TNNI3K and cardiomyopathy: Next, considering that Mypt1/Yap1 is an upstream effector of Nfatc1, regulating the translocation of Nfatc1 into the nucleus,5 we tested the hypothesis that pharmacologic blockade of Nfatc1 into the nucleus in the tnni3k mutant would confer a cardioprotective effect on the tnni3k splicing mutation-based cardiomyopathy and CCD.