Molecular Basis of Tail-Anchored Membrane Protein Targeting

尾锚定膜蛋白靶向的分子基础

• 批准号: 8315954
• 负责人: Robert J Keenan
• 金额: $ 10.15万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-05 至 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8315954
• 关键词: ADP-AlF4; ATP Hydrolysis; ATP phosphohydrolase; Active Sites; Binding; Binding Sites; Biochemical; Biochemical Genetics; Biogenesis; Biological; Cell Death; Cell physiology; Cells; Cellular biology; Chronic; Complex; Data; Development; Endoplasmic Reticulum; Ensure; Family; Goals; Health; In Vitro; Integral Membrane Protein; Lead; Libraries; Liver diseases; Malignant Neoplasms; Maps; Mediating; Membrane; Membrane Proteins; Molecular; Molecular Conformation; Names; Neurodegenerative Disorders; Nucleotides; Outer Mitochondrial Membrane; Pathology; Pathway interactions; Physiological; Play; Process; Property; Proteins; Reagent; Recombinants; Regulation; Resolution; Role; Signal Recognition Particle; Signal Transduction; Site; Staging; Structure; Substrate Interaction; Surface; Tail; Testing; Viral; Work; base; crosslink; directed evolution; genetic analysis; in vivo; insight; interdisciplinary approach; mutant; novel; novel therapeutics; programs; receptor; receptor binding; trafficking

DESCRIPTION (provided by applicant): The overall goal of this program is to develop a detailed molecular understanding of a novel post- translational targeting pathway that directs insertion of tail-anchored (TA) membrane proteins into the endoplasmic reticulum (ER) membrane. TA proteins constitute a large family of integral membrane proteins that play critical roles in virtually all aspects of cell biology, ranging from intracellular trafficking and viral replication to regulation of cell death. Despite the physiological importance of these proteins, the machinery and molecular mechanisms that mediate recognition, targeting, and insertion of TA proteins into the correct organellar membrane are poorly understood. The targeting and insertion of newly synthesized proteins into the ER membrane is an essential cellular process. For most membrane proteins, this is achieved co-translationally in a process mediated by the signal recognition particle. However, for the nearly 5% of all eukaryotic membrane proteins that are tail-anchored, targeting is achieved post-translationally. This process is mediated by a newly discovered and evolutionarily conserved ATPase, termed TRC40, which interacts with an ER-bound receptor to ensure efficient and accurate TA protein targeting. In an important breakthrough, we have recently determined high-resolution crystal structures of TRC40. Based upon this structural information, the following specific hypotheses will be tested. 1) Recognition of specific physiochemical properties of the targeting signal directs selective TA protein targeting by TRC40. 2) Conformational changes in TRC40 regulate its ATPase activity and TA substrate interactions. 3) The TRC receptor catalyzes these conformational changes through specific interactions with the TRC40-TA substrate complex. Using a powerful interdisciplinary approach, we will establish the fundamental biochemical and biophysical principles that underlie the process of TA protein targeting and insertion. The specific aims of this project are: 1. To determine the molecular basis of selective TA substrate recognition by TRC40 2. To determine how conformational changes in TRC40 regulate ATPase activity and TA substrate interactions 3. To establish how the TRC receptor coordinates targeting and release of TA proteins at the ER membrane PUBLIC HEALTH RELEVANCE: Tail-anchored (TA) membrane proteins play critical roles in virtually all aspects of cell biology. Given the role of TA proteins in pathologies ranging from cancer, neurodegenerative disease and chronic liver diseases (to name only a few), it is clear that a detailed mechanistic understanding of the targeting, membrane insertion and regulation of TA proteins is of fundamental cell biological and physiological significance. The studies described here will provide insight into the molecular details of TA membrane protein biogenesis, and may ultimately lead to the development of new therapeutic strategies that work by modulating the targeting of TA membrane proteins.

描述（由申请人提供）：该程序的总体目标是对一种新型的转化后靶向途径进行详细的分子理解，该途径将尾巴锚定（TA）膜蛋白插入内质网（ER）膜。 TA蛋白构成了一大批整合膜蛋白，它们在细胞生物学的几乎所有方面都起着关键作用，范围从细胞内运输和病毒复制到调节细胞死亡。尽管这些蛋白质具有生理重要性，但对介导，靶向和插入TA蛋白介导的机制和分子机制知之甚少。 将新合成的蛋白靶向和插入到ER膜中是必不可少的细胞过程。对于大多数膜蛋白，这是在信号识别粒子介导的过程中共译。但是，对于所有尾锚的真核膜蛋白中，近5％的靶向是在跨化后实现的。该过程是由新发现和进化保守的ATPase介导的，该ATPase称为TRC40，该ATPase与ER结合的受体相互作用，以确保有效，准确的TA蛋白靶向。在一个重要的突破中，我们最近确定了TRC40的高分辨率晶体结构。 基于这些结构信息，将测试以下特定假设。 1）识别靶向信号的特定生理化学特性，将TRC40的选择性TA蛋白靶向。 2）TRC40的构象变化调节其ATPase活性和TA底物相互作用。 3）TRC受体通过与TRC40-TA底物复合物的特定相互作用来催化这些构象变化。使用强大的跨学科方法，我们将建立基本的生化和生物物理原理，这些原理是TA蛋白靶向和插入过程的基础。该项目的具体目的是：1。确定TRC40 2的选择性TA底物识别的分子基础。确定TRC40中的构象变化如何调节ATPase活性和TA底物相互作用3。 公共卫生相关性：尾锚（TA）膜蛋白在细胞生物学的几乎所有方面都起着至关重要的作用。鉴于TA蛋白在癌症，神经退行性疾病和慢性肝病（仅举几例）中的作用，很明显，对靶向，膜插入和调节TA蛋白的详细机械理解是基本细胞生物学和生理意义的。此处描述的研究将洞悉TA膜蛋白生物发生的分子细节，并最终可能导致开发新的治疗策略，这些策略通过调节TA膜蛋白的靶向而起作用。