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: 8666935
• 负责人: MARK L DELL'ACQUA
• 金额: $ 47.85万
• 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 2018-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8666935
• 关键词: A kinase anchoring protein; Acute; Adrenergic Receptor; Aging; Alzheimer' s Disease; Attention deficit hyperactivity disorder; Autistic Disorder; Binding; Biochemical; Bipolar Disorder; Brain; Calcineurin; 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; Disease; Distal; Docking; Down Syndrome; Electric Stimulation; Feedback; Fluorescence Recovery After Photobleaching; Gene Expression; Gene Expression Regulation; Gene Targeting; Genes; Genetic Transcription; Glutamate Receptor; Glutamates; Goals; Hippocampus (Brain); Image; Impaired cognition; Inherited; Intellectual functioning disability; Knock-in Mouse; Lasers; Lead; Learning; Leucine Zippers; Life; Link; Major Depressive Disorder; Measures; Membrane; Memory; Molecular; Molecular Profiling; Monitor; Mus; Neurodegenerative Disorders; Neuronal Plasticity; Neurons; Pathway interactions; Phosphoric Monoester Hydrolases; Phosphotransferases; Positioning Attribute; Process; Protein Kinase; Proteins; Receptor Activation; Regulation; Reporter Genes; 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; activating transcription factor; autism spectrum disorder; base; cellular imaging; genome wide association study; mRNA Expression; mutant; nervous system disorder; neuronal cell body; neuropsychiatry; novel; novel therapeutics; nuclear factors of activated T-cells; postsynaptic; programs; public health relevance; response; signal processing; transcription factor; voltage

DESCRIPTION (provided by applicant): 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 alpha-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.

描述（由申请人提供）：在海马神经元中，体细胞-树突状细胞CaV1.2 L型电压门控Ca 2+通道（LTCC）在兴奋-转录（E-T）偶联中发挥作用。突触后神经元中打开LTCC的去极化通过Ca 2+调节的激酶和磷酸酶激活转录因子cAMP反应元件结合蛋白（CREB）和活化T细胞核因子（NFAT）。由于LTCC转录调控是学习和记忆基础的兴奋性突触可塑性的持久形式所必需的，因此了解LTCC信号传导如何导致有效的时空特异性突触-核通信至关重要。突触到核信号传导中一个至关重要的问题是：树突状突触后纳米结构域中E-T偶联Ca 2+信号中的早期信号如何转换为长距离可靠地传递到核的信号？ 突触后支架蛋白A激酶锚定蛋白（AKAP）79/150通过修饰的亮氨酸拉链（LZ）基序与CaV 1.2结合。该AKAP通过两亲性α-螺旋基序锚定cAMP依赖性蛋白激酶（PKA），并通过非典型PxIxIT对接基序锚定Ca 2 +-钙调蛋白（CaM）-活化的蛋白磷酸酶-2B（钙调磷酸酶; CaN）。PKA与AKAP 79/150的结合支持神经元LTCC电流幅度的增强，这与通过AKAP锚定的CaN的Ca 2+依赖性反馈有力地相反。AKAP定位的CaN的LTCC激活也是K+去极化触发的NFAT易位到细胞核和转录激活所需的。然而，对于LTCC-AKAP-CaN-NFAT通路，关键的突触-核信号传导问题仍然存在：（1）AKAP 79/150信号传导复合物是否特异性地调节突触后谷氨酸受体激活所激发的树突中LTCC Ca 2+内流;（2）树突中的这些Ca 2+信号是否局部激活最终作用于核中的CaN-NFAT信号传导;（3）受此信号通路调节的神经元靶基因是什么？（4）此过程是否参与突触可塑性？我们将在三个目标中探索这些关键问题，这三个目标依赖于Ca 2+成像（Aim 1），CaN和NFAT成像（Aim 2）以及基因转录分析（Aim 3）的组合。将在表达AKAP突变体的神经元或脑切片中研究AKAP 79/150对LTCC Ca 2+内流、CaN-NFAT信号动力学和活性依赖性基因转录的调节，所述AKAP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-核通讯中的一个中心假设，即突触后Ca 2+信号在树突中局部重新编码为基于蛋白质的信号（例如，NFAT），并传递到细胞核，以控制可塑性相关基因的表达。