Binds the cAMP response element (CRE) (consensus: 5'-GTGACGT[AC][AG]-3'), a sequence present in many viral and cellular promoters. Binds to the Tax-responsive element (TRE) of HTLV-I. Mediates PKA-induced stimulation of CRE-reporter genes. Represses the expression of FTH1 and other antioxidant detoxification genes. Triggers cell proliferation and transformation (By similarity). Binds DNA as a dimer. Interacts with HIPK2 and CDK3. Interacts with MOTS-c, a peptide produced by the mitochondrially encoded 12S rRNA MT-RNR1; the interaction occurs in the nucleus following metabolic stress. Phosphorylated at Ser-196 by HIPK2 in response to genotoxic stress. This phosphorylation promotes transcription repression of FTH1 and other antioxidant detoxification genes. The CDK3-mediated phosphorylation at Ser-63 promotes its transactivation and transcriptional activities (By similarity). Phosphorylated at Ser-63 by RPS6KA4 and RPS6KA5 in response to mitogenic or stress stimuli. Belongs to the bZIP family. ATF subfamily.