The mechanism of ESCRT-mediated surveillance of the nuclear envelope barrier

ESRT 介导的核膜屏障监测机制

• 批准号: 9923678
• 负责人: Charles Patrick Lusk
• 金额: $ 34.34万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9923678
• 关键词: Active Biological Transport; Address; Affinity Chromatography; Amyotrophic Lateral Sclerosis; Binding Proteins; Biochemistry; Cell Differentiation process; Cell model; Cells; Complex; Cytolysis; DNA; Data; Diffusion; Electron Microscopy; Elements; Ensure; Eukaryotic Cell; Event; Family; Filament; Functional disorder; Future; Genetic; Genetic Transcription; Goals; Homo; Kinetics; Laboratories; Lead; Light; Link; Malignant Neoplasms; Mammalian Cell; Mediating; Membrane; Membrane Fusion; Membrane Proteins; Mind; Modeling; Molecular; Monitor; Morphology; Nerve Degeneration; Neurodegenerative Disorders; Nuclear; Nuclear Envelope; Nuclear Inner Membrane; Nuclear Outer Membrane; Nuclear Pore; Nuclear Pore Complex; Pathway interactions; Property; Proteins; Publishing; Quality Control; Rupture; Saccharomycetales; Scheme; Site; Sorting - Cell Movement; System; Tertiary Protein Structure; Toxic effect; Translations; Work; arm; cancer cell; cellular pathology; electron tomography; emerin; experimental study; human disease; member; nanobodies; nucleocytoplasmic transport; polymerization; reconstitution; recruit; seal; segregation; tool

Summary The discrete segregation of nuclear and cytosolic contents is a hallmark feature of all eukaryotic cells. It is achieved by the impermeability of the nuclear envelope membranes and the size-selective and active transport properties of nuclear pore complexes (NPCs), massive transport channels that span the nuclear envelope. Interestingly, it is becoming clear that there is a deleterious intermixing of cytosolic and nuclear contents in several human disease cell models where either NPC function or the integrity of the nuclear membranes is perturbed. Examples include the targeting of the nuclear transport machinery by the transcription and translation of hexanucleotide repeat expansions that are causative of neurodegenerative diseases, and nuclear rupture events observed in cancer cells. Through our work and others, we are discovering surveillance mechanisms that protect the nuclear compartment from aberrant NPCs and/or nuclear membrane ruptures. Indeed, we have discovered that even the “normal” remodeling of the nuclear envelope membranes during NPC assembly can, if not monitored, lead to a loss of nuclear-cytosolic compartmentalization. Here, we will use budding yeast as a model to determine the molecular mechanisms that govern the surveillance of de novo NPC assembly, which depends on the recruitment of the membrane bending and scission endosomal sorting required for transport (ESCRT) machinery to nascent NPC assembly sites. Our work is consistent with a model in which integral inner nuclear membrane proteins of the Lap2, emerin, MAN1 (LEM) domain family serve as adaptors to link defective NPC assembly intermediates to the ESCRTs, which seal off defective NPCs under a double membrane. In this proposal, we will pinpoint what step(s) in NPC assembly are under surveillance while defining the mechanism by which cells differentiate between functional and non-functional NPCs. The long term goal is to fully define and ultimately reconstitute the NPC assembly surveillance mechanism to illuminate fundamental mechanisms of quality control and membrane remodeling while providing a new conceptual framework to understand human disease mechanisms that present with disruptions in the nuclear envelope barrier.

概括 核和胞质内容物的离散分离是所有真核细胞的标志特征。 通过核膜的不渗透性以及尺寸选择性和主动运输来实现 核孔复合体（NPC）的特性，即跨越核膜的大量运输通道。 暗示，越来越清楚的是，细胞质和细胞核内容物存在有害的混合。 几种人类疾病细胞模型，其中 NPC 功能或核膜的完整性受到影响 例子包括通过转录和靶向核运输机制。 导致神经退行性疾病的六核苷酸重复扩展的翻译和核 通过我们和其他人的工作，我们发现了在癌细胞中观察到的破裂事件。 保护核区室免受异常 NPC 和/或核膜破裂影响的机制。 事实上，我们发现即使是核膜的“正常包膜”重塑 如果不进行监测，NPC 组装可能会导致核-胞质区划的丧失。 使用芽殖酵母作为模型来确定控制从头监测的分子机制 NPC组装，这取决于膜弯曲和分裂内体分选的招募 我们的工作与模型一致。 其中 Lap2、emerin、MAN1 (LEM) 结构域家族的完整内核膜蛋白作为 适配器将有缺陷的 NPC 组装中间体连接到 ESCRT，从而将有缺陷的 NPC 密封在 在本提案中，我们将确定 NPC 组装中的哪些步骤受到监视。 定义细胞区分功能性和非功能性 NPC 的机制。 任期目标是全面界定并最终重构全国人大会议监督机制，以阐明 质量控制和膜重塑的基本机制，同时提供新的概念 理解人类疾病机制的框架，这些机制呈现出核破坏的包络 障碍。