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Molecular computation by the CaMKII holoenzyme

CaMKII 全酶的分子计算

基本信息

批准号：
10754843
负责人：
Carolyn Nicole Brown
金额：
$ 3.72万
依托单位：
UNIVERSITY OF COLORADO DENVER
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-08-01 至 2025-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10754843
关键词：
Address Affinity Avidity Binding Biochemical Biochemistry Biophysics Calmodulin Cells Cognition Complex Data Development Disease Excitatory Synapse Fluorescence Frequencies Geometry Hippocampus Holoenzymes Impairment In Vitro Individual Learning Long-Term Potentiation Mediating Mediator Memory Mental Depression Modeling Molecular Molecular Computations Mutate N-Methyl-D-Aspartate Receptors Negative Staining Neurodegenerative Disorders Neurons Phosphotransferases Positioning Attribute Process Proteins Reaction Regulation Role Signal Transduction Spectrum Analysis Stimulus Structure Synapses Synaptic plasticity Variant calmodulin-dependent protein kinase II cognitive function dimer experimental study insight monomer mutant nervous system disorder neuropsychiatric disorder response spatiotemporal stoichiometry three dimensional structure tool training opportunity

项目摘要

PROJECT SUMMARY Learning, cognition, and memory require dynamic remodeling of hippocampal synapses, which in turn requires Ca2+/calmodulin-dependent kinase II (CaMKII). CaMKII mediates two opposing modes of synaptic plasticity, long term potentiation (LTP) and depression (LTD), that are induced by distinct Ca2+ stimuli. Both low and high Ca2+ induce CaMKII autophosphorylation (p) at T286, that is required for both LTP and LTD. Additionally, LTP requires CaMKII binding to the NMDA receptor subunit, GluN2B, during high [Ca2+] while LTD requires CaMKII autophosphorylation at T305/306 during low [Ca2+]. Further, these three mechanisms can undergo complex cross-regulation which requires the CaMKII 12-meric holoenzyme. Interestingly, pT286 positively regulates both GluN2B binding and pT305/306 while GluN2B binding and pT305/306 are mutually exclusive. It is unknown how these reactions and interactions are spatiotemporally encoded within holoenzymes and thus how LTP versus LTD signal computation is accomplished by CaMKII. For example, it has been shown that pT286 must occur between two neighboring kinase domains in the holoenzyme. It is still unclear what determines a functional kinase domain neighbor. Moreover, in vitro binding studies have shown that CaMKII holoenzymes are required for binding to GluN2B, suggesting that this interaction may require multiple subunits. Still, it is unknown what is the required stoichiometry and subunit geometry required for CaMKII-GluN2B binding. Initial results suggest that the holoenzyme rules for pT286 and GluN2B binding are fundamentally different. Therefore, this proposal will investigate my hypothesis that LTP versus LTD mechanisms are regulated by structurally distinct features within CaMKII holoenzymes. The approach will utilize several CaMKII “structural mutants” that have disrupted holoenzyme structure (hexamers, dimers, and monomers). These mutants will be used as tools to define the spatiotemporal dynamics of autophosphorylation within holoenzymes and the subunit stoichiometry and geometry required for GluN2B binding. The results of this proposal will provide insight into how molecular signal computation underlying the LTP versus LTD decision is encoded within CaMKII holoenzymes.

项目概要学习、认知和记忆需要海马突触的动态重塑，这反过来又需要 Ca2+/钙调蛋白依赖性激酶 II (CaMKII)。 CaMKII 介导两种相反的突触可塑性模式，长术语增强 (LTP) 和术语抑制 (LTD)，由不同的 Ca2+ 刺激引起。低 Ca2+ 和高 Ca2+ 在 T286 处诱导 CaMKII 自磷酸化 (p)，这是 LTP 和 LTD 所必需的。此外，LTP 需要 CaMKII 在高 [Ca2+] 期间与 NMDA 受体亚基 GluN2B 结合，而 LTD 则需要 CaMKII 低 [Ca2+] 期间 T305/306 处的自磷酸化。此外，这三种机制可能经历复杂的过程交叉调节需要 CaMKII 12 聚体全酶。有趣的是，pT286 积极调节两者 GluN2B 结合和 pT305/306 而 GluN2B 结合和 pT305/306 是相互排斥的。未知如何这些反应和相互作用是在全酶内时空编码的，因此 LTP 与 LTD信号计算由CaMKII完成。例如，已经表明 pT286 必定发生全酶中两个相邻激酶结构域之间。目前尚不清楚是什么决定了功能激酶结构域邻居。此外，体外结合研究表明需要 CaMKII 全酶与 GluN2B 的结合，表明这种相互作用可能需要多个亚基。仍然未知是什么 CaMKII-GluN2B 结合所需的化学计量和亚基几何形状。初步结果表明 pT286 和 GluN2B 结合的全酶规则根本不同。因此，本提案将研究我的假设，即 LTP 与 LTD 机制是由内部结构上不同的特征调节的 CaMKII 全酶。该方法将利用几个 CaMKII“结构突变体”，这些突变体已经破坏了全酶结构（六聚体、二聚体和单体）。这些突变体将被用作定义全酶内自磷酸化的时空动力学和亚基化学计量和 GluN2B 结合所需的几何形状。该提案的结果将深入了解分子信号如何 LTP 与 LTD 决策的计算是在 CaMKII 全酶中编码的。