Among the transcription factors, MEF2A, MEF2B, MEF2D, STAT3, GATA4, SOX9, SOCS3, HSF1, and YAP (20–27) which play important roles in cardiomyopathies, we found that MEF2B was a downstream target of YB-1 in cardiomyocytes. The gene discussed is MEF2D; the disease is cardiomyopathy.