Immunopurification and Characterization of Rat Adipocyte Caveolae Suggest Their Dissociation from Insulin Signaling

Adipocytes play an important role in the insulin-dependent regulation of organismal fuel metabolism and express caveolae at levels as high or higher than any other cell type. Recently, a link between insulin signaling and caveolae has been suggested; nevertheless, adipocyte caveolae have been the su...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 2003-05, Vol.278 (20), p.18321-18329
Main Authors: Souto, Ricardo P, Vallega, Gino, Wharton, Jonathan, Vinten, Jorgen, Tranum-Jensen, Jorgen, Pilch, Paul F
Format: Article
Language:English
Subjects:
Adipocytes - cytology
Adipocytes - metabolism
Animals
Antibodies, Monoclonal - metabolism
Biotinylation
Blotting, Western
Caveolae - metabolism
Caveolin 1
Caveolins - metabolism
CD36 Antigens - metabolism
Cell Membrane - metabolism
Electrophoresis, Polyacrylamide Gel
Immunohistochemistry
Insulin - metabolism
Membrane Microdomains - metabolism
Membrane Proteins - metabolism
Microscopy, Fluorescence
Models, Biological
Precipitin Tests
Rats
Receptor, Insulin - metabolism
Signal Transduction
Subcellular Fractions
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Adipocytes play an important role in the insulin-dependent regulation of organismal fuel metabolism and express caveolae at levels as high or higher than any other cell type. Recently, a link between insulin signaling and caveolae has been suggested; nevertheless, adipocyte caveolae have been the subject of relatively few studies, and their contents have been minimally characterized. With the aid of a new monoclonal antibody, we developed a rapid procedure for the immunoisolation of caveolae derived from the plasma membrane of adipocytes, and we characterized their protein content. We find that immunopurified adipocyte caveolae have a relatively limited protein composition, and they lack the raft protein, flotillin, and insulin receptors. Immunogold labeling and electron microscopy of the adipocyte plasma membrane confirmed the lack of insulin receptors in caveolae. In addition to caveolins, the structural components of caveolae, their major protein constituents, are the semicarbazide-sensitive amine oxidase and the scavenger lipoprotein receptor CD36. The results are consistent with a role for caveolae in lipid flux in and of adipocytes.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M211541200