The function of ATF3 (activating transcription factor 3, ENSG00000162772) is as follows. This protein binds the cAMP response element (CRE) (consensus: 5'-GTGACGT[AC][AG]-3'), a sequence present in many viral and cellular promoters. Represses transcription from promoters with ATF sites. It may repress transcription by stabilizing the binding of inhibitory cofactors at the promoter. . [Isoform 2]: Activates transcription presumably by sequestering inhibitory cofactors away from the promoters. . [Isoform 3]: Stress-induced isoform, counteracts the transcriptional repression of isoform 1. .