title: Lipid droplet analysis in caveolin-deficient adipocytes: alterations in surface phospholipid composition and maturation defects.
abstract: Caveolins form plasmalemnal invaginated caveolae. They also locate around intracellular lipid droplets but their role in this location remains unclear. By studying primary adipocytes that highly express caveolin-1, we characterized the impact of caveolin-1 deficiency on lipid droplet proteome and lipidome. We identified several missing proteins on the lipid droplet surface of caveolin-deficient adipocytes and showed that the caveolin-1 lipid droplet pool is organized as multi-protein complexes containing cavin-1, with similar dynamics as those found in caveolae. On the lipid side, caveolin deficiency did not qualitatively alter neutral lipids in lipid droplet, but significantly reduced the relative abundance of surface phospholipid species: phosphatidylserine and lysophospholipids. Caveolin-deficient adipocytes can form only small lipid droplets, suggesting that the caveolin-lipid droplet pool might be involved in lipid droplet size regulation. Accordingly, we show that caveolin-1 concentration on adipocyte lipid droplets positively correlated with lipid droplet size in obese rodent models and human adipocytes. Moreover, rescue experiments by caveolin- green fluorescent protein in caveolin-deficient cells exposed to fatty acid overload demonstrated that caveolin-coated lipid droplets were able to grow larger than caveolin-devoid lipid droplets. Altogether, these data demonstrate that the lipid droplet-caveolin pool impacts on phospholipid and protein surface composition of lipid droplets and suggest a functional role on lipid droplet expandability.
authors: Centre de Recherche des Cordeliers, INSERM, U872, Université Pierre et Marie Curie - Paris 6, France.
authors: Cédric M
authors: CM
authors: Blouin
authors: Soazig
authors: S
authors: Le Lay
authors: Anita
authors: A
authors: Eberl
authors: Harald C
authors: HC
authors: Köfeler
authors: Ida Chiara
authors: IC
authors: Guerrera
authors: Christophe
authors: C
authors: Klein
authors: Xavier
authors: X
authors: Le Liepvre
authors: Françoise
authors: F
authors: Lasnier
authors: Olivier
authors: O
authors: Bourron
authors: Jean-François
authors: JF
authors: Gautier
authors: Pascal
authors: P
authors: Ferré
authors: Eric
authors: E
authors: Hajduch
authors: Isabelle
authors: I
authors: Dugail
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D051242:Caveolin 1 / Q000172:deficiency* / Q000378:metabolism; D006801:Humans; D051379:Mice; D010743:Phospholipids / Q000737:chemistry* / Q000378:metabolism*; D020543:Proteome / Q000737:chemistry / Q000378:metabolism; D051381:Rats
chemical_list: D051242:Caveolin 1; D010743:Phospholipids; D020543:Proteome