Figure 2. Abnormal calcium handling as a cause of arrhythmic phenotype in LMNA-mutant iPSC-CMs.

a, Representative Ca²⁺ transients of control and mutant iPSC-CMs. b, Quantification of cells exhibiting arrhythmic waveforms in control and mutant iPSC-CMs. c, d, Immunoblot analysis of phospho-RYR2, RYR2, phospho-CAMK2D, and CAMK2D levels in control and mutant iPSC-CMs. Data are expressed as mean ± s.e.m., and a two-tailed Student’s t-test was used to calculate P values. n=3. Numbers above the line show significant P values. e, Quantification of cells exhibiting arrhythmic waveforms in mutant iPSC-CMs (III-3; WT/MT) treated with 1 uM of KN92 or KN93 for 24 hr. All traces were recorded for 20 sec. The Ca2+ transients in a were repeated as described in b independently with similar results. The Immunoblot data in c were repeated twice independently with similar results.