Oligomeric structure of caveolin: implications for caveolae membrane organization.
A 22-kDa protein, caveolin, is localized to the cytoplasmic surface of plasma membrane specializations called caveolae. We have proposed that caveolin may function as a scaffolding protein to organize and concentrate signaling molecules within caveolae. Here, we show that caveolin interacts with itself to form homooligomers. Electron microscopic visualization of these purified caveolin homooligomers demonstrates that they appear as individual spherical particles. By using recombinant expression of caveolin as a glutathione S-transferase fusion protein, we have defined a region of caveolin's cytoplasmic N-terminal domain that mediates these caveolin-caveolin interactions. We suggest that caveolin homooligomers may function to concentrate caveolin-interacting molecules within caveolae. In this regard, it may be useful to think of caveolin homooligomers as "fishing lures" with multiple "hooks" or attachment sites for caveolin-interacting molecules.
Sargiacomo
M
M
Whitehead Institute for Biomedical Research, Cambridge, MA 02142-1479, USA.
Scherer
P E
PE
Tang
Z
Z
Kübler
E
E
Song
K S
KS
Sanders
M C
MC
Lisanti
M P
MP
D000818:Animals; D001710:Biotin; D051242:Caveolin 1; D022461:Caveolins; D002460:Cell Line; D002462:Cell Membrane / Q000648:ultrastructure; D002499:Centrifugation, Density Gradient; D002850:Chromatography, Gel; D003432:Cross-Linking Reagents; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D007668:Kidney; D008024:Ligands; D008168:Lung / Q000648:ultrastructure; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D008970:Molecular Weight; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000648:ultrastructure; D013388:Succinimides
D051242:Caveolin 1; D022461:Caveolins; D003432:Cross-Linking Reagents; D008024:Ligands; D046911:Macromolecular Substances; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D013388:Succinimides; D001710:Biotin; C035760:bis(sulfosuccinimidyl)suberate