ANALYSIS OF ESCRT FUNCTION IN ENDOLYSOSOMAL TRAFFICKING

内溶酶体转运中 ESCRT 功能的分析

基本信息

批准号：
9264291
负责人：
Phyllis I Hanson
金额：
$ 37.43万
依托单位：
WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-01-01 至 2020-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9264291
关键词：
ATP phosphohydrolase Automobile Driving Binding Biogenesis Cell division Cell membrane Cellular Membrane Complex Core Protein Cultured Cells Cytoplasm Defect Dendrites Disease Electron Microscopy Evolution Excision Filament Future Golgi Apparatus HIV Budding Hereditary Spastic Paraplegia Homo Human In Vitro Individual Lysosomes Malignant Neoplasms Mediating Membrane Membrane Proteins Modeling Molecular Molecular Conformation Morphology Multivesicular Body Nerve Degeneration Nuclear Envelope Organelles Pathway interactions Physiological Polymers Process Proteins Reaction Recycling Role Science Sorting - Cell Movement Surface System Testing Vesicle Viral Work Yeasts chediak-higashi syndrome functional group in vivo late endosome membrane model preference protein complex protein degradation protein function repaired retrograde transport trafficking

项目摘要

The Endosomal Sorting Complex Required for Transport (ESCRT) machinery is a set of interacting protein complexes responsible for cargo selection and biogenesis of intralumenal vesicles inside endosomal multivesicular bodies, also known as late endosomes. Evolutionary conservation and the discovery that ESCRTs are required for topologically equivalent processes including viral budding, cytokinetic abscission, and nuclear envelope closure led to the now widely accepted concept that ESCRTs are uniquely involved in membrane fission for reactions that share this topology. ESCRT-III proteins act by changing conformation and polymerizing into membrane-remodeling filaments that spiral on the inside – negatively curved – surface of membrane tubules, ultimately pulling the tubules closed to drive membrane fission and release. Intriguingly, there are twelve ESCRT-III proteins in humans that are not functionally interchangeable. Beyond identification of different molecular binding partners, there has been little structural distinction among these proteins to explain their unique physiological importance. We recently made the surprising discovery that two human ESCRT-III proteins – CHMP1B and IST1 – assemble into filaments that spiral around the outside – positively curved – surface of membrane tubules, forming external coats in vitro and in vivo. This unexpected preference for positively curved membrane tubules challenges the dogma that the membrane deforming and fission activity associated with ESCRT-III filaments is limited to a single topology and prompts us to reconsider established paradigms for ESCRT-III function. This project will (1) define the topology preference of particular ESCRT-III homo- and heteropolymers polymers and the corresponding distribution of endogenous ESCRT-III proteins across the endosomal system, (2) establish the role(s) of representative ESCRT-III proteins in distinct endosomal cargo trafficking pathways, and (3) compare the effects of depleting different ESCRT-III proteins on endosomal and lysosomal morphology. This work will expand our understanding of the ESCRT-III membrane remodeling system with significant implications for future studies of trafficking and organization within the endolysosomal system.

运输所需的内体分选复合物 (ESCRT) 机制是一组相互作用的蛋白质负责内体内腔内囊泡的货物选择和生物发生的复合物多囊泡体，也称为晚期内涵体。 ESCRT 是拓扑等效过程所必需的，包括病毒出芽、细胞分裂、和核膜封闭导致了现在广泛接受的概念，即 ESRTs 独特地参与共享这种拓扑结构的膜裂变反应通过改变构象起作用。聚合成膜重塑细丝，在内部螺旋状——负弯曲—— 膜管表面，最终拉动膜管关闭以驱动膜裂变和释放。有趣的是，人类中有 12 种 ESCRT-III 蛋白在功能上不可互换。除了识别不同的分子结合伴侣外，结构上几乎没有区别我们最近在这些蛋白质中解释了它们独特的生理重要性。发现两种人类 ESCRT-III 蛋白 - CHMP1B 和 IST1 - 组装成螺旋状的细丝围绕膜管的外表面（正弯曲），在体外和体内形成外层这种对正弯曲膜管的意外偏好挑战了“生物体”的教条。与 ESCRT-III 丝相关的膜变形和裂变活动仅限于单一拓扑并促使我们重新考虑 ESCRT-III 功能的既定范例。该项目将 (1) 定义特定 ESCRT-III 均聚物和杂聚物的拓扑偏好以及相应的内源性 ESCRT-III 蛋白在内体系统中的分布，(2) 确定不同内体货物运输途径中的代表性 ESCRT-III 蛋白，以及 (3) 比较这项工作将研究消耗不同 ESCRT-III 蛋白对内体和溶酶体形态的影响。扩大我们对 ESCRT-III 膜重塑系统的理解，对内溶酶体系统内贩运和组织的未来研究。