Regulation of G protein-coupled receptor signaling and trafficking

G蛋白偶联受体(GPCRs)在协调细胞快速反应能力方面发挥着重要作用 对他们的环境做出反应。激动剂与GPCR结合促进异三聚体G的初始激活 蛋白质，它调节下游信号。激动剂占据的GPCRs然后与GPCRK相互作用 (GRKs)，它特异性地使受体磷酸化，以及Drastins，它与GRK磷酸化结合 受体及其在gpr脱敏、内吞和信号转导中的作用。一个核心问题推动着 目前的GPCR研究涉及了解GPCR与G的相互作用的动力学和结构 蛋白质、GRK和阻滞剂。我的实验室目前正在使用各种策略，包括X射线 结晶学、生化和生物物理分析以及分子和细胞生物学，以更好地了解 GRKs和阻滞素对GPCRs调控的动态以及这些过程在疾病中的潜在作用。 在本申请中，我们建议解决四个问题，这四个问题是理解机制的核心 参与GRK和arrestin对GPCR信号和贩运的调控。我们能不能得到结构和 对GPCR/GRK复合体的动态洞察？虽然我们目前对关键地区知之甚少， 调节GRK与GPCRs的相互作用或这种相互作用最终如何调节GRK激活，我们的 初步研究揭示了β2肾上腺素能受体(β2AR)与GRK5和GRK5之间的三个结合热点 提示当与受体结合时，GRK5的构象发生了很大的变化。β-arrestin是如何与 β2-肾上腺素能受体和β-2-Adaptin、β-arrestins在调节gpr信号转导和 因此，进一步了解这些相互作用具有重要意义。此外，结构性的 当受体与其主要下游靶点结合时的差异应该为候选 目标区域，以便有选择地加强或破坏特定的互动。α-arrestins是否扮演了一个广泛的角色 在规范GPCRs交易和信号方面的作用？我们发现α-arrestin ARRDC3作为一种 切换以调节β2AR的内体停留时间和随后的细胞内信号转导。我们会 执行ARRDC 3与β2AR相互作用的结构/功能分析，并评估ARRDC是否具有 在调节gpr功能方面具有广泛的作用。偏向激动症的分子和结构基础是什么？当它 显然，通过许多GPCR发送有偏见的信号最终可能被证明是重要的 治疗价值，从字面上讲，对配体的结构和机制基础一无所知 偏向GPCR信号转导。总体而言，对这些问题的更详细的理解具有巨大的意义 对开发更有效的治疗各种疾病的药物的影响。

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.