Role of beta-arrestins in G protein-coupled receptor sorting and signaling

项目描述 GPCR信号传导对于多种生理过程是必不可少的。GPCR信号也可以发挥作用， 在多种疾病的发病机制中发挥积极作用。GPCR通常受到严格调控，因此信号 适当的幅度和持续时间，这些监管过程中的任何扰动都可能 有害的通常，GPCR信号传导受G蛋白偶联受体激酶（GRKs）和GPCR抑制剂的严格调节。 逮捕抑制蛋白与质膜上的GRK磷酸化GPCR结合，通过以下方式终止信号传导： 促进G蛋白解偶联和受体内吞。GRKs和GRKs- 抑制蛋白调节GPCR信号传导仍然知之甚少。本提案的目的是阐明 GRKs和<$-arrestins控制GPCR信号传导的分子机制。最近，我们描述了一个 抑制蛋白作为内体分选分子的新功能， 介导GPCR从内体到溶酶体的分选，导致受体降解和长期 信号的衰减。然而，缺乏对这一新功能的机械洞察力。抑制蛋白-1介导 趋化因子受体CXCR 4的内体分选，这也需要E3泛素连接酶的作用 AIP 4和ESCRT（运输所需的内体分选复合物）机制。How？-arrestin-1 与AIP 4和ESCRT功能性整合以介导CXCR 4内体分选仍有待进一步研究。 测定基于我们强有力的初步数据，我们假设，抑制蛋白-1调节ESCRT 控制CXCR 4内体运输和信号传导的机制。我们提出以下两个具体目标： 目的1：确定<$-arrestin-1与AIP 4和ESCRT整合的分子机制， 对照CXCR 4内体分选。目的2：确定ESCRTs调控的分子机制 CXCR 4信号传导和功能。我们将利用一系列最先进的生化技术， 分子和细胞生物学和成像方法来完成这些目标。我们预计， 从这一建议中获得的知识将导致确定新的和创新的方法， 操纵GPCR信号以预防和治疗多种疾病。

Project Description GPCR signaling is essential for a wide variety of physiological processes. GPCR signaling can also play an active role in the pathogenesis of multiple diseases. GPCRs are normally tightly regulated so that signals are of the appropriate magnitude and duration and any perturbations in these regulatory processes can be deleterious. Typically, GPCR signaling is tightly regulated by G protein-coupled receptor kinases (GRKs) and ¿-arrestins. ¿-arrestins bind to GRK-phosphorylated GPCRs at the plasma membrane to terminate signaling by promoting G protein uncoupling and receptor endocytosis. The molecular mechanisms by which GRKs and ¿- arrestins regulate GPCR signaling remain poorly understood. The goal of this proposal is to elucidate the molecular mechanisms by which GRKs and ¿-arrestins govern GPCR signaling. Recently, we described a novel function for ¿-arrestins, as endosomal sorting molecules, whereby they function on endosomes to mediate sorting of GPCRs from endosomes to lysosomes, leading to receptor degradation and long-term attenuation of signaling. However, mechanistic insight into this new function is lacking. ¿-arrestin-1 mediates endosomal sorting of the chemokine receptor CXCR4, which also requires the action of the E3 ubiquitin ligase AIP4 and the ESCRT (endosomal sorting complex required for transport) machinery. How ¿-arrestin-1 functionally integrates with AIP4 and ESCRTs to mediate CXCR4 endosomal sorting remains to be determined. Based on our strong preliminary data we hypothesize that ¿-arrestin-1 regulates the ESCRT machinery to control CXCR4 endosomal trafficking and signaling. We propose the following two specific aims: Aim 1: To determine the molecular mechanisms by which ¿-arrestin-1 integrates with AIP4 and ESCRTs to control CXCR4 endosomal sorting. Aim 2: To determine the molecular mechanisms by which ESCRTs regulate CXCR4 signaling and function. We will utilize a comprehensive series of state-of-the-art biochemical, molecular and cellular biology and imaging approaches to complete these aims. We anticipate that new knowledge gained from this proposal will lead to the identification of new and innovative approaches to manipulate GPCR signaling to prevent and treat a variety of diseases.