Fig. 4
From: FRET-based cyclic GMP biosensors measure low cGMP concentrations in cardiomyocytes and neurons
Yellow PfPKG detects low cGMP from GC-A stimulation in stellate ganglion neurons. a, b, d, e Recording of FRET ratio (CFP/Venus for PfPKG, CFP/YFP for cGi-500) in single stellate ganglion neurons expressing the indicated biosensors and stimulated with either the GC-A agonist BNP or the sGC activator BAY 41-2272 at increasing concentrations. The responses were then maximized by stimulating with SIN-1 (20 µM) and IBMX (100 µM). FRET signal was normalized to that prior to stimulation. Traces are mean ± SEM from 10 (PfPKG) and 16 cells (cGi-500) in (a) and (b) and eight (PfPKG) and 14 cells (cGi-500) in (d) and (e). c, f Quantification of FRET responses in (a), (b), (d), and (e). Data are mean ± SEM. *p = 0.012 cGi-500 vs. PfPKG for BNP (250 nM) (Two-way ANOVA assuming sphericity with Sidak’s multiple comparisons test). g Maximal FRET response at the saturating stimulation (SIN-1 20 µM+IBMX 100 µM). Data are median with interquartile range from 18 (PfPKG) and 31 (cGi-500) cells. *p < 0.0001 vs. PfPKG biosensor (Two-tailed Mann–Whitney test)
