Architecture of inhibitory G protein signaling in the hippocampus

海马抑制性 G 蛋白信号传导的结构

• 批准号: 10659438
• 负责人: Kirill A. Martemyanov
• 金额: $ 66.58万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10659438
• 关键词: Ablation; Adaptor Signaling Protein; Adenylate Cyclase; Affect; Affective; Aminobutyric Acids; Architecture; Behavior; Binding; Biochemical; Biological Assay; Brain; Cells; Cognition; Cognitive; Collaborations; Complex; Coupling; Custom; Data; Dedications; Disease; Electrophysiology (science); Elements; Ensure; Enzymes; Epilepsy; Family; G-Protein-Coupled Receptors; GTP-Binding Protein Regulators; GTP-Binding Proteins; Genetic; Goals; Hippocampus; Interdisciplinary Study; Investments; Ion Channel; Knowledge; Mediating; Modeling; Molecular; Mus; Negative Finding; Neurologic; Neurons; Neurotransmitters; Optical reporter; Optics; Orphan; Play; Protein Family; Proteins; RGS Proteins; Receptor Signaling; Regulation; Research Proposals; Resolution; Role; Route; Shapes; Signal Pathway; Signal Transduction; Signaling Protein; Structure; Synaptic plasticity; Testing; Therapeutic Intervention; Time; Work; assay development; convict; design; gain of function; gamma-Aminobutyric Acid; genetic manipulation; hippocampal pyramidal neuron; innovation; insight; loss of function; member; multidisciplinary; nervous system disorder; novel; novel therapeutic intervention; palmitoylation; predictive modeling; programs; receptor; reconstitution; tool; tool development

SUMMARY Dysregulation of inhibitory G protein-dependent signaling, including signaling controlled by the GABAB receptor (GABABR), is implicated in many neurological disorders and diseases. In the hippocampus (HPC), GABABR exerts much of its inhibitory influence by activating G protein-gated Inwardly Rectifying K+ (GIRK/Kir3) channels and by inhibiting Adenylyl Cyclase (AC). We have shown that GABABR-GIRK signaling in the HPC is modulated by Regulator of G protein Signaling (RGS) proteins of the R7 sub-family, which sharpen the timing and dampen the sensitivity of this signaling pathway. The R7 RGS sub-family includes RGS6 and RGS7, which form stable complexes with G5. Genetic ablation of RGS7/G5 complexes in mice profoundly alters GABABR-GIRK signaling, disrupting synaptic plasticity and HPC-dependent behaviors. R7 RGS/G5 complexes can also associate with adaptor proteins, including the small palmitoylated protein R7BP and an orphan Class C GPCR (GPR158). Our recent work suggests the intriguing prospect that discrete R7 RGS/G5 complexes, together with R7BP and GPR158, play an essential role in the selective routing of GABABR signals to GIRK channels or AC. These findings fuel our central hypothesis that R7 RGS/G5 complexes and their adaptors orchestrate the assembly of inhibitory "signalosomes” – distinct physical and/or functional arrays of receptors, G proteins, RGS and related proteins, and effectors – to ensure the dedicated and selective regulation of effector enzymes and ion channels by GABABR. To test this innovative hypothesis, we propose a multi-disciplinary program with two AIMs: 1) Identify mechanisms mediating GABABR-effector signaling dynamics and compartmentalization. We will employ loss- and gain-of-function/rescue genetic manipulations in HPC pyramidal neurons, along with electrophysiological and real-time optical assessments of GABABR-effector signaling, to test the prospect that discrete R7 RGS/G5 complexes and their adaptors, working in concert with their inhibitory G protein substrates, orchestrate the assembly of distinct and dedicated GABABR-GIRK and GABABR-AC signalosomes. 2) Interrogate the organization of the GABABR-GIRK signalosome. Leveraging insights derived from our recent crystal structure of RGS7/G5 and associated predictive modeling, we will use cell-based biochemical and optical reporter assays, as well as orthogonal biochemical reconstitution approaches, to test hypotheses related to interactions and interfaces among GABABR-GIRK signalosome elements. Structural insights into GABABR- GIRK signalosome assembly will then be exploited to probe the functional relevance of specific interactions. Summary: Our efforts will reveal whether R7 RGS/G5 complexes and adaptors orchestrate selective signaling between GABABR and its effectors. This project will yield new mechanistic insights into the functional and physical compartmentalization of GABABR-effector signaling, knowledge that can be used to design novel therapeutic interventions for neurological disorders and diseases characterized by aberrant GABABR-dependent signaling.

概括 抑制性G蛋白依赖性信号传导的失调，包括由GABAB接收器控制的信号传导 （Gababr）在许多神经系统疾病和疾病中实施。在海马（HPC）中，Gababr 通过激活G蛋白质门控的K+（GIRK/KIR3）通道来发挥其许多抑制作用 并通过抑制腺苷酸环化酶（AC）。我们已经表明，HPC中的Gababr-Girk信号传导已调制 通过R7子家庭的G蛋白信号传导（RGS）蛋白的调节剂，该蛋白可以锐化时间和该死 该信号通路的灵敏度。 R7 RGS子家庭包括RGS6和RGS7，它们形成稳定 与G5的复合物。小鼠中RGS7/G5复合物的遗传消融深刻改变了Gababr-Girk 信号，破坏突触可塑性和HPC依赖性行为。 R7 RGS/G5复合物也可以 与衔接蛋白合作，包括小棕榈酰化蛋白R7BP和孤儿C级GPCR （GPR158）。我们最近的工作表明，令人着迷 R7BP和GPR158，在GABABR信号与Girk通道或AC的选择性路由中起着至关重要的作用。 这些发现助长了我们的中心假设，即R7 RGS/G5络合物及其适配器协调了 抑制性“信号体”的组装 - 受体，G蛋白，RGS的不同物理和/或功能阵列 以及相关蛋白质和作用 - 确保对效应酶的专用和选择性调节 Gababr的离子通道。为了检验这一创新的假设，我们提出了一个多学科计划 目的：1）确定介导Gababr-peffer信号传导动力学和分室化的机制。我们 员工会在HPC锥体神经元中雇员损失和功能收益/救援遗传操作 Gababr-效应器信号传导的电生理和实时光学评估，以测试前景 离散的R7 RGS/G5复合物及其适配器，与抑制性G蛋白底物一起工作， 策划不同的，专用的Gababr-Girk和Gababr-AC信号体的组装。 2） 询问Gababr-Girk信号体的组织。利用我们最新的见解 RGS7/G5和相关的预测建模的晶体结构，我们将使用基于细胞的生化和 光学记者测定以及正交生化重建方法，以检验与假设相关的 与Gababr-Girk信号体元素之间的相互作用和接口。对Gababr-的结构见解 然后，将探索Girk信号体组装以探测特定相互作用的功能相关性。 摘要：我们的努力将揭示R7 RGS/G5复合物和适配器是否协调选择性信号 在Gababr及其影响之间。该项目将对功能的新机械见解和 Gababr-效应器信号传导的物理分区化，可用于设计新颖的知识 对神经系统疾病和疾病的治疗干预措施，其特征是Gababr依赖性异常 信号。