Structural and Allosteric Mechanisms of mGluR Activation

mGluR 激活的结构和变构机制

• 批准号: 10679316
• 负责人: Alexa Strauss
• 金额: $ 4.77万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10679316
• 关键词: Address; Affinity; Agonist; Alzheimer' s Disease; Anxiety; Architecture; Binding; Biological Assay; Brain; Brain region; C-terminal; Cells; Complex; Coupled; Coupling; Cryoelectron Microscopy; Cysteine; Cysteine-Rich Domain; Data; Dimerization; Disease; Drug Targeting; Exhibits; Extracellular Domain; Family; G-Protein-Coupled Receptors; GTP-Binding Proteins; Glutamates; Heterodimerization; Heterogeneity; Homo; In Vitro; Kinetics; Length; Ligand Binding; Ligand Binding Domain; Ligands; Mediating; Mental Depression; Mental disorders; Metabotropic Glutamate Receptors; Modeling; Molecular; Molecular Conformation; Molecular Probes; Mutation; Nervous System; Neurotransmitters; Pathway interactions; Pattern; Pharmacology; Physiological; Play; Property; Publishing; Receptor Activation; Receptor Signaling; Reporting; Resolution; Role; Schizophrenia; Sequence Homology; Series; Shapes; Structure; Synapses; Synaptic Transmission; System; Techniques; Transmembrane Domain; Visualization; Work; biophysical analysis; biophysical techniques; comparative; dimer; extracellular; improved; insight; metabotropic glutamate receptor 2; metabotropic glutamate receptor 3; nervous system disorder; neurotransmitter release; novel; patch clamp; pharmacologic; positive allosteric modulator; receptor; receptor function; recruit; response; tool

ABSTRACT In the nervous system, G protein coupled receptors (GPCRs) serve to detect the precise spatial and temporal pattern of neurotransmitter release to modulate synaptic transmission. The metabotropic glutamate receptors (mGluRs) are family C GPCRs that sense the excitatory neurotransmitter glutamate. mGluRs are constitutive dimers with a large extracellular ligand binding domain which is connected to a seven-helix transmembrane domain via an intermediate cysteine-rich linker. There are eight mGluR subtypes, which are expressed in overlapping regions of the brain and play distinct roles at the synapse. Additionally, mGluRs readily form heterodimers, increasing the molecular diversity and functional complexity of this system. Recent breakthroughs in cryogenic electron microscopy (cryo-EM) have led to full-length structures of mGluRs, providing an improved understanding of the overall architecture of this receptor. However, these structures raise further questions regarding the dynamic rearrangements that occur upon activation. While the extracellular domain is known to undergo glutamate-induced rearrangements, how these conformational changes are coupled to yield activation and G protein recruitment at the TMD remains to be defined. Additionally, how this coupling is tuned across mGluR homo- and heterodimer subtypes to produce the observed differences in activation properties is unknown. The group II mGluRs are ideal candidates for addressing these questions and are the focus of this proposal. Group II mGluRs consist of mGluR2 and mGluR3, which have the highest sequence homology of all mGluRs, yet still show distinct glutamate affinity, kinetics, and basal activity. Furthermore, mGluR2 and mGluR3 readily heterodimerize in the brain. In this proposal, I will use a combination of cryo-EM structural analysis and functional assays in addition to subtype specific pharmacological compounds. Using these tools, I will probe the conformational dynamics of group II mGluRs, with a focus on the allosteric mechanisms that couple ligand binding to transmembrane domain activation. Together, this work will provide a high-resolution picture of activation for mGluR homo- and heterodimers.

抽象的 在神经系统中，G 蛋白偶联受体 (GPCR) 用于检测精确的空间和时间信号。 神经递质释放模式以调节突触传递。代谢型谷氨酸受体 (mGluR) 是 C 族 GPCR，可感知兴奋性神经递质谷氨酸。 mGluR 是组成型的 具有大的细胞外配体结合结构域的二聚体，该结构域连接到七螺旋跨膜 通过中间富含半胱氨酸的接头的结构域。 mGluR 有八种亚型，其表达形式为 大脑的重叠区域并在突触中发挥不同的作用。此外，mGluR 很容易形成 异二聚体，增加了该系统的分子多样性和功能复杂性。近期突破 低温电子显微镜 (cryo-EM) 的研究已经获得了 mGluR 的全长结构，从而提供了改进的 了解该受体的整体结构。然而，这些结构引发了进一步的问题 关于激活时发生的动态重排。虽然已知细胞外结构域 经历谷氨酸诱导的重排，这些构象变化如何耦合以产生激活 TMD 处的 G 蛋白募集仍有待定义。此外，如何调整这种耦合 mGluR 同二聚体和异二聚体亚型产生观察到的激活特性差异 未知。 II 组 mGluR 是解决这些问题的理想候选者，也是本文的重点 提议。 II 组 mGluR 由 mGluR2 和 mGluR3 组成，它们在所有 mGluR 中具有最高的序列同源性 mGluR，但仍表现出独特的谷氨酸亲和力、动力学和基础活性。此外，mGluR2 和 mGluR3 很容易在大脑中形成异二聚体。在这个提案中，我将结合使用冷冻电镜结构分析和 除了亚型特定药理学化合物之外的功能测定。使用这些工具，我将探究 II 组 mGluR 的构象动力学，重点关注配体偶联的变构机制 结合跨膜结构域激活。总之，这项工作将提供一个高分辨率的图片 mGluR 同二聚体和异二聚体的激活。