@article{mbs:/content/journal/micro/10.1099/00221287-131-3-623, author = "Eilam, Y. and Lavi, *H. and Grossowicz, N.", title = "Cytoplasmic Ca2+Homeostasis Maintained by a Vacuolar Ca2+Transport System in the Yeast Saccharomyces cerevisiae", journal= "Microbiology", year = "1985", volume = "131", number = "3", pages = "623-629", doi = "https://doi.org/10.1099/00221287-131-3-623", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-131-3-623", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "Differential extraction of Ca2+ from the cytoplasmic and vacuolar pools of the yeast Saccharomyces cerevisiae, using DEAE-dextran, revealed that most of the cellular Ca2+ was bound, precipitated or sequestered within the vacuole. When the concentration of Ca2+ in the medium was raised from 10–6 m to 10–3 m, cytoplasmic Ca2+ homeostasis was maintained at 5·8 × 10–6 to 2·3 × 10–5 m, whereas the vacuoles accumulated higher concentrations of Ca2+. The results indicate that the vacuoles function as a cytoplasmic Ca2+ buffering system and as the major sequestering organelle for Ca2+. A respiratory-deficient mutant (ρ°) displayed a similar intracellular distribution of Ca2+ to the wild-type. When cells were permeabilized by DEAE-dextran the vacuoles were still capable of Ca2+ uptake. This uptake proceeded without the addition of ATP or glucose in fresh preparations but required the addition of ATP after incubation of the permeabilized cells in buffered sorbitol for 2 h. The results are consistent with the proposed Ca2+/H+ antiport in the vacuolar membrane, which is driven by Δ μ ¯ H + formed by the H+-ATPase pumping H+ into the vacuole.", }