Human TPX2 is required for targeting Aurora-A kinase to the spindle.
Human TPX2 is required for targeting Aurora-A kinase to the spindle.
复制标题
人类TPX2是将极光-A激酶靶向纺锤体所必需的。
DOI：
10.1083/jcb.200204155
复制
发表时间：
2002-08-19
影响因子：
7.8
通讯作者：
Nigg, Erich A
中科院分区：
文献类型：
--
作者：
Kufer, Thomas A;Sillje, Herman H W;Korner, Roman;Gruss, Oliver J;Meraldi, Patrick;Nigg, Erich A
Aurora-A是一种丝氨酸苏氨酸激酶，与有丝分裂纺锤体的组装和维持有关。在这里，我们展示了人类极光-A与TPX2结合，TPX2是纺锤体的重要组成部分。经质谱仪鉴定，TPX2是HeLa细胞有丝分裂提取物中与Aurora-A特异共沉淀的主要蛋白质。相反，在TPX2免疫沉淀物中可以检测到Aurora-A。这表明这两种蛋白质的亚群在体内经历了复杂的形成。结合研究表明，TPX2的NH2末端可以直接与Aurora-A的COOH末端催化结构域相互作用。尽管这种相互作用并不需要激酶活性，但TPX2很容易被Aurora-A磷酸化。在siRNA介导的TPX2从细胞中消除后，Aurora-A与纺锤体微管的联系被取消，尽管它与纺锤体极点的联系没有受到影响。相反，siRNA耗尽Aurora-A对TPX2的定位没有可检测到的影响。我们认为，人TPX2是将Aurora-A激酶靶向到纺锤体所必需的。反过来，Aurora-A可能在纺锤体组装过程中调节TPX2的功能。
Aurora-A is a serine-threonine kinase implicated in the assembly and maintenance of the mitotic spindle. Here we show that human Aurora-A binds to TPX2, a prominent component of the spindle apparatus. TPX2 was identified by mass spectrometry as a major protein coimmunoprecipitating specifically with Aurora-A from mitotic HeLa cell extracts. Conversely, Aurora-A could be detected in TPX2 immunoprecipitates. This indicates that subpopulations of these two proteins undergo complex formation in vivo. Binding studies demonstrated that the NH2 terminus of TPX2 can directly interact with the COOH-terminal catalytic domain of Aurora-A. Although kinase activity was not required for this interaction, TPX2 was readily phosphorylated by Aurora-A. Upon siRNA-mediated elimination of TPX2 from cells, the association of Aurora-A with the spindle microtubules was abolished, although its association with spindle poles was unaffected. Conversely, depletion of Aurora-A by siRNA had no detectable influence on the localization of TPX2. We propose that human TPX2 is required for targeting Aurora-A kinase to the spindle apparatus. In turn, Aurora-A might regulate the function of TPX2 during spindle assembly.