ATF-1 is a bZIP transcription factor that is a member of the cyclic AMP (cAMP)-response element-binding protein (CREB) family. Like other members of the CREB family, ATF-1 mediates signals from numerous physiological stimuli and activates target genes through cAMP-response elements, resulting in the regulation of a broad array of cellular responses. ATF-1 can be phosphorylated at Ser63 by protein kinase A (PKA), calmodulin-dependent protein kinase (CaMK), and cyclin-dependent kinase 3 (CDK3), which recruits CBP/p300 and enhances transcriptional activity. ATF-1 expression levels have been found to be elevated in lymphomas and metastatic melanoma cells, where it contributes to tumor growth.
