光受体G蛋白的法化玛子单元对于GTP结合至关重要
Nature
|August 16, 1990
概括
玛子单元 (T gamma-2) 上的法纳西尔修饰对于转化素在视觉细胞中的GTP结合活性至关重要. 这种修改区分了活跃的Tβ-玛-2与不活跃的Tβ-玛-1组件.
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:
- 转化素是一种异构三分子G蛋白,对于视觉细胞中的光传导至关重要.
- 牛转化素的Tβ-玛子单位可以分为两种形式:Tβ-玛-1和Tβ-玛-2.
- 与Tβ-玛-1相比,Tβ-玛-2显著增强了GTP与Tα-α的结合.
研究的目的:
- 调查Tβ-玛-1和Tβ-玛-2的差异活性的分子基础.
- 为了确定翻译后修改在转化素功能中的作用.
主要方法:
- 对T玛-1和T玛-2子单位的翻译后修改的分析.
- 生物化学试验测量在修改后的子单位的存在下测量GTP结合活性.
主要成果:
- 活性T马-2亚单元具有与其C终端的氨酸相连的法尼西尔部分,该部分进一步被甲基化.
- 不活跃的T玛-1亚单元缺乏这些修饰.
- 玛子单元的法尼基化对于转录素的GTP结合活性是不可或缺的.
结论:
- 玛子单元的翻译后法内基化对于转化素的激活至关重要.
- 类似的修改可能涉及其他G蛋白玛子单元在信号传导中的功能.
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...
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 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...


