Mitotic Regulator SKAP Forms a Link between Kinetochore Core Complex KMN and Dynamic Spindle Microtubules
Mitotic Regulator SKAP Forms a Link between Kinetochore Core Complex KMN and Dynamic Spindle Microtubules
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有丝分裂调节器 SKAP 在动粒核心复合体 KMN 和动态纺锤体微管之间形成联系
DOI：
10.1074/jbc.m112.406652
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发表时间：
2012-11-16
影响因子：
4.8
通讯作者：
Yao, Xuebiao
中科院分区：
文献类型：
--
作者：
Wang, Xiwei;Zhuang, Xiaoxuan;Yao, Xuebiao
有丝分裂中的染色体分离是通过着丝粒和纺锤体微管之间的动态相互作用来协调的。我们最近的研究表明，有丝分裂运动 CENP-E 与 SKAP 合作，在有丝分裂中协调精确的染色体运动。然而，着丝粒核心微管结合活性 KMN (KNL1-MIS12-NDC80) 如何调节微管正端动力学仍然难以捉摸。在这里，我们发现了 MIS13 和 SKAP 之间的一种新颖的相互作用，它协调着丝粒和动态纺锤体微管之间的精确相互作用。 SKAP 与 MIS13 物理相互作用并指定 SKAP 的动粒定位。小干扰 RNA 对 MIS13 的抑制消除了 SKAP 的动粒定位。全内反射荧光显微镜分析表明，SKAP 在体外表现出 EB1 依赖性、微管正端加载和跟踪。重要的是，SKAP 对于活细胞有丝分裂过程中着丝粒振荡和微管正端动力学至关重要。基于这些发现，我们推断 SKAP 构成了纺锤体微管正端和有丝分裂染色体之间的动态联系，以实现忠实的细胞分裂。
Chromosome segregation in mitosis is orchestrated by the dynamic interactions between the kinetochore and spindle microtubules. Our recent study shows that mitotic motor CENP-E cooperates with SKAP to orchestrate an accurate chromosome movement in mitosis. However, it remains elusive how kinetochore core microtubule binding activity KMN (KNL1-MIS12-NDC80) regulates microtubule plus-end dynamics. Here, we identify a novel interaction between MIS13 and SKAP that orchestrates accurate interaction between kinetochore and dynamic spindle microtubules. SKAP physically interacts with MIS13 and specifies kinetochore localization of SKAP. Suppression of MIS13 by small interfering RNA abrogates the kinetochore localization of SKAP. Total internal reflection fluorescence microscopic assays demonstrate that SKAP exhibits an EB1-dependent, microtubule plus-end loading and tracking in vitro. Importantly, SKAP is essential for kinetochore oscillations and dynamics of microtubule plus-ends during live cell mitosis. Based on those findings, we reason that SKAP constitutes a dynamic link between spindle microtubule plus-ends and mitotic chromosomes to achieve faithful cell division.