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来自众多效应子分子的G蛋白偶联受体（GPCR）的感官和翻译信号，并在协调中起着至关重要的作用。细胞能够快速响应其环境。具体而言，我的研究集中在理解非统计激活的G蛋白偶联受体（GPCR）的功能上。该提案将集中于G蛋白偶联受体G1的粘附（ADGRG1；也称为GPR56）。 ADGRG1是GPCR的自催化激活粘附家族的成员。 ADGRG1在称为GPCR蛋白解析位点（GPS）的站点上经历自动催化事件，该事件导致由2个链组成的异质二聚体的细胞表面表达，一个大型的细胞外N端片段（ADGRG1-NT）和膜结合的C端片段（ADGRGG1-CT）以及与之相关的链接，并与之相关。人们认为，通过与细胞外基质组件结合和剪切力，将ADGRG-NT从ADGRG-CT中删除，从而导致ADGRG1-CT抑制作用，通过G-蛋白质和ß-rartestin的G-蛋白质和受体信号传导的固定配体和受体信号传导释放和参与。用于ADGRG1的独特蛋白水解激活模式导致不可逆的激活，这些受体通常被描述为“一人和完成” GPCR。这与固体马的可逆结合形成鲜明对比，该马匹激活了大多数井研究GPCR，例如ß2-肾上腺肾上腺素受体（ß2-AR）或血管紧张素II受体II型1型（AT1），这些（AT1）经常被回收回到受体内部化和离子后的细胞表面回收到细胞表面。因此，粘合剂GPCR可能会参与细胞内分类机制和分隔的信号传导，这些信号与固体马酮结合GPCR不同。总体假设：ADGRG1与其他同一个激活的GPCR（如ß2-AR和AT1）不同的细胞内囊泡运输和信号传导途径，这是由于不可逆的自身催化活化而导致的。为了理解ADGRG1信号传导和运输，我们将：AIM1。定义ADGRG1 C末端尾氨基酸序列，以调节与ß-rastins相互作用的相互作用。 AIM 2。定义囊泡贩运途径，用于adgrg1的内在化和De-Novo合成受体运输到细胞膜的囊泡贩运途径。 AIM 3。为ADGRG1定义细胞表面和内体信号传导库。意义：这些研究将解决有关非统计激活GPCR的信号传导和囊泡转运机制的基本问题。鉴于这类受体的重要生理作用和激活的独特机制，这些研究可能会揭示调节GPCR信号传导和内吞命运的途径和机制的多样性。