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 (By similarity). It may repress transcription by stabilizing the binding of inhibitory cofactors at the promoter (By similarity). Binds DNA as a homodimer or a heterodimer. Interacts with KAT5; promoting KAT5 autoacetylation and KAT5 deubiquitination by USP7. Belongs to the bZIP family. ATF subfamily.