G-protein coupled receptors (GPCRs) play a critical role in relaying
extracellular stimuli to intracellular downstream targets. GPCRs represent at
least one third of the marketed drug targets and GPCR trafficking has been
increasingly appreciated as one important aspect of the normal GPCR life
cycle. Here we describe a new assay platform employing a genetically
targetable pH sensor to visualize GPCR trafficking.