Polo-like kinase 1 directs assembly of the HsCyk-4 RhoGAP/Ect2 RhoGEF complex to initiate cleavage furrow formation.
Polo-like kinase 1 directs assembly of the HsCyk-4 RhoGAP/Ect2 RhoGEF complex to initiate cleavage furrow formation.
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polo样激酶1指导HSCYK-4 RHOGAP/ECT2 RHOGEF复合物的组装，以启动裂解沟的形成。
DOI：
10.1371/journal.pbio.1000110
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发表时间：
2009-05-05
期刊：
影响因子：
9.8
通讯作者：
Glotzer M
中科院分区：
文献类型：
--
作者：
Wolfe BA;Takaki T;Petronczki M;Glotzer M
Polo样激酶1通过在有丝分裂纺锤体中间区的Cyk-4-centralspindlin复合物上为RhoA激活剂Ect 2创建对接位点，促进将细胞一分为二的收缩环的组装。为了高保真地完成细胞分裂，胞质分裂必须与染色体分离相协调。哺乳动物Polo样激酶1，Plk 1，可能作为一个关键环节，因为它是必需的染色体分离和建立分裂平面后后期开始。RhoGEF Ect 2的中央纺锤体定位池促进小GTdR RhoA的激活，其驱动赤道皮质处的收缩环组装。在这里，我们研究了Plk 1如何促进Ect 2的中央纺锤体招募。Plk 1磷酸化RhoGAP HsCyk-4在中心纺锤体的非催化N末端，产生由Ect 2的BRCA 1 C末端（BRCT）重复识别的磷酸化表位。未能磷酸化HsCyk-4阻断Ect 2向中央纺锤体的募集以及随后的开沟诱导。微管，以及微管相关蛋白（MAP）Prc 1，促进Plk 1磷酸化HsCyk-4。HsCyk-4的磷酸化模拟版本的表征表明Plk 1通过多个靶点促进Ect 2募集。总的来说，我们的数据显示，HsCyk-4-Ect 2复合物的形成受到多层调控，以确保RhoA激活发生在分裂后期分离的姐妹染色单体之间。动物细胞中的细胞分裂平面是由有丝分裂后期早期纺锤体的位置决定的，但是导致分裂平面正确形成的分子信号还没有完全理解。肌动蛋白和肌球蛋白丰富的收缩环，物理上分为两个细胞，定位到假定的分裂平面通过局部激活的分子开关蛋白，RhoA。RhoA被Ect 2激活，Ect 2与分裂平面附近微管（中区微管）上发现的蛋白质复合物centralspindlin结合。中枢纺锤体蛋白的一个关键成分是Cyk-4，一种假定的RhoA负调节因子。在这里，我们分析了负责将RhoA激活剂Ect 2靶向中间区微管的机制。我们发现，Polo样激酶1（Plk 1），部分通过微管相关蛋白Prc 1，磷酸化Cyk-4。Ect 2与磷酸化的Cyk-4结合，然后能够激活RhoA并诱导收缩环的适当形成。因此，我们的研究阐明了动物细胞中确保正确分裂平面形成的信号级联的重要细节。
Polo-like kinase 1 promotes assembly of the contractile ring that divides a cell in two by creating a docking site for the RhoA activator Ect2 on the Cyk-4-containing centralspindlin complex at the midzone of the mitotic spindle. To complete cell division with high fidelity, cytokinesis must be coordinated with chromosome segregation. Mammalian Polo-like kinase 1, Plk1, may function as a critical link because it is required for chromosome segregation and establishment of the cleavage plane following anaphase onset. A central spindle–localized pool of the RhoGEF Ect2 promotes activation of the small GTPase RhoA, which drives contractile ring assembly at the equatorial cortex. Here, we have investigated how Plk1 promotes the central spindle recruitment of Ect2. Plk1 phosphorylates the noncatalytic N terminus of the RhoGAP HsCyk-4 at the central spindle, creating a phospho-epitope recognized by the BRCA1 C-terminal (BRCT) repeats of Ect2. Failure to phosphorylate HsCyk-4 blocks Ect2 recruitment to the central spindle and the subsequent induction of furrowing. Microtubules, as well as the microtubule-associated protein (MAP) Prc1, facilitate Plk1 phosphorylation of HsCyk-4. Characterization of a phosphomimetic version of HsCyk-4 indicates that Plk1 promotes Ect2 recruitment through multiple targets. Collectively, our data reveal that formation of the HsCyk-4-Ect2 complex is subject to multiple layers of regulation to ensure that RhoA activation occurs between the segregated sister chromatids during anaphase. The plane of cell division in animal cells is determined by the position of the mitotic spindle during early anaphase, but the molecular signaling that leads to proper formation of the division plane is not fully understood. The actin- and myosin-rich contractile ring, which physically divides a cell in two, localizes to the presumptive division plane through the local activation of a molecular switch protein, RhoA. RhoA is activated by Ect2, which binds to the protein complex centralspindlin found on microtubules in the vicinity of the division plane (the midzone microtubules). One critical component of centralspindlin is Cyk-4, a putative negative regulator of RhoA. Here, we have analyzed the mechanisms that are responsible for targeting the RhoA activator Ect2 to the midzone microtubules. We show that Polo-like kinase 1 (Plk1), in part through the microtubule-associated protein Prc1, phosphorylates Cyk-4. Ect2 binds to phosphorylated Cyk-4 and is then able to activate RhoA and induce proper formation of the contractile ring. Our study therefore has elucidated important details of the signaling cascade in animal cells that ensures proper division-plane formation.
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DOI：
10.1083/jcb.200511061
发表时间：
2006-01-30
期刊：
The Journal of cell biology
影响因子：
--
作者：
Gruneberg U;Neef R;Li X;Chan EH;Chalamalasetty RB;Nigg EA;Barr FA
通讯作者：
Barr FA
影响因子：
3.7
作者：
Brennan IM;Peters U;Kapoor TM;Straight AF
通讯作者：
Straight AF
影响因子：
4.8
作者：
Lee, MS;Edwards, RA;Glover, JNM
通讯作者：
Glover, JNM
影响因子：
5.7
作者：
Lansing, Timothy J.;McConnell, Randy T.;Cheung, Mui
通讯作者：
Cheung, Mui
DOI：
10.1073/pnas.0701140104
发表时间：
2007-03-13
影响因子：
11.1
作者：
Burkard, Mark E.;Randall, Catherine L.;Jallepalli, Prasad V.
通讯作者：
Jallepalli, Prasad V.