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.

谷氨酸突触的快速传递是建立在精确而复杂的分子组织基础上的