Abrieu A, Kahana J A, Wood K W, Cleveland D W
Ludwig Institute for Cancer Research, University of California San Diego, La Jolla 92093-0660, USA.
Cell. 2000 Sep 15;102(6):817-26. doi: 10.1016/s0092-8674(00)00070-2.
Accurate chromatid separation is monitored by a checkpoint mechanism that delays anaphase onset until all centromeres are correctly attached to the mitotic spindle. Using Xenopus egg extracts, the kinetochore-associated microtubule motor protein CENP-E is now found to be required for establishing and maintaining this checkpoint. When CENP-E function is disrupted by immunodepletion or antibody addition, extracts fail to arrest in response to spindle damage. Mitotic arrest can be restored by addition of high levels of soluble MAD2, demonstrating that the absence of CENP-E eliminates kinetochore-dependent signaling but not the downstream steps in checkpoint signal transduction. Because it directly binds both to spindle microtubules and to the kinetochore-associated checkpoint kinase BUBR1, CENP-E is a central component in the vertebrate checkpoint that modulates signaling activity in a microtubule-dependent manner.
一种检查点机制会监测染色单体的精确分离，该机制会延迟后期开始，直到所有着丝粒都正确附着到有丝分裂纺锤体上。利用非洲爪蟾卵提取物，现已发现着丝粒相关的微管运动蛋白CENP-E是建立和维持该检查点所必需的。当通过免疫去除或添加抗体破坏CENP-E功能时，提取物无法响应纺锤体损伤而停滞。通过添加高水平的可溶性MAD2可恢复有丝分裂停滞，这表明CENP-E的缺失消除了着丝粒依赖性信号传导，但并未消除检查点信号转导的下游步骤。由于CENP-E直接与纺锤体微管以及着丝粒相关的检查点激酶BUBR1结合，因此它是脊椎动物检查点中的核心成分，该检查点以微管依赖性方式调节信号传导活性。
