Cholesterol depletion in adipocytes causes caveolae collapse concomitant with proteosomal degradation of cavin-2 in a switch-like fashion

PLoS One. 2012;7(4):e34516. doi: 10.1371/journal.pone.0034516. Epub 2012 Apr 6.

Abstract

Caveolae, little caves of cell surfaces, are enriched in cholesterol, a certain level of which is required for their structural integrity. Here we show in adipocytes that cavin-2, a peripheral membrane protein and one of 3 cavin isoforms present in caveolae from non-muscle tissue, is degraded upon cholesterol depletion in a rapid fashion resulting in collapse of caveolae. We exposed 3T3-L1 adipocytes to the cholesterol depleting agent methyl-β-cyclodextrin, which results in a sudden and extensive degradation of cavin-2 by the proteasome and a concomitant movement of cavin-1 from the plasma membrane to the cytosol along with loss of caveolae. The recovery of cavin-2 at the plasma membrane is cholesterol-dependent and is required for the return of cavin-1 from the cytosol to the cell surface and caveolae restoration. Expression of shRNA directed against cavin-2 also results in a cytosolic distribution of cavin-1 and loss of caveolae. Taken together, these data demonstrate that cavin-2 functions as a cholesterol responsive component of caveolae that is required for cavin-1 localization to the plasma membrane, and caveolae structural integrity.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 3T3-L1 Cells
  • Adipocytes / cytology
  • Adipocytes / drug effects
  • Adipocytes / metabolism*
  • Animals
  • Caveolae / drug effects
  • Caveolae / metabolism*
  • Cholesterol / deficiency*
  • Fibroblasts
  • Genetic Vectors
  • HEK293 Cells
  • Humans
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / pharmacology
  • Lentivirus
  • Membrane Proteins / metabolism*
  • Mice
  • Primary Cell Culture
  • Proteasome Endopeptidase Complex / metabolism*
  • Protein Isoforms / metabolism
  • Protein Transport / drug effects
  • Proteolysis / drug effects
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • RNA-Binding Proteins
  • Signal Transduction / drug effects
  • beta-Cyclodextrins / pharmacology

Substances

  • Cavin1 protein, mouse
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors
  • Membrane Proteins
  • Protein Isoforms
  • RNA, Small Interfering
  • RNA-Binding Proteins
  • beta-Cyclodextrins
  • methyl-beta-cyclodextrin
  • Cholesterol
  • Proteasome Endopeptidase Complex