在G蛋白合信号系统中的动态支架
Prashant Mishra1, Michael Socolich, Mark A Wall
1Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-9050, USA.
Cell
|October 10, 2007
概括
在Drosophila光受体中,INAD支架使用了氧化还原开关机制. 在PDZ5中的这种动态形状变化调节了视觉信号和行为在毫秒时间尺度.
科学领域:
- 分子和细胞生物学分子和细胞生物学
- 神经科学是一个神经科学.
- 结构生物学 结构生物学
背景情况:
- 在Drosophila光受体细胞中,INAD支架对于视觉信号转导至关重要,它组织了必不可少的多蛋白质复合体.
- PDZ域是已知的蛋白相互作用模块,但它们的动态调节仍然是积极研究的领域.
研究的目的:
- 研究INAD支架的结构动态,特别关注其PDZ域的氧化还原依赖行为.
- 阐明 PDZ 域对视觉信号和 in vivo 行为的形状变化的功能后果.
主要方法:
- 用X射线晶体学来确定INAD PDZ域在不同氧化还原状态中的结构.
- 在体内生化测试检测光依赖的二硫化物键形成.
- 转基因Drosophila表达突变INAD蛋白质的生成和行为分析.
主要成果:
- 一个INAD PDZ域 (PDZ5) 在减少和氧化状态之间经历了氧化还原依赖的形态转换.
- 氧化状态的特点是由于分子内二硫化键的存在,由于分子内二硫化键的存在,氧化状态具有扭曲的联结部位,这种联结部位在体内暴露于光线时短暂地形成.
- 被锁定在减少状态中的PDZ5突变的在视觉响应终止和视觉引导行为方面表现出严重的缺陷.
结论:
- INAD的功能是一个动态的分子机器,而不是一个静态的脚手架,利用结构交换来调节信号.
- 在PDZ域中,氧依赖的形状变化提供了对信号传导的毫秒时间尺度调节的机制.
- 这项研究揭示了PDZ域调节的新机制,这对理解信号通路中的动态蛋白质复合体功能有意义.
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