SfN 2025 – Cell-Based Tools for the Elucidation of GPR75 Signalling and Identification of GPR75 Modulators

GPR75 has emerges as a potential metabolic disease target, but inconsistent ligand activity reports have hindered progress. At Sygnature Discovery, we have developed a suits of functional, cell-based assays to characterize GPR75 signalling and identify modulators with confidence.

Using inducible HEK cell systems, we demonstrated constitutive activity though CRE reporter and β-arrestin recruitment assays, revealing inverse relationships between cAMP and β-arrestin signals. Orthogonal readouts, including G-protein dissociation and HiBiT-tagged surface expression, confirmed coupling preferences towards Gαi3 and Gαq pathways. These assays were optimized for high-throughput screening in 96- and 384-well formats, achieving strong assay windows and reproducible Z-factors, providing a robust platform to support agonist, inverse-agonist, and bias discovery for this orphan receptor.