Tau-Mediated Regulation and Dysregulation of Protein Phosphatase 1

Tau 介导的蛋白磷酸酶 1 的调节和失调

基本信息

批准号：
10320053
负责人：
Nicholas M Kanaan
金额：
$ 52.7万
依托单位：
MICHIGAN STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-04-01 至 2024-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10320053
关键词：
Address Affect Affinity Alzheimer&apos s Disease Alzheimer&apos s disease related dementia Automobile Driving Axon Axonal Transport Binding Biological Assay Biology Cell Culture Techniques Cell Fractionation Data Deletion Mutation Disease FTD with parkinsonism Functional disorder Goals Health Healthcare Human Impairment In Situ Inherited Injections Knock-in Knock-in Mouse Knowledge Lead Ligation Light Link Maps Mass Spectrum Analysis Mediating Microscopy Microtubule-Associated Proteins Microtubules Modeling Modification Molecular Mus Mutation Nerve Degeneration Neurons Nuclear Protein Phosphatase Oligonucleotides Pathologic Pathology Pathway interactions Phenotype Phosphoric Monoester Hydrolases Phosphorylation Physiological Play Point Mutation Protein Isoforms Protein phosphatase Regulation Resolution Role Signal Pathway Signal Transduction Structure Subcellular Fractions Synapses Tauopathies Testing Thinking Toxic effect Viral Vector Work axonal degeneration delivery vehicle in vivo in vivo Model insight knock-down mouse model mutant neurotoxicity novel pre-formed fibril protein activation protein protein interaction small hairpin RNA squid axon tau Proteins tau aggregation tau function tau mutation

项目摘要

Tau is a microtubule-associated protein that is abnormally phosphorylated and aggregates in Alzheimer’s disease (AD) and AD-related dementias, leading to its impaired functionality. No disease modifying treatment exists for these diseases, making them a significant healthcare priority. Though we have known for decades that several modifications are intimately associated with sporadic disease and mutations in tau directly cause inherited degenerative tauopathies, the precise molecular pathways engaged by pathological tau proteins to actively cause neurodegeneration are unknown. This knowledge gap remains a significant and critical problem that this proposal aims to address. Current thinking in the field suggests that disease-related tau modifications exert toxicity by disruption of microtubules and/or by enhancing tau aggregation. However, evidence from our group and others supports an alternative explanation. That is, tau acts to regulate signaling pathways and tau toxicity is due to an aberration of this function. Using the isolated axoplasm from squid giant axons, we discovered a functional signaling motif in the N-terminus of tau called the phosphatase-activating domain (PAD) that activates a protein phosphatase-1 (PP1)-dependent signaling cascade. We also identified that known pathological changes in tau (e.g. phosphorylation and oligomerization) alter tau’s structure leading to aberrant PAD-dependent activation of this pathway and axonal toxicity. We propose to focus on determining whether tau normally regulates PP1-dependent functions in neurons and on PP1-dependent pathways of tau toxicity. Our central hypothesis is that, through a PP1-dependent mechanism, tau normally regulates neuronal function and health, but in disease tau causes axonal, synaptic and/or neuronal toxicity through aberrations of this mechanism. In Aim 1, we will test the hypothesis that specific motifs within tau and PP1 are critical for the interaction with and activation of PP1 by tau proteins. We will use a combination of point mutations/deletions to map the specific domains in tau and PP1 isoforms that underlie tau’s ability to bind and activate PP1. In Aim 2, we will test the hypothesis that tau localizes with PP1 in specific subcellular compartments where it regulates PP1-dependent pathways. Here, we will use novel human tau-KI mouse primary neuron cultures and a combination of super-resolution microscopy, subcellular fraction and other protein-protein interaction assays to determine where in neurons tau and PP1 interact. Also, we will knockdown tau to determine its functional relationship to multiple PP1-dependent pathways in neurons. In Aim 3, we will test the hypothesis that disease forms of tau drive toxicity via PP1-dependent mechanisms. We will use a novel tau pre-formed fibril seeding model in the hTau-KI mice as well as the PS19 mutant tau mouse line to provide the critical in vivo translational insights for the tau-PP1 relationship and how disease forms of tau lead to PP1-dependent toxicity. Together, the proposed studies will fill critical gaps in our knowledge and will produce a significant impact by identifying important physiological and pathological roles for tau in regulating PP1 in neurons.

Tau 是一种微管相关蛋白，在阿尔茨海默病中异常磷酸化并聚集疾病（AD）和 AD 相关痴呆，导致其功能受损。没有疾病修饰治疗。尽管我们几十年来就知道这些疾病的存在，使其成为重要的医疗保健优先事项。一些修饰与散发性疾病密切相关，tau 突变直接导致遗传性退行性 tau 病，病理性 tau 蛋白参与的精确分子途径这种知识差距仍然是一个重大而关键的问题。该提案旨在解决该领域目前的想法表明与疾病相关的 tau 修饰。然而，我们的证据表明，通过破坏微管和/或增强 tau 聚集来发挥毒性。研究小组和其他人支持另一种解释，即 tau 蛋白发挥调节信号通路的作用，并且 tau 蛋白发挥作用。毒性是由于这种功能的异常造成的，我们使用从鱿鱼巨轴突中分离出来的轴浆。在 tau 的 N 末端发现了一个功能性信号基序，称为磷酸酶激活结构域 (PAD) 可激活蛋白磷酸酶 1 (PP1) 依赖性信号级联反应。 tau 的已知病理变化（例如磷酸化和寡聚化）会改变 tau 的结构，从而导致我们建议重点确定该通路的 PAD 依赖性激活和轴突毒性。 tau 是否正常调节神经元中的 PP1 依赖性功能以及 tau 的 PP1 依赖性通路我们的中心假设是，tau 蛋白通过 PP1 依赖性机制正常调节神经元。功能和健康，但在疾病中 tau 通过畸变引起轴突、突触和/或神经元毒性在目标 1 中，我们将测试 tau 和 PP1 内的特定基序对于该机制至关重要的假设。我们将使用点突变/缺失的组合来与 PP1 相互作用并被 tau 蛋白激活。绘制 tau 和 PP1 同工型的特定结构域，这些结构域是 tau 结合和激活 PP1 能力的基础。我们将检验以下假设：tau 与 PP1 一起定位于其调节的特定亚细胞区室中在这里，我们将使用新型人 tau-KI 小鼠原代神经元培养物和结合超分辨率显微镜、亚细胞组分和其他蛋白质-蛋白质相互作用测定确定神经元中 tau 和 PP1 相互作用的位置此外，我们还将敲除 tau 以确定其功能。与神经元中多个 PP1 依赖性通路的关系在目标 3 中，我们将检验疾病的假设。我们将使用一种新型 tau 预形成原纤维种子来驱动毒性。 hTau-KI 小鼠以及 PS19 突变 tau 小鼠系的模型，以提供关键的体内翻译对 tau-PP1 关系以及 tau 疾病形式如何导致 PP1 依赖性毒性的见解。拟议的研究将填补我们知识中的关键空白，并将通过确定 tau 在调节神经元 PP1 中发挥重要的生理和病理作用。