CALCIUM HOMEOSTASIS IN YEAST-CELLS EXPOSED TO HIGH-CONCENTRATIONS OF CALCIUM - ROLES OF VACUOLAR H+-ATPASE AND CELLULAR ATP
CALCIUM HOMEOSTASIS IN YEAST-CELLS EXPOSED TO HIGH-CONCENTRATIONS OF CALCIUM - ROLES OF VACUOLAR H+-ATPASE AND CELLULAR ATP
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DOI：
10.1016/0014-5793(93)81739-m
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发表时间：
1993-01-18
期刊：
影响因子：
3.5
通讯作者：
EILAM, Y
中科院分区：
文献类型：
--
作者：
HALACHMI, D;EILAM, Y
在酿酒酵母的单倍体和二倍体细胞中测定细胞溶质Ca 2+浓度（[Ca 2 +]i），用indo-1加载并暴露于含有一系列Ca 2+浓度的培养基。[Ca2在用葡萄糖预孵育并暴露于培养基中的0.1 μ M-10 mMCa 2+的细胞中，[Ca 2 +]i稳态维持在100-150 nM水平。在暴露于50 mM Ca ~（2+）的细胞中测定了略高水平的[Ca ~（2+）]i。用代谢抑制剂而不是葡萄糖预孵育导致细胞ATP水平降低和[Ca 2 +]i稳态受损;暴露于10 mM CaCl 2的细胞中[Ca 2 +]i达到800 nM。没有功能性液泡H+-ATP酶的DELTAvma 4突变株的细胞具有升高的[Ca 2 +]i水平，当与葡萄糖预孵育并暴露于10 mM CaCl 2时达到1.8 μ M。在与代谢抑制剂预孵育的突变体细胞中测量到更高水平的[Ca 2 +]i。这一结果表明液泡在维持[Ca 2 +] i-稳态中的中心作用，并表明存在一种额外的非液泡ATP需要机制，该机制有助于保持[Ca 2 +]i在低水平。
Cytosolic Ca2+ concentrations ([Ca2+]i) were determined in haploid and diploid cells of Saccharomyces cerevisiae, loaded with indo-1 and exposed to media containing a range of Ca2+ concentrations. [Ca2+]i homeostasis was maintained at the 100-150 nM level in cells which were pre-incubated with glucose and exposed to 0.1 muM-10 mM Ca2+ in the medium. Slightly higher levels of [Ca2+]i Were determined in cells exposed to 50 mM Ca2+. Pre-incubation with metabolic inhibitors instead of glucose caused a reduction in cellular ATP levels and an impaired [Ca2+]i homeostasis; [Ca2+]i reached 800 nM in cells exposed to 10 mM CaCl2. Cells of the DELTAvma4 mutant strain, with no functional vacuolar H+-ATPase, had elevated levels of [Ca2+]i, reaching 1.8 muM when pre-incubated with glucose and exposed to 10 mM CaCl2. Higher levels of [Ca2+]i were measured in the mutant cells which were pre-incubated with metabolic inhibitors. This result indicates the central role of the vacuoles in maintaining [Ca2+]i-homeostasis and suggests the presence of an additional non-vacuolar ATP-requiring mechanism which contributes to keeping [Ca2+]i at low levels.