Calcium-induced calcium release mediated by a voltage-activated cation channel in vacuolar vesicles from red beet.
Little is known about the mechanisms underlying calcium-induced Ca2+ release (CICR) in plants. The slow-activating vacuolar (SV) channel is both permeable to, and activated by Ca2+, and is therefore a prime candidate for a role in CICR. Cytosol-side-out vacuolar membrane vesicles loaded with 45Ca2+ showed voltage- and Ca(2+)-dependent Ca2+ release, which was sensitive to the SV channel modulators DIDS, protein phosphatase 2B and calmodulin. Significantly, voltage-dependent Ca2+ release strongly depended on cytoplasmic Ca2+ concentrations. The results support the notion that CICR occurs in plant cells and that the process can be catalysed by the SV channel on the vacuolar membrane.
Bewell
M A
MA
Department of Biology, University of York, UK.
Maathuis
F J
FJ
Allen
G J
GJ
Sanders
D
D
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D019703:Calcineurin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology*; D020013:Calcium Signaling / Q000187:drug effects; D002147:Calmodulin / Q000494:pharmacology; D019663:Chenopodiaceae / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D007425:Intracellular Membranes / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D010766:Phosphorylation; D011188:Potassium / Q000494:pharmacology; D013997:Time Factors; D014617:Vacuoles / Q000378:metabolism*
D015220:Calcium Channels; D002147:Calmodulin; D019703:Calcineurin; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D011188:Potassium; D002118:Calcium