Figure 4

AKAR2-AKAP12 fusion protein biosensor: FRET signaling in response to beta-adrenergic stimulation. Stably transfected A431 clones expressing AKAR-AKAP12 were serum starved over night and then stimulated with beta-adrenergic agonist (isoproterenol, 10 mM) for 30 min. Image and fluorescence density were recorded for CFP and YFP in the absence and following the 30 min challenge with isoproterenol (+ISO, 30 min). The recordings for CFP and YFP were sampled at 10 sec intervals. The images shown are representative of a large array of images collected for this purpose.