Transcription factor. Binds to the oxygen responsive element of COX4I2 and activates its transcription under hypoxia conditions (4% oxygen), as well as normoxia conditions (20% oxygen) (PubMed:23303788). . This is the function of ENSG00000106153 (CHCHD2, coiled-coil-helix-coiled-coil-helix domain containing 2).