Rapid Production of Assay Ready Cells for GPCR Drug Discovery

G-protein coupled receptors (GPCRs) regulate various physiological processes. They are targeted by hundreds of existing drugs used to treat or moderate conditions as diverse as asthma, hypertension, diabetes and Alzheimer’s disease. GPCRs have also been implicated in multiple forms of cancer, including colon, pancreatic and appendix cancer, increasing interest in GPCR drug discovery. GPCRs are large, membrane-spanning cell surface receptors that are challenging to purify and crystallize, making cell lines overexpressing these proteins valuable tools for drug discovery. Developing stable cell lines expressing GPCRs can be particularly difficult. Once established, GPCR expression is prone to drift; some commercially available GPCR-expressing cell lines have very limited passage stability. An alternative is to use transiently transfected Assay Ready Cells, which can be prepared in less than an hour using MaxCyte^® electroporation in physiologically relevant host cell types. Here we assess the response of HEK 293 cells transiently expressing the M1 muscarinic GPCR to carbachol, a GPCR activator that increases calcium flux. We present data demonstrating the ability to control the responsiveness of Assay Ready Cells transiently transfected with varying plasmid DNA concentrations, enabling researchers to fine tune the sensitivity of their GPCR assays.