Direct activation of the fission yeast PAK Shk1 by the novel SH3 domain protein, Skb5.
Direct activation of the fission yeast PAK Shk1 by the novel SH3 domain protein, Skb5.
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新型 SH3 结构域蛋白 Skb5 直接激活裂殖酵母 PAK Shk1。
DOI：
10.1074/jbc.274.51.36052
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Marcus,S
中科院分区：
文献类型：
--
作者：
Yang,P;Pimental,R;Lai,H;Marcus,S
P21激活的蛋白激酶(PAK)同系物Shk1是裂殖酵母中细胞存活所必需的。Shk1在调节细胞形态、性分化和有丝分裂INS中的作用已经确立。庞贝。在这份报告中，我们描述了一种新的SH3结构域蛋白Skb5的遗传和分子特征，该蛋白是Shk1相互作用蛋白双杂交筛选的结果。携带kb5基因缺失的S.pombeccell在正常生长条件下没有明显的表型缺陷，但当受到高渗应激时，细胞形状变为球形，生长受阻。Shk1调节子Skb1的过表达可以抑制这两种缺陷。Shk1 INS过表达导致的生长抑制。Pombecells明显受到kb5基因零突变的抑制，提示Skb5在体内对Shk1的功能起积极作用。与这一概念一致，我们证明了Skb5刺激Shk1催化功能INS。庞贝壳。此外，也许最重要的是，我们证明了细菌表达的重组Skb5蛋白在体外直接刺激了重组Shk1激动酶的催化活性。本文描述的这些数据和其他数据表明，Skb5是裂解酵母中Shk1的直接激活剂。
The p21-activated kinase (PAK) homolog Shk1 is essential for cell viability in the fission yeastSchizosaccharomyces pombe. Roles have been established for Shk1 in the regulation of cell morphology, sexual differentiation, and mitosis inS. pombe. In this report, we describe the genetic and molecular characterization of a novel SH3 domain protein, Skb5, identified as a result of a two-hybrid screen for Shk1 interacting proteins.S. pombecells carrying a deletion of theskb5gene exhibit no discernible phenotypic defects under normal growth conditions, but when subjected to hypertonic stress, become spheroidal in shape and growth impaired. Both of these defects can be suppressed by overexpression of the Shk1 modulator, Skb1. The growth inhibition that results from overexpression of Shk1 inS. pombecells is markedly suppressed by a null mutation in theskb5gene, suggesting that Skb5 contributes positively to the function of Shk1in vivo. Consistent with this notion, we show that Skb5 stimulates Shk1 catalytic function inS. pombecells. Furthermore, and perhaps most significantly, we show that bacterially expressed recombinant Skb5 protein directly stimulates the catalytic activity of recombinant Shk1 kinasein vitro. These and additional data described herein demonstrate that Skb5 is a direct activator of Shk1 in fission yeast.