MAPK3 and cardiomyopathy: To investigate the role of Slc25a49 in Dox‐induced cardiomyopathy, we generated mice with tamoxifen‐induced, cardiac‐specific Slc25a49 gene knockout by interbreeding Slc25a49flox/flox mice with Myh6‐Cre/ERT2 transgenic mice (Slc25a49flox/flox; Myh6‐Cre/ERT2; Figure S1A–C, Supporting Information).