggregation properties of the 'heavy' forms of both enzymes indicate that they possess a collagen-like tail, and their stepwise dissociation by trypsin confirms that they correspond to triple (A12) and double (A8) collagen-tailed tetramers. In addition to this dissociating effect, trypsin digests an important fraction of the catalytic units of AChE, in a progressive manner, removing as much as 30% of the enzyme's mass, without inactivation of the tetramers and of the tailed molecules. The trypsin-modified AChE forms closely resemble the corresponding mammalian AChE forms in their hydrodynamic properties. It is not known whether the trypsin-digestible peptides, which do not appear to be involved in the ionic or hydrophobic interactions of the enzymes, are a fragment of the catalytic subunit or whether they constitute distinct polypeptides.
ESTHER : Allemand_1981_J.Neurochem_36_860
PubMedSearch : Allemand_1981_J.Neurochem_36_860
PubMedID: 6259292

Title : Collagen-tailed and hydrophobic components of acetylcholinesterase in Torpedo marmorata electric organ - Bon_1980_Proc.Natl.Acad.Sci.U.S.A_77_4464
Author(s) : Bon S , Massoulie J
Ref : Proceedings of the National Academy of Sciences of the United States of America , 77 :4464 , 1980
Abstract : We have distinguished three fractions of acetylcholinesterase (AcChoE; acetylcholine acetylhydrolase, EC 3.1.1.7) from Torpedo marmorata electric organs, according to their solubilization characteristics. The low-salt-aggregating collagen-tailed forms are soluble in high-salt buffers; their hydrodynamic properties ae not modified in the presence of detergents. They constitute the A fraction, which amounts to about a third of the tissue's AcChoE activity. The low-salt-soluble (LSS) and detergent-soluble (DS) fractions are not sensitive to ionic strength and collagenase. In the presence of nonionic detergents or bile salts, both fractions behave as a monodisperse "6.3S" form, the properties of which have been investigated mostly in the case of Triton X-100. Disulfide bond reduction dissociates the detergent form into a smaller "5S" form. These two forms are thought to be, respectively, detergent-associated dimers and monomers. In the absence of detergent, the LSS fraction is polydisperse: it contains a major 8S component, 11S and 14S components, and faster-sedimenting aggregates, which appear to represent dimers, tetramers, and higher polymers. The heterogeneity of the 8S component in gel filtration suggests that it also contains variable noncatalytic elements. Upon removal of the detergent the DS fraction forms ill-defined aggregates. Trypsin induces quaternary rearrangements of part of the 8S component into 11S and 14S components, which are still convertible into the detergent form; therefore trypsin probably digests noncatalytic elements. Pronase and proteinase K, on the other hand, convert the enzyme into a dimeric form, G2, that does not interact with detergents, probably by cleaving a minor fragment of the subunit that is involved in hydrophobic interactions.
ESTHER : Bon_1980_Proc.Natl.Acad.Sci.U.S.A_77_4464
PubMedSearch : Bon_1980_Proc.Natl.Acad.Sci.U.S.A_77_4464
PubMedID: 6933497

Title : Asymmetric and globular forms of acetylcholinesterase in mammals and birds - Bon_1979_Proc.Natl.Acad.Sci.U.S.A_76_2546
Author(s) : Bon S , Vigny M , Massoulie J
Ref : Proceedings of the National Academy of Sciences of the United States of America , 76 :2546 , 1979
Abstract : We have identified six molecular forms of acetylcholinesterase (AcChoE: acetylcholine hydrolase, EC 3.1.1.7) in extracts from bovine superior cervical ganglia. We show that three of them resemble the collagen-tailed forms of Electrophorus AcChoE in their hydrodynamic parameters, low-salt aggregation properties, and collagenase sensitivity. The six molecular forms of bovine AcChoE appear structurally homologous to the six forms of electric fish AcChoE that have previously been characterized. They include globular molecules (monomers, dimers, and tetramers) and asymmetric aggregating molecules that possess a collagen-like tail associated with one, two, and three tetramers. We propose to call the globular forms G1, G2, and G4 and the asymmetric forms A4, A8, and A12, the subscripts indicating the number of catalytic subunits. In spite of quantitative differences in their molecular parameters, the AcChoE forms from rat and chicken are clearly homologous to those of bovine AcChoE. Thus the nomenclature we introduce is very probably valid for the main AcChoE molecular forms, at least in vertebrates, and should help to clarify structural relationships and homologies among them. This model, however, does not claim to represent entirely the complex polymorphism of AcChoE, because more or less hydrophobic variants of the G forms have been observed, and because other molecular associations cannot be excluded. We discuss the significance of the globular and collagen-tailed structure for the molecular localization of AcChoE.
ESTHER : Bon_1979_Proc.Natl.Acad.Sci.U.S.A_76_2546
PubMedSearch : Bon_1979_Proc.Natl.Acad.Sci.U.S.A_76_2546
PubMedID: 288044

Title : The subunit structure of mammalian acetylcholinesterase: catalytic subunits, dissociating effect of proteolysis and disulphide reduction on the polymeric forms -
Author(s) : Vigny M , Bon S , Massoulie J , Gisiger V
Ref : Journal of Neurochemistry , 33 :559 , 1979
PubMedID: 469545

Title : Distribution of acetylcholinesterase molecular forms in neural and non- neural sections of human muscle -
Author(s) : Carson S , Bon S , Vigny M , Massoulie J , Fardeau M
Ref : FEBS Letters , 97 :348 , 1979
PubMedID: 761642

Title : Active-site catalytic efficiency of acetylcholinesterase molecular forms in Electrophorus, torpedo, rat and chicken - Vigny_1978_Eur.J.Biochem_85_317
Author(s) : Vigny M , Bon S , Massoulie J , Leterrier F
Ref : European Journal of Biochemistry , 85 :317 , 1978
Abstract : The active sites of acetylcholinesterase multiple forms from four widely different zoological species (Electrophorus, Torpedo, rat and chicken) were titrated using a stable, irreversible phosphorylating inhibitor (O-ethyl-S2-diisopropylaminoethyl methyl-phosphonothionate). In all cases, we found that within a given species, the molecular forms we examined were equivalent in their catalytic activity per active site. As pure preparations of the molecular forms of Electrophorus acetylcholinesterase were available, we were able to establish that one inhibitor molecule binds per monomer unit for each of them. This had already been shown by several authors for the tetrameric globular form, but not for the tailed molecules. Analysis of the phosphorylation reaction showed that they are equally reactive. Under our experimental conditions, their turnover number per site was 4.4 x 10(7) mol of acetylthiocholine hydrolysed . h-1 at 28 degrees C, pH 7.0. The corresponding value was less than half for Torpedo (1.64 x 10(7) mol . h-1), and again lower for rat (1.32 x 10(7) mol . h-1) and chicken (1.05 x 10(7) mol . h-1). In the case of rat acetylcholinesterase, the activity per active site of solubilized (with or without Triton X-100) and membrane-bound enzyme were identical. We discuss the implications of these findings with respect to the quaternary structure of acetylcholinesterase, and to the physico-chemical state and physiological properties of its molecular forms.
ESTHER : Vigny_1978_Eur.J.Biochem_85_317
PubMedSearch : Vigny_1978_Eur.J.Biochem_85_317
PubMedID: 648523

Title : The dependence of acetylcholinesterase aggregation at low ionic strength upon a polyanionic component -
Author(s) : Bon S , Cartaud J , Massoulie J
Ref : European Journal of Biochemistry , 85 :1 , 1978
PubMedID: 639808

Title : Dumbbell-shaped associations of tailed Electrophorus acetylcholinesterase molecules -
Author(s) : Bon S , Cartaud J , Massoulie J
Ref : Mol Biol Rep , 4 :61 , 1978
PubMedID: 642943

Title : Electrophorus acetylcholinesterase. Biochemical and electron microscope characterization of low ionic strength aggregates - Cartaud_1978_J.Cell.Biol_77_315
Author(s) : Cartaud J , Bon S , Massoulie J
Ref : Journal of Cell Biology , 77 :315 , 1978
Abstract : The "tailed" molecules of Electrophorus (electric eel) acetylcholinesterase aggregate under conditions of low ionic strength. These aggregates have been studied by sedimentation analysis and high-resolution electron microscopy. They consist of bundles of at least half a dozen molecules, the tails of which are packed side by side, to form the core of the structure. Although aggregation is normally fully reversible, aggregates were irreversibly stabilized by methylene blue-sensitized photo-oxidation. This process was shown to consist of a singlet oxygen oxidation reaction and probably involves methionine or histidine residues. It did not modify the structural or hydrodynamic characteristics of the aggregates.
ESTHER : Cartaud_1978_J.Cell.Biol_77_315
PubMedSearch : Cartaud_1978_J.Cell.Biol_77_315
PubMedID: 649654

Title : Collagenase sensitivity and aggregation properties of Electrophorus acetylcholinesterase - Bon_1978_Eur.J.Biochem_89_89
Author(s) : Bon S , Massoulie J
Ref : European Journal of Biochemistry , 89 :89 , 1978
Abstract : Tailed forms of Electrophorus acetylcholinesterase, mainly A (9 S) and C (14.2 S) forms, have been subjected to collagenase treatment. Several steps have been identified, yielding molecules which have lost different portions of the tail, and eventually resulting in separation of the isolated tetramers. These modifications result in the disappearance of the low-ionic strength aggregating properties. The molecules which have retained relatively large fragments of the tail do not aggregate in the same conditions as the intact forms, but still form small aggregates in the presence of high levels of polyanions. A model of the tailed molecules, illustrating the existence of discrete collagenase-sensitive regions in the tail, is discussed.
ESTHER : Bon_1978_Eur.J.Biochem_89_89
PubMedSearch : Bon_1978_Eur.J.Biochem_89_89
PubMedID: 212272

Title : An active monomeric form of Electrophorus electricus acetylcholinesterase -
Author(s) : Bon S , Massoulie J
Ref : FEBS Letters , 67 :99 , 1976
PubMedID: 955109

Title : Torpedo marmorata acetylcholinesterase\; a comparison with the Electrophorus electricus enzyme. Molecular forms, subunits, electron microscopy, immunological relationship - Rieger_1976_Eur.J.Biochem_68_513
Author(s) : Rieger F , Bon S , Massoulie J , Cartaud J , Picard B , Benda P
Ref : European Journal of Biochemistry , 68 :513 , 1976
Abstract : Electron microscopy, sequential degradation by hydrolytic enzymes and the physical-chemical properties of the molecular forms of Torpedo acetylcholinesterase indicate that these molecules are structurally related to each other in the same way as the molecular forms of Electrophorus acetylcholinesterase: all are derived from a complex structure in which three tetrameric groups of subunits are associated with a rod-like 'tail'. In aged preparations the catalytic subunits are split into fragments in a manner similar to those of Electrophorus acetylcholinesterase. Immunological cross-reaction between both enzymes demonstrates the occurrence of common antigenic sites. The enzymes from the two sources, however, are different in their molecular weights and susceptibility to hydrolytic enzymes. Also, Torpedo acetylcholinesterase does not precipitate with either isologous or heterologous antibodies.
ESTHER : Rieger_1976_Eur.J.Biochem_68_513
PubMedSearch : Rieger_1976_Eur.J.Biochem_68_513
PubMedID: 61859

Title : Molecular forms of Electrophorus acetylcholinesterase. Molecular weight and composition - Bon_1976_Eur.J.Biochem_68_523
Author(s) : Bon S , Huet M , Lemonnier M , Rieger F , Massoulie J
Ref : European Journal of Biochemistry , 68 :523 , 1976
Abstract : Molecular weights for the series of six Electrophorus acetylcholinesterase forms have been determined either by the sedimentation-diffusion equilibrium method or, particularly in the case of the very scarce G' and G inches forms, from their Stokes radius and sedimentation coefficient values. Both methods are in excellent agreement. The results provide good evidence for the model previously proposed, G inches, G' and G containing one, two and four subunits, whereas A, C and D possess, in addition to respectively one, two and three tetrameric sets of such subunits, a structural element, the tail. Although the amino acid composition of 'tailed' and globular forms did not reveal any significant feature of this element, its mass, about 100 000 daltons, could be deduced from a comparison of molecular weights for the two classes of acetylcholinesterase forms. This value is in close agreement with electron microscopic data. The tail is thought to consist of three 30 000-dalton strands.
ESTHER : Bon_1976_Eur.J.Biochem_68_523
PubMedSearch : Bon_1976_Eur.J.Biochem_68_523
PubMedID: 976271

Title : Affinity chromatography of acetylcholinesterase. The importance of hydrophobic interactions - Massoulie_1976_Eur.J.Biochem_68_531
Author(s) : Massoulie J , Bon S
Ref : European Journal of Biochemistry , 68 :531 , 1976
Abstract : An easily prepared affinity column for acetylcholinesterase is described, which may be operated at ionic strength high enough to prevent aggregation of the asymmetric forms of the enzyme. Specific elution by tetraethylammonium or decamethonium was quantitative. The performance of this column is comparable to that of the column described by Dudai and Silman. It is shown that the hexyl 'spacer arm' strongly participates in the enzyme binding and that its replacement with the more hydrophilic spermine chain lowers the affinity. The hexyl chain itself is shown to bind acetylcholinesterase, although with lower affinity and capacity than the complete column. This binding is also partly reversed by inhibitors. Such hydrophobic columns bind the native asymmetric forms of the enzyme more strongly than the lytic globular ones. The aromatic quaternary ligang inhibits Electrophorus but not Torpedo acetylcholinesterase; therefore the column does not retain the Torpedo enzyme. Differences in Km between acetylcholinesterases of the two species also point to differences in their active sites.
ESTHER : Massoulie_1976_Eur.J.Biochem_68_531
PubMedSearch : Massoulie_1976_Eur.J.Biochem_68_531
PubMedID: 976272

Title : Molecular forms of Electrophorus acetylcholinesterase the catalytic subunits: fragmentation, intra- and inter-subunit disulfide bonds -
Author(s) : Bon S , Massoulie J
Ref : FEBS Letters , 71 :273 , 1976
PubMedID: 1001444

Title : Interactions between lectins and electric eel acetylcholinesterase -
Author(s) : Bon S , Rieger F
Ref : FEBS Letters , 53 :282 , 1975
PubMedID: 1137955

Title : Molecular forms of acetylcholinesterase -
Author(s) : Massoulie J , Bon S , Rieger F , Vigny M
Ref : Croatica Chemica Acta , 47 :163\ , 1975
PubMedID:

Title : Fine structure of electric ell acetylcholinesterase -
Author(s) : Cartaud J , Rieger F , Bon S , Massoulie J
Ref : Brain Research , 88 :127 , 1975
PubMedID: 1122392

Title : [Electron microscopic studies on stretched and globular acetylcholinesterase molecules of the electric eel (Electrophorus electricus)]. [French] -
Author(s) : Rieger F , Bon S , Massoulie J
Ref : European Journal of Biochemistry , 34 :539 , 1973
PubMedID: 4736704

Title : [Properties of elongated acetylcholinesterase molecules in solution. Stokes radius, density, and mass]. [French] -
Author(s) : Bon S , Rieger F , Massoulie J
Ref : European Journal of Biochemistry , 35 :372 , 1973
PubMedID: 4736923

Title : Phospholipids in native Electrophorus acetylcholinesterase -
Author(s) : Rieger F , Bon S , Massoulie J
Ref : FEBS Letters , 36 :12 , 1973
PubMedID: 4747596

Title : Electrophorus acetylcholinesterase: a glycoprotein\; molecular weight of its subunits -
Author(s) : Powell JT , Bon S , Rieger F , Massoulie J
Ref : FEBS Letters , 36 :17 , 1973
PubMedID: 4747597

Title : [Spontaneous conversion of native acetylcholinesterasic forms of the Gymnotus electric organ, to the globular form]. [French] -
Author(s) : Rieger F , Bon S , Massoulie J
Ref : Comptes Rendus de l Academie des Sciences , 274 :1753 , 1972
PubMedID: 4624804

Title : [Various globular and elongated acetylcholinesterases in electric organs of fishes]. [French] -
Author(s) : Massoulie J , Rieger F , Bon S
Ref : European Journal of Biochemistry , 21 :542 , 1971
PubMedID: 5098771

Title : [Relations between molecular complexes of acetylcholinesterase]. [French] -
Author(s) : Massoulie J , Rieger F , Bon S
Ref : Comptes Rendus de l Academie des Sciences , 270 :1837 , 1970
PubMedID: 4986806