Caveolae: biochemical analysis.
Caveolae appear in a multitude of processes encompassing growth regulation and trafficking. We demonstrate the abundant presence of ESA/reggie-1/flotillin-2, ATP synthase beta subunit and annexin V in endothelial caveolae by immunopurification of caveolae from vascular endothelial membrane. Five proteins are abundant in a caveolin-1 protein complex, analyzed by sucrose gradient velocity sedimentation following octyl-beta-D-glucopyranoside extraction. Caveolin-1 alpha interacts with caveolin-1beta, caveolin-2, actin, the microsomal form of NADH cytochrome B5 reductase and ESA/reggie-1/flotillin-2 as shown by co-immunoprecipitation. We propose the concept that ATP biosynthesis in caveolae regulates mechanosignaling and is induced by membrane depolarization and a proton gradient. Pressure stimuli and metabolic changes may trigger gene regulation in endothelial cells, involving a nuclear conformer of caveolin-1, shown here with an epitope-specific caveolin-1 antibody, and immediate response of ion channel activity, regulated by ESA/reggie-1/flotillin-2.
Division of Biochemistry, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
Christian
C
Chatenay-Rivauday
Z Petek
ZP
Cakar
Paul
P
Jenö
Elena S
ES
Kuzmenko
Klaus
K
Fiedler
D000818:Animals; D017304:Annexin A5 / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D021941:Caveolae / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D051242:Caveolin 1; D051243:Caveolin 2; D022461:Caveolins / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D002460:Cell Line; D042966:Cytochrome-B(5) Reductase / Q000276:immunology / Q000378:metabolism; D042783:Endothelial Cells / Q000276:immunology / Q000378:metabolism; D047468:Immunoprecipitation; D008168:Lung / Q000166:cytology / Q000276:immunology; D008565:Membrane Proteins / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D051381:Rats
D017304:Annexin A5; C495541:Cav1 protein, mouse; C495537:Cav1 protein, rat; D051242:Caveolin 1; D051243:Caveolin 2; D022461:Caveolins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C106354:flotillins; D042966:Cytochrome-B(5) Reductase; D006180:Proton-Translocating ATPases