Regulation of Vps4 during ESCRT function

ESRT 功能期间 Vps4 的调节

基本信息

批准号：
9001194
负责人：
DAVID J KATZMANN
金额：
$ 34.19万
依托单位：
MAYO CLINIC ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-03-01 至 2019-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9001194
关键词：
ATP phosphohydrolase Address Binding Biogenesis Biological Assay Biological Process Cell physiology Communicable Diseases Complex Cytokinesis Cytoplasm Data Disease Ensure Excision Face Family member Frontotemporal Dementia Goals Hereditary Spastic Paraplegia Human In Vitro Integral Membrane Protein Link Malignant Neoplasms Mediating Membrane Membrane Proteins Modeling Modification Multivesicular Body Neurodegenerative Disorders Pathway interactions Process Proteins Reaction Recruitment Activity Recycling Regulation Role Saccharomyces cerevisiae Signal Transduction Site Sorting - Cell Movement Staging Structure System Testing Ubiquitin Vesicle Viral Virus Yeasts endosome lumen exosome extracellular vesicles hypertension prevention in vivo inhibitor/antagonist insight man mutant nervous system disorder novel polymerization prevent public health relevance trafficking tumorigenesis ubiquitin isopeptidase vesicular release

项目摘要

DESCRIPTION (provided by applicant): Endosomal Sorting Complexes Required for Transport (ESCRTs) is critical for a number of fundamental cellular processes including: degradation of transmembrane proteins through the formation of multivesicular bodies (MVBs) during endocytic trafficking, abscission during cytokinesis, budding of enveloped viruses, and biogenesis of some exosomes. Perturbations of ESCRT function have been linked with promoting tumorigenesis and neurological diseases, including hereditary spastic paraplegia and frontotemporal dementia. Dissecting ESCRT function is therefore critical for understanding cellular physiology in both normal and disease states. ESCRTs were originally identified in Saccharomyces cerevisiae, and yeast MVB sorting serves as the best understood model with which to dissect ESCRT function. MVB sorting can be broken into two steps: the recognition/sequestration of cargoes into microdomains, and the budding of these microdomains into the lumen of the endosome to form intralumenal vesicles (ILVs). The canonical signal for cargo inclusion into an ILV is covalent modification with ubiquitin (Ub). Ub binding domains within the early ESCRTs (subcomplexes termed ESCRT-0, -I, and -II) concentrate Ub-modified cargoes into endosomal microdomains. Early ESCRTs also recruit the late ESCRTs (ESCRT-III and associated factors such as Bro1 and Vps4) responsible for membrane deformation and ILV scission. The AAA-ATPase Vps4 also disassembles ESCRT-III to recycle subunits for additional rounds of function. Early and late ESCRT functions are coordinated to facilitate efficient MVB sorting. One aspect of this coordination is removal of Ub from cargo prior to ILV budding. Bro1 is critical in this process through binding to Ub, recruiting the ubiquitin isopeptidase (DUb) Doa4, and modulating ESCRT-III function via Vps4. Our data indicate that Bro1 can both inhibit and stimulate Vps4 activity and Doa4 can relieve Bro1 inhibitory activity. These observations suggest Bro1 acts as a switch to coordinate early and late ESCRT functions to facilitate flux through the MVB pathway. Our central hypothesis is that Bro1 changes from a negative regulator to a positive regulator of Vps4 during the progression of the sorting reaction to coordinate early and late ESCRT function. This hypothesis will be tested through testing three sub-hypothesis: i) Bro1 inhibits ESCRT-III disassembly to promote cargo transfer to ESCRT-III and into the ILV; ii) Bro1 stimulates Vps4 to accelerate ESCRT- III remodeling and complete ILV budding; and iii) a checkpoint is responsible for converting Bro1 from an inhibitor to an activator of Vps4. Addressing these mechanisms of Bro1 function will provide novel insights into analogous roles for human Bro1 Family members Alix and HD-PTP in extracellular vesicle release, cytokinesis and MVB sorting in human systems.

描述（由适用提供）：运输所需的内体分类复合物（ESCRT）对于多种基本的细胞过程至关重要，包括：通过内吞作用期间多粒细胞贩运的多质体（MVB）降解跨膜蛋白的降解，在细胞因子的脱落过程中，在细胞因素的脱落，生物植入术中的浮肿，并构成了某些杂种。 ESCRT功能的扰动与促进肿瘤发生和神经系统疾病有关，包括遗传性痉挛性截瘫和额颞痴呆。因此，解剖ESCRT功能对于理解正常和疾病状态的细胞生理学至关重要。最初在酿酒酵母中鉴定出ESCRT，酵母MVB排序是剖析ESCRT功能的最佳理解模型。 MVB排序可以分为两个步骤：将货物的识别/隔离为微区，以及这些微区域的萌芽到内体的腔内形成腔内蔬菜（ILV）。将货物纳入ILV的规范信号与泛素（UB）共价修改。早期ESCRT（称为ESCRT -0，-I和-II）内的UB结合结构域将UB修饰的货物集中在内体微区域中。早期的ESCRT还招募了负责膜变形和ILV Scission的晚期ESCRT（ESCRT-III和相关因素，例如BRO1和VPS4）。 AAA-ATPase VPS4还将ESCRT-III分解为回收亚基，以获得额外的功能。早期和晚期的ESCRT功能是协调的，以促进有效的MVB分类。该协调的一个方面是在ILV萌芽之前从货物中清除UB。 BRO1通过与UB结合，招聘而在此过程中至关重要泛素异肽酶（DUB）DOA4，并通过VPS4调节ESCRT-III函数。我们的数据表明BRO1可以抑制和刺激VPS4活性，而DOA4可以挽救BRO1抑制活性。这些观察结果表明，BRO1是协调早期和晚期ESCRT函数的转换，以促进通过MVB途径的通量。我们的中心假设是，在分类反应的进展过程中，BRO1从负调节剂变为VPS4的正调节剂，以协调早期和晚期ESCRT功能。该假设将通过测试三个亚问题来检验：i）Bro1抑制ESCRT-III拆卸以促进货物转移到ESCRT-III并进入ILV； ii）BRO1刺激VPS4加速ESCRT-III重塑和完整的ILV芽； iii）检查点负责将BRO1从抑制剂转换为VPS4激活剂。解决BRO1功能的这些机制将提供对人Bro1家族成员ALIX和HD-PTP类似作用的新颖见解，在人类系统中的细胞外囊泡释放，细胞因子和MVB分类中。