Phosphorylation of HsMis13 by aurora B kinase is essential for assembly of functional kinetochore
Phosphorylation of HsMis13 by aurora B kinase is essential for assembly of functional kinetochore
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Aurora B 激酶对 HsMis13 的磷酸化对于功能性动粒的组装至关重要
DOI：
10.1074/jbc.m804207200
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发表时间：
2008-09-26
影响因子：
4.8
通讯作者：
Yao, Xuebiao
中科院分区：
文献类型：
--
作者：
Yang, Yong;Wu, Fang;Yao, Xuebiao
有丝分裂中的染色体运动是由纺锤体微管和着丝粒之间的动态相互作用来调控的，着丝粒是组装在染色体着丝粒DNA上的一个多蛋白复合体。在这里，我们证明了人的HsMis13被Aurora B激酶磷酸化是HeLa细胞中功能动粒组装所必需的。Aurora B在体外和体内与HsMis13相互作用。HsMis13是Aurora B的同源底物，其磷酸化位点定位于Ser-100和Ser-109。用小干扰RNA或化学抑制剂抑制Aurora B激酶可以消除HsMis13的定位，但不能消除HsMis12对着丝粒的定位。此外，不可磷酸化但不能野生型和模拟磷酸化的HsMis13未能定位到动粒，表明Aurora B需要磷酸化才能将HsMis13组装到动粒。事实上，HsMis13在动粒上的定位受Aurora B激酶的时空调控，它对于招募外部动粒成分如Ndc80和CENP-E进行功能动粒组装是必不可少的。重要的是，模拟磷酸的突变体HsMis13恢复了CENP-E在动粒上的组装，并在Aurora B抑制的细胞中跨姊妹动粒发展了张力。因此，我们推测，HsMis13被Aurora B磷酸化是组织稳定的双向微管动粒附着所必需的，这对于有丝分裂中忠实的染色体分离是必不可少的。
Chromosome movements in mitosis are orchestrated by dynamic interactions between spindle microtubules and the kinetochore, a multiprotein complex assembled onto centro-meric DNA of the chromosome. Here we show that phosphorylation of human HsMis13 by Aurora B kinase is required for functional kinetochore assembly in HeLa cells. Aurora B interacts with HsMis13 in vitro and in vivo. HsMis13 is a cognate substrate of Aurora B, and the phosphorylation sites were mapped to Ser-100 and Ser-109. Suppression of Aurora B kinase by either small interfering RNA or chemical inhibitors abrogates the localization of HsMis13 but not HsMis12 to the kinetochore. In addition, non-phosphorylatable but not wild type and phospho-mimicking HsMis13 failed to localize to the kinetochore, demonstrating the requirement of phosphorylation by Aurora B for the assembly of HsMis13 to kinetochore. In fact, localization of HsMis13 to the kinetochore is spatiotemporally regulated by Aurora B kinase, which is essential for recruiting outer kinetochore components such as Ndc80 components and CENP-E for functional kinetochore assembly. Importantly, phospho-mimicking mutant HsMis13 restores the assembly of CENP-E to the kinetochore, and tension developed across the sister kinetochores in Aurora B-inhibited cells. Thus, we reason that HsMis13 phosphorylation by Aurora B is required for organizing a stable bi-oriented microtubule kinetochore attachment that is essential for faithful chromosome segregation in mitosis.