Importin-β targets HURP to kinetochore-fibers in coordination with Ran-GTP in human mitotic cells
Importin-β targets HURP to kinetochore-fibers in coordination with Ran-GTP in human mitotic cells
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Importin-β 与人有丝分裂细胞中的 Ran-GTP 协同作用，将 HURP 靶向着丝粒纤维
DOI：
10.1101/473538
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Kiyomitsu T
中科院分区：
文献类型：
--
作者：
Tsuchiya K;Hayashi H;Nishina M;Okumura M;Kanemaki MT;Goshima G;Kiyomitsu T
在有丝分裂期间，双极纺锤体在染色体周围组装以有效地捕获染色体。先前的研究表明，染色体衍生的Ran-GTP梯度通过从抑制性进口蛋白中释放纺锤体组装因子（SAFs）来促进染色体周围的纺锤体组装。然而，Ran在核质间期运输和有丝分裂纺锤体组装中的双重功能使其在体细胞有丝分裂中的作用难以评估。在这里，利用生长素诱导的人类细胞降解技术，我们开发了急性有丝分裂降解实验，系统地分离了Ran的间期功能，分析了Ran的有丝分裂作用。与主流模型相反，我们发现Ran通路对于发生在与染色体空间分离的位点的纺锤体组装活动不是必需的，包括激活NuMA以进行纺锤体极点聚焦或靶向TPX2。相反，需要Ran-GTP将HURP和HSET特异定位在染色体近端区域。我们证明了Ran-GTP和importin-β协同促进HURP在染色体附近的动态微管结合-解离循环，从而导致稳定的着丝纤维形成。有趣的是，这种途径优先在中期前期而不是中期建立适当的纺锤体长度。总之，我们提出Ran通路是激活特异性靠近染色体的SAFs所必需的，但在人类有丝分裂纺锤体组装过程中并不普遍。ran依赖的纺锤体组装可能与平行途径相结合，以激活包括NuMA在内的saf，使纺锤体极点聚焦远离染色体。利用生长素诱导降解技术，我们开发了人类细胞中Ran通路的有丝分裂降解实验。Ran通路对于激活NuMA进行纺锤极聚焦并不是必需的。Ran通路动态极化HURP，并在前期优先定义有丝分裂纺锤体长度。在人类有丝分裂细胞中，需要Ran-GTP来激活染色体附近的特异性SAFs，但不是普遍的。
During mitosis, a bipolar spindle is assembled around chromosomes to efficiently capture chromosomes. Previous work proposed that a chromosome-derived Ran-GTP gradient promotes spindle assembly around chromosomes by liberating spindle assembly factors (SAFs) from inhibitory importins. However, Ran’s dual functions in interphase nucleocytoplasmic transport and mitotic spindle assembly have made it difficult to assess its mitotic roles in somatic cells. Here, using auxin-inducible degron technology in human cells, we developed acute mitotic degradation assays to dissect Ran’s mitotic roles systematically and separately from its interphase function. In contrast to the prevailing model, we found that the Ran pathway is not essential for spindle assembly activities that occur at sites spatially separated from chromosomes, including activating NuMA for spindle pole focusing or for targeting TPX2. In contrast, Ran-GTP is required to localize HURP and HSET specifically at chromosome-proximal regions. We demonstrated that Ran-GTP and importin-β coordinately promote HURP’s dynamic microtubule binding-dissociation cycle near chromosomes, which results in stable kinetochore-fiber formation. Intriguingly, this pathway acts to establish proper spindle length preferentially during prometaphase, rather than metaphase. Together, we propose that the Ran pathway is required to activate SAFs specifically near chromosomes, but not generally during human mitotic spindle assembly. Ran-dependent spindle assembly is likely coupled with parallel pathways to activate SAFs, including NuMA, for spindle pole focusing away from chromosomes.HighlightsUsing auxin-inducible degron technology, we developed mitotic degradation assays for the Ran pathway in human cells.The Ran pathway is non-essential to activate NuMA for spindle pole focusing.The Ran pathway dynamically polarizes HURP and defines mitotic spindle length preferentially during prometaphase.Ran-GTP is required to activate SAFs specifically near chromosomes, but not generally, in human mitotic cells.
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影响因子：
64.5
作者：
Tomomi Kiyomitsu;I. Cheeseman
通讯作者：
Tomomi Kiyomitsu;I. Cheeseman
DOI：
10.1083/jcb.201710094
发表时间：
2018-08-06
期刊：
The Journal of cell biology
影响因子：
--
作者：
Sikirzhytski V;Renda F;Tikhonenko I;Magidson V;McEwen BF;Khodjakov A
通讯作者：
Khodjakov A
影响因子：
3.3
作者：
Cai, Shang;Weaver, Lesley N.;Walczak, Claire E.
通讯作者：
Walczak, Claire E.
影响因子：
7.7
作者：
Hueschen, Christina L.;Kenny, Samuel J.;Dumont, Sophie
通讯作者：
Dumont, Sophie
用于胞质分裂的从头中央纺锤体微管生成
DOI：
--
发表时间：
2010
期刊：
影响因子：
--
作者：
上原亮太;五島剛太
通讯作者：
五島剛太