Bromodomain, cbp_like subfamily. Cbp (CREB binding protein or CREBBP) is an acetyltransferase acting on histone, which gives a specific tag for transcriptional activation and also acetylates non-histone proteins. CREBBP binds specifically to phosphorylated CREB protein and augments the activity of phosphorylated CREB to activate transcription of cAMP-responsive genes. Bromodomains are 110 amino acid long domains, that are found in many chromatin associated proteins. Bromodomains can interact specifically with acetylated lysine.