Architecture of inhibitory G protein signaling in the hippocampus

海马抑制性 G 蛋白信号传导的结构

基本信息

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
项目类别：
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

项目摘要

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失调，包括由 GABAB 受体控制的信号传导 (GABABR)，与许多神经系统紊乱和疾病有关。通过激活 G 蛋白门控内向整流 K+ (GIRK/Kir3) 通道发挥其大部分抑制作用通过抑制腺苷酸环化酶 (AC)，我们发现 HPC 中的 GABABR-GIRK 信号传导受到调节。由 R7 亚家族的 G 蛋白信号传导 (RGS) 蛋白调节器，可锐化时间并抑制 R7 RGS 亚家族包括 RGS6 和 RGS7，形成稳定的信号通路。小鼠中 RGS7/G5 复合物的基因消除显着改变了 GABABR-GIRK。信号传导、破坏突触可塑性和 HPC 依赖性行为也可以。与接头蛋白相关，包括小棕榈酰化蛋白 R7BP 和孤儿 C 类 GPCR (GPR158)。我们最近的工作表明了离散 R7 RGS/G5 复合物的有趣前景。 R7BP 和 GPR158 在 GABABR 信号选择性路由至 GIRK 通道或 AC 中发挥着重要作用。这些发现支持了我们的中心假设，即 R7 RGS/G5 复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 的独特物理和/或功能阵列以及相关蛋白质和效应子——确保效应酶和效应子的专门和选择性调节为了测试这一创新假设，我们提出了一个包含两个的多学科计划。目标：1) 确定介导 GABABR 效应器信号动力学和区室化的机制。将在 HPC 锥体神经元中采用功能丧失和功能获得/救援遗传操作，以及 GABABR效应信号传导的电生理学和实时光学评估，以测试前景离散的 R7 RGS/G5 复合物及其接头，与其抑制性 G 蛋白底物协同工作，协调不同且专用的 GABABR-GIRK 和 GABABR-AC 信号体的组装 2)。利用我们最近的见解来探究 GABABR-GIRK 信号体的组织。 RGS7/G5 的晶体结构和相关的预测模型，我们将使用基于细胞的生物化学和光学报告分析以及正交生化重建方法，以检验相关假设 GABABR-GIRK 信号体元件之间的相互作用和界面对 GABABR- 的结构见解。然后将利用 GIRK 信号体组装来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传导该项目将对 GABABR 及其效应器之间的功能和效应产生新的机制见解。 GABABR 效应器信号传导的物理分区，可用于设计新颖的知识针对以异常 GABABR 依赖性为特征的神经系统疾病和疾病的治疗干预发信号。