Transcytotic efflux from early endosomes is dependent on cholesterol and glycosphingolipids in polarized hepatic cells.

摘要: We examined the role that lipid rafts play in regulating apical protein trafficking polarized hepatic cells. Rafts are postulated to form trans-Golgi network where they recruit newly synthesized residents and mediate their direct transport plasma membrane. In hepatocytes, single transmembrane glycolipid-anchored proteins take "indirect" route. They transported from basolateral membrane endocytosed transcytosed surface. Do sort along this circuitous pathway? took two approaches answer question. First, we determined detergent solubility of selected biosynthetic pathway insolubility was acquired. Second, used pharmacological agents deplete raft components assessed effects on basolateral-to-apical transcytosis. found cholesterol glycosphingolipids required for delivery early endosomes subapical compartment. contrast, fluid phase uptake clathrin-mediated internalization recycling receptors were only mildly impaired. Apical did not correlate with depletion or impaired transcytosis, suggesting other factors contribute insolubility. Examination Fao cells also revealed raft-dependent sorting does require cell context.