Phospholipid, cholesterol, polypeptide and glycoprotein composition of hepatic endosome subfractions.
The composition of hepatic endosome subfractions was compared directly with that of plasma membranes and Golgi-apparatus fractions. The neutral lipid and phospholipid composition of two endosome subfractions separated on Nycodenz gradients from a parent endosome fraction was similar to that of plasma membranes. The phospholipid/cholesterol ratios and the sphingomyelin contents were high, as in plasma membranes. However, the phosphatidylserine content was low. Endosomal subfractions contained a simpler polypeptide profile than did plasma membranes. However, a large number of glycoproteins were common to both fractions. Two endosome-specific glycoproteins, of Mr 59 000 and 38 000, were identified. Sialic acid was present at concentrations higher than in plasma membranes. The results indicate that endosomal membranes have a similar composition to plasma membranes that probably reflects their functional interaction during endocytosis and receptor recycling.
Evans
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Hardison
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D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D011992:Endosomes / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D010455:Peptides / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012794:Sialic Acids / Q000032:analysis; D013347:Subcellular Fractions / Q000378:metabolism
D006023:Glycoproteins; D010455:Peptides; D010743:Phospholipids; D012794:Sialic Acids; D002784:Cholesterol