BubR1 phosphorylates CENP-E as a switch enabling the transition from lateral association to end-on capture of spindle microtubules
BubR1 phosphorylates CENP-E as a switch enabling the transition from lateral association to end-on capture of spindle microtubules
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BubR1 磷酸化 CENP-E 作为开关，实现纺锤体微管从横向关联过渡到末端捕获
DOI：
10.1038/s41422-019-0178-z
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发表时间：
2019-07-01
期刊：
影响因子：
44.1
通讯作者：
Yao, Xuebiao
中科院分区：
文献类型：
--
作者：
Huang, Yuejia;Lin, Lin;Yao, Xuebiao
无错误的有丝分裂依赖于染色体精确地附着在纺锤体微管上，这些染色体的动力聚集，它们在后期的分离，以及在有丝分裂出口处纺锤体中间区的组装。着丝粒相关的驱动蛋白马达CENP-E，其结合伴侣是BubR 1，已经被牵连在未对齐的染色体的聚集和从侧向运动舞蹈微管协会到端对捕获的过渡中。虽然以前提出是一个假激酶，在这里，我们报告的激酶域ofDrosophila melanogasterBubR 1的结构，揭示其折叠成构象预测是催化活性。BubR 1被证明是一个真正的激酶，其磷酸化的CENP-E开关它从一个横向连接的微管马达加端微管尖端跟踪器。使用计算建模来鉴定bubristatin作为靶向N-末端延伸的αN1螺旋和BubR 1激酶结构域的αC螺旋的选择性BubR 1激酶拮抗剂。CENP-E磷酸化的抑制被证明可以阻止在着丝粒处的适当微管捕获，并且令人惊讶地，阻止在有丝分裂出口处的中心纺锤体的适当组装。因此，BubR 1介导的CENP-E磷酸化产生了一个时间开关，使从横向过渡到端对微管捕获和组织微管到稳定的中间区阵列。
Error-free mitosis depends on accurate chromosome attachment to spindle microtubules, powered congression of those chromosomes, their segregation in anaphase, and assembly of a spindle midzone at mitotic exit. The centromere-associated kinesin motor CENP-E, whose binding partner is BubR1, has been implicated in congression of misaligned chromosomes and the transition from lateral kinetochore-microtubule association to end-on capture. Although previously proposed to be a pseudokinase, here we report the structure of the kinase domain ofDrosophila melanogasterBubR1, revealing its folding into a conformation predicted to be catalytically active. BubR1 is shown to be a bona fide kinase whose phosphorylation of CENP-E switches it from a laterally attached microtubule motor to a plus-end microtubule tip tracker. Computational modeling is used to identify bubristatin as a selective BubR1 kinase antagonist that targets the αN1 helix of N-terminal extension and αC helix of the BubR1 kinase domain. Inhibition of CENP-E phosphorylation is shown to prevent proper microtubule capture at kinetochores and, surprisingly, proper assembly of the central spindle at mitotic exit. Thus, BubR1-mediated CENP-E phosphorylation produces a temporal switch that enables transition from lateral to end-on microtubule capture and organization of microtubules into stable midzone arrays.