Label-free Profiling of Ligands for Endogenous GPCRs Using a Cell-Based High Throughput Screening Technology

Abstract

G protein-coupled receptors (GPCRs) are the largest family of cell surface receptors and the largest class of drug targets. The activation of GPCRs is known to lead to the dynamic translocation of multiple signaling molecules or molecular assemblies during its signaling cycle, and in many cases cytoskelatal reorganization. Such a movement and/or reorganization results in dynamic redistribution of cellular contents, equivalent to dynamic mass redistribution (DMR), which can be monitored online in living cells using Corning® Epic™ system – a label-free and non-invasive biosensor system that is centered around resonant waveguide grating (RWG) biosensors.

The resultant DMR signal offers a novel and functional optical signature for studying GPCR signaling and screening GPCR drug compounds. The theoretical considerations and assay principles are first described. The unique optical signatures for over 20 endogenous G_q, G_s and G_i-coupled receptors in A431 human epidermoid carcinoma cells are presented. As exampled in studying the signaling pathways and network interactions of endogenous GPCRs, as well as screening GPCR ligands using both kinetic and endpoint measurements, Corning® Epic™ system is an easily scaleable biosensor HTS platform for G_q, G_s and G_iGPCR drug discovery and deorphanization.