Regulation of mitotic spindle formation by the RhoA guanine nucleotide exchange factor ARHGEF10
Regulation of mitotic spindle formation by the RhoA guanine nucleotide exchange factor ARHGEF10
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DOI：
10.1186/1471-2121-10-56
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发表时间：
2009-07-28
期刊：
影响因子：
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通讯作者：
Satoh, Takaya
中科院分区：
文献类型：
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作者：
Aoki, Takuji;Ueda, Shuji;Satoh, Takaya
背景资料：Dbl家族鸟嘌呤核苷酸交换因子ARHGEF 10最初被鉴定为与周围神经的神经传导速度减慢相关的基因的产物。然而，ARHGEF 10在哺乳动物细胞中的功能在分子水平上是完全未知的。ARHGEF 10不包含任何独特的功能域，除了串联Dbl同源性pleckstrin同源性和推定的跨膜domains.Results：在这里，我们表明，RhoA是ARHGEF 10的底物。在G1/S期和M期，ARHGEF 10定位于HeLa细胞的中心体。此外，基于RNA干扰的ARHGEF 10敲低导致M期多极纺锤体形成。每个纺锤极似乎都含有一个由两个中心粒和中心粒周围物质组成的中心体。RhoA的下调引起了类似的表型，ARHGEF 10敲低后异常的有丝分裂纺锤体形成被组成性激活的RhoA的异位表达所拯救。ARHGEF 10敲除后，多核细胞没有增加，与Y-27632治疗相反，Y-27632是RhoA效应激酶ROCK的特异性药理学抑制剂，不仅诱导多极纺锤体形成，而且诱导多核化。因此，不受调节的中心体复制，而不是畸变的胞质分裂可能是负责ARHGEF 10敲低依赖性多极纺锤体的形成。我们进一步分离了驱动蛋白样马达蛋白KIF 3B作为ARHGEF 10的结合伴侣。敲除KIF 3B再次引起多极纺锤体表型。当ARHGEF 10、RhoA或KIF 3B的表达被RNA interference.Conclusion废除时，在S期阻滞的骨肉瘤U2 OS细胞中也观察到了额外的中心体表型：总的来说，我们的研究结果表明，ARHGEF 10控制下的一种新的RhoA依赖的信号通路在细胞分裂周期的调节中具有关键作用。该途径不参与胞质分裂的调节，但可能调节中心体复制。驱动蛋白样马达蛋白KIF 3B可能通过与ARHGEF 10结合来调节ARHGEF 10-RhoA通路。
Background: The Dbl family guanine nucleotide exchange factor ARHGEF10 was originally identified as the product of the gene associated with slowed nerve-conduction velocities of peripheral nerves. However, the function of ARHGEF10 in mammalian cells is totally unknown at a molecular level. ARHGEF10 contains no distinctive functional domains except for tandem Dbl homology-pleckstrin homology and putative transmembrane domains.Results: Here we show that RhoA is a substrate for ARHGEF10. In both G1/S and M phases, ARHGEF10 was localized in the centrosome in adenocarcinoma HeLa cells. Furthermore, RNA interference-based knockdown of ARHGEF10 resulted in multipolar spindle formation in M phase. Each spindle pole seems to contain a centrosome consisting of two centrioles and the pericentriolar material. Downregulation of RhoA elicited similar phenotypes, and aberrant mitotic spindle formation following ARHGEF10 knockdown was rescued by ectopic expression of constitutively activated RhoA. Multinucleated cells were not increased upon ARHGEF10 knockdown in contrast to treatment with Y-27632, a specific pharmacological inhibitor for the RhoA effector kinase ROCK, which induced not only multipolar spindle formation, but also multinucleation. Therefore, unregulated centrosome duplication rather than aberration in cytokinesis may be responsible for ARHGEF10 knockdown-dependent multipolar spindle formation. We further isolated the kinesin-like motor protein KIF3B as a binding partner of ARHGEF10. Knockdown of KIF3B again caused multipolar spindle phenotypes. The supernumerary centrosome phenotype was also observed in S phase-arrested osteosarcoma U2OS cells when the expression of ARHGEF10, RhoA or KIF3B was abrogated by RNA interference.Conclusion: Collectively, our results suggest that a novel RhoA-dependent signaling pathway under the control of ARHGEF10 has a pivotal role in the regulation of the cell division cycle. This pathway is not involved in the regulation of cytokinesis, but instead may regulate centrosome duplication. The kinesin-like motor protein KIF3B may modulate the ARHGEF10-RhoA pathway through the binding to ARHGEF10.