May play an important role in endothelial cell activation. May act as a nuclear transcription factor that negatively regulates the expression of cardiac genes. Interacts with TTN/titin and YBX1. Expressed in heart, cardiac muscle. Expression was first clearly detected as early as 8.5 dpc specifically in heart and is regulated temporally and spatially in the myocardium. Transcripts are present in uniformly high levels in the myocardium. Throughout cardiac development, expression is specific for the myocardium; endocardial cushions and valves exhibit only background levels of signal. Transcript levels persist but gradually decrease in neonatal, 2-week-old, and adult hearts.