DNA-binding protein inhibitor ID-3 (ID3)

Transcriptional regulator (lacking a basic DNA binding domain) which negatively regulates the simple helix-loop-helix (bHLH) transcription factors by forming heterodimers and inhibiting their DNA binding and transcriptional activity. Implicated in regulating many different cellular processes, including cellular growth, senescence, differentiation, apoptosis, angiogenesis, and neoplastic transformation.

Involved in myogenesis by inhibiting skeletal muscle and cardiac myocyte differentiation and boosting muscle precursor cells proliferation. Inhibits the binding of E2A-containing protein complexes to muscle creatine kinase E-box enhancer.