MW: ~20.6kD. Purity >90% (SDS-PAGE). ATF3 (activating transcription factor 3) is a member of the mammalian activation transcription factor/cAMP responsive element-binding (CREB) protein family of transcription factors. This protein binds the cAMP response element (CRE) (consensus: 5'-GTGACGT[AC][AG]-3'), a sequence present in many viral and cellular promoters. Multiple transcript variants encoding two different isoforms have been found for this gene. The longer isoform represses rather than acti