Houenou_1991_J.Neurosci.Res_29_244

We have studied the physicochemical properties of acetylcholinesterase (AChE) during embryonic development of normal and functionally impaired mouse skeletal muscle, focusing on the tailed asymmetric (16S) form of the enzyme. The muscle-specific 16S AChE exists in two different variants. One is associated with extracellular matrix and is high-salt soluble (HSS, also termed hydrophilic AChE), whereas the other form is anchored to cell membranes and is detergent extractable (DE, or hydrophobic AChE). Before innervation during normal embryonic development, both hydrophilic and hydrophobic 16S AChE exist in equal amounts. After muscle innervation, there was an increase (amounting three-fold on E18) in the levels of hydrophilic vs. hydrophobic 16S AChE. This alteration of the relative proportions of the two variants of 16S AChE did not occur in chronically inactive muscles either from the mouse mutant, muscular dysgenesis, or from tetrodotoxin-treated mouse embryos. Taken together with previous reports, the present results suggest that postsynaptic membrane depolarization-induced Ca2+ fluxes are important in modulating not only the synthesis of 16S AChE, but also the relative proportions of both physicochemical variants of this molecular form of AChE.