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.

总结 抑制性G蛋白依赖性信号传导失调，包括GABAB受体控制的信号传导 （GABABR）与许多神经障碍和疾病有关。在海马（HPC），GABABR 其抑制作用主要是通过激活G蛋白门控的抑制整流钾通道（GIRK/Kir 3）发挥的 和通过抑制腺苷酸环化酶（AC）。我们已经证明，GABABR-GIRK信号在HPC中被调节， 通过R7亚家族的G蛋白信号转导调节器（RGS）蛋白，其使时间变快并抑制 这个信号通路的敏感性。R7 RGS亚家族包括RGS 6和RGS 7，其形成稳定的 与G-15的复合物。小鼠中RGS 7/GIR 5复合物的基因切除深刻地改变了GABABR-GIRK 信号传导，破坏突触可塑性和HPC依赖性行为。R7 RGS/G β 5复合物还可以 与衔接蛋白相关，包括小的棕榈酰化蛋白R7 BP和孤儿C类GPCR （GPR158）。我们最近的工作表明了一个有趣的前景，即离散的R7 RGS/G β 5复合物， R7 BP和GPR 158在GABABR信号选择性路由到GIRK通道或AC中起重要作用。 这些发现支持了我们的中心假设，即R7 RGS/G β 5复合物及其衔接子协调了细胞的生长。 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 和相关的蛋白质和效应物-以确保效应酶的专用和选择性调节， 离子通道GABABR。为了验证这一创新假设，我们提出了一个多学科的计划， AIM：1）确定介导GABABR效应物信号传导动力学和区室化的机制。我们 将在HPC锥体神经元中采用功能丧失和获得/拯救遗传操作，沿着 电生理学和实时光学评估GABABR效应信号，以测试前景， 离散的R7 RGS/G β 5复合物及其衔接子，与它们的抑制性G蛋白底物协同工作， 协调不同的和专用的GABABR-GIRK和GABABR-AC信号体的组装。（二） 询问GABABR-GIRK信号体的组织。利用从我们最近的 RGS 7/GST 15的晶体结构和相关的预测模型，我们将使用基于细胞的生化和 光学报告基因测定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的结构性见解- GIRK信号体组装将被用来探测特定相互作用的功能相关性。 总结：我们的努力将揭示R7 RGS/G β 5复合物和衔接子是否协调选择性信号传导 GABABR及其效应物之间的联系该项目将产生新的机械见解的功能和 GABABR效应信号传导的物理区室化，可用于设计新的 用于以异常GABABR依赖性为特征的神经障碍和疾病的治疗干预 信号