The dihydrosphingosine-1-phosphate phosphatases of Saccharomyces cerevisiae are important regulators of cell proliferation and heat stress responses
The dihydrosphingosine-1-phosphate phosphatases of Saccharomyces cerevisiae are important regulators of cell proliferation and heat stress responses
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DOI：
10.1042/0264-6021:3420667
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发表时间：
1999-09-15
影响因子：
4.1
通讯作者：
Obeid, LM
中科院分区：
文献类型：
--
作者：
Mao, CG;Saba, JD;Obeid, LM
我们已经鉴定了酿酒酵母的YSR 2和YSR 3作为编码二氢鞘氨醇-1-磷酸磷酸酶的基因，所述二氢鞘氨醇-1-磷酸磷酸酶参与调节鞘脂代谢[Mao，Wadleigh，Jenkins，Hannun和Obeid（1997）J. Biol，Chem.272，28690-28694]。在这项研究中，我们探讨了这些酶可能在S。YSR 2、YSR 3或两者的缺失不影响酵母细胞的活力或生长速率。然而，过表达YSR 2显著延长细胞生长的倍增时间，而过表达YSR 3仅轻微影响细胞生长。细胞周期分析表明，无论是YSR 2还是YSR 3的过表达，都导致细胞周期停滞在G1期，YSR 2的破坏，而不是YSR 3，赋予了耐热性增加，另一方面，YSR 2或YSR 3的过表达降低了耐热性。使用标记的二氢鞘氨醇和二氢鞘氨醇-1-P（DHS-1-P），我们发现YSR 2的过表达显著增加神经酰胺形成，而YSR 2、YSR 3或两者的缺失积累DHS-1-P，并且YSR 2的缺失减少神经酰胺形成。总之，这些结果表明YSR 2的表型与不同鞘脂的内源性水平的变化相关。绿色荧光蛋白标记显示，在指数生长的细胞中，YSR 2和YSR 3具有相同的细胞定位于内质网。然而，YSR 2和YSR 3在mRNA水平上存在差异：YSR 2的mRNA水平显著高于YSR 3，这种差异可能导致这两种蛋白质表现出的功能差异。此外，这项研究还涉及鞘脂及其代谢在酵母的生长和热应激反应的调节。
We have identified YSR2 and YSR3 of Saccharomyces cerevisiae as genes encoding dihydrosphingosine-1-phosphate phophatases which are involved in regulation of sphingolipid metabolism [Mao, Wadleigh, Jenkins, Hannun and Obeid (1997) J. Biol, Chem. 272, 28690-28694]. In this study, we explored the physiological roles that these enzymes may have in S. cerevisiae, Deletion of either YSR2, YSR3 or both did not affect viability or growth rate of yeast cells. However, overexpression of YSR2 significantly prolonged the doubling time of cell growth, whereas overexpression of YSR3 affected cell growth only slightly. Cell cycle analysis suggested that overexpression of either YSR2 or, to a lesser extent, YSR3 caused cell cycle arrest at the G1 phase, Disruption of YSR2, but not YSR3, conferred increased thermotolerance, On the other hand, overexpression of either YSR2 or YSR3 diminished thermotolerance. Using labelled dihydro-sphingosine and dihydrosphingosine-1-P (DHS-1-P), we found that overexpression of YSR2 significantly increased ceramide formation, whereas deletion of YSR2, YSR3, or both, accumulated DHS-1-P, and deletion of YSR2 decreased ceramide formation. Together, these results show that the phenotypes of YSR2 are associated with changes in endogenous levels of the different sphingolipids. Green fluorescent protein tagging showed that in the exponentially growing cells, YSR2 and YSR3 had the same cellular localization to endoplasmic reticulum. However, YSR2 and YSR3 differ in mRNA levels: YSR2 had significantly higher mRNA levels than YSR3, This discrepancy might result in the functional differences that these proteins exhibited. In addition, this study implicates sphingolipids and their metabolism in the regulation of growth and heat stress responses of the yeast S, cerevisiae.