Molecular Mechanisms of Synaptic G Protein-Coupled Receptors

突触G蛋白偶联受体的分子机制

• 批准号: 9381245
• 负责人: Joshua Levitz
• 金额: $ 40.86万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2022-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9381245
• 关键词: Area; Biophysics; Coupling; Dimerization; Disease; Drug Targeting; Energy Transfer; Environment; G-Protein-Coupled Receptors; GABA Receptor; GTP-Binding Protein alpha Subunits, Gs; GTP-Binding Proteins; Glutamates; Goals; Health; Hippocampus (Brain); Kinetics; Lead; Ligand Binding; Ligand Binding Domain; Ligands; Link; Long-Term Depression; Measurement; Measures; Membrane; Mental disorders; Metabotropic Glutamate Receptors; Methods; Molecular; Molecular Conformation; Motion; Nervous system structure; Neurotransmitters; Optical Methods; Optics; Pattern; Pharmacology; Population; Process; Receptor Activation; Reporter; Research; Rhodopsin; Role; Signal Transduction; Specificity; Synapses; Synaptic Transmission; Transmembrane Domain; Work; beta-adrenergic receptor; biological systems; desensitization; detector; dimer; extracellular; glutamatergic signaling; improved; insight; nervous system disorder; neuronal excitability; neurotransmitter release; optical sensor; optogenetics; protein activation; receptor; response; single molecule; spatiotemporal

Project Summary In many biological systems G protein-coupled receptors (GPCRs) provide a crucial molecular link between the dynamics of the extracellular environment and the associated intracellular signaling response. In the nervous system, GPCRs serve as detectors of precise patterns of neurotransmitter release and are able to, in turn, modulate neuronal excitability and synaptic transmission. Of particular importance are the class C metabotropic glutamate (mGluR) and GABA receptors (GABABR), which respond to the major excitatory and inhibitory neurotransmitters, respectively, and serve as drug targets for neurological and psychiatric disorders. Unfortunately, our understanding of their underlying molecular mechanisms of signaling remain limited due to a lack of methods for the direct measurement and manipulation of their activity with high specificity and spatial and temporal precision. Furthermore, the biophysical activation mechanism of class C GPCRs is particularly challenging to decipher because unlike class A GPCRs, such as rhodopsin or ß-adrenergic receptors, they contain large, extracellular ligand binding domains (LBDs) that multimerize and couple, via a poorly understood mechanism, to a transmembrane domain (TMD). Our recent work has established new optical methods for directly measuring mGluR assembly and conformational dynamics at the single molecule level and has also produced an optogenetic method to manipulate receptors with subtype selectivity and high spatiotemporal precision using photoswitchable tethered ligands. These breakthroughs have advanced our understanding of how mGluRs dimerize and the initial molecular motions that lead to cooperative receptor activation, but many fundamental questions remain. In research area 1 we will dissect the activation mechanism of mGluRs and GABABRs in a quantitative, interdisciplinary way using optical approaches, including single molecule Forster resonance energy transfer (FRET) to measure conformational dynamics, in conjunction with functional reporters and detailed structural analysis. The long-term goal is to understand, biophysically, how allosteric inter-domain and inter-subunit coupling interactions permit orthosteric and allosteric ligand binding to produce G protein activation. This work will give major insight into the fundamental activation processes of a large class of membrane receptors and should provide a deeper understanding of their molecular pharmacology. In research area 2 we will improve and harness the power of optical sensors of activation and optogenetic control of receptors to probe the kinetics of different mGluR subtypes at the level of activation, signaling, and desensitization and to dissect their spatiotemporal signaling profiles at hippocampal synapses. In the long term we plan to use this information to probe the mechanism of induction of long-term depression by pre-synaptic, post-synaptic, and glial mGluR populations. This work will provide a dynamic picture of mGluR signaling that has been missing from the field and will strengthen our molecular understanding of the role of these receptors in synaptic modulation in health and disease.

项目概要 在许多生物系统中，G 蛋白偶联受体 (GPCR) 在动力学之间提供了至关重要的分子联系。 在神经系统中，GPCR 发挥着细胞外环境和相关细胞内信号反应的作用。 神经递质释放精确模式的探测器，能够反过来调节神经兴奋性和突触 特别重要的是 C 类代谢型谷氨酸 (mGluR) 和 GABA 受体 (GABABR)。 分别对主要的兴奋性和抑制性神经递质产生反应，并作为神经系统和神经系统疾病的药物靶点 不幸的是，我们对其信号传导的潜在分子机制的理解仍然有限。 由于缺乏直接测量和操纵其活动的高度特异性和空间和操作方法 此外，C 类 GPCR 的生物物理激活机制尤其难以破译。 因为与 A 类 GPCR（例如视紫红质或 β-肾上腺素受体）不同，它们含有大的细胞外配体结合 通过一种知之甚少的机制，多聚化并耦合到跨膜结构域（TMD）的结构域（LBD）。 我们最近的工作建立了直接测量 mGluR 组装和构象的新光学方法 单分子水平的动力学，还产生了一种光遗传学方法来操纵亚型受体 使用光开关系留配体的选择性和高时空精度这些突破推动了我们的发展。 了解 mGluRs 如何二聚以及导致协同受体激活的初始分子运动，但许多 在研究领域 1 中，我们将剖析 mGluR 和 GABABR 的激活机制。 使用光学方法（包括单分子福斯特共振能量）的定量、跨学科方法 转移（FRET）来测量构象动力学，结合功能生产和详细结构 长期目标是从生物物理学角度了解变构域间和亚基间耦合相互作用。 允许正构和变构配体结合以产生 G 蛋白激活。 一大类膜受体的基本激活过程，应该提供对其的更深入的了解 在研究领域 2，我们将改进和利用光学传感器的激活和作用。 受体的光遗传学控制，以在激活、信号传导、 从长远来看，脱敏并剖析它们在海马突触的时空信号传导谱。 我们计划利用这些信息来探讨突触前、突触后、 这项工作将提供该领域缺失的 mGluR 信号传导的动态图景。 并将加强我们对这些受体在健康和疾病突触调节中的作用的分子理解。