Quality control of mislocalized membrane proteins

错误定位膜蛋白的质量控制

基本信息

批准号：
10665785
负责人：
Sichen Shao
金额：
$ 34.75万
依托单位：
HARVARD MEDICAL SCHOOL
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-07-15 至 2027-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10665785
关键词：
ATP phosphohydrolase Affect Alzheimer&apos s Disease Amyotrophic Lateral Sclerosis Binding Biogenesis Biological Assay Biosynthetic Proteins Cell Surface Receptors Cell physiology Cells Cellular Membrane Client Collaborations Cytosol Defect Degradation Pathway Disease Dislocations Dissection Endoplasmic Reticulum Ensure Face Functional disorder Goals Health Homeostasis Human Huntington Disease Hydrophobicity Impairment Ion Channel Knowledge Longevity Mediating Membrane Membrane Proteins Mitochondria Mitochondrial Membrane Protein Mitochondrial Proteins Modeling Molecular N-terminal Neurodegenerative Disorders Neurons Neurotransmitters Organelles Organism Parkinson Disease Process Protein Biosynthesis Proteins Proteome Quality Control Reaction Ribosomes Role Site Sorting Surface Synaptic Vesicles System Tail Transmembrane Domain Triage effective therapy insight preservation proteostasis secretory protein trafficking transmission process

项目摘要

PROJECT SUMMARY The identities and functions of cellular membrane-bound compartments such as the endoplasmic reticulum (ER), mitochondria, and synaptic vesicles, are largely determined by protein composition. Organelle dysfunction and impaired membrane protein quality control (QC) are hallmarks of neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), Alzheimer's, Parkinson's, and Huntington's disease. Molecular- level insights into the mechanisms that ensure high-fidelity membrane protein biogenesis are required to understand how neurodegenerative diseases develop and identify effective treatments. All membrane proteins face two fundamental biosynthetic challenges. First, they must localize to the correct cellular membrane. Second, they must insert hydrophobic transmembrane domains into target membranes in the correct orientation. It is not known how cells meet these basic biosynthetic requirements for the diverse membrane proteins that make up 25-30% of the proteome. Using single-spanning membrane proteins as models, we have established experimental systems of membrane protein biosynthesis and QC that are tractable for mechanistic dissection. With these systems, we recently discovered that the ER-resident transporter ATP13A1 dislocates mislocalized mitochondrial membrane proteins. Protein dislocation by ATP13A1 provides opportunities for correct targeting and is required to maintain mitochondrial protein localization. In this proposal, we will leverage ATP13A1 function as a molecular handle to study the mechanisms that lead to, recognize, and eliminate aberrant proteins at the ER. In Aim 1, we will identify the biosynthetic factors that aberrantly insert mitochondrial membrane proteins into the ER and determine how these mechanisms contribute to mitochondrial protein homeostasis. In Aim 2, we will investigate the QC mechanisms that selectively recognize and target mislocalized mitochondrial membrane proteins for ER-associated degradation (ERAD). In Aim 3, we will investigate the topogenesis of type II membrane proteins that should insert into the ER with their N- terminus in the cytosol. Because a subset of type II proteins is selectively destabilized by ATP13A1 depletion, we hypothesize that these proteins harbor specific features prone to insertion in the wrong orientation, resulting in the need for ATP13A1-mediated dislocation. Completion of this project will reveal mechanisms that mis- insert membrane proteins into the ER, generate a mechanistic model of a mammalian ERAD pathway, and shed light on how a handful of biosynthetic and QC factors handle a large and diverse clientele. Altogether, these findings will reveal molecular-level insights into membrane protein QC target selection and mechanistic principles underlying how cellular biosynthetic and QC mechanisms collaborate to ensure the integrity of membrane protein biogenesis needed to preserve neuronal function.

项目概要细胞膜结合区室（例如内质网）的特性和功能 (ER)、线粒体和突触小泡很大程度上由蛋白质组成决定。细胞器功能障碍和膜蛋白质量控制 (QC) 受损是神经退行性疾病的标志，包括肌萎缩侧索硬化症 (ALS)、阿尔茨海默病、帕金森病和亨廷顿舞蹈病。分子- 需要对确保高保真膜蛋白生物合成的机制有深入的了解了解神经退行性疾病如何发展并确定有效的治疗方法。所有膜蛋白面临两个基本的生物合成挑战。首先，它们必须定位到正确的细胞膜。其次，他们必须以正确的方式将疏水性跨膜结构域插入目标膜中方向。目前尚不清楚细胞如何满足不同膜的基本生物合成要求占蛋白质组 25-30% 的蛋白质。使用单跨膜蛋白作为模型，我们有建立了易于机械处理的膜蛋白生物合成和质量控制实验系统解剖。通过这些系统，我们最近发现 ER 驻留转运蛋白 ATP13A1 脱位线粒体膜蛋白定位错误。 ATP13A1 造成的蛋白质错位提供了机会正确的靶向并且是维持线粒体蛋白定位所必需的。在本提案中，我们将利用 ATP13A1 作为分子手柄来研究导致、识别和消除的机制 ER 中的异常蛋白质。在目标 1 中，我们将识别异常插入的生物合成因子线粒体膜蛋白进入内质网并确定这些机制如何促进线粒体蛋白质稳态。在目标 2 中，我们将研究选择性识别的 QC 机制并针对错误定位的线粒体膜蛋白进行内质网相关降解（ERAD）。在目标 3 中，我们将研究 II 型膜蛋白的拓扑发生，这些蛋白应以其 N- 插入 ER 中末端位于细胞质中。因为 II 型蛋白的一个子集会因 ATP13A1 耗尽而选择性地不稳定，我们假设这些蛋白质具有容易以错误方向插入的特定特征，从而导致需要 ATP13A1 介导的错位。该项目的完成将揭示错误的机制将膜蛋白插入 ER，生成哺乳动物 ERAD 通路的机制模型，以及揭示了少数生物合成和质量控制因子如何应对大量且多样化的客户。共，这些发现将揭示膜蛋白 QC 靶点选择和机制的分子水平见解细胞生物合成和 QC 机制如何协作以确保完整性的基本原理保护神经元功能所需的膜蛋白生物发生。