CRCNS: Regulation of assembly and disassembly of the postsynaptic density during synaptic plasticity and its effect on AMPAR trapping

CRCNS：突触可塑性过程中突触后密度组装和拆卸的调节及其对 AMPAR 捕获的影响

• 批准号: 10613548
• 负责人: MARY B KENNEDY
• 金额: $ 30.45万
• 依托单位: SALK INSTITUTE FOR BIOLOGICAL STUDIES
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-15 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10613548
• 关键词: AMPA Receptors; Affinity; Binding; Binding Proteins; Biochemical; Brain; Child; Complex; Computer Models; Core Protein; Cytosol; DLG4 gene; Dendrites; Dendritic Spines; Diffuse; Diffusion; Electrophysiology (science); Elements; Engineering; Enzymes; Epilepsy; Equilibrium; Excision; Fluorescence Microscopy; Genetic; Glutamate Receptor; Glutamates; Goals; Guanosine Triphosphate Phosphohydrolases; In Vitro; Instruction; Intellectual functioning disability; International; Intervention; Joints; Laboratories; Learning; Ligand Binding Domain; Ligands; Liquid substance; Measurement; Measures; Medical; Membrane; Memory; Mental Health; Mental disorders; Methods; Mission; Modeling; Molecular; Mutate; Mutation; N-Methylaspartate; National Institute of Mental Health; Neurons; Patients; Phase; Phosphorylation; Physical condensation; Play; Property; Protein Binding Domain; Proteins; Recording of previous events; Regulation; Research; Role; Scaffolding Protein; Signal Transduction; Site; Surface; Synapses; Synaptic Membranes; Synaptic Transmission; Synaptic plasticity; Therapeutic; United States National Institutes of Health; Universities; Vertebral column; Vision; Work; autism spectrum disorder; calmodulin-dependent protein kinase II; cognitive disability; computational neuroscience; density; experimental study; improved; nano; nanoscale; postsynaptic; presynaptic; programs; protein complex; receptor; receptor binding; response; scaffold; superresolution microscopy; synergism; trafficking; two-dimensional; ultra high resolution

Fast glutamatergic synaptic transmission is based on a precise and complex molecular organization which requires the control of the number of AMPA-type glutamate receptors (AMPARs) at the postsynaptic sites of glutamatergic synapses on dendritic spines. The number of AMPARs varies as a function of pre- and postsynaptic activation history of the synapse. It is now well described that synapses can change their number of AMPARs and therefore, their response properties through biochemical mechanisms of synaptic plasticity. In this way, information is stored in the brain. The overall goal of this project is to use quantitative models and experiments to answer two fundamental questions about the role of an abundant postsynaptic protein, synGAP, in regulation of the numbers of AMPARs. Numerous experiments in intact neurons have revealed that the level of synGAP expressed at synapses is inversely correlated with the amount of AMPARs available at the synapses, and that synGAP helps to regulate changes in AMPAR numbers during synaptic plasticity. The enzymatic GAP domain of synGAP acts as a ratchet to adjust the rates of addition and removal of AMPARs from the surface of the dendrite. SynGAP also contains a sight that binds tightly to the major scaffold protein PSD-95 via its three protein-binding PDZ domains. Important to the mental health mission of the NIMH, SynGAP plays a critical role in learning and memory in the Brain and mutation of SynGAP is implicated in cognitive disabilities. The project is divided into two broad Aims. In Aim 1, we will answer the question: What are the mechanisms by which synGAP controls the amount of AMPA receptor in the postsynaptic density (PSD) - by control of surface amount and/or by control of availability of PDZ domain binding sites in the synapse? We will improve our existing computational model of the competition between synGAP and AMPARs for binding to PSD-95 by incorporating it into our model of AMPAR trafficking. We will use genetics and sophisticated molecular engineering to experimentally disentangle the two mechanisms. Effects on the nano-organization of AMPARs will be measured by super- resolution fluorescence microscopy and electrophysiology. Results of these experiments will be used to constrain our model of AMPAR trafficking. Aim 2, Through the synergy of experimental and computational approaches, we will address the questions: How does the formation of the condensate between synGAP and PSD-95, and the presence of additional PDZ domain-binding proteins (GluN2 receptor subunits, neuroligin, nNOS, CRIPT, etc.) influence the nano-organization of AMPAR-TARPs in the PSD in the basal state and during synaptic plasticity? RELEVANCE (See instructions): We propose a combination of computational and experimental work that will help clarify the role of synGAP in regulation of AMPARs in CNS synapses, including its role in mental illness. The work will impact a specific medical condition termed “SynGAP haploinsufficiency” or “MRD5”, in which SynGAP is mutated in ~1% of children with sporadic non-syndromic cognitive disability accompanied by autism and/or epilepsy. The medical impacts of this work are potentially quite significant as it could help to point toward specific molecular interventions with therapeutics that could improve the lives of patients with these afflictions.

快速谷氨酸突触传递基于精确而复杂的分子结构， 需要控制突触后位点 AMPA 型谷氨酸受体 (AMPAR) 的数量 AMPAR 的数量随着前和树突棘的变化而变化。 突触的突触后激活历史现在已经很好地描述了突触可以改变它们的状态。 AMPAR 的数量及其通过突触生化机制的响应特性 通过这种方式，信息被存储在大脑中，这个项目的总体目标是使用定量。 模型和实验回答了关于丰富的突触后作用的两个基本问题 蛋白质 synGAP 在完整神经元中调节 AMPAR 数量。 研究表明，突触中表达的 synGAP 水平与突触的数量呈负相关。 突触处有 AMPAR，synGAP 有助于调节 AMPAR 数量的变化 在突触可塑性过程中，synGAP 的酶促 GAP 结构域充当调节速率的棘轮。 从树突表面添加和去除 AMPAR 还包含结合的视线。 通过其三个蛋白质结合 PDZ 结构域与主要支架蛋白 PSD-95 紧密结合。 SynGAP 在 NIMH 的心理健康使命中在大脑和记忆的学习和记忆中发挥着关键作用 SynGAP 突变与认知障碍有关。该项目分为两个主要目标。 1、我们来回答这个问题：synGAP通过什么机制来控制AMPA的量 突触后密度（PSD）中的受体 - 通过控制表面量和/或通过控制可用性 突触中的 PDZ 结构域结合位点？我们将改进现有的计算模型 通过将 PSD-95 纳入我们的模型中，synGAP 和 AMPAR 之间竞争与 PSD-95 的结合 我们将利用遗传学和复杂的分子工程进行实验。 解开这两种机制。对 AMPAR 纳米组织的影响将通过超测量来测量。 这些实验的结果将用于分辨率荧光显微镜和电生理学。 目标 2，通过实验和计算的协同作用来限制我们的 AMPAR 贩运模型。 方法，我们将解决以下问题：synGAP 之间的冷凝物是如何形成的 和 PSD-95，以及其他 PDZ 结构域结合蛋白（GluN2 受体亚基， Neuroligin、nNOS、CRIPT 等）影响基底层 PSD 中 AMPAR-TARP 的纳米组织 状态和突触可塑性期间？ 相关性（参见说明）： 我们提出了计算和实验工作的结合，这将有助于阐明 synGAP 的作用 这项工作将影响 CNS 突触中 AMPAR 的调节，包括其在精神疾病中的作用。 称为“SynGAP 单倍体不足”或“MRD5”的特定医疗状况，其中 SynGAP 在 约 1% 的儿童患有散发性非综合征性认知障碍，并伴有自闭症和/或癫痫症。 这项工作的医学影响可能相当重大，因为它可以帮助指出具体的方向 分子干预疗法可以改善患有这些疾病的患者的生活。