Cytoskeletal modification of Rho guanine nucleotide exchange factor activity: identification of a Rho guanine nucleotide exchange factor as a binding partner for Sept9b, a mammalian septin
Cytoskeletal modification of Rho guanine nucleotide exchange factor activity: identification of a Rho guanine nucleotide exchange factor as a binding partner for Sept9b, a mammalian septin
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DOI：
10.1038/sj.onc.1208101
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发表时间：
2005-01-06
期刊：
影响因子：
8
通讯作者：
Inagaki, M
中科院分区：
文献类型：
--
作者：
Nagata, KI;Inagaki, M
小 GTP 酶 Rho 和 septin 家族蛋白被认为与肿瘤发生有关。我们通过酵母双杂交筛选，鉴定出 Rho-鸟嘌呤核苷酸交换因子 (GEF) 作为哺乳动物 sept9b 的结合伴侣。我们将这种分子命名为脓毒蛋白相关 RhoGEF (SA-RhoGEF)。分子解剖分析表明 SA-RhoGEF 的 C 末端区域表现出与 Sept9b 的 N 末端可变区的结合。通过免疫沉淀分析发现 SA-RhoGEF 与 REF52 成纤维细胞中的 septin 复合物相关，可能是通过与 Sept9b 直接相互作用。免疫荧光分析揭示了 SA-RhoGEF 和 Sept9b 与肌动蛋白应力纤维在 REF52 细胞中的共定位，并且它们沿着应力纤维的共定位很可能取决于它们的相互作用。在瞬时表达分析中，Sept9b 抑制 COS7 和 HeLa 细胞中 SA-RhoGEF 依赖性 Rho 激活。 SA-RhoGEF 及其在 REF52 细胞中表达的片段改变了内源性脓毒症。哀叹结构。据我们所知，SA-RhoGEF 是第一个在脓毒蛋白和 Rho 信号传导之间提供联系的分子。
Small GTPase Rho and septin family proteins are thought to be related to tumorigenesis. We have identified a Rho-guanine nucleotide exchange factor (GEF) as a binding partner for a mammalian septin Sept9b using yeast two-hybrid screening. We termed this molecule septin-associated RhoGEF (SA-RhoGEF). Molecular dissection analyses indicated that the C-terminal area of SA-RhoGEF exhibited binding to the N-terminal variable region of Sept9b. SA-RhoGEF was found by immunoprecipitation analysis to associate with septin complexes in REF52 fibroblast cells, maybe through direct interaction with Sept9b. Immunofluorescence analyses revealed the colocalization of SA-RhoGEF and Sept9b along with actin stress fibers in REF52 cells, and their colocalization along stress fibers was most likely to depend on their mutual interaction. In transient expression analyses, Sept9b inhibited SA-RhoGEF-dependent Rho activation in COS7 and HeLa cells. SA-RhoGEF and its fragments expressed in REF52 cells altered endogenous septin. lament structures. To our knowledge, SA-RhoGEF is the first molecule providing a link between septins and Rho signaling.