The chromokinesin kid is required for maintenance of proper metaphase spindle size
The chromokinesin kid is required for maintenance of proper metaphase spindle size
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DOI：
10.1091/mbc.e05-03-0244
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发表时间：
2005-11-01
影响因子：
3.3
通讯作者：
Yamamoto, T
中科院分区：
文献类型：
--
作者：
Tokai-Nishizumi, N;Ohsugi, M;Yamamoto, T
人类染色质蛋白Kid/Kinesin-10是一种基于微管(MT)的正端导向马达，具有微管和DNA结合域，是染色体在中期平板正确对齐所必需的。在这里，我们进行了RNA干扰实验，以耗尽HeLa细胞中的内源性Kid，并证实Kid耗竭细胞的中期染色体臂排列存在缺陷。此外，我们注意到纺锤体长度的缩短，导致极到极的距离只有野生型的80%。与Kid共同定位的纺锤体微管束变得不那么健壮。挽救两种儿童缺乏症的表型--中期染色体排列不精确和纺锤体缩短--表现出不同的要求。缺乏DNA结合域或NIT马达ATPase的突变体未能修复前者的缺陷，而修复缩短的纺锤体表型不需要任何活性。KID在体外也表现出微管捆绑活性，缩短纺锤体表型的挽救与捆绑活性表现出相似的结构域要求，不同之处在于挽救需要一个捆绑不需要的盘绕结构域。这些结果表明，与其在染色体运动中的作用不同，Kid通过调节纺锤体微管的稳定来促进纺锤体的形态发生。
The human chromokinesin Kid/kinesin-10, a plus end-directed microtubule (MT)-based motor with both microtubuleand DNA-binding domains, is required for proper chromosome alignment at the metaphase plate. Here, we performed RNA interference experiments to deplete endogenous Kid from HeLa cells and confirmed defects in metaphase chromosome arm alignment in Kid-depleted cells. In addition, we noted a shortening of the spindle length, resulting in a pole-to-pole distance only 80% of wild type. The spindle microtubule-bundles with which Kid normally colocalize became less robust. Rescue of the two Kid deficiency phenotypes-imprecise chromosome alignment at metaphase and shortened spindles-exhibited distinct requirements. Mutants lacking either the DNA-binding domain or the NIT motor ATPase failed to rescue the former defect, whereas rescue of the shortened spindle phenotype required neither activity. Kid also exhibits microtubule bundling activity in vitro, and rescue of the shortened spindle phenotype and the bundling activity displayed similar domain requirements, except that rescue required a coiled-coil domain not needed for bundling. These results suggest that distinct from its role in chromosome movement, Kid contributes to spindle morphogenesis by mediating spindle microtubules stabilization.