The GLP-1 receptor, one of the most successful drug targets for the treatment of type 2 diabetes and obesity, is known to engage multiple intracellular signaling proteins. However, it remains less explored how the receptor interacts with proteins on the cell membrane. Here, we present a ligand-based proximity labeling approach to interrogate the native cell membrane interactome for the GLP-1 receptor after agonist simulation. Our study identified several unreported putative cell membrane interactors for the endogenous receptor in either a pancreatic β cell line or a neuronal cell line. We further uncovered new regulators of GLP-1 receptor-mediated signaling and insulinotropic responses in β cells. Additionally, we obtained a time-resolved cell membrane interactome map for the receptor in β cells. Therefore, our study provides a new approach that is generalizable to map endogenous cell membrane interactomes for G-protein-coupled receptors to decipher the molecular basis of their cell-type-specific functional regulation.

GLP-1 受体是治疗 2 型糖尿病和肥胖症最成功的药物靶点之一，已知可结合多种细胞内信号蛋白。然而，受体如何与细胞膜上的蛋白质相互作用的研究仍然较少。在这里，我们提出了一种基于配体的邻近标记方法，用于在激动剂模拟后询问 GLP-1 受体的天然细胞膜相互作用组。我们的研究在胰腺 β 细胞系或神经元细胞系中鉴定了几种未报告的内源性受体的假定细胞膜相互作用因子。我们进一步发现了 β 细胞中 GLP-1 受体介导的信号传导和促胰岛素反应的新调节因子。此外，我们还获得了 β 细胞受体的时间分辨细胞膜相互作用组图。因此，我们的研究提供了一种新方法，可普遍绘制 G 蛋白偶联受体的内源细胞膜相互作用组图，以破译其细胞类型特异性功能调节的分子基础。