Factors and Functions of Contact Sites between Membrane-bound and Membrane-less Organelles

膜结合和无膜细胞器接触位点的因素和功能

• 批准号: 10712759
• 负责人: Jason Edward Lee
• 金额: $ 40万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-18 至 2028-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10712759
• 关键词: Basic Science; Binding; Biochemical; Biophysics; Cell physiology; Cells; Cytoplasm; Dependence; Disease; Endoplasmic Reticulum; Eukaryotic Cell; Goals; Health; In Vitro; Life Cycle Stages; Lipids; Maintenance; Malignant Neoplasms; Mediating; Membrane; Messenger RNA; Molecular; Morphology; Nerve Degeneration; Organelles; Pathway interactions; Physical condensation; Play; Process; Proteins; Quality Control; RNA; RNA Processing; RNA Virus Infections; Reaction; Research; Role; Site; Structure; Testing; Translating; Work; aqueous; imaging approach; in vivo; insight; live cell imaging; mRNA Translation; prevent; programs; protein aggregation; recruit; stress granule; translational medicine; vesicle transport

PROJECT SUMMARY A hallmark of eukaryotic cells is the ability to compartmentalize essential reactions into membrane-bound and membrane-less organelles. Membrane-bound organelles form collaborative networks through transport vesicles and inter-organellar interaction domains to traffic cargo and distribute lipids throughout the cell. Conversely, membrane-less organelles mobilize the aqueous portion of cells into condensed structures called condensates. The majority of membrane-less condensates enrich for RNAs and various proteins, which control RNA processing and function at nearly every step of the mRNA life cycle. We and others have recently identified a new class of inter-organelle interactions between membrane-bound organelles, such as the endoplasmic reticulum, and membrane-less RNA-sequestering condensates, such as stress granules. Thus, the long-term goal of my research program is to define how and why these two types of organelles interact to gain a more seamless understanding of how the cytoplasm is organized in health and disease. The objective of this proposal is to identify the factors and utilities of interaction domains between the endoplasmic reticulum and two well- studied RNA-sequestering condensates. Our central hypothesis is that the endoplasmic reticulum plays crucial roles in RNA condensate formation, maintenance, and disassembly through the formation of membrane-to- condensate interactions. Although in vitro and in vivo studies on RNA and protein condensation have revealed the some molecular and biophysical principles of condensates, the contribution of membranes to condensate mechanisms are poorly understood. In the first Project, my lab will elucidate how condensate components are recruited to the endoplasmic reticulum to stimulate RNA condensate formation and inhibition of mRNA translation. We will use biochemical and live-cell imaging approaches to identify the key membrane factors that control this new class of interaction domains. These studies will allow us to identify the molecular mechanisms behind our previous discovery of a surprising dependence of membrane-less condensate abundance on endoplasmic reticulum morphology. In the second Project, we will dissect endoplasmic reticulum-dependent mechanisms of stress granule disassembly. Specifically, we will identify new disassembly factors by taking advantage of our newly developed ability to uncouple stress granule fission from dissolution. Additionally, we will test whether increasing the rate of endoplasmic reticulum-mediated stress granule fission can drive the disassembly of disease-associated aggregates. Collectively, this work will reveal how a new cellular niche between membrane-bound and membrane-less organelles drives the dynamic compartmentalization and quality control of RNA processes. Therefore, we anticipate that the proposed work will have important implications for both basic science and translational medicine targeting neurodegeneration, cancer, and RNA viral infection.

项目总结 真核细胞的一个标志是能够将必要的反应划分为膜结合的和 无膜细胞器。膜结合细胞器通过转运小泡形成协同网络 以及细胞器间相互作用域，以运输货物和在细胞内分布脂质。相反， 无膜细胞器将细胞的水部分动员成被称为凝结物的浓缩结构。 大多数无膜冷凝物富含RNA和各种控制RNA的蛋白质 几乎在信使核糖核酸生命周期的每一步都有其加工和功能。我们和其他人最近发现了一种 膜结合细胞器之间的新的细胞器间相互作用，如内质 网状结构，以及无膜隔离RNA的凝聚体，如应激颗粒。因此，从长远来看， 我的研究计划的目标是定义这两种细胞器如何以及为什么相互作用，以获得更多 对细胞质在健康和疾病中是如何组织的无缝理解。这项提议的目的是 是确定内质网与两个井之间相互作用区域的因素和用途。 研究了隔离RNA的冷凝物。我们的中心假设是内质网起着至关重要的作用。 通过形成膜到膜在RNA缩合物的形成、维持和分解中的作用 凝析油相互作用。尽管在体外和体内对RNA和蛋白质缩合的研究揭示了 凝析油的一些分子和生物物理原理，膜对凝析油的贡献 人们对这一机制知之甚少。在第一个项目中，我的实验室将阐明凝析油成分是如何 募集到内质网刺激RNA凝集物的形成和抑制mRNA 翻译。我们将使用生化和活细胞成像方法来确定关键的膜因素， 控制这类新的互动域。这些研究将使我们能够确定分子机制。 在我们之前发现的无膜凝析油丰度惊人地依赖于 内质网形态。在第二个项目中，我们将剖析内质网依赖 应力作用下颗粒解体的机理。具体地说，我们将通过采取以下措施确定新的拆卸因素 我们新开发的将应力颗粒裂变与溶解分离的能力的优势。此外，我们还将 检测提高内质网介导的应激颗粒裂变率是否能推动 疾病相关聚集体的解体。总而言之，这项工作将揭示一个新的细胞利基 膜结合细胞器和无膜细胞器之间的动态划分和质量 对RNA过程的控制。因此，我们预计拟议的工作将对以下方面产生重要影响 基础科学和转化医学都针对神经退行性变、癌症和RNA病毒感染。