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). ATF3 alone can bind DNA, but it preferentially forms heteromeric complexes with JUN and JUNB and does not interact with FOS. Expressed in tissues containing skeletal muscle or smooth muscle (PubMed:1902565). Expressed in cutaneous and muscular sensory neurons (PubMed:19913522). Up-regulated in regenerating neurons after nerve injury (PubMed:19913522). Rapidly and highly induced in regenerating liver and mitogen-stimulated cells (PubMed:1902565). Belongs to the bZIP family. ATF subfamily.