SUMOylation of Grb2 enhances the ERK activity by increasing its binding with Sos1.
SUMOylation of Grb2 enhances the ERK activity by increasing its binding with Sos1.
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Grb2 的 SUMO 化通过增加与 Sos1 的结合来增强 ERK 活性
DOI：
10.1186/1476-4598-13-95
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发表时间：
2014-04-29
期刊：
影响因子：
37.3
通讯作者：
Huang J
中科院分区：
文献类型：
--
作者：
Qu Y;Chen Q;Lai X;Zhu C;Chen C;Zhao X;Deng R;Xu M;Yuan H;Wang Y;Yu J;Huang J
背景Grb2（生长因子受体结合蛋白 2）是通过将 Sos1（七同源物 1 的儿子）或其他蛋白与激活的 RTK（例如 EGFR）连接来维持 ERK 活性的关键接头蛋白。目前，除了其磷酸化之外，关于 Grb2 的翻译后修饰 (PTM) 知之甚少。由于新出现的证据强调了 SUMO 化（小泛素相关修饰剂）（一种可逆 PTM）在调节蛋白质功能中的重要性，我们想知道 Grb2 是否可以被 SUMO 化，从而影响其功能，特别是在 Ras/MEK/ERK 途径中。 SUMO化测定。为了测试ERK活性和细胞转化，使用小鼠成纤维细胞系NIH/3T3和小鼠结肠癌细胞系CMT-93进行Grb2敲低、异位再表达、细胞转化和迁移实验。采用免疫沉淀 (IP) 来寻找与 SUMO 修饰的 Grb2 相互作用的蛋白质。通过小鼠异种移植肿瘤模型验证Grb2 SUMO化在体内调控肿瘤发生。结果Grb2可以被SUMO1在N端SH3结构域和SH2结构域之间的连接区第56位赖氨酸(K56)处SUMO化。 Grb2 的敲低降低了 ERK 活性，并在体外和体内抑制了细胞运动和肿瘤发生，这些都可以通过稳定异位重新表达野生型 Grb2（而非突变型 Grb2K56R）来挽救。此外，Grb2在K56处的SUMO化增加了Grb2-Sos1复合物的形成，进而导致Ras/MEK/MAPK通路的激活。结论我们的结果提供了Grb2在体内SUMO化的证据，并且这种修饰通过增加Grb2-Sos1复合物的形成增强了ERK活性，从而可能促进细胞运动、转化和肿瘤发生。
BackgroundGrb2 (Growth factor receptor-bound protein 2) is a key adaptor protein in maintaining the ERK activityvialinking Sos1 (Son of sevenless homolog 1) or other proteins to activated RTKs, such as EGFR. Currently, little knowledge is available concerning the post-translational modification (PTM) of Grb2 except for its phosphorylation. Since emerging evidences have highlighted the importance of SUMOylation (Small ubiquitin-related modifier), a reversible PTM, in modulating protein functions, we wondered if Grb2 could be SUMOylated and thereby influences its functions especially involved in the Ras/MEK/ERK pathway.MethodsSUMOylation of Grb2 was analyzed with thein vivoSUMOylation assay using the Ni2+-NTA affinity pulldown and thein vitro E.coli-based SUMOylation assay. To test the ERK activity and cell transformation, the murine fibroblast cell line NIH/3T3 and the murine colon cancer cell line CMT-93 were used for the experiments including Grb2 knockdown, ectopic re-expression, cell transformation and migration. Immunoprecipitation (IP) was employed for seeking proteins that interact with SUMO modified Grb2. Xenograft tumor model in mice was conducted to verify that Grb2 SUMOylation regulated tumorigenesisin vivo.ResultsGrb2 can be SUMOylated by SUMO1 at lysine 56 (K56), which is located in the linker region between the N-terminal SH3 domain and the SH2 domain. Knockdown of Grb2 reduced the ERK activity and suppressed cell motility and tumorigenesisin vitroandin vivo, which were all rescued by stable ectopic re-expression of wild-type Grb2 but not the mutant Grb2K56R. Furthermore, Grb2 SUMOylation at K56increased the formation of Grb2-Sos1 complex, which sequentially leads to the activation of Ras/MEK/MAPK pathway.ConclusionsOur results provide evidences that Grb2 is SUMOylatedin vivoand this modification enhances ERK activitiesviaincreasing the formation of Grb2-Sos1 complex, and may consequently promote cell motility, transformation and tumorigenesis.
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影响因子：
64.8
作者：
LI, N;BATZER, A;SCHLESSINGER, J
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影响因子：
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