Mechanisms of Neuronal Calcineurin-NFAT Synapse-to-Nucleus Signaling

神经元钙调神经磷酸酶-NFAT 突触至细胞核信号转导机制

• 批准号: 9815268
• 负责人: MARK L DELL'ACQUA
• 金额: $ 3.89万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-12-01 至 2019-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9815268
• 关键词: A kinase anchoring protein; Acute; Aging; Alzheimer' s Disease; Attention deficit hyperactivity disorder; Binding; Biochemical; Bipolar Disorder; Brain; Calcineurin; Calcium Channel; Calcium Signaling; Calcium ion; Calmodulin; Candidate Disease Gene; Cell Communication; Cell Mobility; Cell Nucleus; Code; Communication; Complex; Coupling; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cyclic AMP-Responsive DNA-Binding Protein; Data; Dendrites; Dendritic Spines; Development; Distal; Docking; Down Syndrome; Electric Stimulation; Expression Profiling; Feedback; Fluorescence Recovery After Photobleaching; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Glutamate Receptor; Glutamates; Goals; Hippocampus (Brain); Image; Impaired cognition; Inherited; Intellectual functioning disability; Knock-in Mouse; Lasers; Lead; Learning; Leucine Zippers; Link; Major Depressive Disorder; Measures; Membrane; Memory; Molecular; Monitor; Mus; Neurodegenerative Disorders; Neuronal Plasticity; Neurons; Nuclear Translocation; Pathway interactions; Phosphoric Monoester Hydrolases; Phosphotransferases; Positioning Attribute; Process; Protein Kinase; Proteins; Receptor Activation; Regulation; Reporter Genes; Research Design; Risk; Scaffolding Protein; Schizophrenia; Shapes; Signal Pathway; Signal Transduction; Single Nucleotide Polymorphism; Slice; Synapses; Synaptic plasticity; T-Cell Activation; Testing; Time; Timothy syndrome; Transcriptional Activation; Transcriptional Regulation; Vertebral column; activating transcription factor; autism spectrum disorder; base; beta-adrenergic receptor; cellular imaging; genome wide association study; imaging approach; live cell imaging; mRNA Expression; mutant; nervous system disorder; neuronal cell body; neuropsychiatric disorder; novel; novel therapeutics; nuclear factors of activated T-cells; postsynaptic; postsynaptic neurons; programs; recruit; response; spatiotemporal; transcription factor; transcriptome sequencing; voltage

Mechanisms of Neuronal Calcineurin-NFAT Synapse-to-Nucleus Signaling Project Summary/Abstract In hippocampal neurons, somato-dendritic CaV1.2 L-type voltage-gated Ca2+ channels (LTCC) function in excitation-transcription (E-T) coupling. Depolarizations that open LTCCs in postsynaptic neurons activate the transcription factors cAMP-response element binding protein (CREB) and nuclear factor of activated T-cells (NFAT) through Ca2+-regulated kinases and phosphatases. Because LTCC transcriptional regulation is required for long-lasting forms of excitatory synaptic plasticity that underlie learning and memory, it is crucial to understand how LTCC signaling leads to efficient, spatiotemporally specific synapse-to-nucleus communication. A question of fundamental importance in synapse-to-nucleus signaling is: how are early signals in E-T coupling―Ca2+ signals in dendritic postsynaptic nanodomains―transduced into signals that are reliably relayed over long distances to the nucleus? The postsynaptic scaffold protein A-kinase anchoring protein (AKAP) 79/150 binds to CaV1.2 through a modified leucine zipper (LZ) motif. This AKAP anchors both the cAMP- dependent protein kinase (PKA), via an amphipathic α-helical motif, and the Ca2+-calmodulin (CaM)-activated protein phosphatase-2B (calcineurin; CaN), via an atypical PxIxIT docking motif. Anchoring of PKA to AKAP79/150 supports enhancement of neuronal LTCC current amplitude that is potently opposed by Ca2+-dependent feedback through AKAP-anchored CaN. LTCC activation of AKAP-localized CaN is also required for K+ depolarization-triggered NFAT translocation to the nucleus and activation of transcription. However, key synapse-to-nucleus signaling questions remain for the LTCC-AKAP-CaN-NFAT pathway: (1) does the AKAP79/150 signaling complex regulate LTCC Ca2+ influx specifically in dendrites excited by postsynaptic glutamate receptor activation; (2) do these Ca2+ signals in dendrites locally activate CaN-NFAT signaling that ultimately acts in the nucleus; (3) what are the neuronal target genes regulated by this signaling pathway; and (4) is this process engaged during synaptic plasticity? We will explore these crucial questions in three aims that rely upon a combination of Ca2+ imaging (Aim 1), CaN and NFAT imaging (Aim 2), and gene transcription analyses (Aim 3). AKAP79/150 regulation of LTCC Ca2+ influx, CaN-NFAT signaling dynamics, and activity-dependent gene transcription will be investigated in neurons or brain slices expressing AKAP mutants that alter PKA anchoring, CaN anchoring, or LZ domain binding. The overall goal of this project is to test a central hypothesis in synapse-to-nucleus communication that postsynaptic Ca2+ signals are locally re-coded in dendrites as protein-based signals (e.g., NFAT), and relayed to the nucleus to control plasticity-associated gene expression.

神经元钙调神经磷酸酶-NFAT 突触至细胞核信号转导机制 项目概要/摘要 在海马神经元中，体细胞树突 CaV1.2 L 型电压门控 Ca2+ 通道 (LTCC) 在激发-转录 (E-T) 耦合中发挥作用。打开 LTCC 的去极化 突触后神经元激活转录因子 cAMP 反应元件结合蛋白 (CREB) 和活化 T 细胞核因子 (NFAT) 通过 Ca2+ 调节激酶和 磷酸酶。因为 LTCC 转录调控是持久形式所必需的 兴奋性突触可塑性是学习和记忆的基础，了解如何实现这一点至关重要 LTCC 信号传导可实现高效、时空特异性的突触与细胞核通讯。 突触到细胞核信号传导的一个根本重要问题是：早期信号是如何产生的？ 在E-T耦合中——树突状突触后纳米结构域中的Ca2+信号——转换成信号 能可靠地远距离传送到原子核吗？ 突触后支架蛋白 A 激酶锚定蛋白 (AKAP) 79/150 结合 CaV1.2 通过修饰的亮氨酸拉链 (LZ) 基序。该 AKAP 锚定了 cAMP- 依赖蛋白激酶 (PKA)，通过两亲性 α-螺旋基序和 Ca2+-钙调蛋白 (CaM)-激活的蛋白磷酸酶-2B（钙调神经磷酸酶；CaN），通过非典型 PxIxIT 对接 主题。 PKA 锚定到 AKAP79/150 支持神经元 LTCC 电流的增强 通过 AKAP 锚定的 CaN，Ca2+ 依赖性反馈会强烈反对该振幅。 K+ 去极化触发的 NFAT 也需要 LTCC 激活 AKAP 定位的 CaN 易位至细胞核并激活转录。然而，关键的突触到细胞核 LTCC-AKAP-CaN-NFAT 通路的信号传导问题仍然存在：(1) AKAP79/150 是否 信号复合物调节突触后兴奋的树突中的 LTCC Ca2+ 流入 谷氨酸受体激活； (2) 树突中的这些Ca2+信号是否局部激活CaN-NFAT 最终在细胞核中起作用的信号； (3) 神经元调控的靶基因有哪些？ 该信号通路； （4）这个过程在突触可塑性期间参与吗？我们将 通过结合 Ca2+ 成像（Aim 1)、CaN 和 NFAT 成像（目标 2）以及基因转录分析（目标 3）。 AKAP79/150 LTCC Ca2+ 流入、CaN-NFAT 信号动力学和活性依赖性基因的调节 将在表达 AKAP 突变体的神经元或脑切片中研究转录，这些突变体改变 PKA 锚定、CaN 锚定或 LZ 结构域结合。该项目的总体目标是测试 突触与细胞核通讯的一个中心假设是，突触后 Ca2+ 信号是 在树突中局部重新编码为基于蛋白质的信号（例如 NFAT），并转发到细胞核 控制可塑性相关基因的表达。