Microtubule-severing activity of the AAA plus ATPase Katanin is essential for female meiotic spindle assembly
Microtubule-severing activity of the AAA plus ATPase Katanin is essential for female meiotic spindle assembly
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DOI：
10.1242/dev.140830
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发表时间：
2016-10-01
期刊：
影响因子：
4.6
通讯作者：
Pintard, Lionel
中科院分区：
文献类型：
--
作者：
Joly, Nicolas;Martino, Lisa;Pintard, Lionel
在大多数动物中，雌性减数分裂纺锤体是在没有中心体的情况下组装的。微管（MT）是如何组织成无中心体减数分裂纺锤体的知之甚少。在秀丽隐杆线虫中，雌性减数分裂纺锤体的组装需要MEI-1和MEI-2，它们构成微管切割AAA+ ATP酶Katanin。然而，MEI-2的作用是未知的，是否MT切割所需的减数分裂纺锤体组装尚不清楚。在这里，我们表明，MEI-2的重要作用是赋予MT结合Katanin，这反过来又刺激ATP酶活性的MEI-1，导致MT切断。为了直接测试MT切割对减数分裂纺锤体组装的贡献，我们设计了Katanin变体，其保留了MT结合和MT捆绑活性，但对MT切割无活性。对这些变异体的体内分析显示，微管结构紊乱，缺乏集中的纺锤体极，这让人想起Katanin功能丧失表型，表明MT切割活性对C.优美的总之，我们的结果揭示了MEI-2的重要作用，并提供了第一个直接证据支持MT切割在C.优雅的
In most animals, female meiotic spindles are assembled in the absence of centrosomes. How microtubules (MTs) are organized into acentrosomal meiotic spindles is poorly understood. In Caenorhabditis elegans, assembly of female meiotic spindles requires MEI-1 and MEI-2, which constitute the microtubule-severing AAA+ ATPase Katanin. However, the role of MEI-2 is not known and whether MT severing is required for meiotic spindle assembly is unclear. Here, we show that the essential role of MEI-2 is to confer MT binding to Katanin, which in turn stimulates the ATPase activity of MEI-1, leading to MT severing. To test directly the contribution of MT severing to meiotic spindle assembly, we engineered Katanin variants that retained MT binding and MT bundling activities but that were inactive for MT severing. In vivo analysis of these variants showed disorganized microtubules that lacked focused spindle poles reminiscent of the Katanin loss-of-function phenotype, demonstrating that the MT-severing activity is essential for meiotic spindle assembly in C. elegans. Overall, our results reveal the essential role of MEI-2 and provide the first direct evidence supporting an essential role of MT severing in meiotic spindle assembly in C. elegans.