相关实验视频
Updated: Jul 16, 2026

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RhoC GTPase Activation Assay
Published on: August 22, 2010
激活GTPase的蛋白质Rap1GAP使用一种催化性阿斯巴拉基因
Oliver Daumke1, Michael Weyand, Partha P Chakrabarti
1Max-Planck-Institut für Molekulare Physiologie, Otto-Hahnstr. 11, 44227 Dortmund, Germany.
Nature
|May 14, 2004
概括
Rap1GAP是Rap1信号的调节器,它使用催化剂阿斯巴拉金,而不是阿尔金因,来刺激GTP水解. 这种独特的机制不同于其他GTPase激活蛋白,对结核性硬化有影响.
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
- 结构生物学 结构生物学
背景情况:
- 拉普1是一种Ras类GTPase,调节细胞粘附和信号通路.
- 拉普1活性由GTP酶激活蛋白 (GAPs) 控制,这些蛋白质增强了GTP水解.
- 与其他Ras类蛋白质不同,Rap1缺乏用于GTP水解的催化性谷氨酸,其GAPs在结构上是不同的.
研究的目的:
- 为了阐明Rap1GAP的催化机制,Rap1的特定激活剂.
- 确定Rap1GAP独特的GTPase激活功能的结构基础.
主要方法:
- 进行X射线晶体学以确定Rap1GAP催化域的结构.
- 位点定向突变发生,以调查特定氨基酸的作用.
- 光定位和停止流动的动力测试来测量酶活性.
主要成果:
- 在2.9 Å分辨率下确定了Rap1GAP催化域的晶体结构.
- Rap1GAP采用催化阿斯巴拉金残留物,而不是在其他GAP中发现的催化氨酸,以促进GTP水解.
- 突变分析和动力学测试证实了阿斯巴拉金在Rap1GAP的功能中的重要作用.
结论:
- 拉普1GAP利用了一种新型的催化机制,涉及阿斯巴拉金残留物来激活Rap1 GTPase.
- 这种独特的机制突显了GAP功能的多样性,并对了解状硬化等疾病有潜在的影响.
相关概念视频
GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...
Rab Proteins
Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...
Rab Cascades
Rab GTPases act in a regulated cascade during membrane fusion, helping the lipid bilayers mix. The Rab family of proteins are active when bound to GTP, and inactive when bound to GDP. Hence, they act as guanine nucleotide-dependent molecular switches. Rab-GTP recognizes and binds to long or short-range tethering proteins to capture the target vesicle. These tethers coordinate with SNAREs on the vesicle and the target membrane to assemble the trans SNARE complex that locks the mixing bilayers.
Small GTPases - Ras and Rho
Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Three regulatory proteins control their activity:
Activation and Inactivation of G Proteins
Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...

