GTP BINDING PROTEINS AND ADENYLATE CYCLASE

GTP 结合蛋白和腺苷酸环化酶

• 批准号: 3966536
• 负责人: S C TSAI
• 金额: --
• 依托单位: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3966536
• 关键词: adenosine diphosphate; adenylate cyclase; bacterial toxins; centrifugation; chromatography; enzyme complex; enzyme reconstitution; fluorine; gel electrophoresis; guanosine triphosphate; hormone regulation /control mechanism; pertussis; phosphodiesterases; radiotracer; rhodopsin; ribose; vanadium

Guanyl nucleotide-binding (G) proteins couple agonist interaction with cell surface receptors to an intracellular enzymatic response. In the adenylate cyclase system, inhibitory and stimulatory effects are mediated through the guanyl nucleotide-binding proteins, Gi and Gs, respectively. In the visual excitation complex, the photon receptor rhodopsin is linked to its effector, cGMP phosphodiesterase, through transducin. Bovine brain contains another G protein, Go. The G proteins are heterotrimers of Alpha, Beta, and Gamma subunits; the Alpha-subunits catalyze receptor-stimulated GTP hydrolysis. The interaction of GoAlpha with the BetaGamma subunits and rhodopsin reconstituted in phosphatidylcholine vesicles was examined. The GTPase activity of GoAlpha purified from bovine brain was stimulated by photolyzed, but not dark, rhodopsin and was enhanced by bovine retinal TBetaGamma or by rabbit liver GBetaGamma. GoAlpha in the presence of GBetaGamma is a substrate for pertussis toxincatalyzed ADP-ribosylation; the modification was inhibited by photolyzed rhodopsin and enhanced by GDPBetaS. ADP-ribosylation of GoAlpha by pertussis toxin inhibited photolyzed rhodopsin-stimulated but not basal GTPase activity. It would appear from this and prior studies that GoAlpha is similar to TAlpha and GiAlpha; all three exhibit photolyzed rhodopsin-stimulated GTPase activity, are pertussis toxin substrates, and functionally couple to TBetaGamma. Monoclonal and polyclonal antibodies against G protein subunits have been prepared and characterized. Some of these have effects on function and some have been useful for identification of G proteins in tissues.

鸟苷酸结合（G）蛋白偶联激动剂与细胞相互作用 细胞内酶反应的表面受体。 在腺苷酸中 环化酶系统，抑制和刺激作用是通过介导的 鸟苷酸结合蛋白，分别为Gi和Gs。 在视觉 激发复合物，光子受体视紫红质连接到其 效应子，cGMP磷酸二酯酶，通过转导。 牛脑 含有另一种G蛋白Go G蛋白是α的异源三聚体， β和γ亚基; α亚基催化受体刺激的 GTP水解。 GoAlpha与BetaGamma亚基的相互作用 检测了在磷脂酰胆碱囊泡中重构的视紫红质。 的 从牛脑中纯化的GoAlpha的GT3活性通过以下刺激： 光解，但不是黑暗，视紫红质和增强牛视网膜 TBetaGamma或兔肝GBetaGamma。 GoAlpha在存在 GBetaGamma是百日咳毒素催化ADP-核糖基化的底物; 光降解的视紫红质对修饰有抑制作用， GDPBetaS。 百日咳毒素抑制GoAlpha的ADP-核糖基化 光解的视紫红质刺激的但不是基础的GT3活性。 它将 从这项研究和先前的研究中可以看出，GoAlpha与TAlpha相似， GiAlpha;所有三种都表现出光解视紫红质刺激的GT3活性， 是百日咳毒素底物，并在功能上与T β γ偶联。 针对G蛋白亚基的单克隆和多克隆抗体已经被发现， 制备和表征。 其中一些对功能有影响， 有些已用于鉴定组织中的G蛋白。