Fig. 5

The KO-cardiomyocytes exhibited calcium transient abnormality. A The left panel: The representative line-scan image of WT-cardiomyocytes and KO-cardiomyocytes stained with Fluo-4. The right panel: Calcium transient profile derived from the left panel. B Space-averaged calcium transients showed parameters measured for analysis of calcium handling. C–G Quantification of peak, time to peak, decay time, contraction duration, and beating rate in WT-cardiomyocytes and KO-cardiomyocytes, n = 6. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001; unpaired two-sided Student’s t test. H Comparison of CAMK2D at transcriptional level between WT-cardiomyocytes and KO-cardiomyocytes by qRT-PCR. n = 3 independent experiments. **P < 0.01. I Immunoblot analysis of CaMKII in WT-cardiomyocytes and KO-cardiomyocytes