Regulation of G protein-coupled receptor signaling and trafficking

G蛋白偶联受体（GPCRs）在协调细胞快速凋亡的能力中起重要作用。 回应他们的环境。激动剂与GPCR的结合促进异源三聚体G 蛋白质，介导下游信号传导。激动剂占据的GPCR然后与GPCR激酶相互作用 （GRK），其特异性磷酸化受体，和抑制蛋白，其结合GRK-磷酸化受体。 受体和功能的GPCR脱敏，内吞作用和信号。一个核心问题， 目前的GPCR研究涉及了解GPCR与G 蛋白质GRKs和抑制蛋白我的实验室目前正在使用各种策略，包括X射线 晶体学、生物化学和生物物理分析以及分子和细胞生物学，以更好地了解 GRKs和抑制蛋白调控GPCR的动力学以及这些过程在疾病中的潜在作用。 在这个应用程序中，我们提出了四个问题，这是理解机制的核心 参与GRK和GPCR信号传导和运输的抑制蛋白调节。我们能否获得结构和 GPCR/GRK复合体的动态洞察力虽然我们目前对关键区域知之甚少， 介导GRK与GPCR的相互作用，或者这种相互作用最终如何调节GRK激活，我们的研究 初步研究揭示了β2-肾上腺素能受体（β2AR）和GRK 5之间的三个结合“热点”， 表明GRK 5在与受体结合后发生了大的构象变化。β-抑制蛋白如何与 β2-肾上腺素能受体和β2-适应素？β-抑制蛋白在调节GPCR信号传导中起核心作用， 因此，进一步了解这些相互作用具有重要意义。此外，结构 受体与其主要下游靶点结合时的差异应提供对候选者的了解。 靶向区域，以选择性地增强或破坏特定的相互作用。α-抑制蛋白是否发挥广泛的 在调控GPCR运输和信号传递中的作用？我们已经发现α-arrestin ARRDC 3作为一种 开关以调节β2AR的内体停留时间和随后的细胞内信号传导。我们将 进行ARRDC 3与β2AR相互作用的结构/功能分析，并评估ARRDC 3是否具有与β 2AR相互作用的功能。 在调节GPCR功能中的广泛作用。偏性激动作用的分子和结构基础是什么？虽然 很明显，通过许多GPCR的偏置信号可能最终被证明是重要的 尽管配体具有治疗价值，但从字面上讲，对配体可以 偏置GPCR信号传导。总的来说，对这些问题的更详细的理解具有巨大的意义。 这对开发更有效的药物来治疗各种疾病具有重要意义。

G protein-coupled receptors (GPCRs) play an essential role in coordinating the ability of cells to rapidly respond to their environment. Agonist binding to a GPCR promotes initial activation of heterotrimeric G proteins, which mediates downstream signaling. Agonist-occupied GPCRs then interact with GPCR kinases (GRKs), which specifically phosphorylate the receptor, and arrestins, which bind to GRK-phosphorylated receptors and function in GPCR desensitization, endocytosis, and signaling. A central question that drives current GPCR research involves understanding the dynamics and structures of GPCR interactions with G proteins, GRKs and arrestins. My laboratory is currently using a variety of strategies including X-ray crystallography, biochemical and biophysical analysis, and molecular and cellular biology to better understand the dynamics of GPCR regulation by GRKs and arrestins and the potential role of these processes in disease. In this application, we propose to address four questions that are central to understanding the mechanisms involved in GRK and arrestin regulation of GPCR signaling and trafficking. Can we obtain structural and dynamic insight on a GPCR/GRK complex? While we currently know little about the critical regions that mediate GRK interaction with GPCRs or how this interaction ultimately regulates GRK activation, our preliminary studies reveal three binding “hot spots” between the β2-adrenergic receptor (β2AR) and GRK5 and suggest large conformational changes in GRK5 upon binding to the receptor. How does β-arrestin interact with the β2-adrenergic receptor and β2-adaptin? β-arrestins play a central role in regulating GPCR signaling and trafficking so further understanding these interactions has important implications. Moreover, structural differences in the receptor when bound to its major downstream targets should provide insight on candidate regions to target in order to selectively enhance or disrupt specific interactions. Do α-arrestins play a broad role in regulating GPCR trafficking and signaling? We have found that the α-arrestin ARRDC3 functions as a switch to modulate the endosomal residence time and subsequent intracellular signaling of the β2AR. We will perform structure/function analysis of ARRDC3 interaction with the β2AR and assess whether ARRDCs have a broad role in regulating GPCR function. What is the molecular and structural basis of biased agonism? While it is evident that biased signaling through a number of GPCRs may ultimately prove to be of significant therapeutic value, literally nothing is known about the structural and mechanistic basis by which ligands can bias GPCR signaling. Overall, a more detailed understanding into these questions has tremendous implications for the development of more effective drugs to treat a wide variety of diseases.