A Fully Automated [ 35 S]GTPγS Scintillation Proximity Assay for the High-Throughput Screening of G i -Linked G Protein-Coupled Receptors

Abstract

The diversity of physiological functions mediated by the GPCR superfamily provides a rich source of molecular targets for drug discovery programs. Consequently, a variety of assays have been designed to identify lead molecules based on ligand binding or receptor function. In one of these, the binding of [³⁵S]GTPγS, a nonhydrolyzable analogue of GTP, to receptor-activated G-protein α subunits represents a unique functional assay for GPCRs and is well suited for use with automated HTS. Here we compare [³⁵S]GTPγS scintillation proximity binding assays for two different G_i-coupled GPCRs, and describe their implementation with automated high-throughput systems.