An intracellular ATP-dependent calcium pump within the yeast Schizosaccharomyces pombe, encoded by the gene cta3.
We have permeabilized the plasma membranes of Schizosaccharomyces pombe cell with nystatin and measured ATP-dependent Ca2+ uptake in the presence of KNO3 and a protonophore in order to inhibit Ca2+ uptake into the vacuole. ATP-dependent Ca2+ accumulation into non-vacuolar Ca(2+)-storing organelles was detected. This Ca2+ uptake activity was maximal at pH 6 and inhibited by vanadate, the inhibitor of P-type ATPases. The null mutation of cta3, a putative Ca2+ gene, [Ghislain, M., Goffeau, A., Halachmi, D. and Eilam, Y. (1990) J. Biol. Chem. 265, 18400-18407] strongly reduced the level of ATP-dependent Ca2+ uptake into non-vacuolar intracellular storing organelles. This result suggests that cta3 encodes an intracellular ATP-dependent Ca2+ pump. The residual ATP-dependent Ca2+ uptake in the mutant strain indicated the presence of a second nonvacuolar, intracellular Ca(2+)-ATPase encoded by a different gene.
Halachmi
D
D
Department of Bacteriology, Hebrew University, Hadassah Medical School, Jerusalem, Israel.
Ghislain
M
M
Eilam
Y
Y
D000255:Adenosine Triphosphate / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000235:genetics*; D002413:Cations, Divalent / Q000378:metabolism; D005434:Flow Cytometry; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D012568:Schizosaccharomyces / Q000254:growth & development / Q000378:metabolism*; D014638:Vanadates / Q000494:pharmacology
D002413:Cations, Divalent; D014638:Vanadates; D000255:Adenosine Triphosphate; D000252:Calcium-Transporting ATPases; D002118:Calcium