XKCM1 acts on a single protofilament and requires the C terminus of tubulin
XKCM1 acts on a single protofilament and requires the C terminus of tubulin
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DOI：
10.1006/jmbi.2001.5360
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发表时间：
2002-02-22
影响因子：
5.6
通讯作者：
Nogales, E
中科院分区：
文献类型：
--
作者：
Niederstrasser, H;Salehi-Had, H;Nogales, E
微管在细胞周期中的稳定性受到许多细胞因子的调节，其中一些稳定微管，另一些促进微管的分解。XKCM 1是一种驱动蛋白样蛋白，诱导微管解聚，是有丝分裂纺锤体组装所必需的。我们研究了XKCM 1对不同微管蛋白聚合物的结合和解聚作用，以了解其作用机制。锌诱导的微管蛋白聚合物，其特征在于一个反平行的原丝排列，解聚XKCM 1，表明这种酶作用于一个单一的原丝。GDP-微管蛋白环对应于微管蛋白的低能状态，仅在抑制XKCM 1解聚活性的条件下稳定，但可以通过与AMPPNP结合的XKCM 1稳定。由枯草杆菌蛋白酶处理的微管蛋白（缺乏微管蛋白C-末端尾部）制成的微管蛋白聚合物对XKCM 1诱导的解聚具有抗性，这表明微管蛋白的酸性尾部与Kin I蛋白特有的XKCM 1中的碱性残基的相互作用是解聚所需的。(C)2002年爱思唯尔科学有限公司
The stability of microtubules during the cell-cycle is regulated by a number of cellular factors, some of which stabilize microtubules and others that promote breakdown. XKCM1 is a kinesin-like protein that induces microtubule depolymerization and is required for mitotic spindle assembly. We have examined the binding and depolymerization effects of XKCM1 on different tubulin polymers in order to learn about its mechanism of action. Zinc-induced tubulin polymers, characterized by an anti-parallel protofilament arrangement, are depolymerized by XKCM1, indicating that this enzyme acts on a single protofilament. GDP-tubulin rings, which correspond to the low-energy state of tubulin, are stable only under conditions that inhibit XKCM1 depolymerizing activity, but can be stabilized by XKCM1 bound to AMPPNP. Tubulin polymers made of subtilisin-treated tubulin (lacking the tubulin C-terminal tail) are resistant to XKCM1-induced depolymerization, suggesting that the interaction of the acidic tail of tubulin with basic residues in XKCM1 unique to Kin I proteins is required for depolymerization. (C) 2002 Elsevier Science Ltd.