Rho1-GEFs Rgf1 and Rgf2 are involved in formation of cell wall and septum, while Rgf3 is involved in cytokinesis in fission yeast
Rho1-GEFs Rgf1 and Rgf2 are involved in formation of cell wall and septum, while Rgf3 is involved in cytokinesis in fission yeast
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DOI：
10.1111/j.1365-2443.2005.00908.x
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发表时间：
2005-12-01
期刊：
影响因子：
2.1
通讯作者：
Mabuchi, I
中科院分区：
文献类型：
--
作者：
Mutoh, T;Nakano, K;Mabuchi, I
Rho GTP酶通过在GDP结合的非活性构象状态和GTP结合的活性构象状态之间进行转换，起到二元分子开关的作用。鸟嘌呤核苷酸交换因子是Rho的关键激活剂。在裂殖酵母中，Rho1已被证明对肌动蛋白、细胞骨架和细胞壁的合成具有调节作用。在这里，我们研究了裂解酵母RhoGEF、Rgf1、Rgf2和Rgf3的功能。结果表明，这些蛋白具有相似的分子结构，它们的功能类似于Rho1的GEF。RGF1或RGF2的破坏均未对细胞产生严重影响。另一方面，RGF3的中断导致了在胞质分裂过程中收缩环的形成、F-肌动蛋白斑块的定位和分隔的严重缺陷。RGF1和RGF2在间期和隔膜中定位于细胞末端。RGF3在分裂部位形成环状结构，位于收缩环外、Rho1聚集的隔膜内。总之，Rgf1和Rgf2表现出功能冗余，这些RhoGEF的作用可能不同于Rgf3。Rho1可能被Rgf3在分裂部位激活，并参与收缩环的形成和/或维持和隔膜。
The Rho GTPase acts as a binary molecular switch by converting between a GDP-bound inactive and a GTP-bound active conformational state. The guanine nucleotide exchange factors (GEFs) are critical activators of Rho. Rho1 has been shown to regulate actin cytoskeleton and cell wall synthesis in the fission yeast Schizosaccharomyces pombe. Here we studied function of fission yeast RhoGEFs, Rgf1, Rgf2, and Rgf3. It was shown that these proteins have similar molecular structures, and function as GEFs for Rho1. Disruption of either rgf1 or rgf2 did not show a serious effect on the cell. On the other hand, disruption of rgf3 caused severe defects in contractile ring formation, F-actin patch localization, and septation during cytokinesis. Rgf1 and Rgf2 were localized to the cell ends during interphase and the septum. Rgf3 formed a ring at the division site, which was located outside the contractile ring and inside the septum where Rho1 was accumulated. In summary, Rgf1 and Rgf2 show functional redundancy, and roles of these RhoGEFs are likely to be different from that of Rgf3. Rho1 is likely to be activated by Rgf3 at the division site, and involved in contractile ring formation and/or maintenance and septation.