The mitotic checkpoint kinase NEK2A regulates kinetochore microtubule attachment stability
The mitotic checkpoint kinase NEK2A regulates kinetochore microtubule attachment stability
复制标题
有丝分裂检查点激酶 NEK2A 调节着丝粒微管附着稳定性
DOI：
10.1038/onc.2008.34
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发表时间：
2008-07-03
期刊：
影响因子：
8
通讯作者：
Yao, X.
中科院分区：
文献类型：
--
作者：
Du, J.;Cai, X.;Yao, X.
整个染色体的丢失或获得，通常与癌症相关的染色体不稳定性形式被认为是由细胞分裂期间的异常染色体分离引起的。有丝分裂中染色体的分离是由着丝粒与纺锤体微管的相互作用所协调的。我们的研究表明，NEK 2A是一个着丝粒相关的蛋白激酶，对忠实的染色体分离至关重要。然而，尚不清楚NEK 2A如何确保有丝分裂中染色体的准确分离。在这里，我们表明，NEK 2A介导的Hec 1（在癌症中高度表达）磷酸化是必不可少的有丝分裂中忠实的动粒微管附件。利用磷酸化特异性抗体，我们的研究表明，NEK 2A在有丝分裂过程中磷酸化Hec 1的Ser 165。虽然这样的磷酸化是不需要的装配Hec 1的动粒，非磷酸化突变体Hec 1 S165的表达扰乱染色体congression，并导致在微管附着错误，包括syntelic和monotelic附件急剧增加。我们的体外重建实验表明，Hec 1结合微管在低亲和力和磷酸化的NEK 2A，防止异常的kinetochore-microtubule连接在体内，增加的Ndc 80复合物的微管在体外的亲和力。因此，我们的研究阐明了一种新的调节机制，其中NEK 2A激酶操作染色体与纺锤体微管的忠实附着，从而防止细胞分裂过程中染色体的不稳定性。
Loss or gain of whole chromosome, the form of chromosome instability commonly associated with cancers is thought to arise from aberrant chromosome segregation during cell division. Chromosome segregation in mitosis is orchestrated by the interaction of kinetochores with spindle microtubules. Our studies show that NEK2A is a kinetochore-associated protein kinase essential for faithful chromosome segregation. However, it was unclear how NEK2A ensures accurate chromosome segregation in mitosis. Here we show that NEK2A-mediated Hec1 (highly expressed in cancer) phosphorylation is essential for faithful kinetochore microtubule attachments in mitosis. Using phospho-specific antibody, our studies show that NEK2A phosphorylates Hec1 at Ser165 during mitosis. Although such phosphorylation is not required for assembly of Hec1 to the kinetochore, expression of non-phosphorylatable mutant Hec1 S165 perturbed chromosome congression and resulted in a dramatic increase in microtubule attachment errors, including syntelic and monotelic attachments. Our in vitro reconstitution experiment demonstrated that Hec1 binds to microtubule in low affinity and phosphorylation by NEK2A, which prevents aberrant kinetochore-microtubule connections in vivo, increases the affinity of the Ndc80 complex for microtubules in vitro. Thus, our studies illustrate a novel regulatory mechanism in which NEK2A kinase operates a faithful chromosome attachment to spindle microtubule, which prevents chromosome instability during cell division.