Fig. 2
From: FRET-based cyclic GMP biosensors measure low cGMP concentrations in cardiomyocytes and neurons
PfPKG biosensors detect sGC-stimulated cGMP increase in HEK293 cells. a Confocal images of living HEK293 cells expressing the Yellow PfPKG biosensor. Scale bar: 10 µm. b Confocal images of living HEK293 cells expressing the Red PfPKG biosensor. Scale bar: 10 µm. c, d Recording of FRET ratio between CFP and Venus (c) or T-sapphire and Dimer2 (d) in single HEK293 cells expressing the indicated biosensor and stimulated with the NO donor SNAP (50 nM) and the PDE inhibitor IBMX (100 µM), where indicated. FRET was normalized to that prior to stimulation. Shown are traces representative of four (Yellow PfPKG) and five (Red PfPKG) individual cells. Pseudocolour images show CFP/Venus and Tsapphire/Dimer2 ratios at the start and end of experiment. e Maximal FRET response at the saturating stimulation (SNAP + IBMX). Data are mean ± SEM from 14 (Yellow PfPKG) and 12 (Red PfPKG) cells. *p = 0.027 vs. Red PfPKG (Two-tailed Student’s t test). f cGMP levels in HEK293 cells in the absence (Ctr) or presence of 50 nM or 100 µM SNAP (10 min stimulation). Data are mean ± SEM from 4 to 5 individual experiments
