Caveolin-1 and caveolin-3 regulate Ca2+ homeostasis of single smooth muscle cells from rat cerebral resistance arteries.
The role of caveolins, signature proteins of caveolae, in arterial Ca(2+) regulation is unknown. We investigated modulation of Ca(2+) homeostasis by caveolin-1 and caveolin-3 using smooth muscle cells from rat cerebral resistance arteries. Membrane current and Ca(2+) transients were simultaneously measured with voltage-clamped single cells. Membrane depolarization triggered Ca(2+) current and increased intracellular Ca(2+) concentration ([Ca(2+)](i)). After repolarization, elevated [Ca(2+)](i) returned to the resting level. Ca(2+) removal rate was determined from the declining phase of the Ca(2+) transient. Application of caveolin-1 antibody or caveolin-1 scaffolding domain peptide, corresponding to amino acid residues 82-101 of caveolin-1, significantly slowed Ca(2+) removal rate at a measured [Ca(2+)](i) of 250 nM, with little effect at a measured [Ca(2+)](i) of 600 nM. Application of caveolin-3 antibody or caveolin-3 scaffolding domain peptide, corresponding to amino acid residues 55-74 of caveolin-3, also significantly slowed Ca(2+) removal rate at a measured [Ca(2+)](i) of 250 nM, with little effect at a measured [Ca(2+)](i) of 600 nM. Likewise, application of calmodulin inhibitory peptide, autocamtide-2-related inhibitory peptide, and cyclosporine A, inhibitors for calmodulin, Ca(2+)/calmodulin-dependent protein kinase II, and calcineurin, also significantly inhibited Ca(2+) removal rate at a measured [Ca(2+)](i) of 250 nM but not at 600 nM. Application of cyclopiazonic acid, a sarcoplasmic reticulum Ca(2+) ATPase inhibitor, also significantly inhibited Ca(2+) removal rate at a measured [Ca(2+)](i) of 250 nM but not at 600 nM. Our results suggest that caveolin-1 and caveolin-3 are important in Ca(2+) removal of resistance artery smooth muscle cells.
Kamishima
T
T
Department of Human Anatomy and Cell Biology, School of Biomedical Sciences, University of Liverpool, Ashton Street, Liverpool, UK.
Burdyga
T
T
Gallagher
J A
JA
Quayle
J M
JM
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D051242:Caveolin 1 / Q000378:metabolism*; D051243:Caveolin 2 / Q000378:metabolism*; D002478:Cells, Cultured; D002536:Cerebral Arteries / Q000378:metabolism*; D006706:Homeostasis / Q000502:physiology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014655:Vascular Resistance / Q000502:physiology
D051242:Caveolin 1; D051243:Caveolin 2; D002118:Calcium