Verges_2004_J.Biol.Chem_279_9030

Reference

Title : Endocytosis of hepatic lipase and lipoprotein lipase into rat liver hepatocytes in vivo is mediated by the low density lipoprotein receptor-related protein - Verges_2004_J.Biol.Chem_279_9030
Author(s) : Verges M , Bensadoun A , Herz J , Belcher JD , Havel RJ
Ref : Journal of Biological Chemistry , 279 :9030 , 2004
Abstract :

In isolated cell studies, the internalization and degradation of hepatic lipase (HL) has been linked to its binding to the low density lipoprotein receptor-related protein (LRP). We have utilized the receptor-associated protein (RAP), a universal inhibitor of high affinity ligand binding to LRP, to evaluate the participation of LRP in the endocytosis of HL and lipoprotein lipase (LPL). We isolated a total endosome fraction from rat livers after a 30-min infusion of recombinant RAP, administered as a glutathione S-transferase conjugate (GST-RAP). GST-RAP infusion had no effect on the concentration of HL in liver homogenates, but its concentration in blood plasma increased progressively by 20%, and enrichment over homogenate of HL in endosomes was reduced by 50% as compared with infusion of GST alone. The concentrations of LPL in liver and plasma were 1.4 and 0.5%, respectively, those of HL, but endosomal enrichment of the two enzymes was similar ( approximately 10-fold). GST-RAP infusion had no effect on the concentration of LPL in liver but increased its concentration in blood plasma by 250% and reduced its endosomal enrichment by 95% or greater. GST-RAP infusion also reduced endosomal enrichment of LRP by 40%, but enrichment of several other endocytic receptors was unaffected. Endosomal enrichment of several membrane trafficking proteins associated with the endocytic pathway in hepatocytes was unaffected by GST-RAP with the exception of early endosome endosome antigen 1, which was reduced by 85%. We conclude that HL is partially and LPL almost exclusively taken up into rat hepatocytes after binding to the endocytic receptor LRP.

PubMedSearch : Verges_2004_J.Biol.Chem_279_9030
PubMedID: 14701798

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Citations formats

Verges M, Bensadoun A, Herz J, Belcher JD, Havel RJ (2004)
Endocytosis of hepatic lipase and lipoprotein lipase into rat liver hepatocytes in vivo is mediated by the low density lipoprotein receptor-related protein
Journal of Biological Chemistry 279 :9030

Verges M, Bensadoun A, Herz J, Belcher JD, Havel RJ (2004)
Journal of Biological Chemistry 279 :9030