The microtubule-destabilizing kinesin XKCM1 regulates microtubule dynamic instability in cells
The microtubule-destabilizing kinesin XKCM1 regulates microtubule dynamic instability in cells
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DOI：
10.1091/mbc.e01-12-0143
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发表时间：
2002-08-01
影响因子：
3.3
通讯作者：
Walczak, CE
中科院分区：
文献类型：
--
作者：
Kline-Smith, SL;Walczak, CE
细胞微管的动态活动受到微管稳定蛋白和不稳定蛋白之间的平衡的严格调控。对非洲爪哇卵提取物的研究表明，在间期和有丝分裂过程中，主要的MT不稳定因素是激动素相关蛋白XKCM1，它以依赖于ATP的方式解聚MT末端。在这里，我们研究了XKCM1的过表达和抑制对脊椎动物体细胞MT动态调节的影响。我们发现XKCM1是PtK2细胞中的一种MT不稳定酶，并且XKCM1调节细胞MT的动力学。我们的结果表明，XKCM1水平的扰动改变了细胞MTS的突变频率和救援频率。此外，我们发现，在有丝分裂过程中，XKCM1的过度表达或KCM1的抑制会导致异常纺锤体的形成和有丝分裂的延迟。XKCM1过多的纺锤体缺陷主要包括单星纺锤体和单极纺锤体，以及带有不正确染色体附着的小的前中期纺锤体。KCM1在有丝分裂过程中受到抑制，导致前中期纺锤体的MTS过长，纺锤体的两极部分分离，MT呈放射状排列。这些结果表明，KCM1在哺乳动物细胞的间期和有丝分裂的MT动力学调控中起着关键作用。
The dynamic activities of cellular microtubules (MTs) are tightly regulated by a balance between MT-stabilizing and -destabilizing proteins. Studies in Xenopus egg extracts have shown that the major MT destabilizer during interphase and mitosis is the kinesin-related protein XKCM1, which depolymerizes MT ends in an ATP-dependent manner. Herein, we examine the effects of both overexpression and inhibition of XKCM1 on the regulation of MT dynamics in vertebrate somatic cells. We found that XKCM1 is a MT-destabilizing enzyme in PtK2 cells and that XKCM1 modulates cellular MT dynamics. Our results indicate that perturbation of XKCM1 levels alters the catastrophe frequency and the rescue frequency of cellular MTs. In addition, we found that overexpression of XKCM1 or inhibition of KCM1 during mitosis leads to the formation of aberrant spindles and a mitotic delay. The predominant spindle defects from excess XKCM1 included monoastral and monopolar spindles, as well as small prometaphase-like spindles with improper chromosomal attachments. Inhibition of KCM1 during mitosis led to prometaphase spindles with excessively long MTs and spindles with partially separated poles and a radial MT array. These results show that KCM1 plays a critical role in regulating both interphase and mitotic MT dynamics in mammalian cells.