Polo Kinase Interacts with RacGAP50C and Is Required to Localize the Cytokinesis Initiation Complex
Polo Kinase Interacts with RacGAP50C and Is Required to Localize the Cytokinesis Initiation Complex
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DOI：
10.1074/jbc.m110.103887
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发表时间：
2010-09-10
影响因子：
4.8
通讯作者：
Gregory, Stephen L.
中科院分区：
文献类型：
--
作者：
Ebrahimi, Saman;Fraval, Hamilton;Gregory, Stephen L.
胞质分裂中肌动球蛋白收缩环的组装和收缩依赖于Rho在赤道皮质的激活，这里称为胞质起始复合体，该复合体位于微管相关的动蛋白样蛋白(KLP)之间，属于racGAP家族的成员，与RhoGlobal Pebble之间的复合体。最近，哺乳动物Polo激酶原基因Plk1的活性被认为与这种复合体的形成有关。我们在这里展示了Polo激酶通过与racGAP50C结合直接与胞质分裂起始复合体相互作用。我们发现Polo激酶的一个新的结构域，称为中间域，直接与racGAP50C相互作用，并且Polo激酶对于KLP-racGAP中心纺锤体复合体定位到细胞赤道和纺锤体中区是必不可少的。在没有Polo激酶的情况下，racGAP50C和Pav-KLP不能正常定位，而是装饰沿其长度的微管。我们的结果表明，Polo激酶直接与保守的胞质分裂起始复合体结合，并且作为胞质分裂的第一步，需要触发中心纺锤体定位。
The assembly and constriction of an actomyosin contractile ring in cytokinesis is dependent on the activation of Rho at the equatorial cortex by a complex, here termed the cytokinesis initiation complex, between a microtubule-associated kinesin-like protein (KLP), a member of the RacGAP family, and the RhoGEF Pebble. Recently, the activity of the mammalian Polo kinase ortholog Plk1 has been implicated in the formation of this complex. We show here that Polo kinase interacts directly with the cytokinesis initiation complex by binding RacGAP50C. We find that a new domain of Polo kinase, termed the intermediate domain, interacts directly with RacGAP50C and that Polo kinase is essential for localization of the KLP-RacGAP centralspindlin complex to the cell equator and spindle midzone. In the absence of Polo kinase, RacGAP50C and Pav-KLP fail to localize normally, instead decorating microtubules along their length. Our results indicate that Polo kinase directly binds the conserved cytokinesis initiation complex and is required to trigger centralspindlin localization as a first step in cytokinesis.