Two adjacent docking sites in the yeast Hog1 mitogen-activated protein (MAP) kinase differentially interact with the Pbs2 MAP kinase kinase and the Ptp2 protein tyrosine phosphatase
Two adjacent docking sites in the yeast Hog1 mitogen-activated protein (MAP) kinase differentially interact with the Pbs2 MAP kinase kinase and the Ptp2 protein tyrosine phosphatase
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DOI：
10.1128/mcb.01817-07
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发表时间：
2008-04-01
影响因子：
5.3
通讯作者：
Saito, Haruo
中科院分区：
文献类型：
--
作者：
Murakami, Yulia;Tatebayashi, Kazuo;Saito, Haruo
丝裂原活化蛋白激酶（MAPK）及其调节因子之间的功能相互作用需要特定的对接相互作用。在这里，我们调查的机制，酵母菌的调节Hog 1 MAPK特异性相互作用，其激活剂，MAPK激酶Pbs 2，其主要灭活剂，蛋白磷酸酶Ptp 2。我们发现，在N-末端非催化区域的Pbs 2，一个特定的Hog 1结合域，称为HBD-1。我们还定义了Hog 1中两个相邻的Pbs 2结合位点，即共同对接（CD）结构域和Pbs 2结合结构域2（PBD-2）。PBD-2对接位点似乎在完整的Hog 1分子中被空间阻断，但其对Pbs 2的亲和力在Hog 1的较短片段中是明显的。CD和PBD-2对接位点都是Pbs 2最佳激活Hog 1所必需的，在这两个位点都不存在的情况下，Hog 1不能被Pbs 2激活。这些数据表明，最初的相互作用的Pbs 2与CD网站可能会引起构象变化的Hog 1，使PBD-2网站变得可访问。CD和PBD-2对接位点也参与Hog 1和Ptp 2之间的特异性相互作用，并控制活化的Hog 1的动态去磷酸化。因此，CD和PBD-2对接位点在Hog 1的激活和失活中起着关键作用。
Functional interactions between a mitogen-activated protein kinase (MAPK) and its regulators require specific docking interactions. Here, we investigated the mechanism by which the yeast osmoregulatory Hog1 MAPK specifically interacts with its activator, the MAPK kinase Pbs2, and its major inactivator, the protein phosphatase Ptp2. We found, in the N-terminal noncatalytic region of Pbs2, a specific Hog1-binding domain, termed HBD-1. We also defined two adjacent Pbs2-binding sites in Hog1, namely, the common docking (CD) domain and Pbs2-binding domain 2 (PBD-2). The PBD-2 docking site appears to be sterically blocked in the intact Hog1 molecule, but its affinity to Pbs2 is apparent in shorter fragments of Hog1. Both the CD and the PBD-2 docking sites are required for the optimal activation of Hog1 by Pbs2, and in the absence of both sites, Hog1 cannot be activated by Pbs2. These data suggest that the initial interaction of Pbs2 with the CD site might induce a conformational change in Hog1 so that the PBD-2 site becomes accessible. The CD and PBD-2 docking sites are also involved in the specific interaction between Hog1 and Ptp2 and govern the dynamic dephosphorylation of activated Hog1. Thus, the CD and the PBD-2 docking sites play critical roles in both the activation and inactivation of Hog1.