Regulation of NMDAR-Mediated Synaptic Signaling

NMDAR 介导的突触信号传导的调节

• 批准号: 10533340
• 负责人: Andres Villu Maricq
• 金额: $ 52.85万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-15 至 2026-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10533340
• 关键词: Active Biological Transport; Amino Acids; Behavior; Binding; Biological Models; Caenorhabditis elegans; Cell model; Chimera organism; Clinical; Data; Development; Disease; Drosophila genus; Exhibits; Genes; Genetic; Genetic Screening; Genetic Techniques; Glutamate Receptor; Glutamates; Goals; Homologous Gene; Invertebrates; Kinetics; Learning; Long-Term Potentiation; Maps; Mediating; Memory; Mental Depression; Mental Health; Mental disorders; Modality; Modeling; Molecular; Molecular Motors; Mutation; N-Methylaspartate; Nervous System; Neurodegenerative Disorders; Neurons; Neurophysiology - biologic function; Neurotransmitters; Process; Proteins; Recombinants; Regulation; Research; Resolution; Role; Scaffolding Protein; Schizophrenia; Signal Transduction; Site; Structure; Synapses; Synaptic plasticity; Testing; Transgenic Organisms; Work; chemical genetics; experimental study; in vivo; insight; nervous system disorder; neural; neural circuit; new therapeutic target; novel; novel therapeutics; optogenetics; overexpression; postsynaptic; presynaptic; protein protein interaction; receptor; synaptic function

PROJECT SUMMARY/ABSTRACT We propose to study the NMDA-subtype (NMDARs) of ionotropic glutamate receptors (iGluRs) and their regulation by NRAP-1, the first identified NMDAR-specific auxiliary protein, which we recently discovered in a genetic screen for modifiers of NMDAR-mediated behavior in C. elegans. NMDARs are evolutionarily conserved and well known for their role in synaptic plasticity, i.e., long-term potentiation (LTP); their importance for cellular models of learning and memory; and their direct or indirect involvement in many neurological and psychiatric disorders. Although NRAP-1 modifies the function of postsynaptic NMDARs, we showed that it was released by presynaptic glutamatergic neurons. This discovery provided a major conceptual advance in our understanding of the regulation of NMDAR-mediated synaptic signaling, with implications for both the control of synaptic strength and for certain clinical disorders involving NMDARs. In preliminary experiments, we successfully obtained crystals of recombinantly produced NRAP-1 and determined the crystal structure at 1.9 Å resolution. Elucidating the structure of NRAP-1 has provided important new insight into how NRAP-1 modifies NMDAR function. By studying vertebrate and C. elegans NMDARs, we have also demonstrated a fundamental importance for the NMDAR amino-terminal domain (ATD) with respect to both receptor gating and to the mechanism of action of NRAP-1. We now plan to build on this foundational work and ask how NRAP-1 functions to modulate NMDAR function, i.e., what are the interactions between NRAP-1 and NMDARs, and how do these interactions change receptor kinetics? In contrast to overexpression of NMDARs, we discovered that overexpression of NRAP-1 in vivo significantly increased NMDAR-mediated currents and behavior. This has important implications for the control of synaptic plasticity. Furthermore, we found that NRAP-1 is actively transported along neural processes. Together, these findings suggest that modulating NRAP-1 secretion might be a mechanism used to regulate activity dependent changes in synaptic strength. Therefore, we will address the molecular requirements for the transport and secretion of NRAP-1. The relevance of our proposed studies is high because disorders of NMDAR-mediated signaling are implicated in synaptopathies associated with neurodegenerative disorders as well as for mental health illnesses such as schizophrenia and depression. Synaptic molecules are evolutionarily conserved, and our understanding of the mechanisms that regulate synaptic signaling has greatly benefited from genetics-based studies in invertebrates such as Drosophila and C. elegans. Notably, NMDARs and NRAP-1-like proteins appear to have co-evolved suggesting that vertebrate NMDARs are likely regulated by auxiliary proteins. We therefore anticipate that our planned studies will help provide a framework for a new mechanistic understanding of NMDARs centered on protein-protein interactions.

项目概要/摘要 我们建议研究离子型谷氨酸受体 (iGluR) 的 NMDA 亚型 (NMDAR) 及其作用 NRAP-1 是第一个确定的 NMDAR 特异性辅助蛋白，我们最近在 线虫 NMDAR 介导行为修饰因子的遗传筛选。 NMDAR 正在进化 因其在突触可塑性（即长时程增强（LTP））中的作用而保守且众所周知；他们的重要性 用于学习和记忆的细胞模型；以及他们直接或间接参与许多神经系统和 精神疾病。尽管 NRAP-1 改变了突触后 NMDAR 的功能，但我们表明它是 由突触前谷氨酸能神经元释放。这一发现为我们的研究提供了重大的概念性进展 了解 NMDAR 介导的突触信号传导的调节，对控制 突触强度以及涉及 NMDAR 的某些临床疾病。在初步实验中，我们 成功获得重组产生的NRAP-1晶体，并确定晶体结构1.9 分辨率。阐明 NRAP-1 的结构为了解 NRAP-1 如何发挥作用提供了重要的新见解 修改NMDAR功能。通过研究脊椎动物和线虫 NMDAR，我们还证明了 NMDAR 氨基末端结构域 (ATD) 对于受体门控和 NRAP-1 的作用机制。我们现在计划以这项基础工作为基础，并询问 NRAP-1 如何 调节 NMDAR 功能的功能，即 NRAP-1 和 NMDAR 之间的相互作用是什么，以及 这些相互作用如何改变受体动力学？与 NMDAR 的过度表达相反，我们发现 体内过度表达 NRAP-1 显着增加 NMDAR 介导的电流和行为。这 对于突触可塑性的控制具有重要意义。此外，我们发现 NRAP-1 积极 沿着神经过程运输。总之，这些发现表明调节 NRAP-1 分泌可能 是一种用于调节突触强度活动依赖性变化的机制。因此，我们将解决 NRAP-1 运输和分泌的分子要求。我们提出的研究的相关性 之所以高，是因为 NMDAR 介导的信号传导紊乱与以下疾病相关的突触病有关 神经退行性疾病以及精神分裂症和抑郁症等精神健康疾病。 突触分子在进化上是保守的，我们对调节机制的理解 突触信号传导极大地受益于无脊椎动物（例如果蝇和 C.线虫。值得注意的是，NMDAR 和 NRAP-1 样蛋白似乎共同进化，表明脊椎动物 NMDAR 可能受辅助蛋白调节。因此，我们预计我们计划的研究将有助于 为以蛋白质-蛋白质为中心的 NMDAR 新机制理解提供框架 互动。