CA2+ REGULATION OF PHOSPHATIDYLINOSITOL TURNOVER IN THE PLASMA-MEMBRANE OF TOBACCO SUSPENSION-CULTURE CELLS
CA2+ REGULATION OF PHOSPHATIDYLINOSITOL TURNOVER IN THE PLASMA-MEMBRANE OF TOBACCO SUSPENSION-CULTURE CELLS
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DOI：
10.1016/0167-4889(91)90140-s
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发表时间：
1991-06-07
期刊：
影响因子：
--
通讯作者：
MUTO, S
中科院分区：
文献类型：
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作者：
KAMADA, Y;MUTO, S
采用双水相分离法分离烟草悬浮培养细胞质膜，研究了植物磷脂酰肌醇（PI）周转相关酶的生化特性。 亚微摩尔浓度的Ca ~（2+）抑制PI激酶和4-磷酸磷脂酰肌醇（PIP）激酶，刺激磷脂酶C。 甘油二酯（DG）激酶被Ca ~（2+）抑制，但需要高于生理水平的浓度。 根据上述结果，我们假设以下方案：磷脂酶C的信号耦合激活产生IP 3，IP 3诱导细胞内Ca 2+室中的Ca 2+释放，增加的细胞质Ca 2+反过来激活磷脂酶C，并导致细胞质Ca 2+水平进一步增加。 这抑制PI激酶和PIP激酶，并导致磷脂酶C的底物PIP 2的有限供应。 因此，IP 3产生减少，Ca 2+动员停止。 然后通过质膜和内质网上的Ca 2+泵以及质膜和液泡膜上的Ca 2 +/H+反向转运蛋白使胞质Ca 2+恢复到稳定水平。
The biochemical properties of the enzymes involved in phosphatidylinositol (PI) turnover in higher plants were investigated using the plasma membrane isolated from tobacco suspension culture cells by aqueous two-phase partitioning. Submicromolar concentrations of Ca2+ inhibited PI kinase and phosphatidylinositol 4-phosphate (PIP) kinase and stimulated phospholipase C. Diacylglycerol (DG) kinase was inhibited by Ca2+, but required a higher concentration than the physiological level. From the above results we postulate the following scheme: signal coupled activation of phospholipase C produces IP3 which induces Ca2+ release from the intracellular Ca2+ compartment, the increased cytoplasmic Ca2+ in turn activates phospholipase C and causes a further increase of the cytoplasmic Ca2+ level. This inhibits PI kinase and PIP kinase and brings about a limited supply of PIP2, the substrate of phospholipase C. Consequently, IP3 production decreases and Ca2+ mobilization ceases. Then cytosolic Ca2+ returns to the stationary level by the Ca2+ pump at the plasma membrane and at the endoplasmic reticulum and Ca2+/H+ antiporter at the plasma membrane and at the tonoplast.