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 核和胞质含量的离散分离是所有真核细胞的标志性特征。这是 通过核包膜膜的不渗透和尺寸选择性和主动转运来实现 核孔复合物（NPC）的性质，跨越核包膜的大规模运输通道。 有趣的是，很明显，在 NPC功能或核机制的完整性的几种人类病细胞模型是 忐忑。示例包括通过转录和 神经退行性疾病和核的六核苷酸重复膨胀的翻译 在癌细胞中观察到的破裂事件。通过我们的工作和其他人，我们发现了监视 保护核腔室免受异常NPC和/或核膜破裂的机制。 确实，我们发现，即使在 NPC组装可以（如果不监测）会导致核溶质膜分隔的损失。在这里，我们会的 使用发芽的酵母作为模型来确定控制从头监测的分子机制 NPC组装，取决于膜弯曲和科学内体分类的募集 运输（ESCRT）机械到新生NPC组装站点所需的所需。我们的工作与模型一致 其中LAP2，Emerin，Man1（LEM）域的整体内部核膜蛋白充当 将有缺陷的NPC组件中间体链接到ESCRT的适配器，该中间位于ESCRT中 双膜。在此提案中，我们将确定NPC组装中的哪一步正在监视，而 定义细胞区分功能和非功能性NPC的机制。长 术语目标是充分定义并最终重建NPC组装监视机制以照明 质量控制和膜重塑的基本机制，同时提供新的概念 理解核包膜中断的人类疾病机制的框架 障碍。