Regulation of AKAP79 Postsynaptic Membrane Targeting

AKAP79 突触后膜靶向的调节

• 批准号: 8248318
• 负责人: MARK L DELL'ACQUA
• 金额: $ 39.1万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2013-05-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8248318
• 关键词: A kinase anchoring protein; Actins; Acute; Alzheimer' s Disease; Binding; Brain Injuries; Cadherins; Calcineurin; Cell Adhesion Molecules; Cessation of life; Cognition; Controlled Study; Cyclic AMP-Dependent Protein Kinases; Cytoskeleton; DLG1 gene; Dendritic Spines; Down Syndrome; Epilepsy; Event; Excision; Excitatory Synapse; F-Actin; Funding; Glutamate Receptor; Health; Hippocampus (Brain); Knock-in Mouse; Knock-out; Lead; Learning; Link; Long-Term Depression; Long-Term Potentiation; Mediating; Membrane; Memory; Mental Depression; Mental disorders; Methods; Morphology; Movement; Mus; Mutant Strains Mice; N-Methylaspartate; N-terminal; Neurodegenerative Disorders; Neurons; Pathway interactions; Phosphatidylinositol 4,5-Diphosphate; Phospholipase C; Phosphorylation; Play; Postsynaptic Membrane; Process; Protein Dephosphorylation; Protein Kinase; Proteins; RNA Interference; Rattus; Receptor Activation; Recruitment Activity; Regulation; Role; Scaffolding Protein; Schizophrenia; Signal Pathway; Signal Transduction; Signaling Protein; Slice; Stroke; Structure; Surface; Synapses; Synaptic plasticity; Testing; Vertebral column; cofilin; computerized data processing; density; depolymerization; human disease; link protein; membrane-associated guanylate kinase; mutant; nervous system disorder; novel; overexpression; palmitoylation; polymerization; postsynaptic; presynaptic density protein 95; protein protein interaction; receptor function; scaffold

DESCRIPTION (provided by applicant): At the postsynaptic density (PSD) of neuronal excitatory synapses, AMPA (AMPAR) and NMDA (NMDAR) glutamate receptors are linked to signaling proteins and the actin cytoskeleton in dendritic spines through a network of scaffolding proteins that play important roles during synaptic plasticity underlying learning and memory. AMPARs are recruited to dendritic spines through NMDAR activation during induction of long term potentiation (LTP) in hippocampal neurons through pathways that also increase spine size and actin polymerization. Phosphorylation of AMPAR-GluR1 subunits by the cAMP-dependent protein kinase (PKA) may promote surface expression of AMPARs recruited during LTP. In contrast, induction of long-term depression (LTD) leads to calcineurin-protein phosphatase 2B (CaN) mediated dephosphorylation of PKA phosphorylated GluR1, removal of AMPARs from synapses and depolymerization of spine actin followed by spine shrinkage. However, mechanisms for coordinately regulating AMPAR localization, phosphorylation, and spine structural plasticity are not well understood. A-kinase-anchoring protein (AKAP) 79/150 (human79/rodent150) is a PKA and CaN anchoring protein linked to NMDARs and AMPARs through PSD-95 and SAP97 membrane-associated guanylate kinase (MAGUK) scaffolds. AKAP79/150 is targeted to spines by an N-terminal basic region that binds phosphatidylinositol-4,5-bisphosphate (PIP2), F-actin, and cadherin adhesion molecules. Importantly, findings from the last funding period and recent preliminary studies indicate that AKAP79 is recruited to spines in LTP through palmitoylation of its targeting domain and that AKAP79 overexpression enhances dendritic spine size and AMPAR activity through MAGUK binding. In contrast, NMDAR-CaN signaling pathways implicated in AMPAR depression and spine shrinkage in LTD disrupt AKAP79/150 interactions with actin, MAGUKs and cadherins and lead to loss of the AKAP and anchored PKA from synapses. This AKAP79/150 translocation from spines depends on actin reorganization and phospholipase C (PLC) cleavage of PIP2, and preliminary studies suggest additional modulation by palmitoylation. Thus, AKAP79/150 is likely to play important structural and signaling roles in plasticity. Due to the complexity of PKA and CaN signaling in neurons and the multi-functionality of scaffold proteins such as AKAP79/150, it is a considerable challenge to understand the specific postsynaptic functions served by these proteins using simple pharmacologic, knock-out or RNAi approaches because these methods eliminate all functions at once. Thus, in this project we will pair RNAi knockdown with a mutant replacement approach in cultured rat neurons in addition to using a novel AKAP150 knock-in mutant mouse to probe the functions of specific AKAP79/150 membrane targeting motifs and protein-protein interactions in control of postsynaptic structure and function during induction of LTD and LTP. The hypotheses that we will be testing are that regulation of AKAP79/150 postsynaptic targeting and signaling by palmitoylation (Aim 1), MAGUK scaffolding interactions (Aim 1), and CaN anchoring (Aims 2 & 3) coordinately regulate dendritic spine structure and AMPAR function in plasticity. PUBLIC HEALTH RELEVANCE: The AKAP79/150-organized neuronal excitatory postsynaptic signaling processes we are studying that control dendritic spine structure and glutamate receptor function are believed to be relevant for mechanisms of altered synaptic plasticity and cognition in neurological disorders such as Alzheimer's and epilepsy and mental health disorders such as Down syndrome and schizophrenia. These same pathways also have relevance for understanding how excessive glutamate receptor activation leads to excitotoxic neuronal death in neurodegenerative diseases, brain injury and stroke. In particular, regulation of glutamate receptor activity and dendritic spine structural changes have been implicated in both plasticity and excitoxicity, thus understanding the role of AKAP79/150 in controlling these events through both its structural interactions and signaling functions is important for understanding basic synaptic processes that are altered in human disease.

描述（由申请人提供）：在神经元兴奋性突触的突触后密度（PSD）上，AMPA（AMPAR）和NMDA和NMDA（NMDAR）（NMDAR）谷氨酸受体与信号蛋白和肌动蛋白细胞骨骼有关，通过在造型蛋白质的范围下进行塑料素的网络，在树突中的肌动蛋白细胞骨骼。在海马神经元中长期增强（LTP）期间，通过NMDAR激活通过NMDAR激活将AMPAR募集到树突状刺，这也通过增加脊柱大小和肌动蛋白聚合的途径。通过CAMP依赖性蛋白激酶（PKA）对AMPAR-GLUR1亚基的磷酸化可能会促进LTP期间募集的AMPAR的表面表达。相反，长期抑郁症（LTD）的诱导导致钙调神经蛋白 - 磷酸酶2b（CAN）介导的PKA磷酸化GLUR1的去磷酸化，从突触中去除AMPAR并从突触中去除AMPAR，然后脊柱肌动蛋白的去聚合，然后通过脊柱收缩。但是，尚不清楚协调调节AMPAR定位，磷酸化和脊柱结构可塑性的机制。 A-激酶锚定蛋白（AKAP）79/150（Human79/Rodent150）是PKA，可以通过PSD-95和SAP97膜相关的鸟苷酸酯激酶（Maguk）锚定与NMDARS和AMPAR相关的蛋白质。 AKAP79/150的目标是结合磷脂酰肌醇-4,5-双磷酸（PIP2），F-肌动蛋白和钙粘蛋白粘附分子的N末端基本区域。重要的是，上一个融资期和最近的初步研究的发现表明，通过其靶向域的棕榈酰化，AKAP79被招募到LTP中的棘突，并且AKAP79的过表达通过杂志结合增强了树突状的脊柱大小和AMPAR活性。相反，LTD中与AMPAR抑郁症和脊柱收缩有关的NMDAR-CAN信号通路破坏了AKAP79/150与肌动蛋白，Maguks和Cadherins的相互作用，并导致AKAP的丧失，并从突触中锚定PKA。这种来自棘突的AKAP79/150易位取决于肌动蛋白的重组和PIP2的磷脂酶C（PLC）裂解，初步研究表明棕榈酰化的其他调节。因此，AKAP79/150可能在可塑性中起重要的结构和信号传导作用。由于PKA和CAN信号在神经元中的复杂性以及脚手架蛋白（例如AKAP79/150）的多功能性，因此了解这些蛋白质使用简单的药理，敲除或RNAI方法来理解这些蛋白质的特定突触后功能是一个巨大的挑战，因为这些方法可以一次消除所有功能。因此，在这个项目中，除了使用新型的AKAP150敲门突变小鼠外，我们还将将RNAi敲低与突变替代方法与突变替代方法配对，以探测特定AKAP79/150膜靶向基序的功能和蛋白质 - 蛋白质 - 蛋白质 - 蛋白质 - 蛋白质 - 在控制后结构和LTD和LTD诱导过程中的功能中的功能。我们将要测试的假设是通过棕榈酰化（AIM 1），Maguk脚手架相互作用（AIM 1）对AKAP79/150的突触后靶向和信号进行调节（AIMS 2＆3）协同调节了树突状的脊柱结构和Ampar在可塑性中的功能。 PUBLIC HEALTH RELEVANCE: The AKAP79/150-organized neuronal excitatory postsynaptic signaling processes we are studying that control dendritic spine structure and glutamate receptor function are believed to be relevant for mechanisms of altered synaptic plasticity and cognition in neurological disorders such as Alzheimer's and epilepsy and mental health disorders such as Down syndrome and schizophrenia.这些相同的途径也与理解过度谷氨酸受体激活如何导致神经退行性疾病，脑损伤和中风的兴奋性神经元死亡有关。特别是，谷氨酸受体活性和树突状脊柱结构变化的调节与可塑性和兴奋性毒性有关，因此了解AKAP79/150在控制这些事件中通过其结构相互作用和信号传导函数在控制这些事件中的作用对于理解人类疾病中改变的基本突触过程至关重要。