Abstract
Protein kinases, as crucial signaling molecules, represent an emerging class of drug targets, and the ability to assay their activities in living cells with high-throughput screening should provide exciting opportunities for drug discovery and chemical and functional genomics. Here, we describe a general method for high-throughput reading of dynamic kinase activities using ratiometric fluorescent sensors, and showcase an example of reading intracellular activities of protein kinase A (PKA) and the cyclic adenosine monophosphate (cAMP)/PKA pathway downstream of many G-protein coupled receptors (GPCRs). We further demonstrate the first compound screen based on the ability of compounds to modulate dynamic kinase activities in living cells and show that such screening of a collection of clinical compounds has successfully identified modulators of the GPCR/cAMP/PKA pathway.