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

Content Provider	Semantic Scholar
Copyright Year	2003
Abstract	We examined the role that lipid rafts play in regulating apical protein trafficking in polarized hepatic cells. Rafts are postulated to form in the trans-Golgi network where they recruit newly synthesized apical residents and mediate their direct transport to the apical plasma membrane. In hepatocytes, single transmembrane and glycolipid-anchored apical proteins take the "indirect" route. They are transported from the trans-Golgi to the basolateral plasma membrane where they are endocytosed and transcytosed to the apical surface. Do rafts sort hepatic apical proteins along this circuitous pathway? We took two approaches to answer this question. First, we determined the detergent solubility of selected apical proteins and where in the biosynthetic pathway insolubility was acquired. Second, we used pharmacological agents to deplete raft components and assessed their effects on basolateral-to-apical transcytosis. We found that cholesterol and glycosphingolipids are required for delivery from basolateral early endosomes to the subapical compartment. In contrast, fluid phase uptake and clathrin-mediated internalization of recycling receptors were only mildly impaired. Apical protein solubility did not correlate with raft depletion or impaired transcytosis, suggesting other factors contribute to apical protein insolubility. Examination of apical proteins in Fao cells also revealed that raft-dependent sorting does not require the polarized cell context.
File Format	PDF HTM / HTML
Alternate Webpage(s)	http://www.molbiolcell.org/content/early/2003/04/04/mbc.E02-12-0816.full.pdf
PubMed reference number	12857857v1
Volume Number	14
Issue Number	7
Journal	Molecular biology of the cell
Language	English
Access Restriction	Open
Subject Keyword	Anabolism Anatomical compartments Apical plasma membrane Basolateral plasma membrane Biosynthetic Pathways Cholesterol Clathrin Detergents Endosomes Glycolipids Glycosphingolipids Golgi Apparatus Hepatocyte Pharmacology Recycling Transcytosis lipid raft trans-Golgi Network
Content Type	Text
Resource Type	Article