Mechanistic basis of Nek7 activation through Nek9 binding and induced dimerization.
Mechanistic basis of Nek7 activation through Nek9 binding and induced dimerization.
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DOI：
10.1038/ncomms9771
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发表时间：
2015-11-02
影响因子：
16.6
通讯作者：
Bayliss R
中科院分区：
文献类型：
--
作者：
Haq T;Richards MW;Burgess SG;Gallego P;Yeoh S;O'Regan L;Reverter D;Roig J;Fry AM;Bayliss R
有丝分裂纺锤体的组装需要调节Nek7和Nek9等蛋白激酶的活性。Nek7被Tyr97突入活性位点而被自身抑制，并被Nek9的非催化c端结构域（CTD）激活。CTD结合明显释放了自身抑制，因为Tyr97对苯丙氨酸的突变独立于Nek9增加了Nek7的活性。这里我们发现Nek9-CTD的自结合是Nek7激活所必需的。我们将Nek9的最小Nek7结合区定位到残基810-828上。Nek7Y97F与Nek9810-828结合的晶体结构揭示了Nek7激酶结构域c -叶上的结合位点。Nek7Y97F结晶为激酶结构域n -裂片之间的背对背二聚体，其中界面内的特定接触与残基97的构象耦合。因此，我们提出Nek9-CTD通过促进背对二聚化来激活Nek7，释放自抑制酪氨酸残基，这是一种在不相关的激酶家族中保守的机制。NEK7是一种参与有丝分裂的激酶，受NEK9激酶的调控。在这里，作者确定了NEK9中与NEK7结合的区域，并发现调控机制涉及二聚化与活性位点结构变化的耦合。
Mitotic spindle assembly requires the regulated activities of protein kinases such as Nek7 and Nek9. Nek7 is autoinhibited by the protrusion of Tyr97 into the active site and activated by the Nek9 non-catalytic C-terminal domain (CTD). CTD binding apparently releases autoinhibition because mutation of Tyr97 to phenylalanine increases Nek7 activity independently of Nek9. Here we find that self-association of the Nek9-CTD is needed for Nek7 activation. We map the minimal Nek7 binding region of Nek9 to residues 810–828. A crystal structure of Nek7Y97F bound to Nek9810–828 reveals a binding site on the C-lobe of the Nek7 kinase domain. Nek7Y97F crystallizes as a back-to-back dimer between kinase domain N-lobes, in which the specific contacts within the interface are coupled to the conformation of residue 97. Hence, we propose that the Nek9-CTD activates Nek7 through promoting back-to-back dimerization that releases the autoinhibitory tyrosine residue, a mechanism conserved in unrelated kinase families. NEK7, a kinase involved in mitosis, is regulated by the kinase NEK9. Here the authors identify the region in NEK9 that binds NEK7 and find that the mechanism of regulation involves dimerization coupled to structural changes in the active site.