棒G蛋白α子单元上的一个位点,它介导了效应器激活
H M Rarick1, N O Artemyev, H E Hamm
1Department of Physiology and Biophysics, University of Illinois College of Medicine, Chicago 60680.
概括
研究人员确定了G蛋白的α子单元 (transducin alpha t) 上的一个特定区域,该区域会激活循环关素3 .
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 细胞信号传输 细胞信号传输
背景情况:
- 关氨酸核酸结合蛋白 (G蛋白) 是由受体激活的关键信号转换器.
- 通过不太了解的机制,G蛋白调节效应蛋白,如酶和离子通道.
- 转化素 (Gt) 是一种G蛋白,对于棒光受体中的光传导至关重要.
研究的目的:
- 确定G蛋白转化素α子单元上负责激活循环诺辛3',5'-单酸二化酶 (cGMP PDE) 的特定部位.
- 阐明alpha t子单元中的相互作用域,该相互作用域将受体激活与效应器激活联系起来.
主要方法:
- 网站导向的突变发生和合成,以映射功能域.
- 生物化学测试以测量基化酶 (PDE) 活性.
主要成果:
- 从转化素αt (αt) 的COOH终端区域中发现的一种22氨基酸 (残留物293-314) 完全模仿完整的αt子单元的活性.
- 这种激活了cGMP酸化酶 (PDE).
- 已识别的功能部位位于α t子单元的受体激活域附近.
结论:
- 阿尔法t子单元的COOH终端区域包含了cGMP PDE的效应器相互作用和激活的关键部位.
- 这一区域似乎也参与了受体结合,这表明它在信号传导中发挥了双重作用.
- 阐明这种相互作用部位可以了解光传导的分子机制.
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.
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...
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...
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...


