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.

我的研究计划的长期目标是了解g蛋白偶联受体的功能。g蛋白偶联受体（gpcr）感知和传递来自众多效应分子的信号，并在协调细胞对环境的快速反应能力方面发挥重要作用。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。该提案将重点关注粘附g蛋白偶联受体g1 （ADGRG1，也称为GPR56）。ADGRG1是GPCRs自催化激活粘附家族的一员。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个链组成的异源二聚体，一个大的细胞外n端片段（ADGRG1- nt）和一个膜结合的c端片段（ADGRG1- ct），它们保持相关且非共价连接。研究人员认为，ADGRG-NT通过与细胞外基质组分的结合和剪切力从ADGRG-CT中去除，从而导致ADGRG1-CT的去抑制、释放和结合，以及通过G-蛋白和ß-阻滞蛋白信号传导的栓系配体和受体。ADGRG1独特的蛋白水解激活模式导致不可逆激活，这些受体通常被描述为“一了之”的gpcr。这与可溶性激素的可逆结合形成对比，可溶性激素可以激活大多数研究中的GPCRs，如ß2-肾上腺素能受体（ß2- ar）或血管紧张素II受体1型（AT1），它们在受体的内化和解离后经常被回收到细胞表面。由此可见，粘附型gpcr可能参与细胞内分选机制和区隔化信号，这与可溶性激素结合型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，与其他激素激活的gpcr（如ß2-AR和AT1）不同。为了了解ADGRG1信号和贩运，短期内，我们将：目标1。定义ADGRG1 c端尾部氨基酸序列，调控与ß-阻滞蛋白的相互作用。目标2。确定ADGRG1内化的囊泡转运途径，以及重新合成的受体转运至细胞膜的囊泡转运途径。目标3。确定ADGRG1的细胞表面和内体信号库。意义：这些研究将解决关于非典型激活GPCR的信号传导和囊泡运输机制的基本问题。鉴于这类受体的重要生理作用和独特的激活机制，这些研究可能会揭示调控gpcr信号传导和内吞命运的途径和机制的多样性。