Docking interactions of the JNK scaffold protein WDR62.
Docking interactions of the JNK scaffold protein WDR62.
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DOI：
10.1042/bj20110284
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发表时间：
2011-11-01
期刊：
影响因子：
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通讯作者：
Aronheim A
中科院分区：
文献类型：
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作者：
Cohen-Katsenelson K;Wasserman T;Khateb S;Whitmarsh AJ;Aronheim A
JNK（c-Jun N-末端激酶）是MAPK（丝裂原活化蛋白激酶）信号级联的一部分。支架蛋白同时与MAPK信号通路的各种组分结合，在信号传递和MAPK调节中起着至关重要的作用。WDR 62（WD repeat domain 62）是JNK支架蛋白。WDR 62内的隐性突变导致严重的大脑皮质畸形。在本研究中，我们证明了WDR 62与JNK 2和JNK 2激活激酶MKK 7（MAPK激酶7）的内源性和过表达蛋白质的关联。WDR 62与JNK 2和MKK 7的结合通过直接的蛋白质-蛋白质相互作用发生。我们绘制了负责与JNK关联的WDR 62的对接结构域。WDR 62通过位于C末端的D结构域基序与所有JNK同种型相互作用。缺乏推定的JNK结合结构域的WDR 62突变体不能激活和招募JNK到细胞颗粒。此外，由WDR 62对接结构域组成的合成肽在体外抑制JNK 2活性。WDR 62与JNK 2的结合需要JNK CD和艾德结构域，并且结合所需条件与先前描述的JNK 2与JIP 1（JNK相互作用蛋白1）的结合所需条件不同。接下来，我们表征了WDR 62和MKK 7之间的关联。WDR 62与MKK 7 β1亚型直接结合，不依赖于JNK结合，但不能与MKK 7 α1相互作用。此外，MKK 7 β1募集使WDR 62去磷酸化的蛋白磷酸酶。有趣的是，导致严重大脑发育缺陷的WDR 62过早终止突变并不能消除WDR 62与JNK或MKK 7的关联。因此，此类突变代表独立于JNK信号传导的WDR 62功能的丧失。
JNK (c-Jun N-terminal kinase) is part of a MAPK (mitogen-activated protein kinase) signalling cascade. Scaffold proteins simultaneously associate with various components of the MAPK signalling pathway and play a crucial role in signal transmission and MAPK regulation. WDR62 (WD repeat domain 62) is a JNK scaffold protein. Recessive mutations within WDR62 result in severe cerebral cortical malformation. In the present study we demonstrate the association of WDR62 with endogenous and overexpressed proteins of both JNK2 and the JNK2-activating kinase MKK7 (MAPK kinase 7). Association of WDR62 with JNK2 and MKK7 occurs via direct protein–protein interactions. We mapped the docking domain of WDR62 responsible for the association with JNK. WDR62 interacts with all JNK isoforms through a D domain motif located at the C-terminus. A WDR62 mutant lacking the putative JNK-binding domain fails to activate and recruit JNK to cellular granules. Furthermore, a synthetic peptide composed of the WDR62 docking domain inhibits JNK2 activity in vitro. WDR62 association with JNK2 requires both the JNK CD and ED domains, and the binding requisite is distinct from that of the previously described JNK2 association with JIP1 (JNK-interacting protein 1). Next, we characterized the association between WDR62 and MKK7. WDR62 associates directly with the MKK7β1 isoform independently of JNK binding, but fails to interact with MKK7α1. Furthermore, MKK7β1 recruits a protein phosphatase that dephosphorylates WDR62. Interestingly, a premature termination mutation in WDR62 that results in severe brain developmental defects does not abrogate WDR62 association with either JNK or MKK7. Therefore such mutations represent a loss of WDR62 function independent of JNK signalling.