Elevated cytosolic free Ca2+ concentrations and massive Ca2+ accumulation within vacuoles, in yeast mutant lacking PMR1, a homolog of Ca2+‐ATPase

• Published in: FEBS letters 1996-08, Vol.392 (2), p.194-200
• Main Authors: Halachmi, D., Eilam, Y.
• Format: Article
• Language: English
• Subjects: 2[N-morpholino]ethanesulfonic acid; [Ca2+]i; [Ca2+]out; Ca2+-ATPase; Calcium - antagonists & inhibitors; Calcium - metabolism; Calcium-Transporting ATPases - genetics; Calcium-Transporting ATPases - metabolism; concentration of Ca2+ in the suspending solution; concentration of free cytosolic calcium; Cytosol - metabolism; Cytosolic Ca2+ homeostasis; dimethylglutaric acid; DMG; endoplasmic reticulum; Golgi; HEPES; Ion Transport; Magnesium - metabolism; MES; Mutation; N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid; PMR1 gene; Saccharomyces cerevisiae; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Vacuolar Ca2; Vacuoles - metabolism
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(96)00799-5

The Ca2+‐ATPase homolog of Saccharomyces cerevisiae, PMR1, cloned by Rudolph et al. (Cell 58 (1989) 133–145) is required for normal Golgi functions. We have investigated the role of Pmr1‐protein in maintaining homeostasis of cytosolic free Ca2+ concentration ([Ca2+]i). It was found that exposure to moderately high Ca2+ concentrations led to elevated levels of [Ca2+]i in cells of pmr1 null mutant, in comparison with cells of pmr2 isogenic mutant (defective in cell‐membrane Na+‐ATPase) and of an isogenic wild type. In addition, we showed that PMR1 deletion causes massive accumulation of Ca2+ in the vacuoles and affects the rates of Ca2+ influx and efflux.