Targeting of tail-anchored membrane proteins by the Get pathway.

通过 Get 途径靶向尾锚定膜蛋白。

• 批准号: 8490397
• 负责人: William M. Clemons
• 金额: $ 28.32万
• 依托单位: CALIFORNIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8490397
• 关键词: ATP Hydrolysis; ATP phosphohydrolase; Address; Apoptosis; Appearance; Archaea; Binding; Biochemical; Biochemistry; Biogenesis; Biological; Biological Assay; Cell physiology; Commit; Complex; Crystallization; Disease; Endoplasmic Reticulum; Ensure; Environment; Family member; Heat-Shock Proteins 70; Homologous Gene; Hydrolysis; In Vitro; Integral Membrane Protein; Light; Link; Lipids; Malignant Neoplasms; Mediating; Medical; Membrane; Membrane Proteins; Modeling; Molecular Chaperones; Molecular Conformation; Nucleotides; Outer Mitochondrial Membrane; Pathway interactions; Play; Process; Protein Binding; Protein Biosynthesis; Proteins; Regulation; Ribosomes; Role; Route; Signal Recognition Particle; Signal Transduction; Structure; System; Tail; Viral; Work; Yeasts; insight; interest; link protein; molecular dynamics; mutant; novel therapeutics; prevent; programs; receptor; targeted delivery; trafficking

DESCRIPTION (provided by applicant): The biogenesis of integral membrane proteins is an essential and complex process. Until recently, the targeted delivery of an important class, tail-anchored (TA) membrane proteins, was poorly understood. TA-proteins are defined topologically as containing a single trans-membrane domain (TM) near the C-terminus. This constraint prevents them from following the canonical signal recognition particle dependent co-translational targeting pathway. TA-proteins are involved in many key cellular processes including protein localization, vesicular trafficking, regulation of apoptosis and viral assembly and have been linked to a number of diseases. They are found in most eukaryotic membranes; however, they are initially delivered to either the endoplasmic reticulum (ER) or the mitochondrial outer membrane. TA-proteins are targeted to the ER by the newly discovered Get pathway (Guided entry of TA-proteins). In yeast, the central component of this pathway is the targeting factor Get3, a universally conserved ATPase that binds specifically to the TM of a TA-protein and uses ATP hydrolysis to deliver the TA-protein to the ER membrane. At the membrane, two proteins, Get1 and Get2, are thought to act as receptors for Get3 to ensure proper targeting and release of the TA-protein from Get3. Upstream of Get3, the proteins Get4, Get5 and Sgt2 are thought to mediate delivery to Get3 and may play a role in discriminating alternate delivery pathways. The identification of proteins in this pathway has provided an early framework for the targeting model. Recently, key structural work by our group, along with efforts by others, has begun to shed light on this process. Our early work has primed us to fully elucidate the roles of each component in the system. In the following proposal we describe how we plan to characterize each step in targeting both structurally and biochemically. The aims are to 1) determine the role of conformational changes and nucleotide hydrolysis in TA-protein targeting by Get3, 2) understand the process of discriminating TA- substrates and their delivery to Get3 and 3) elucidate the route of insertion of a TA-protein into a membrane.

描述（由申请人提供）：完整膜蛋白的生物合成是一个重要而复杂的过程。直到最近，靶向传递的一个重要类别，尾锚定（TA）膜蛋白，知之甚少。TA蛋白在拓扑学上被定义为在C末端附近含有单个跨膜结构域（TM）。这种限制阻止它们遵循经典信号识别颗粒依赖性共翻译靶向途径。TA蛋白参与许多关键的细胞过程，包括蛋白定位、囊泡运输、细胞凋亡调节和病毒组装，并且与许多疾病有关。它们存在于大多数真核细胞膜中;然而，它们最初被递送到内质网（ER）或线粒体外膜。TA蛋白通过新发现的Get途径（TA蛋白的引导进入）靶向ER。在酵母中，该途径的中心组分是靶向因子Get 3，这是一种普遍保守的ATP酶，其特异性结合TA蛋白的TM，并利用ATP水解将TA蛋白递送至ER膜。在膜上，两种蛋白质Get 1和Get 2被认为是Get 3的受体，以确保适当的靶向和从Get 3释放TA蛋白。在Get 3的上游，蛋白质Get 4、Get 5和Sgt 2被认为介导递送至Get 3，并且可能在区分替代递送途径中起作用。在这一途径中的蛋白质的鉴定为靶向模型提供了早期框架。最近，我们小组的关键结构性工作，沿着其他人的努力，已开始阐明这一进程。我们的早期工作使我们能够充分阐明系统中每个组件的作用。在下面的提案中，我们描述了我们计划如何在结构和生物化学上表征靶向的每个步骤。目的是1）确定构象变化和核苷酸水解在通过Get 3靶向TA-蛋白中的作用，2）理解区分TA-底物及其递送至Get 3的过程，以及3）阐明TA-蛋白插入膜中的途径。