Kinetochore-microtubule attachment relies on the disordered N-terminal tail domain of Hec1.
Kinetochore-microtubule attachment relies on the disordered N-terminal tail domain of Hec1.
复制标题
动力学 - 微管附着依赖于Hec1的无序N末端尾部结构域。
DOI：
10.1016/j.cub.2008.08.012
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发表时间：
2008-11-25
期刊：
影响因子：
--
通讯作者：
Deluca JG
中科院分区：
文献类型：
--
作者：
Guimaraes GJ;Dong Y;McEwen BF;Deluca JG
准确的染色体分离依赖于着丝点在有丝分裂过程中稳定地将染色体附着在纺锤体微管上。一个长期存在的问题是着丝点如何能够稳定地附着在不断生长和收缩的动态微管的正端。异四聚体Ndc80复合物对于细胞中持续的端上着丝酶与微管的结合至关重要，但Ndc80复合物如何形成功能性微管结合位点仍不清楚。在这里，我们展示了Hec1的80个氨基酸的n端“尾巴”是在细胞中产生稳定的着丝酶-微管附着所需的关键结构域。缺乏内源性Hec1的PtK1细胞，在整个n端尾部结构域缺失或n端80个氨基酸尾部结构域无序的Hec1- gfp融合蛋白的保护下，不能产生稳定的着丝点-微管附着体。在Hec1尾部区域内9个氨基酸的突变使其正电荷减少，也会破坏着丝酶与微管的稳定连接。此外，有丝分裂检查点在n端80个氨基酸缺失后仍能保持功能，但在n端207个氨基酸钙钙蛋白同源性（CH）结构域缺失后则不能。这些结果表明着丝点-微管结合依赖于通过无序n端80氨基酸尾部结构域介导的静电相互作用，有丝分裂检查点功能依赖于Hec1的CH结构域。
Accurate chromosome segregation is dependent upon kinetochores stably attaching chromosomes to spindle microtubules during mitosis. A long-standing question is how kinetochores are able to maintain stable attachment to the plus-ends of dynamic microtubules that are continually growing and shrinking. The hetero-tetrameric Ndc80 complex is essential for persistent, end-on kinetochore-microtubule attachment in cells, but how the Ndc80 complex forms functional microtubule binding sites remains unknown. Here we show the 80 amino acid N-terminal “tail” of Hec1 is a key domain required for generating stable kinetochore-microtubule attachments in cells. PtK1 cells depleted of endogenous Hec1 and rescued with Hec1-GFP fusion proteins deleted of the entire N-terminal tail domain or the disordered N-terminal 80 amino acid tail domain fail to generate stable kinetochore-microtubule attachments. Mutation of 9 amino acids within the Hec1 tail domain to reduce its positive charge also abolishes stable kinetochore-microtubule attachment. Furthermore, the mitotic checkpoint remains functional after deletion of the N-terminal 80 amino acids, but not after deletion of the N-terminal 207 amino acid calponin homology (CH) domain. These results demonstrate kinetochore-microtubule binding is dependent on electrostatic interactions mediated through the disordered N-terminal 80 amino acid tail domain and mitotic checkpoint function is dependent on the CH domain of Hec1.
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影响因子：
64.5
作者：
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