Inhibition of volume-regulated anion channels by dominant-negative caveolin-1.
Caveolae are flask-shaped invaginations of the plasma membrane formed by the association of caveolin proteins with lipid rafts. In endothelial cells, caveolae function as signal transduction centers controlling NO synthesis and mechanotransduction. We now provide evidence that the endothelial volume-regulated anion channel (VRAC) is also under the control of the caveolar system. When calf pulmonary artery endothelial (CPAE) cells were transfected with caveolin-1 Delta1-81 (deletion of amino acids 1 to 81), activation of VRAC by hypotonic cell swelling was strongly impaired. Concomitantly, caveolin-1 Delta1-81 disturbed the formation of caveolin-1 containing lipid rafts as evidenced by sucrose density gradient centrifugation. In nontransfected cells, endogenous caveolin-1 typically associated with low-density, detergent-resistant lipid rafts. However, transient expression of caveolin-1 Delta1-81 caused a redistribution of endogenous caveolin-1 to high-density, detergent-soluble membrane fractions. We therefore conclude that the interaction between caveolin-1 and detergent-resistant lipid rafts is an important prerequisite for endothelial VRAC activity.
Trouet
D
D
Laboratory of Physiology, Catholic University of Leuven, Campus Gasthuisberg, Leuven, B-3000, Belgium.
Hermans
D
D
Droogmans
G
G
Nilius
B
B
Eggermont
J
J
D000818:Animals; D000838:Anions / Q000378:metabolism*; D018938:Caco-2 Cells; D002417:Cattle; D021941:Caveolae / Q000378:metabolism*; D051242:Caveolin 1; D022461:Caveolins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D002460:Cell Line; D003902:Detergents / Q000737:chemistry; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression; D005799:Genes, Dominant; D006801:Humans; D007038:Hypotonic Solutions / Q000494:pharmacology; D007473:Ion Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D021962:Membrane Microdomains / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D011651:Pulmonary Artery; D051381:Rats; D017384:Sequence Deletion; D013347:Subcellular Fractions / Q000737:chemistry / Q000378:metabolism; D014162:Transfection
D000838:Anions; C495540:CAV1 protein, human; C495537:Cav1 protein, rat; D051242:Caveolin 1; D022461:Caveolins; D003902:Detergents; D007038:Hypotonic Solutions; D007473:Ion Channels