Cell-type and tissue-specific expression of caveolin-2. Caveolins 1 and 2 co-localize and form a stable hetero-oligomeric complex in vivo

J Biol Chem. 1997 Nov 14;272(46):29337-46. doi: 10.1074/jbc.272.46.29337.


Caveolae are microdomains of the plasma membrane that have been implicated in organizing and compartmentalizing signal transducing molecules. Caveolin, a 21-24-kDa integral membrane protein, is a principal structural component of caveolae membrane in vivo. Recently, we and other laboratories have identified a family of caveolin-related proteins; caveolin has been re-termed caveolin-1. Here, we examine the cell-type and tissue-specific expression of caveolin-2. For this purpose, we generated a novel mono-specific monoclonal antibody probe that recognizes only caveolin-2, but not caveolins-1 and -3. A survey of cell and tissue types demonstrates that the caveolin-2 protein is most abundantly expressed in endothelial cells, smooth muscle cells, skeletal myoblasts (L6, BC3H1, C2C12), fibroblasts, and 3T3-L1 cells differentiated to adipocytes. This pattern of caveolin-2 protein expression most closely resembles the cellular distribution of caveolin-1. In line with these observations, co-immunoprecipitation experiments with mono-specific antibodies directed against either caveolin-1 or caveolin-2 directly show that these molecules form a stable hetero-oligomeric complex. The in vivo relevance of this complex was further revealed by dual-labeling studies employing confocal laser scanning fluorescence microscopy. Our results indicate that caveolins 1 and 2 are strictly co-localized within the plasma membrane and other internal cellular membranes. Ultrastructurally, this pattern of caveolin-2 localization corresponds to caveolae membranes as seen by immunoelectron microscopy. Despite this strict co-localization, it appears that regulation of caveolin-2 expression occurs independently of the expression of either caveolin-1 or caveolin-3 as observed using two different model cell systems. Although caveolin-1 expression is down-regulated in response to oncogenic transformation of NIH 3T3 cells, caveolin-2 protein levels remain unchanged. Also, caveolin-2 protein levels remain unchanged during the differentiation of C2C12 cells from myoblasts to myotubes, while caveolin-3 levels are dramatically induced by this process. These results suggest that expression levels of caveolins 1, 2, and 3 can be independently up-regulated or down-regulated in response to a variety of distinct cellular cues.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3T3 Cells
  • Adipocytes / cytology
  • Adipocytes / metabolism
  • Animals
  • Biopolymers
  • Caveolin 1
  • Caveolin 2
  • Caveolins*
  • Cell Line, Transformed
  • Cell Membrane / metabolism
  • Humans
  • Intracellular Membranes / metabolism
  • Intracellular Membranes / ultrastructure
  • Membrane Proteins / biosynthesis
  • Membrane Proteins / metabolism*
  • Mice
  • Microscopy, Immunoelectron
  • Molecular Sequence Data


  • Biopolymers
  • CAV1 protein, human
  • Cav1 protein, mouse
  • Caveolin 1
  • Caveolin 2
  • Caveolins
  • Membrane Proteins

Associated data

  • GENBANK/AF035752