Characterization of Ca(2+)/H(+) exchange in the plasma membrane of Saccharomyces cerevisiae.
Arch Biochem Biophys
; 537(1): 125-32, 2013 Sep 01.
Article
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| MEDLINE
| ID: mdl-23871844
ABSTRACT
The characteristics of the Ca(2+)/H(+) exchange were directly investigated in functionally inverted (inside-out) plasma membrane vesicles isolated from yeast using an aqueous two-phase partitioning method. Results showed that following the generation of an inside-acid pH gradient (fluorescence quenching), addition of Ca(2+) caused movement of H(+) out of the vesicles (fluorescence recovery). The Ca(2+)/H(+) exchange displayed saturation kinetics with respect to extravesicular Ca(2+) and ATP concentrations in the plasma membrane, and showed specificity for Ca(2+). The protonophore FCCP (carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone), abolished the fluorescence quenching and consequently inhibited Ca(2+)/H(+) exchange in plasma membrane vesicles. Vanadate, which is known to inhibit the plasma membrane H(+)-ATPase, significantly decreased the Ca(2+)-dependent transport of H(+) out of vesicles. When the electrical potential across the plasma membrane was dissipated with valinomycin and potassium, the rate of Ca(2+)/H(+) exchange increased compared to that of the control without valinomycin, indicating that the stoichiometric ratio for this exchange is greater than 2H(+)Ca(2+). These data suggest that Ca(2+) is transported out of yeast cells through a Ca(2+)/H(+) exchange system that is driven by the proton-motive force generated by the plasma membrane H(+)-ATPase.
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Bases de datos:
MEDLINE
Asunto principal:
Saccharomyces cerevisiae
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Activación del Canal Iónico
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Membrana Celular
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Adenosina Trifosfato
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Calcio
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Antiportadores
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Proteínas de Transporte de Catión
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Hidrógeno
Idioma:
En
Revista:
Arch Biochem Biophys
Año:
2013
Tipo del documento:
Article
País de afiliación:
China