Optical tools for visualizing and controlling human GLP-1 receptor activation with high spatiotemporal resolution

• DOI: 10.7554/elife.86628
• Publication Date: 2023-04-11T10:49:37Z
• Authors: Loïc Duffet; Elyse T Williams; Andrea Gresch; Simin Chen; Musadiq A Bhat; Dietmar Benke; Nina Hartrampf; Tommaso Patriarchi
• Keywords: 10120 Department of Chemistry; 0301 basic medicine; QH301-705.5; Science; 11558 Neuroscience Center Zurich; 10050 Institute of Pharmacology and Toxicology; 610 Medicine & health; Genetics and Molecular Biology; Glucagon-Like Peptide-1 Receptor; 03 medical and health sciences; Biochemistry and Chemical Biology; Glucagon-Like Peptide 1; 540 Chemistry; Humans; GLP1R; Biology (General); neuropeptide; genetically encoded sensor; 0303 health sciences; General Immunology and Microbiology; General Neuroscience; Q; R; General Medicine; photocage; Liraglutide; General Biochemistry; 570 Life sciences; biology; Medicine; fluorescence

The glucagon-like peptide-1 receptor (GLP1R) is a broadly expressed target of peptide hormones with essential roles in energy and glucose homeostasis, as well as of the blockbuster weight-loss drugs semaglutide and liraglutide. Despite its large clinical relevance, tools to investigate the precise activation dynamics of this receptor with high spatiotemporal resolution are limited. Here, we introduce a novel genetically encoded sensor based on the engineering of a circularly permuted green fluorescent protein into the human GLP1R, named GLPLight1. We demonstrate that fluorescence signal from GLPLight1 accurately reports the expected receptor conformational activation in response to pharmacological ligands with high sensitivity (max ΔF/F0=528%) and temporal resolution (τON = 4.7 s). We further demonstrated that GLPLight1 shows comparable responses to glucagon-like peptide-1 (GLP-1) derivatives as observed for the native receptor. Using GLPLight1, we established an all-optical assay to characterize a novel photocaged GLP-1 derivative (photo-GLP1) and to demonstrate optical control of GLP1R activation. Thus, the new all-optical toolkit introduced here enhances our ability to study GLP1R activation with high spatiotemporal resolution.