PYP1 AND PYP2 PTPASES DEPHOSPHORYLATE AN OSMOSENSING MAP KINASE CONTROLLING CELL-SIZE AT DIVISION IN FISSION YEAST
PYP1 AND PYP2 PTPASES DEPHOSPHORYLATE AN OSMOSENSING MAP KINASE CONTROLLING CELL-SIZE AT DIVISION IN FISSION YEAST
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DOI：
10.1101/gad.9.17.2117
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发表时间：
1995-09-01
影响因子：
10.5
通讯作者：
WILKINSON, MG
中科院分区：
文献类型：
--
作者：
MILLAR, JBA;BUCK, V;WILKINSON, MG
裂殖酵母中pyp 1和pyp 2 PTPases的同时失活导致异常的细胞形态和生长停滞。自发的隐性突变，绕过了pyp 1和pyp 2的要求，并存在于两个互补组被分离，sty 1和stg 2。sty 1（-）和sty 2（-）突变体细胞在有丝分裂起始的时间上显著延迟。我们已经分离出sty 1基因，它编码的MAP激酶，是密切相关的一个亚家族的MAP激酶调节的渗透胁迫，包括酿酒酵母HOG 1和人CSBP 1。我们发现，sty 2是等位基因的WIS 1 MAP激酶激酶和三角洲sty 1和三角洲WIS 1细胞不能在高渗透压介质中生长。渗透胁迫诱导Sty 1的酪氨酸磷酸化和分裂时细胞大小的减少。Pyp 2在体外与Sty 1结合并使其酪氨酸去磷酸化。我们发现，WIS 1依赖的诱导pyp 2 mRNA是负责酪氨酸去磷酸化的Sty 1在体内长期暴露于渗透胁迫。我们的结论是，Pyp 1和Pyp 2是酪氨酸特异性的MAB激酶磷酸酶，它能调节MAP激酶Sty 1，Sty 1作用于Wis 1 MAP激酶的下游，以控制裂殖酵母分裂时的细胞大小。
Simultaneous inactivation of pyp1 and pyp2 PTPases in fission yeast leads to aberrant cell morphology and growth arrest. Spontaneous recessive mutations that bypass the requirement for pyp1 and pyp2 and reside in two complementation groups were isolated, sty1 and stg2. sty1(-) and sty2(-) mutant cells are substantially delayed in the timing of mitotic initiation. We have isolated the sty1 gene, which encodes a MAP kinase that is closely related to a subfamily of MAP kinases regulated by osmotic stress including Saccharomyces cerevisiae HOG1 and human CSBP1. We find that sty2 is allelic to the wis1 MAP kinase kinase and that Delta sty1 and Delta wis1 cells are unable to grow in high osmolarity medium. Osmotic stress induces both tyrosine phosphorylation of Sty1 and a reduction in cell size at division. Pyp2 associates with and tyrosine dephosphorylates Sty1 in vitro. We find that wis1-dependent induction of pyp2 mRNA is responsible for tyrosine dephosphorylation of Sty1 in vivo on prolonged exposure to osmotic stress. We conclude that Pyp1 and Pyp2 are tyrosine-specific MAB kinase phosphatases that inactivate an osmoregulated MAP kinase, Sty1, which acts downstream of the Wis1 MAP kinase kinase to control cell size at division in fission yeast.