ch-TOGp is required for microtubule aster formation in a mammalian mitotic extract
ch-TOGp is required for microtubule aster formation in a mammalian mitotic extract
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DOI：
10.1074/jbc.275.16.12346
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发表时间：
2000-04-21
影响因子：
4.8
通讯作者：
Compton, DA
中科院分区：
文献类型：
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作者：
Dionne, MA;Sanchez, A;Compton, DA
哺乳动物有丝分裂提取物中紫杉醇诱导的微管聚合在中心体独立的过程中形成星形阵列，该过程由微管马达和结构蛋白驱动。这些微管aster准确地反映了有丝分裂纺锤杆形成的非中心体方面。我们在这里发现结肠-肝肿瘤过表达基因（ch-TOGp）是这些aster的丰富成分。我们制备了ch-TOGp特异性抗体，并通过免疫消耗表明ch-TOGp是微管aster组装所必需的。在没有ch-TOGp的情况下，微管聚合受到严重抑制，ch-TOGp免疫沉淀的银染色分析表明，ch-TOGp不存在于预形成的复合物中，并且是在免疫耗尽期间从提取物中去除的唯一蛋白质。此外，在没有ch-TOGp的情况下，微管聚合效率的降低取决于ATP。这些结果表明，ch-TOGp是在哺乳动物有丝分裂提取物中组装的微管紫菀的主要成分，并且即使存在紫杉醇，在该系统中也需要以atp依赖的方式进行稳健的微管聚合。这些数据，结合其他生物中ch-TOGp相关蛋白的生化和遗传数据，表明ch-TOGp是有丝分裂过程中调节微管动力学的关键因素。
Microtubules induced to polymerize with taxol in a mammalian mitotic extract organize into aster-like arrays in a centrosome-independent process that is driven by microtubule motors and structural proteins. These microtubule asters accurately reflect the noncentrosomal aspects of mitotic spindle pole formation. We show here that colonic-hepatic tumor-overexpressed gene (ch-TOGp) is an abundant component of these asters. We have prepared ch-TOGp-specific antibodies and show by immunodepletion that ch-TOGp is required for microtubule aster assembly. Microtubule polymerization is severely inhibited in the absence of ch-TOGp, and silver stain analysis of the ch-TOGp immunoprecipitate indicates that it is not present in a preformed complex and is the only protein removed from the extract during immunodepletion. Furthermore, the reduction in microtubule polymerization efficiency in the absence of ch-TOGp is dependent on ATP. These results demonstrate that ch-TOGp is a major constituent of microtubule asters assembled in a mammalian mitotic extract and that it is required for robust microtubule polymerization in an ATP-dependent manner in this system even though taxol is present. These data, coupled with biochemical and genetic data derived from analysis of ch-TOGp-related proteins in other organisms, indicate that ch-TOGp is a key factor regulating microtubule dynamics during mitosis.