G Protein-Coupled Receptors -- Structure and Regulation

G 蛋白偶联受体——结构和调控

• 批准号: 8601084
• 负责人: Elliott M Ross
• 金额: $ 39.75万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1981
• 资助国家: 美国
• 起止时间: 1981-08-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8601084
• 关键词: Accounting; Adenylate Cyclase; Affinity; Agonist; Animals; Awareness; Behavior; Binding; Biochemical; Biochemical Reaction; Bioinformatics; Biological; Cell physiology; Cells; Chemosensitization; Complex; Coupled; Coupling; Data; Dependence; Disease; Enzymes; Equilibrium; G-Protein Signaling Pathway; G-Protein-Coupled Receptors; GTP-Binding Proteins; GTPase-Activating Proteins; Goals; Guanosine Triphosphate; Guanosine Triphosphate Phosphohydrolases; Hydrolysis; Kinetics; Libraries; Ligands; Link; Mammalian Cell; Mediating; Modeling; Monitor; Mutation; Output; Pathway interactions; Pattern; Pharmaceutical Preparations; Phospholipase C; Phospholipids; Physiology; Problem Solving; Process; Protein Binding; Protein Isoforms; Proteins; Reaction; Regulation; Research; Scheme; Signal Transduction; Signaling Protein; Stimulus; Structure; Sum; System; Testing; Therapeutic; Time; Translating; Vesicle; base; catalyst; chemical reaction; detector; extracellular; human RIPK1 protein; information processing; mutant; novel; plant fungi; protein activation; protein protein interaction; receptor; receptor coupling; receptor function; research study; response; synergism; Accounting; Adenylate Cyclase; Affinity; Agonist; Animals; Awareness; Behavior; Binding; Biochemical; Biochemical Reaction; Bioinformatics; Biological; Cell physiology; Cells; Chemosensitization; Complex; Coupled; Coupling; Data; Dependence; Disease; Enzymes; Equilibrium; G-Protein Signaling Pathway; G-Protein-Coupled Receptors; GTP-Binding Proteins; GTPase-Activating Proteins; Goals; Guanosine Triphosphate; Guanosine Triphosphate Phosphohydrolases; Hydrolysis; Kinetics; Libraries; Ligands; Link; Mammalian Cell; Mediating; Modeling; Monitor; Mutation; Output; Pathway interactions; Pattern; Pharmaceutical Preparations; Phospholipase C; Phospholipids; Physiology; Problem Solving; Process; Protein Binding; Protein Isoforms; Proteins; Reaction; Regulation; Research; Scheme; Signal Transduction; Signaling Protein; Stimulus; Structure; Sum; System; Testing; Therapeutic; Time; Translating; Vesicle; base; catalyst; chemical reaction; detector; extracellular; human RIPK1 protein; information processing; mutant; novel; plant fungi; protein activation; protein protein interaction; receptor; receptor coupling; receptor function; research study; response; synergism

DESCRIPTION (provided by applicant): We propose to study the biochemical mechanisms that underlie the timing and integration of G protein-mediated signals in cells. G protein signaling modules control diverse cellular functions in response to equally diverse inputs. Consequently, G protein signaling is involved in many disease processes, and is the target of a huge number of drugs. G protein modules consist of a conserved group of interacting proteins: receptors, G protein Ga and Gbg subunits, GTPase activating proteins (GAP) and effector proteins. A mammalian cell typically expresses about 30 G protein-coupled receptors, half-dozen G proteins and GAPs and a dozen effectors. Mechanism of action is conserved, but varies quantitatively to allow different cells to respond to extracellular signals with a wide variety of kinetic patterns, intracellular outputs and modes of signal integration. Output from a G protein module quantitatively reflects a balance of receptor-catalyzed G protein activation and GAP-promoted deactivation. The rates of signal initiation and termination thus seem linked to the level of output, but cells can control response kinetics and response levels independently. We developed a quantitative framework for analyzing how receptors and GAPs interact to solve this problem. We will test mechanisms of receptor-GAP interaction and evaluate how and when each contributes to the temporal control of signaling. They include the ability of GAPs to stabilize the association of receptors and G proteins and to directly potentiate receptor function. We recently discovered that Gaq and Gbg, each of which stimulates phospholipase C-bs (PLC- bs) in response to different receptors, together stimulate the PLC-b3 isoform with strong synergism, 10 times the sum of the activities evoked by each subunit individually. Gaq-Gbg synergism is observed in diverse animal cells. We showed that Gaq-Gbg synergism can be explained by a classical two-state allosteric model, and we propose to test the physical basis of that interaction. Further, this model predicts that any two-state enzyme that is stimulated by two different ligands will display significant synergism only if its basal activity is very low, < 0.1% of maximum. We will test this prediction by evaluating constitutively active PLC-b3 mutants for loss of synergism and constitutively deactivated PLC- b2 mutants, which should acquire synergistic regulation. We will also use this prediction to search for novel regulatory enzymes that can act as coincidence detectors for two or more ligands.

描述（由申请人提供）：我们建议研究细胞中G蛋白介导的信号的时间和整合的生化机制。 G蛋白信号传导模块控制着响应同样多样的输入的各种细胞功能。因此，G蛋白信号传导参与了许多疾病过程，并且是大量药物的目标。 G蛋白模块由一组保守的相互作用蛋白组成：受体，G蛋白GA和GBG亚基，GTPase激活蛋白（GAP）和效应蛋白。哺乳动物细胞通常表达约30克蛋白偶联受体，六个G蛋白和间隙以及十几个效应子。作用机理是保守的，但具有数量的变化，以使不同的细胞对具有多种动力学模式，细胞内输出和信号整合模式的细胞外信号响应。 G蛋白模块的输出定量反映了受体催化的G蛋白激活和间隙促进的失活的平衡。因此，信号启动和终止的速率似乎与输出水平有关，但是细胞可以独立控制响应动力学和响应水平。我们开发了一个定量框架，用于分析受体和间隙如何相互作用以解决此问题。我们将测试受体隙相互作用的机制，并评估每个人如何以及何时有助于信号的时间控制。它们包括间隙稳定受体和G蛋白缔合的能力以及直接增强受体功能的能力。 我们最近发现，GAQ和GBG刺激磷脂酶C-BS（PLC-BS）响应不同的受体，共同刺激PLC-B3具有强协同作用，是每个亚基单个亚基唤起的活动之和10倍。在多种动物细胞中观察到GAQ-GBG协同作用。我们表明，GAQ-GBG协同作用可以通过经典的两态变构模型来解释，我们建议测试这种相互作用的物理基础。此外，该模型预测，只有在其基础活性非常低，<最大的0.1％的情况下，被两种不同配体刺激的任何两态酶都会显示出显着的协同作用。我们将通过评估组成性活跃的PLC-B3突变体来测试这一预测，以损失协同作用和组成性停用的PLC-B2突变体，这应该获得协同的调节。我们还将使用此预测来搜索可以充当两个或多个配体的巧合探测器的新型调节酶。