MSS4, a phosphatidylinositol-4-phosphate 5-kinase required for organization of the actin cytoskeleton in Saccharomyces cerevisiae
MSS4, a phosphatidylinositol-4-phosphate 5-kinase required for organization of the actin cytoskeleton in Saccharomyces cerevisiae
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DOI：
10.1074/jbc.273.25.15787
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发表时间：
1998-06-19
影响因子：
4.8
通讯作者：
Hall, MN
中科院分区：
文献类型：
--
作者：
Desrivières, S;Cooke, FT;Hall, MN
酿酒酵母蛋白MSS 4是哺乳动物磷脂酰肌醇-4-磷酸（PI（4）P）5-激酶的必需和同源蛋白。在这里，我们证明了MSS 4是一种脂质激酶。MSS 4在体外具有双重底物特异性，将PI（4）P转化为PI（4，5）P-2，并在较小程度上将PI（S）P转化为PI（3，4）P-2;用PI或PI（S）P作为底物时未检测到活性。过表达MSS 4的细胞含有升高水平的PI（4，5）P，而MSS 4突变细胞仅含有正常量的约10%的这种磷酸化磷酸肌醇。此外，缺乏MSS 4的细胞不能形成肌动蛋白电缆，并在极化细胞生长过程中正确定位其肌动蛋白细胞骨架。RHO 2的过表达，编码参与调节肌动蛋白细胞骨架的Rho型GTdR，在mss 4突变体中恢复肌动蛋白的生长和极化分布。这些结果表明，MSS 4是酵母中主要的PI（4）P B-激酶，并提供了体内磷酸肌醇代谢和肌动蛋白细胞骨架组织之间的联系。
The Saccharomyces cerevisiae protein MSS4 is essential and homologous to mammalian phosphatidylinositol-4-phosphate (PI(4)P) 5-kinases. Here, we demonstrate that MSS4 is a lipid kinase. MSS4 has dual substrate specificity in vitro, converting PI(4)P to PI(4,5)P-2 and to a lesser extent PI(S)P to PI(3, 4)P-2; no activity was detected with PI or PI(S)P as a substrate. Cells overexpressing MSS4 contain an elevated level specifically of PI(4,5)P,, whereas mss4 mutant cells have only approximately 10% of the normal amount of this phosphorylated phosphoinositide. Furthermore, cells lacking MSS4 are unable to form actin cables and to properly localize their actin cytoskeleton during polarized cell growth. Overexpression of RHO2, encoding a Rho-type GTPase involved in regulation of the actin cytoskeleton, restores growth and polarized distribution of actin in an mss4 mutant. These results suggest that MSS4 is the major PI(4)P B-kinase in yeast and provide a link between phosphoinositide metabolism and organization of the actin cytoskeleton in vivo.