相关实验视频
Updated: Jul 28, 2026

10:37
Comparing the Affinity of GTPase-binding Proteins using Competition Assays
Published on: October 8, 2015
一个Gαα子单元的单独的GTP结合和GTP酶激活域
D W Markby1, R Onrust, H R Bourne
1Department of Pharmcology, University of California, San Francisco 94143.
概括
大多数瓜诺辛三酸酶 (GTPase) 超级家族成员需要一种GTPase激活蛋白 (GAP) 来解瓜诺辛三酸 (GTP). 这项研究表明,G蛋白α子单元插入作为GAP,表明GTPase调节的一般机制.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 细胞信号传递 细胞信号传递
背景情况:
- 瓜诺辛三酸酶 (GTPase) 超级家族通过瓜诺辛三酸盐 (GTP) 水解来调节细胞过程.
- 大多数GTPase都需要GTPase激活蛋白 (GAPs) 来有效地化GTP.
- 异构三级G蛋白α子单元 (Gα) 呈现出快速的GTP水解,与其他GTP酶不同.
研究的目的:
- 为了研究在Gα子单元中发现的独特插入域的生物化学功能.
- 为了确定Gα插入域是否作为GTPase激活蛋白 (GAP).
- 为了阐明由Gαα子单位快速的GTP水解的机制.
主要方法:
- 重组Gα插入域和Gα GTP结合核心域的表达和净化.
- 生物化学分析测量GTP水解速率.
- 分析Gα字母域之间的蛋白质与蛋白质相互作用.
主要成果:
- 证明Gα插入域与Gα GTP结合核心域相互作用.
- 在生物化学上,Gα插入域作为GTPase激活蛋白 (GAP) 起作用.
- 这种相互作用显著加快了G alpha核心域的GTP水解.
结论:
- Gα子单元的插入域充当了内在的GAP,解释了它们快速的GTPase活性.
- 提出了一种对GAP依赖的GTP水解的一般机制,适用于其他GTP相.
- 这一发现为G蛋白信号通路的调节提供了洞察力.
相关概念视频
G-protein Coupled Receptors
G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.
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...
G-protein Coupled Receptors
G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.
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...
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...

