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Comparing the Affinity of GTPase-binding Proteins using Competition Assays
Published on: October 8, 2015
G 域二分化控制了动氨酸组合刺激的 GTPase 活动.
Joshua S Chappie1, Sharmistha Acharya, Marilyn Leonard
1Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland 20892, USA.
Nature
|April 30, 2010
概括
用晶体结构研究了对细胞膜裂变至关重要的GTPaseDynamin. 这揭示了活力是多么的强大.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
背景情况:
- 迪纳明是一种非典型的GTPase,在克拉斯林介导的内细胞分裂过程中对膜裂变至关重要.
- 控制胺基底和组合刺激的GTP水解的精确机制在很大程度上是未知的.
- 已知 GTPase 效应域 (GED) 间接影响动氨酸的 GTPase 活性.
研究的目的:
- 阐明胺的GTPase活性及其调节的结构基础.
- 为了了解组装刺激的GTP在动力中的水解的机制.
- 为了提供关于激素催化膜裂变的见解.
主要方法:
- 确定了人类动氨酸1衍生的最小GTPase-GED融合蛋白的2.0 Å分辨率晶体结构.
- 利用过渡状态模仿GDP.AlF的方法来稳定蛋白质的二维形式.
- 进行结构比较与老鼠动态G域.
主要成果:
- 晶体结构揭示了在GDP的存在下,GTPase-GED融合蛋白的二维状态.
- 该结构阐明了动的催化机制,并证明了G域二分化作为组装刺激的GTP水解的机制.
- 在活性部位中发现了一种离子,这表明它在没有阿金指的情况下稳定过渡状态的作用.
结论:
- 这项研究提供了一个结构性的解释,说明dynamin如何通过G域二分化实现组装刺激的GTP水解.
- 这些发现突出了在过渡状态稳定活性位点中的作用.
- 本文所介绍的结构为我们提供了关于激素介导膜裂变背后的分子机制的重要见解.
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...
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...
Assembly of Signaling Complexes
Multiprotein signaling complexes are formed in a dynamic process involving protein-protein interactions at the cytoplasmic domain of transmembrane receptors or enzymatic and non-enzymatic proteins associated with the receptor. These complexes ensure the activation and propagation of intracellular signals that regulate cell functions.
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Interaction domains in cell signaling
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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...
IP3/DAG Signaling Pathway
Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and produces two-second...

