Complementation analysis in PtdInsP kinase-deficient yeast mutants demonstrates that Schizosaccharomyces pombe and murine Fab1p homologues are phosphatidylinositol 3-phosphate 5-kinases
Complementation analysis in PtdInsP kinase-deficient yeast mutants demonstrates that Schizosaccharomyces pombe and murine Fab1p homologues are phosphatidylinositol 3-phosphate 5-kinases
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DOI：
10.1074/jbc.274.48.33905
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发表时间：
1999-11-26
影响因子：
4.8
通讯作者：
Michell, RH
中科院分区：
文献类型：
--
作者：
McEwen, RK;Dove, SK;Michell, RH
3，5-二磷酸磷脂酰肌醇（PtdIns（3，5）P-2）广泛存在于真核细胞中。在酿酒酵母中，PtdIns（3，5）P-2的合成是由PtdIns 3 P 5激酶Fab 1 p催化的，而这种活性的丧失导致液泡的形态缺陷，表明PtdIns（3，5）P-2对液泡的稳态是必不可少的。因此，我们认为所有Fab 1 p同源物都可能是参与膜运输的PtdIns 3 P Ei激酶。目前还不清楚哪些磷脂酰肌醇磷酸激酶（PIPkin）负责高等真核生物中PtdIns（3，5）P-2的合成。为了阐明PtdIns（3，5）P-2是如何在哺乳动物和其他细胞中合成的，我们确定了酵母和哺乳动物Fab 1 p同源物或哺乳动物I型PIPkins（PtdIns 4P B-激酶）是否在体内产生Ptdins（3，5）P-2。最近克隆的鼠（p235）和粟酒裂殖酵母FAB 1同源物都恢复了Delta fab 1细胞中PtdIns（3，5）P-2的基础合成，并在体外产生PtdIns（3，5）P-2。只有p235能纠正fab 1 S的生长和空泡缺陷。哺乳动物I型PIPkin不支持PtdIns（3，5）P-2合成。因此，FAB 1及其同源物构成了一类独特的III型PIPkin，专门用于PtdIns（3，5）P-2合成。p235和SpFab 1 p补充Delta fab 1细胞表型缺陷的能力不同，表明与其他蛋白因子的相互作用可能对PtdIns（3，5）P-2合成的空间和/或时间调节很重要。这些结果还表明，p235可能调节哺乳动物细胞膜运输的一个步骤，类似于其在酵母中的功能。
Phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P-2) is widespread in eukaryotic cells. In Saccharomyces cerevisiae, PtdIns(3,5)P-2 synthesis is catalyzed by the PtdIns3P 5 kinase Fab1p, and loss of this activity results in vacuolar morphological defects, indicating that PtdIns(3,5)P-2 is essential for vacuole homeostasis, We have therefore suggested that all Fab1p homologues may be PtdIns3P Ei-kinases involved in membrane trafficking. It is unclear which phosphatidylinositol phosphate kinases (PIPkins) are responsible for PtdIns(3,5)P-2 synthesis in higher eukaryotes. To clarify how PtdIns(3,5)P-2 is synthesized in mammalian and other cells, we determined whether yeast and mammalian Fab1p homologues or mammalian Type I PIPkins (PtdIns4P B-kinases) make Ptdins(3,5)P-2 in vivo. The recently cloned murine (p235) and Schizosaccharomyces pombe FAB1 homologues both restored basal PtdIns(3,5)P-2 synthesis in Delta fab1 cells and made PtdIns(3,5)P-2 in vitro. Only p235 corrected the grow-th and vacuolar defects of fab1 S. cerevisiae, A mammalian Type I PIPkin supported no PtdIns(3,5)P-2 synthesis. Thus, FAB1 and its homologues constitute a distinct class of Type III PIPkins dedicated to PtdIns(S,5)P-2 synthesis, The differential abilities of p235 and of SpFab1p to complement the phenotypic defects of Delta fab1 cells suggests that interaction(s) with other protein factors may be important for spatial and/or temporal regulation of PtdIns(3,5)P-2 synthesis. These results also suggest that p235 may regulate a step in membrane trafficking in mammalian cells that is analogous to its function in yeast.