Activating and silencing the mitotic checkpoint through CENP-E-dependent activation/inactivation of BubR1
Activating and silencing the mitotic checkpoint through CENP-E-dependent activation/inactivation of BubR1
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DOI：
10.1016/s0092-8674(03)00475-6
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发表时间：
2003-07-11
期刊：
影响因子：
64.5
通讯作者：
Cleveland, DW
中科院分区：
文献类型：
--
作者：
Mao, YH;Abrieu, A;Cleveland, DW
有丝分裂检查点阻止在每个着丝粒/动粒成功附着到有丝分裂纺锤体微管之前推进到后期。使用纯化的成分和非洲爪蟾卵提取物，kinetochore-associated微管电机CENP-E现在被证明是必不可少的检查点激酶BubR 1的激活剂。由于激酶活性和检查点在提取物中的CENP-E依赖性微管附着或不破坏CENP-E与BubR 1结合的CENP-E抗体结合后沉默，因此CENP-E介导BubR 1信号转导的沉默。检查点信号传导需要正常水平的BubR 1含有与Cdc 20结合有关的功能性Mad 3结构域，但只有一小部分需要激酶活性。这支持BubR 1在检查点中的双功能作用：一种酶促作用需要CENP-E依赖性激活其在着丝粒处的激酶活性，另一种化学计量作用作为Cdc 20的直接抑制剂。
The mitotic checkpoint prevents advance to anaphase prior to successful attachment of every centromere/ kinetochore to mitotic spindle microtubules. Using purified components and Xenopus egg extracts, the kinetochore-associated microtubule motor CENP-E is now shown to be the activator of the essential checkpoint kinase BubR1. Since kinase activity and the checkpoint are silenced following CENP-E-dependent microtubule attachment in extracts or binding of CENP-E antibodies that do not disrupt CENP-E association with BubR1, CENP-E mediates silencing of BubR1 signaling. Checkpoint signaling requires the normal level of BubR1 containing a functional Mad3 domain implicated in Cdc20 binding, but only a small fraction need be kinase competent. This supports bifunctional roles for BubR1 in the checkpoint: an enzymatic one requiring CENP-E-dependent activation of its kinase activity at kinetochores and a stoichiometric one as a direct inhibitor of Cdc20.