Molecular Mechanisms of G protein-coupled Receptor Biased Signaling

研究综述 G蛋白偶联受体（GPCRs）是一个重要的跨膜蛋白超家族， 细胞间的通讯对于感知、运动和思考过程至关重要。的很大一部分 目前批准的药物疗法靶向GPCR，但遭受与GPCR相关的“靶向”副作用。 参与差异信号传导途径称为“功能选择性”或“偏置信号传导”。利用 偏置信号传导代表了设计具有更好的“开启”的途径选择性药物的有希望的方法， 靶向”概况，但在结构水平上的机制，导致偏见的信号仍然很差 明白最近的进展，在结构知识的偏见配体识别，导致了 识别结合口袋基序，如细胞外环2（EL 2）和跨膜（TM）7， 用于通过直接配体接合来“切换”偏置信号传导。使用基于结构的方法，我的实验室 旨在使用各种化学生物学和生物物理学方法来揭示 控制偏置信号的结合口袋。战略将结合结构指导 诱变、正构/变构偏向配体、G蛋白功能的动力学监测和β-抑制蛋白 使用荧光素酶和生物发光共振能量转移（BRET）技术的募集，和结构- “功能选择性”关系（SFSR），以最终确定参与的关键GPCR结合基序 效应子转换这种方法的重点是关键受体，其中有结构知识和G蛋白 和β-抑制蛋白偏向性配体。通过这些研究，全面了解 GPCR偏向信号将引导研究人员走向新一代的上级疗法。 1

Research Summary G protein-coupled receptors (GPCRs) are an important superfamily of seven transmembrane proteins involved in cell-to-cell communication essential for sensing, movement, and thought processes. A significant portion of current approved drug therapies target GPCRs, but suffer from “on-target” side-effects related to the engagement of differential signaling pathways known as “functional selectivity” or “biased signaling.” Exploiting biased signaling represents a promising approach toward designing pathway-selective drugs with better “on- target” profiles, but the mechanisms at the structural level that lead to biased signaling are still poorly understood. Recent advancement in structural knowledge of biased ligand recognition has led to the identification of binding pocket motifs, such as extracellular loop 2 (EL2) and transmembrane (TM) 7, important for `switching' biased signaling via direct ligand engagement. Using a structure-based approach, my laboratory aims to use a variety of chemical biology and biophysical approaches to uncover common mechanisms within the binding pocket that govern biased signaling. Strategies will incorporate a combination of structure-guided mutagenesis, orthosteric/allosteric biased ligands, kinetic monitoring of G protein function and β-arrestin recruitment using luciferase and bioluminescent resonance energy transfer (BRET) techniques, and structure- `functional selectivity' relationships (SFSRs) to ultimately to pin-point key GPCR binding motifs involved in effector switching. This approach focuses on key receptors where there is structural knowledge and G protein and β-arrestin-biased ligands available. Through these studies, a comprehensive mechanistic understanding into GPCR biased signaling will guide researchers toward a new generation of superior therapeutics. 1