CREB1 encodes a transcription factor(cAMP responsive element binding protein 1) that is a member of the leucine zipper family of DNA binding proteins. cAMP responsive element binding protein 1 binds as a homodimer to the cAMP-responsive element, an octameric palindrome. cAMP responsive element binding protein 1 is phosphorylated by several protein kinases, and induces transcription of genes in response to hormonal stimulation of the cAMP pathway. Alternate splicing of CREB1 results in several transcript variants encoding different isoforms.