Required for precocious cardiac adaptation to stress through integrated regulation of the AKT/mTOR pathways and FOXO1. Regulates cardiac homeostasis and plays an important role in protection against cardiac hypertrophy. Acts as a transcriptional cofactor, represses transactivator activity of ISL1 and MYOCD. Interacts with LMNA (PubMed:21498514). Interacts with ISL1 (via N-terminal domain); the interaction represses ISL1 transactivator activity (By similarity). Additional isoforms seem to exist according to PubMed:21498514. Primarily expressed in heart and skeletal muscle. Also detected in liver. Expression is reduced in patients with dilated cardiomyocytes. In murine cardiomyopathy models, deletion of the encoding gene accelerates progress from hypertrophy to heart failure.