A420P mutant iPSCs retain iSkm differentiation potential. A420P mutant iPSCs, defective in NKA mediated Src signaling, formed typical colonies (A and B) and expressed pluripotency marker genes OCT4 and NANOG (C), as observed in WT-iPSCs. These mutant iPSCs were capable of differentiating into Skm with normal gross morphology (E), increased expression of Skm marker genes (D), and positively immunostained with the myosin heavy chain antibody (red, F). RT-qPCR results in (D) were expressed as mean ± SE (n = 3, ∗∗P < .01, ∗∗∗P < .001, NS: not significant by Student’s t test analysis).