The Ste20-like protein kinase, Mst1, dimerizes and contains an inhibitory domain
The Ste20-like protein kinase, Mst1, dimerizes and contains an inhibitory domain
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DOI：
10.1074/jbc.271.35.21049
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发表时间：
1996-08-30
影响因子：
4.8
通讯作者：
Chernoff, J
中科院分区：
文献类型：
--
作者：
Creasy, CL;Ambrose, DM;Chernoff, J
人丝氨酸/苏氨酸蛋白激酶Mst1和Mst2在其催化结构域上与Ste20和p21活化激酶（Pak）具有相当大的同源性。然而，在催化结构域之外，与先前描述的ste20样激酶或其他蛋白质没有明显的同源性。为了了解非同源区域的作用，我们对Mst1进行了结构/功能分析。一系列cooh末端和内部缺失表明，在分子的中心63个氨基酸区域存在抑制激酶活性的元件。去除该结构域可使激酶活性增加约9倍。共免疫沉淀法、酵母双杂交法和体外交联分析表明，Mst1同源二聚体，并且自结合需要极端cooh末端57个氨基酸。大小排斥层析表明Mst1与细胞中的高分子量复合物相关，这表明其他蛋白也可能与该激酶寡聚。虽然失去二聚化本身并不影响激酶活性，但缺乏二聚化和抑制结构域的分子不如只缺乏抑制结构域的分子活跃。Mst1和Mst2的比较表明，这两个功能域都位于两个分子之间的保守区域。
The human serine/threonine protein kinases, Mst1 and Mst2, share considerable homology to Ste20 and p21-activated kinase (Pak) throughout their catalytic domains. However, outside the catalytic domains there are no significant homologies to previously described Ste20-like kinases or other proteins. To understand the role of the nonhomologous regions, we performed a structure/function analysis of Mst1. A series of COOH-terminal and internal deletions indicates that there is an element within a central 63-amino acid region of the molecule that inhibits kinase activity. Removal of this domain increases kinase activity approximately 9-fold. Coimmunoprecipitation assays, the yeast two-hybrid procedure, and in vitro cross-linking analysis indicate that Mst1 homodimerizes and that the extreme COOH-terminal 57 amino acids are required for self-association. Size exclusion chromatography indicates that Mst1 is associated with a high molecular weight complex in cells, suggesting that other proteins may also oligomerize with this kinase. While loss of dimerization alone does not affect kinase activity, a molecule lacking both the dimerization and inhibitory domains is not as active as one which lacks only the inhibitory domain. Comparison of Mst1 and Mst2 indicates that both functional domains lie in regions conserved between the two molecules.