1R21, bHLHb25, Class B basic helix-loop-helix protein 25, DNA binding protein inhibitor ID 3, DNA-binding protein inhibitor ID-3, HEIR 1, HEIR1, Helix loop helix protein HEIR 1, Helix loop helix protein HEIR1, Helix-loop-helix protein HEIR-1, HLH642, ID 3, ID like protein inhibitor HLH 1R21, ID like protein inhibitor HLH 462, ID-like protein inhibitor HLH 1R21, ID3, ID3_HUMAN, Inhibitor of DNA binding 3, Inhibitor of DNA binding 3 dominant negative helix loop helix protein.
ID (inhibitor of DNA binding) HLH proteins lack a basic DNA-binding domain but are able to form heterodimers with other HLH proteins, thereby inhibiting DNA binding. ID-3 inhibits the binding of E2A-containing protein complexes to muscle creatine kinase E-box enhancer. May inhibit other transcription factors.