AKAP Regulation of Neuronal L-type Calcium Channel Signaling to the Nucleus

AKAP 对神经元 L 型钙通道向细胞核信号传导的调节

基本信息

批准号：
8530768
负责人：
MARK L DELL'ACQUA
金额：
$ 53.9万
依托单位：
UNIVERSITY OF COLORADO DENVER
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-12-15 至 2015-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8530768
关键词：
A kinase anchoring protein Acute Adrenergic Agonists Adrenergic Receptor Aging Agonist Alzheimer&apos s Disease Autistic Disorder Binding Brain Calcineurin Calcium Calcium ion Calmodulin Cell Nucleus Cells Chronic Communication Coupling Cyclic AMP Cyclic AMP-Dependent Protein Kinases Cyclic AMP-Responsive DNA-Binding Protein Data Dendrites Dendritic Spines Development Distal Down Syndrome Feedback Forskolin Funding Gene Expression Gene Targeting Genetic Transcription Glutamate Receptor Glutamates Hippocampus (Brain)Image Impaired cognition Intellectual functioning disability Knock-in Mouse L Cells L-Type Calcium Channels Lasers Late Gene Transcriptions Lead Learning Leucine Zippers Link Long-Term Potentiation Luciferases Memory Messenger RNA Molecular Molecular Profiling Monitor Mus Nerve Degeneration Neuronal Plasticity Neurons Nimodipine PIX protein Pathway interactions Phase Phosphoric Monoester Hydrolases Phosphorylation Phosphotransferases Positioning Attribute Protein Binding Protein Kinase RNA Interference Rattus Receptor Activation Regulation Reporter Role Scaffolding Protein Schizophrenia Signal Transduction Site Slice Stimulus Synapses Synaptic plasticity T-Cell Activation Testing Time Timothy syndrome Transcription Factor AP-1 Transcriptional Regulation Vertebral column activating transcription factor calcineurin phosphatase cellular imaging computerized data processing delta protein extracellular mRNA Expression mutant neuronal cell body novel novel therapeutics nuclear factors of activated T-cells postsynaptic protein complex public health relevance response transcription factor voltage

项目摘要

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. Depolarizing stimuli that open LTCCs activate the transcription factors cAMP-response element binding protein (CREB) and nuclear factor of activated T-cells (NFAT) through Ca2+-regulated kinase and phosphatases. Importantly, LTCC transcriptional regulation is required for long-lasting forms of excitatory synaptic plasticity that underlie learning and memory, such as late-phase long-term potentiation (L-LTP). Thus, it is crucial to understand how LTCC activity and signaling are controlled to promote efficient, specific synapse to nucleus communication. The primary question in synapse-to-nucleus signaling is how local Ca2+ signals generated in dendrites are relayed remotely to the nucleus in the soma. In the last funding period, we established the postsynaptic scaffold protein A-kinase anchoring protein (AKAP) 79/150, which binds to CaV1.2 through a modified leucine zipper (LZ) motif and anchors the cAMP-dependent protein kinase (PKA) and Ca2+-calmodulin (CaM)-activated protein phosphatase-2B (calcineurin; CaN), as an essential regulator of neuronal LTCC currents and NFAT activation. We found that AKAP-anchored PKA promoted LTCC current enhancement that was strongly opposed by a Ca2+ negative feedback loop activating AKAP-anchored CaN to favor rapid, calcium-dependent inactivation (CDI). In addition, we found that local LTCC activation of AKAP-anchored CaN was required for NFAT translocation to the nucleus and transcription in response to depolarization. However, key questions remain regarding whether AKAP79/150 regulates LTCC Ca2+ influx specifically in dendritic spines in response to glutamate receptor activation and whether postsynaptic Ca2+ signals restricted in dendrites can locally activate CaN-NFAT signaling to the nucleus. We will explore these questions using a combination of whole-cell LTCC current recordings, local glutamate uncaging, Ca2+ imaging (Aim 1), NFAT imaging (Aim 2), transcriptional analyses, and extracellular recordings of L-LTP (Aim 3). In all three aims, AKAP79/150 regulation of LTCC activity and NFAT signaling will be investigated by expressing PKA anchoring deficient (delta-PKA), CaN anchoring deficient (delta-PIX), and LZ domain (delta-LZ) AKAP79 mutants in in rat neurons or using neurons from AKAP150 delta-PIX and delta-PKA knock-in mice. Overall, this project will test a central hypothesis in synapse-to-nucleus communication that postsynaptic Ca2+ signals are locally decoded in dendrites and then efficiently relayed to the nucleus to control gene expression linked to synaptic plasticity.

描述（申请人提供）：在海马神经元中，体细胞树突CaV1.2 L型电压门控Ca2+通道（LTCC）在兴奋转录（E-T）耦合中发挥作用。打开 LTCC 的去极化刺激通过 Ca2+ 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 细胞的核因子 (NFAT)。重要的是，LTCC 转录调控是学习和记忆基础的长期形式的兴奋性突触可塑性所必需的，例如晚期长时程增强 (L-LTP)。因此，了解如何控制 LTCC 活性和信号传导以促进高效、特异性的突触与细胞核的通讯至关重要。突触到细胞核信号传导的主要问题是树突中产生的局部 Ca2+ 信号如何远程传递到体细胞中的细胞核。在上一个资助期间，我们建立了突触后支架蛋白A激酶锚定蛋白（AKAP）79/150，它通过修饰的亮氨酸拉链（LZ）基序与CaV1.2结合，并锚定cAMP依赖性蛋白激酶（PKA）和 Ca2+-钙调蛋白 (CaM) 激活的蛋白磷酸酶-2B（钙调神经磷酸酶；CaN），作为神经元 LTCC 电流和 NFAT 的重要调节剂激活。我们发现 AKAP 锚定的 PKA 促进了 LTCC 电流的增强，而 Ca2+ 负反馈回路强烈反对激活 AKAP 锚定的 CaN 以促进快速的钙依赖性失活 (CDI)。此外，我们发现 AKAP 锚定的 CaN 的局部 LTCC 激活是 NFAT 易位到细胞核和响应去极化的转录所必需的。然而，关于 AKAP79/150 是否响应谷氨酸受体激活而专门调节树突棘中的 LTCC Ca2+ 流入，以及限制在树突中的突触后 Ca2+ 信号是否可以局部激活到细胞核的 CaN-NFAT 信号传导，关键问题仍然存在。我们将结合全细胞 LTCC 电流记录、局部谷氨酸解笼锁、Ca2+ 成像（目标 1）、NFAT 成像（目标 2）、转录分析和 L-LTP 细胞外记录（目标 3）来探索这些问题。在所有三个目标中，将通过在中表达 PKA 锚定缺陷 (delta-PKA)、CaN 锚定缺陷 (delta-PIX) 和 LZ 结构域 (delta-LZ) AKAP79 突变体来研究 AKAP79/150 对 LTCC 活性和 NFAT 信号传导的调节。大鼠神经元或使用来自 AKAP150 delta-PIX 和 delta-PKA 敲入小鼠的神经元。总体而言，该项目将测试突触与细胞核通讯的一个中心假设，即突触后 Ca2+ 信号在树突中本地解码，然后有效地传递到细胞核，以控制与突触可塑性相关的基因表达。