哺乳动物GIRK2-βγ G-蛋白复合体的X射线结构
Matthew R Whorton1, Roderick MacKinnon
1Laboratory of Molecular Neurobiology and Biophysics, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA.
Nature
|June 7, 2013
概括
在结构上分析了细胞电刺激能力至关重要的G蛋白门内向整流器K ((+) (GIRK) 通道. 该研究揭示了G蛋白子单元如何与GIRK2通道结合,稳定预开状态并阐明通道激活机制.
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.
- 生物物理学的生物物理.
背景情况:
- G-蛋白门内向整流器K ((+) (GIRK) 通道调节心脏和神经细胞中的细胞电刺激能力.
- 这些通道是由通过G蛋白结合受体 (GPCRs) 发出的神经递质信号激活的.
- G蛋白子单元和GIRK通道之间的相互作用是这个信号通路的核心.
研究的目的:
- 确定哺乳动物GIRK2通道与G蛋白βγ子单元复合体中的高分辨率晶体结构.
- 阐明由G蛋白激活GIRK通道的基础结构机制.
- 了解像PIP2和Na(+) 等调节分子在GIRK通道功能中的作用.
主要方法:
- 在3.5 Å分辨率的X射线晶体学.
- 对GIRK2-G蛋白质复合物的结构分析.
- 频道状态的形式分析.
主要成果:
- 晶体结构揭示了四个βγ G-蛋白子单元与四重体GIRK2通道的接口结合.
- 特定的原子和静电相互作用使通道在预开放状态下稳定.
- 这种预开放的构造在结构上是封闭状态和构成性活跃的开放状态之间的中间体.
结论:
- 这些发现支持一种"膜分界"模型,用于激活GIRK通道的G蛋白激活.
- 该结构提供了关于GIRK通道封锁的特征爆发动力学的见解.
- 这项研究为了解GIRK通道由PIP2和Na2+) 离子的多连接体调节提供了结构基础.
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.
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.
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
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
G Protein-coupled Receptors
G Protein-Coupled Receptors or GPCRs are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to sensory stimuli such as light, odors, hormones, cytokines, or neurotransmitters.
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
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...
Transducer Mechanism: G Protein–Coupled Receptors
G Protein–Coupled Receptors (GPCRs) are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to various stimuli. GPCRs regulate critical physiological pathways and are excellent drug targets for treating diseases such as diabetes, cancer, obesity, depression, or Alzheimer's. Nearly 35% of approved drugs implement their therapeutic effects by selectively interacting with specific GPCRs.
GPCRs are also called heptahelical, 7TM, or...
GPCRs are also called heptahelical, 7TM, or...


