Figure 3

Enhanced Ca²⁺ release of RyR2-I784F mutant. HEK293 cells were transfected with eGFP- hRYR2-WT (black symbols) or eGFP- hRYR2-I784F (blue symbols) plasmids for 48 h and loaded with 5 μM Fura-2 for 45 min. Cells were then perfused with KRH buffer at 0.1, 0.5 or 1.0 mM CaCl₂ (dashed lines). Solid lines correspond to the cells treated with cAMP for 20 min prior to the monitoring. (a) Percentage of oscillating cells. (b) Number of spontaneous Ca²⁺ oscillations per minute. (c) Representative traces of Ca²⁺ release under basal conditions and after cAMP treatment. The total numbers of cells analyzed for Ca²⁺ oscillations from three separate experiments under basal conditions were n = 588 for WT cells, and n = 524 for I784F cells; and after cAMP treatment, n = 347 for WT and n = 316 for I784F cells. Data are mean ± SEM. *p ≤ 0.02, **p ≤ 0.001, for RyR2-I784F vs WT-RyR2; ^†p ≤ 0.02, ^††p ≤ 0.001, ^†††p ≤ 0.0001, for cAMP treatment vs basal conditions.