Subcellular organization of Adhesion G-Protein Coupled Receptor (aGPCR) signalling.

粘附 G 蛋白偶联受体 (aGPCR) 信号传导的亚细胞组织。

• 批准号: RGPIN-2019-06166
• 负责人: Ramachandran, Rithwik
• 金额: $ 2.33万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=738753
• 关键词: Subcellular; organization; Adhesion; Protein; Coupled

The long-term objectives of my research program are to understand G-protein coupled receptor function. G-protein-coupled receptors (GPCRs) sense and traduce signals from numerous effector molecules and play an essential role in coordinating the ability of cells to rapidly respond to its environment. Specifically, my research is focused on understanding function of non-canonically activated G-protein coupled receptors (GPCRs). This proposal will focus on the Adhesion G-protein-coupled Receptor-G1 (ADGRG1; also known as GPR56). ADGRG1 is a member of the autocatalytically activated Adhesion Family of GPCRs. ADGRG1 undergoes an auto-catalytic event at a site called the GPCR proteolysis site (GPS), that results in the cell surface expression of a heterodimer consisting of 2 chains, a large extracellular N-terminal fragment (ADGRG1-NT) and a membrane-bound C-terminal fragment (ADGRG1-CT) which remain associated and non-covalently linked. It is believed that the ADGRG-NT is removed from ADGRG-CT through binding to extracellular matrix components and shear force resulting in ADGRG1-CT disinhibition, release and engagement of a tethered ligand and receptor signalling through G--proteins and ß--arrestin. The unique proteolytic mode of activation for ADGRG1 results in irreversible activation and these receptors are often described as "one and done" GPCRs. This is in contrast to the reversible binding of a soluble hormone that activates most well studies GPCRs such as the ß2--adrenergic receptor (ß2-AR) or the angiotensin II receptor type 1 (AT1) that are frequently recycled back to the cell surface following internalization and dissociation of the ligand from the receptor. It follows that adhesion GPCRs might engage intracellular sorting mechanisms and compartmentalized signalling that are distinct from those for soluble hormone binding GPCRs. Overarching hypothesis: ADGRG1 engages intracellular vesicular trafficking and signalling pathways that are distinct from other hormone activated GPCRs such as ß2-AR and AT1 as a result of irreversible auto-catalytic activation. In order to understand ADGRG1 signalling and trafficking, in the short-term, we will: Aim 1. Define ADGRG1 C-terminal tail amino acid sequences regulating interaction with the ß--arrestins. Aim 2. Define the vesicular trafficking route for internalization of ADGRG1 and the vesicular trafficking route for de-novo synthesized receptor trafficking to the cell membrane. Aim 3. Define the cell surface and endosomal signalling repertoire for ADGRG1. Significance: These studies will address fundamental questions regarding the signaling and vesicular transport mechanisms of a non-canonically activated GPCR. Given the important physiological roles and unique mechanisms of activation of this class of receptors, it is likely that these studies will reveal the diversity of pathways and mechanisms regulating the signaling and endocytic fate of GPCRs.

我的研究项目的长期目标是了解 G 蛋白偶联受体 (GPCR) 感知和追踪来自众多效应分子的信号，并在协调细胞快速反应的能力中发挥重要作用。具体来说，我的研究重点是了解非规范激活的 G 蛋白偶联受体 (GPCR) 的功能，本提案将重点关注粘附 G 蛋白偶联受体 -G1。 （ADGRG1；也称为 GPR56）是 GPCR 自催化激活粘附家族的成员，ADGRG1 在称为 GPCR 蛋白水解位点 (GPS) 的位点经历自催化事件，导致细胞表面表达由 2 条链、一个大的细胞外 N 端片段 (ADGRG1-NT) 和一个膜结合的 C 端片段组成的异二聚体(ADGRG1-CT) 仍保持关联且非共价连接，据信 ADGRG-NT 通过与细胞外基质成分结合和剪切力从 ADGRG-CT 上去除，导致 ADGRG1-CT 去抑制、释放和结合。 ADGRG1 独特的蛋白水解激活模式会导致不可逆的激活，并且这些受体通常会被激活。这与可溶性激素的可逆结合相反，后者可激活大多数研究中的 GPCR，例如 β2-肾上腺素受体 (ß2-AR) 或血管紧张素 II 受体 1 (AT1)。配体从受体内化和解离后，它们经常被循环回到细胞表面。因此，粘附 GPCR 可能参与细胞内分选机制和区室化信号传导。与可溶性激素结合 GPCR 不同 总体假设：由于不可逆的自催化激活，ADGRG1 参与细胞内囊泡运输和信号通路，这些通路与其他激素激活的 GPCR（例如 ß2-AR 和 AT1）不同。信号和运输，在短期内，我们将： 目标 1. 定义 ADGRG1 C 端尾部氨基酸序列，调节与目标 2. 定义 ADGRG1 内化的囊泡运输途径和从头合成的受体运输至细胞膜的囊泡运输途径。 目标 3. 定义 ADGRG1 的细胞表面和内体信号传导库。鉴于非规范激活的 GPCR 的重要生理作用和独特机制，这些研究将解决有关信号传导和囊泡运输机制的基本问题。此类受体的激活，这些研究很可能将揭示调节 GPCR 信号传导和内吞命运的途径和机制的多样性。