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，somato dendritic cav1.2 L型电压门控CA2+通道（LTCC）在激发转录（E-T）耦合中的功能。在突触后神经元中开放LTCC的去极化激活了转录因子cAMP响应元件结合蛋白（CREB）和激活的T细胞（NFAT）的核因子（NFAT）通过CA2+调节激酶和磷酸酶。由于LTCC的转录调节是学习和记忆构成的兴奋性突触可塑性形式所必需的，因此了解LTCC信号如何导致有效，时空特定特定的突触与核核通信至关重要。突触到核信号传导的基本意义的问题是：E-T耦合Ca2+信号中的早期信号在树突状后突触后纳米域中如何转移到信号中，这些信号会在长距离远距离转移到核的长距离中可靠地中继？ 突触后支架蛋白A-激酶锚定蛋白（AKAP）79/150通过改良的亮氨酸拉链（LZ）基序与CAV1.2结合。这种AKAP通过两亲性α-螺旋基序和Ca2+-calmodulin（CAM）激活的蛋白磷酸酶-2B（钙调蛋白; CAN）锚定cAMP依赖性蛋白激酶（PKA）（PKA）。将PKA锚定在AKAP79/150上支持了神经元LTCC电流幅度的增强，这些振幅通过AKAP锚定的CAN有效地与Ca2+依赖性反馈相反。 K+去极化触发的NFAT易位向细胞核和转录的激活也需要AKAP平局的LTCC激活。但是，LTCC-AKAP-CAN-NFAT途径仍然存在关键的突触到核信号传导问题：（1）AKAP79/150信号传导复合物是否调节LTCC Ca2+涌入在dendrites中特异性地受到突破性谷氨酸后谷氨酸受体受体激活而激发的； （2）在树突中进行这些Ca2+信号局部激活的CAN-NFAT信号传导，最终作用于核中； （3）该信号通路调节的神经元靶基因是什么？ （4）这个过程在突触可塑性期间是否参与？我们将以三个依赖Ca2+成像（AIM 1），CAN和NFAT成像（AIM 2）和基因转录分析（AIM 3）（AIM 3）的组合（AIM 3）的组合来探讨这些关键问题。 AKAP79/150 LTCC Ca2+流入，CAN-NFAT信号动力学和活动依赖性基因转录的调节将在表达AKAP突变体的神经元或脑切片中进行研究，这些AKAP突变体改变了PKA锚固，CAN锚固或LZ结构域的结合。该项目的总体目标是测试突触到核核通信中的中心假设，即突触后CA2+信号在树突中局部重新编码为基于蛋白质的信号（例如NFAT），并传递到核中以控制可变性相关的基因表达。