title: Cholesterol-induced caveolin targeting to lipid droplets in adipocytes: a role for caveolar endocytosis.
abstract: We have investigated the targeting of caveolin to lipid bodies in adipocytes that express high levels of caveolins and contain well-developed lipid droplets. We observed that the lipid droplets isolated from adipocytes of caveolin-1 knock out mice contained dramatically reduced levels of cholesterol, indicating that caveolin is required for maintaining the cholesterol content of this organelle. Analysis of caveolin distribution by cell fractionation and fluorescent light microscopy in 3T3-L1 adipocytes indicated that addition of cholesterol rapidly stimulated translocation of caveolin to lipid droplets. The cholesterol-induced trafficking of caveolins to lipid droplets was shown to be dynamin- and protein kinase C (PKC)-dependent and modulated by src tyrosine kinase activation, suggesting a role for caveolar endocytosis in this novel trafficking pathway. Consistent with this, caveolae budding was stimulated by cholesterol addition. The present data identify lipid droplets as potential target organelles for caveolar endocytosis and demonstrate a role for caveolin-1 in the maintenance of free cholesterol levels in adipocyte lipid droplets.
authors.affiliation: Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
authors.forename: Soazig
authors.initials: S
authors.lastname: Le Lay
authors.forename: Eric
authors.initials: E
authors.lastname: Hajduch
authors.forename: Margaret R
authors.initials: MR
authors.lastname: Lindsay
authors.forename: Xavier
authors.initials: X
authors.lastname: Le Lièpvre
authors.forename: Christoph
authors.initials: C
authors.lastname: Thiele
authors.forename: Pascal
authors.initials: P
authors.lastname: Ferré
authors.forename: Robert G
authors.initials: RG
authors.lastname: Parton
authors.forename: Teymuras
authors.initials: T
authors.lastname: Kurzchalia
authors.forename: Kai
authors.initials: K
authors.lastname: Simons
authors.forename: Isabelle
authors.initials: I
authors.lastname: Dugail
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000378:metabolism*; D000818:Animals; D021941:Caveolae / Q000502:physiology*; D051242:Caveolin 1 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D002784:Cholesterol / Q000502:physiology*; D004705:Endocytosis / Q000502:physiology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout
chemical_list: D051242:Caveolin 1; D002784:Cholesterol