Phosphorylation of CREB by PKA Authored: Mahajan, SS, 2009-10-29 Edited: Gillespie, ME, 2009-06-02 00:56:21 Protein kinase A has two regulatory subunits and two catalytic subunits which are held together to form the holoenzyme and is activated upon binding of cAMP within the regulatory subunits. Once cAMP binds the regulatory subunits, the catalytic subunits are released to carry out phosphorylation of CREB at serine133. Pubmed17908236 Pubmed19244110 Reactome Database ID Release 43443474 Reactome, http://www.reactome.org ReactomeREACT_20583 Reviewed: Tukey, D, 2009-11-17