Repsl, which may coordinate a wide variety of the cellular actions

Repsl，可以协调多种细胞活动

• 批准号: 10670138
• 负责人: URANO Takeshi
• 金额: $ 2.05万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10670138/
• 关键词: Small GTPase Ras; Small GTPase Ral; Signal Transducer Reps; EGF receptor substrate; EF-hand motif; SH3 domain; non-receptor tyrosine kinase c-src

Ral proteins constitute a family of small GTPases that can be activated by Ras in cells. In the GTP-bound state, Ral proteins bind to RalBp1, a GTPase-activating protein for CDC42 and Rac GTPases. We have used the two-hybrid system in yeast to clone a cDNA for a novel 〜85-kDa protein that can bind to an additional site on RalBP1. This newly identified protein contains an Eps homology (EH) domain, which was first detected in the epidermal growth factor (EGF) receptor substrate Eps15. The RalBP1 associate Eps-homology domain protein, Reps1, is tyrosine-phosphorylated in response to EGF stimulation of cells. In addition, Reps1 has the capacity to form a complex with the SH3 domains of the adapter proteins Crk and Grb2, which may link Reps1 to an EGF-responsive tyrosine kinase, and with epsin and Eps15, which are involved in endocytosis. Finally we found that EGF receptors, but not βィイD22ィエD2-adrenergic receptors, activated c-Src by a Ral-GTPase-dependent mechanism. Thus, Reps1 may coordinate a wide variety of the cellular actions of activated EGF receptors and Ral-GTPases.

Ral蛋白构成了一个小GTP酶家族，可以被细胞中的Ras激活。在GTP结合状态下，Ral蛋白与RalBp 1结合，RalBp 1是CDC 42和Rac GTP酶的GTP酶激活蛋白。我们已经在酵母中使用双杂交系统克隆了一种新的185 kDa蛋白的cDNA，该蛋白可以结合到RalBP 1上的一个额外的位点。这种新鉴定的蛋白质含有Eps同源（EH）结构域，该结构域首次在表皮生长因子（EGF）受体底物Eps 15中检测到。RalBP 1相关的Eps同源结构域蛋白，Reps 1，是酪氨酸磷酸化的细胞EGF刺激的反应。此外，Reps 1有能力与衔接蛋白Crk和Grb 2的SH 3结构域形成复合物，这可能将Reps 1连接到EGF响应性酪氨酸激酶，并与参与内吞作用的epsin和Eps 15形成复合物。最后，我们发现EGF受体通过Ral-GT3依赖性机制激活c-Src，而不是β-D_（22）-D_2肾上腺素能受体。因此，Reps 1可以协调多种激活的EGF受体和Ral-GTP酶的细胞作用。

项目成果

Sterpetti, P.: "Activation of the Lbc Rho exchange factor proto-oncogene by truncation of an extended C terminus that regulates transformation and trageting"Mol. Cell. Biol.. 19. 1334-1345 (1999)

Sterpetti, P.：“通过截短调节转化和靶向的延伸 C 末端来激活 Lbc Rho 交换因子原癌基因”Mol。

Fukumoto,S.: "GD3 Synthase Gene Expression in PC12 Cells Results in the Continuous Activation of TrkA and EPK1/2 and Enhanced Proliferation"J.Biol.Chem.. 275・8. 5832-5838 (2000)

Fukumoto, S.：“PC12 细胞中的 GD3 合酶基因表达导致 TrkA 和 EPK1/2 的持续激活并增强增殖” J.Biol.Chem.. 275・8 (2000)。

Goi,T.: "Reduced expression of deleted colorectal carcinoma (DCC) protein in established colon cancers : Analysis by a specific monoclonal antibody." Br.J.Cancer. 77. 466-471 (1998)

Goi,T.：“已建立的结肠癌中删除的结直肠癌 (DCC) 蛋白的表达减少：通过特定的单克隆抗体进行分析。”

Okajima, T.: "Molecular cloning of brain-specific GD1α synthase (ST6GalNac V) containing CAG/Glutamine repeats"J. Biol. Chem.. 274・43. 30557-30562 (1999)

Okajima, T.：“含有 CAG/谷氨酰胺重复序列的脑特异性 GD1α 合酶 (ST6GalNac V) 的分子克隆”J. Biol. 274・43 (1999)。

Fukumoto, S.: "Expression cloning of mouse cDNA of CMP-NeuAc : Lactosylceramide α2,3-sialyltransferase (GM3 synthase), an enzyme that initiates the synthesis of gangliosides"J. Biol. Chem.. 274・14. 9271-9276 (1999)

Fukumoto, S.：“CMP-NeuAc 的小鼠 cDNA 的表达克隆：乳糖神经酰胺 α2,3-唾液酸转移酶（GM3 合酶），一种启动神经节苷脂合成的酶”J. Biol. 274・14。 (1999)