Fig. 4: The BH4 domains of Bcl-2 and Bcl-X_L inhibit RyR-mediated Ca²⁺ release in Bcl-2 KO PACs.

a–c Typical traces of the Fluo-4AM single-cell Ca²⁺ measurements performed in Bcl-2 KO mouse PACs. At the start of each experiment cells were perfused with NaHEPES containing DMSO (vehicle). After establishing the baseline (200 s), CCK (10 pM) was added and RyR-mediated Ca²⁺ oscillations were measured for 5 min. Then, 50 µM of either the control peptide (a), the BH4 domain of Bcl-2 (b), or the BH4 domain of Bcl-X_L (c) were added for 10 min, in the continuous presence of 10 pM CCK. d Quantification of the experiments: The area under the curve per second (AUC/sec) of the CCK-induced Ca²⁺ release after peptide addition (10 min recording) was compared to the AUC/sec before peptide addition (5 min recording). Each data point represents the measurement of an individual cell. The average values ± SEM are shown (P-value <0.0001). At least three independent experiments were performed per condition (N ≥ 3). For each condition at least 40 cells were recorded