Kinesin-like protein CHO1 is required for the formation of midbody matrix and the completion of cytokinesis in mammalian cells
Kinesin-like protein CHO1 is required for the formation of midbody matrix and the completion of cytokinesis in mammalian cells
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DOI：
10.1091/mbc.01-10-0504
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发表时间：
2002-06-01
影响因子：
3.3
通讯作者：
Kuriyama, R
中科院分区：
文献类型：
--
作者：
Matuliene, J;Kuriyama, R
CHO 1是MKLP 1亚家族的哺乳动物驱动蛋白样马达蛋白。在分裂后期与纺锤体中间区结合，在胞质分裂期集中于中体基质。CHO 1最初与核分裂有关，但CHO 1的无脊椎动物同源物显示在中间区形成和胞质分裂中起作用。为了分析该蛋白在哺乳动物细胞中的作用，我们突变了CHO 1的ATP结合位点并在CHO细胞中表达。突变蛋白（CHO 1F）能够通过ATP非依赖性微管结合位点与微管相互作用，但不能在中央纺锤体的中线处积累，并影响内源性CHO 1的定位。尽管在表达CHO 1F '的细胞中染色体分离、中间区微管成束和胞质分裂的开始正常进行，但胞质分裂的完成受到抑制。子细胞经常进入间期，而连接的微管含有细胞质桥，从致密的中间体基质丢失。通过RNA介导的干扰内源性CHO 1的消耗也影响分裂细胞中中间体基质的形成，引起中间区微管的解体，并导致胞质分裂的失败。因此，CHO 1可能不是有核分裂所必需的，但它是哺乳动物细胞中适当的中间区/中间体形成和胞质分裂所必需的。
CHO1 is a mammalian kinesin-like motor protein of the MKLP1 subfamily. It associates with the spindle midzone during anaphase and concentrates to a midbody matrix during cytokinesis. CHO1 was originally implicated in karyokinesis, but the invertebrate homologues of CHO1 were shown to function in the midzone formation and cytokinesis. To analyze the role of the protein in mammalian cells, we mutated the ATP-binding site of CHO1 and expressed it in CHO cells. Mutant protein (CHO1F) was able to interact with microtubules via ATP-independent microtubule-binding site(s) but failed to accumulate at the midline of the central spindle and affected the localization of endogenous CHO1. Although the segregation of chromosomes, the bundling of midzone microtubules, and the initiation of cytokinesis proceeded normally in CHO1F'-expressing cells, the completion of cytokinesis was inhibited. Daughter cells were frequently entering interphase while connected by a microtubule-containing cytoplasmic bridge from which the dense midbody matrix was missing. Depletion of endogenous CHO1 via RNA-mediated interference also affected the formation of midbody matrix in dividing cells, caused the disorganization of midzone microtubules, and resulted in abortive cytokinesis. Thus, CHO1 may not be required for karyokinesis, but it is essential for the proper midzone/midbody formation and cytokinesis in mammalian cells.