Fig. 2

JellyOp activates G_s-signaling in ESC-derived cardiomyocytes. a Baseline frequencies of unstimulated spontaneously beating EBs expressing JellyOp (n = 12) or GFP only (n = 9) (two-sided unpaired Student's t-test: p = 0.2527). b Spontaneous beating frequency during illumination (blue bar, 309 nW mm⁻²) of a JellyOp (black dots, fit in red see Methods) and a GFP control EB (gray). c Representative frequency trace of a JellyOp EB during stimulation by light (blue bar, 309 nW mm⁻²) or with isoprenaline (red bar, 1 µM). d, e Statistical analysis of maximal beating rate increase (d) and deactivation time constant (τ_off) after termination of stimulation (e) using JellyOp and GFP control EBs (n = 5–12, one-way ANOVA: p = 0.924 (d), Welch ANOVA, p = 0.003 (e), Games–Howell post-test: *p < 0.05). f Representative frequency trace of a JellyOp EB during stimulation by light pulses (20 s, 5 min delay) with stepwise increasing light intensities (2–309 nW mm⁻²). g Relationship between normalized peak frequency increase and light intensity fitted with Hill equation (n = 5). h Frequency trace upon illumination with two supramaximal light intensities (blue arrows: left 1770 and right 2370 nW mm⁻², 20 s). Error bars: S.E.M.