Molecular requirements for the formation of a kinetochore-microtubule interface by Dam1 and Ndc80 complexes
Molecular requirements for the formation of a kinetochore-microtubule interface by Dam1 and Ndc80 complexes
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DOI：
10.1083/jcb.201210091
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发表时间：
2013-01-07
影响因子：
7.8
通讯作者：
Westermann, Stefan
中科院分区：
文献类型：
--
作者：
Lampert, Fabienne;Mieck, Christine;Westermann, Stefan
着丝点是将姐妹染色单体连接到纺锤体并将微管动力学转化为染色体运动的大型蛋白质复合物。在出芽酵母中，着丝点-微管界面是由正端相关的Dam1复合体和着丝点驻留的Ndc80复合体组成的，但它们如何结合工作以及它们之间的物理联系是否对染色体分离至关重要尚不清楚。在这里，我们定义了Ndc80-Dam1相互作用所需的结构元件，并探讨了它们在体内的功能。一个新的ndc80等位基因，选择性地在Dam1结合中受损，显示出生长和染色体分离缺陷。它与n端截断的结合导致了致命，证明了Ndc80 N-tail和Ndc80- dam1接口的重要但部分冗余的作用。相反，Ndc80钙钙蛋白同源结构域的突变取消了着丝点的功能，并且没有被Dam1的存在所补偿。我们的实验揭示了微管耦合器如何合作，并对外部着丝点组装的结构模型施加了重要的约束。
Kinetochores are large protein complexes that link sister chromatids to the spindle and transduce microtubule dynamics into chromosome movement. In budding yeast, the kinetochore-microtubule interface is formed by the plus end-associated Dam1 complex and the kinetochore-resident Ndc80 complex, but how they work in combination and whether a physical association between them is critical for chromosome segregation is poorly understood. Here, we define structural elements required for the Ndc80-Dam1 interaction and probe their function in vivo. A novel ndc80 allele, selectively impaired in Dam1 binding, displayed growth and chromosome segregation defects. Its combination with an N-terminal truncation resulted in lethality, demonstrating essential but partially redundant roles for the Ndc80 N-tail and Ndc80-Dam1 interface. In contrast, mutations in the calponin homology domain of Ndc80 abrogated kinetochore function and were not compensated by the presence of Dam1. Our experiments shed light on how microtubule couplers cooperate and impose important constraints on structural models for outer kinetochore assembly.