Regulation of Nutrient Homeostasis by COMMD proteins

COMMD 蛋白对营养稳态的调节

• 批准号: 10579910
• 负责人: DANIEL D BILLADEAU
• 金额: $ 43.41万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10579910
• 关键词: AGFG1 gene; Actins; Affect; Alleles; Animals; Attention; Back; Binding; Biochemical; Cardiac; Cell Line; Cell membrane; Cell physiology; Cell surface; Complex; Copper; Data; Defect; Development; Elements; Endosomes; Excretory function; Family; Family member; Funding; GLUT-2 protein; Genes; Glucose; Goals; Guanine Nucleotide Exchange Factors; Guanosine Triphosphate; Homeostasis; Insulin; Intestines; LDL Cholesterol Lipoproteins; Laboratories; Lipids; Liver; Location; Mediating; Membrane Proteins; Molecular; Movement; Mutation; Nutrient; Pathway interactions; Phosphatidylinositols; Phosphoric Monoester Hydrolases; Physiological; Plasma; Play; Process; Proteins; Proteomics; Publishing; Recycling; Regulation; Reporting; System; Testing; Wilson disease protein; Work; glucose tolerance; in vivo; member; mouse model; myotubularin; notch protein; nutrition; receptor; recruit; response; sorting nexins; trafficking

Plasma membrane proteins, including receptors and nutrient transporters, undergo internalization into the endosomal compartment, from where these proteins are recycled back to the plasma membrane. This endosomal recycling process is essential to cellular homeostasis. Our laboratories have discovered two interrelated complexes that play key roles in endosomal recycling known as CCC and retriever. Both of these assemblies work in concert with WASH, an endosomally-localized actin nucleating pentameric complex. Significantly, perturbations of these systems have far-reaching consequences, including developmental anomalies, altered copper and lipid handling, and defective glucose tolerance. These physiologic alterations can be traced to faulty trafficking of key receptors and transporters including Notch, ATP7A/ATP7B, LDLR and GLUT2. At its core, the CCC complex contains COMMD proteins, in association with two coiled-coil proteins, CCDC22 and CCDC93. We recently demonstrated that CCC regulates the WASH complex by limiting the amount of endosomal PI(3)P through an interaction with the PI(3)P phosphatase MTMR2. We also uncovered that the CCC complex recruits a cargo recognition complex, termed retriever, whose function is to identify proteins that need to be recycled. While we made great progress in dissecting the mechanistic underpinnings of these systems, our understanding is still rudimentary. The overall goal of this project is to provide a deep mechanistic picture of CCC-mediated regulation of WASH and retriever, focusing our attention on endosomal recycling of nutrient regulators. Based on new emerging data, this proposal will test the hypothesis that the CCC complex coordinates both PI(3)P levels and Rab21 activation to promote retriever-mediated recycling of surface proteins. This project will focus on the following specific aims: (1) Determine the mechanism by which CCC regulates MTMR actions on endosomes. In this aim we will examine how the CCC complex coordinates MTMR actions, particularly by MTMR5, together with activation of Rab21 and retriever recruitment. (2) Define the mechanism by which PI(3)P regulates the recruitment and activity of the WASH complex. In this aim, we will define the mechanisms by which PI(3)P-binding domains in FAM21 and WASH regulate the endosomal recruitment and activity of the WASH complex, and how these activities ultimately impact endosomal trafficking. (3) Examine retriever-dependent regulation of cargo proteins in vivo. In this aim we will utilize newly generated mouse models of retriever deficiency (conditional Vps35l, Vps26c alleles) to examine the contribution of this system to ATP7B and LDLR trafficking in the liver. Furthermore, we will utilize proteomics to define the breadth of plasma membrane proteins regulated by retriever, CCC, and WASH in the mammalian liver. Altogether, this project will elucidate important principles that govern the trafficking of a myriad of cargoes that traverse the endosomal system. Deregulation of these pathways have a broad impact on normal organismal/cellular physiology, thus its scientific impact will have far reaching implications for several biomedical fields.

质膜蛋白质，包括受体和营养转运蛋白，经历内化进入内体区室，从那里这些蛋白质再循环回到质膜。这种内体再循环过程对于细胞内稳态是必不可少的。我们的实验室已经发现了两种相互关联的复合物，它们在称为CCC和retriever的内体回收中发挥关键作用。这两个组件与WASH（一种内体定位的肌动蛋白成核五聚体复合物）协同工作。值得注意的是，这些系统的干扰会产生深远的后果，包括发育异常、铜和脂质处理改变以及葡萄糖耐量缺陷。这些生理变化可追溯到关键受体和转运蛋白（包括Notch、ATP 7A/ATP 7 B、LDLR和GLUT 2）的错误运输。在其核心，CCC复合物含有COMMD蛋白，与两个卷曲螺旋蛋白CCDC 22和CCDC 93相关联。我们最近证明CCC通过与PI（3）P磷酸酶MTMR 2相互作用限制内体PI（3）P的量来调节WASH复合物。我们还发现，CCC复合物招募了一种货物识别复合物，称为检索器，其功能是识别需要回收的蛋白质。虽然我们在剖析这些系统的机械基础方面取得了很大进展，但我们的理解仍然是初步的。这个项目的总体目标是提供一个深入的CCC介导的WASH和寻回犬的调节机制图片，集中我们的注意力在内体再循环的营养调节剂。基于新出现的数据，该提议将检验CCC复合物协调PI（3）P水平和Rab 21活化以促进回收物介导的表面蛋白再循环的假设。本研究的主要目的是：（1）研究CCC调控MTMR作用于核内体的机制。在这个目标中，我们将研究CCC复合物如何协调MTMR行动，特别是MTMR 5，以及Rab 21和寻回犬的激活。(2)定义PI（3）P调节WASH复合体的募集和活性的机制。在这个目标中，我们将定义FAM 21和WASH中PI（3）P结合结构域调节WASH复合物的内体募集和活性的机制，以及这些活动最终如何影响内体运输。(3)检查体内货物蛋白的回收依赖性调节。在这个目标中，我们将利用新产生的小鼠模型的检索缺陷（条件Vps 35 l，Vps 26 c等位基因），以检查该系统的贡献，ATP 7 B和LDLR运输的肝脏。此外，我们将利用蛋白质组学来确定在哺乳动物肝脏中由取回器，CCC和WASH调节的质膜蛋白的宽度。总而言之，这个项目将阐明重要的原则，管理运输的无数货物，穿越内体系统。这些途径的失调对正常的生物体/细胞生理学有广泛的影响，因此其科学影响将对几个生物医学领域产生深远的影响。