Weaver Beth A A, Bonday Zahid Q, Putkey Frances R, Kops Geert J P L, Silk Alain D, Cleveland Don W
Ludwig Institute for Cancer Research, 3080 CMM-East, 9500 Gilman Drive, La Jolla, CA 92093-0670, USA.
J Cell Biol. 2003 Aug 18;162(4):551-63. doi: 10.1083/jcb.200303167.
Centromere-associated protein-E (CENP-E) is an essential mitotic kinesin that is required for efficient, stable microtubule capture at kinetochores. It also directly binds to BubR1, a kinetochore-associated kinase implicated in the mitotic checkpoint, the major cell cycle control pathway in which unattached kinetochores prevent anaphase onset. Here, we show that single unattached kinetochores depleted of CENP-E cannot block entry into anaphase, resulting in aneuploidy in 25% of divisions in primary mouse fibroblasts in vitro and in 95% of regenerating hepatocytes in vivo. Without CENP-E, diminished levels of BubR1 are recruited to kinetochores and BubR1 kinase activity remains at basal levels. CENP-E binds to and directly stimulates the kinase activity of purified BubR1 in vitro. Thus, CENP-E is required for enhancing recruitment of its binding partner BubR1 to each unattached kinetochore and for stimulating BubR1 kinase activity, implicating it as an essential amplifier of a basal mitotic checkpoint signal.
着丝粒相关蛋白E（CENP-E）是一种必需的有丝分裂驱动蛋白，在着丝粒处高效、稳定地捕获微管时发挥作用。它还直接与BubR1结合，BubR1是一种与着丝粒相关的激酶，参与有丝分裂检查点，这是主要的细胞周期控制途径，其中未附着的着丝粒会阻止后期开始。在这里，我们表明，缺乏CENP-E的单个未附着着丝粒无法阻止进入后期，导致体外原代小鼠成纤维细胞25%的分裂以及体内95%的再生肝细胞出现非整倍体。没有CENP-E，着丝粒募集的BubR1水平降低，BubR1激酶活性维持在基础水平。CENP-E在体外与纯化的BubR1结合并直接刺激其激酶活性。因此，CENP-E对于增强其结合伴侣BubR1募集到每个未附着的着丝粒以及刺激BubR1激酶活性是必需的，这表明它是基础有丝分裂检查点信号的重要放大器。
