关于Ras.GTP对Ras特异性核酸交换因子SOS的反激活的结构证据
S Mariana Margarit1, Holger Sondermann, Brian E Hall
1Department of Molecular Genetics and Microbiology, State University of New York at Stony Brook, Stony Brook, NY 11794, USA.
Cell
|March 12, 2003
概括
增长因子受体通过七无之子 (SOS) 激活Ras. Ras.GTP结合一个独特的SOS位点,以全稳定活性位点,并为Ras调节创建一个积极的反循环.
科学领域:
- 分子生物学分子生物学
- 细胞信号传递 细胞信号传递
- 生物化学 生物化学
背景情况:
- 增长因子受体通过激活 Ras 启动细胞信号传递.
- 七无之子 (SOS) 是一个关键的核酸交换因子,激活Ras.
- 拉斯激活涉及向细胞膜招募SOS以促进GTP加载.
研究的目的:
- 为了研究Ras-SOS相互作用的结构基础.
- 阐明 Ras.GTP 影响 SOS 活动的机制.
- 在Ras信号中识别潜在的积极反机制.
主要方法:
- 进行X射线晶体学,以确定Ras与SOS的催化模块结合的结构.
- 生物化学试验研究Ras.GTP和SOS在溶液中的相互作用.
- 对三元复合体形成和核酸释放率的分析.
主要成果:
- 在SOS上发现了一个保存的Ras结合部位,与活跃部位不同.
- 这个网站是专门针对Ras.GTP的.
- 拉斯.GTP结合以全性方式稳定SOS活性位点,增强核酸交换.
- Ras.GTP与SOS (猫) 形成三元复合体,并显著增加了从Ras.GTP释放核酸的速度.
结论:
- Ras.GTP与SOS的结合不仅仅取决于催化部位.
- 在Ras.GTP增强SOS活动的情况下,存在一个积极的反机制.
- 这种机制提供了Ras信号通路的空间和时间调节.
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