Mechanism of VCP interaction and processing of neurodegenerative tau fibrils

VCP相互作用和神经退行性tau原纤维加工的机制

• 批准号: 10463018
• 负责人: Benjamin Creekmore
• 金额: $ 5.18万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10463018
• 关键词: 26S proteasome; ATP phosphohydrolase; Affect; Alzheimer' s Disease; Autophagocytosis; Autopsy; Binding; Binding Proteins; Brain; Cell physiology; Cells; Clinical; Complex; Cryo-electron tomography; Cryoelectron Microscopy; Data; Dementia; Development; Disease; Disease Progression; Drug Targeting; Equilibrium; Excision; Fluorescence; Functional disorder; Goals; Homeostasis; Hybrids; Image; Impaired cognition; In Vitro; Individual; Label; Light; Link; Mediating; Membrane; Methods; Microscopy; Mitochondria; Modeling; Molecular Conformation; Mutation; Nerve Degeneration; Neurodegenerative Disorders; Pathology; Patients; Play; Protein Region; Proteins; Proteome; Recombinants; Regulation; Role; Structure; Tauopathies; Testing; Therapeutic; Time; Ubiquitin; Ubiquitination; cofactor; corticobasal degeneration; insight; link protein; monomer; mutant; neurotoxicity; particle; protein complex; protein function; proteostasis; reaction rate; stoichiometry; tau Proteins; tau aggregation; tau interaction; trafficking; valosin containing protein mutation; valosin-containing protein

Project Summary The goal of this proposal is to study the structure and dynamics of the interaction of the AAA+ ATPase, valosin-containing protein (VCP) with disease-relevant tau fibrils to determine VCP-mediated disease progression and therapeutic potential. Alzheimer's Disease (AD) and Corticobasal degeneration (CBD) are 2 of more than 20 “tauopathies” characterized by different forms of fibrillar tau aggregates. The degree of tau pathology on autopsy correlates with cognitive decline, yet the mechanism of neurotoxicity, disease development, and disease progression in tauopathies remains to be elucidated. Diseases of aggregation indicate a dysfunction in proteostasis – the regulation and balance of the proteome. VCP plays an essential role in proteostasis by removing proteins from complexes, membranes, and aggregates such as those formed by fibrillar tau, thus pointing to VCP as an important player in proteostatic dysfunction and as a potential drug target for tauopathies. VCP has a variety of cofactors that enable it to perform an array of vital cellular. Ufd1 and Npl4 cofactors (UN) together specifically enable VCP to recognize poly-ubiquitinated substrates. AD tau fibrils have high rates of ubiquitination, likely because cells have marked these fibrils for removal by proteins such as VCP. Additionally, mutations within VCP are linked to neurodegenerative disease. A hypoactive VCP mutation first described by the Edward Lee lab clinically presents as dementia and has been shown to promote tau fibril pathology. The hypoactive VCP mutation is thought to reduce VCP function causing the accumulation of tau fibrils, leading to neurodegenerative disease. However, a similar mechanism of VCP inadequately clearing tau fibrils may be present in cases of sporadic tauopathies. VCP/UN, mutant or wild-type, may also get stuck on tau fibrils (possibly due to fibrils' high stability) and be unable to break down the fibril or be released, reducing effective VCP function by trapping it on the fibril. This has been seen with a similar AAA+ ATPase in the 26S proteasome and neurodegenerative aggregates. I propose that for productive disaggregase activity VCP/UN binds unstructured ubiquitin at either end of tau fibrils then pulls off one tau monomer at a time. I also propose the mechanism of action will not change but the stoichiometry and rate of reaction will change between tau fibrils due to differences in fibril structure and ubiquitination. To test this model, in Aim 1 I will structurally characterize how VCP/UN interacts with brain- derived AD and CBD tau fibrils. Structurally understanding how VCP/UN interacts with tau fibrils will help elucidate the protein regions that are crucial to VCP/UN function, and knowing how this interaction changes with fibril type will help understand the generalizability of the VCP/UN fibril interaction. In Aim 2, I will characterize the dynamics of the VCP/UN-tau interaction. Understanding the dynamics of VCP/UN interaction with these fibrils will further elucidate the mechanism of VCP/UN in relation to disease-relevant tau fibrils.

项目摘要 该建议的目的是研究AAA+ ATPase相互作用的结构和动力学， 与疾病相关的tau纤维含瓣膜蛋白（VCP），以确定VCP介导的疾病 进展和治疗潜力。阿尔茨海默氏病（AD）和皮质型变性（CBD）是2 超过20个“ tauopathies”，其特征是不同形式的纤维状tau聚集体。 tau的程度 尸检的病理与认知能力下降相关，但神经毒性，疾病的机制 扭曲病的发育和疾病进展仍有待阐明。聚集的疾病 表明蛋白质的功能障碍 - 蛋白质组的调节和平衡。 VCP扮演着必不可少的 通过去除复合物，膜和聚集体（例如形成的蛋白质）的蛋白质来在蛋白质静脉曲张中的作用 由Fibrillar Tau，因此指出VCP是蛋白抑制功能障碍的重要参与者，并且是潜在药物 tauopathies的目标。 VCP具有多种辅助因子，使其能够执行一系列重要的细胞。 UFD1和NPL4 辅因子（UN）共同使VCP能够识别多泛素化的底物。广告tau纤维有 泛素化率很高，可能是因为细胞标记了这些原纤维以通过蛋白质（例如VCP）去除。 另外，VCP内的突变与神经退行性疾病有关。首先发动的VCP突变 爱德华·李实验室（Edward Lee Lab）描述的临床表现为痴呆症，已被证明可以促进tau纤维 病理。据认为，低连接性VCP突变可降低VCP功能，从而导致TAU的积累 原纤维，导致神经退行性疾病。但是，VCP的类似机制不足清除tau 在零星的呼吸病的情况下，可能存在原纤维。 VCP/UN，突变体或野生型，也可能卡在 tau原纤维（可能是由于原纤维的高稳定性），无法分解原纤维或释放，减少 有效VCP功能通过将其捕获在原纤维上。在26年代，这已经看到了类似的AAA+ ATPase 蛋白酶体和神经退行性聚集体。 我建议，对于生产性分类酶活性VCP/UN在任一端的任一端结合非结构化的泛素 然后，一次tau纤维一次拉开一个tau单体。我还建议行动机理不会改变，但 由于原纤维结构和 泛素化。为了测试该模型，在AIM 1中，我将在结构上表征VCP/UN如何与大脑相互作用 派生的AD和CBD TAU原纤维。结构上了解VCP/联合国与Tau纤维的相互作用将有助于 阐明对VCP/UN功能至关重要的蛋白质区域，并知道这种相互作用如何改变 使用原纤维类型将有助于了解VCP/UN Fibril相互作用的普遍性。在AIM 2中，我会 表征VCP/UN-TAU相互作用的动力学。了解VCP/UN相互作用的动力学 使用这些原纤维将进一步阐明与疾病相关的tau纤维有关的VCP/UN机制。