signaling pathway involving second messengers protein kinase A (PKA) signaling pathway PW:0000543 Protein kinase A (PKA) signaling is a widely used intracellular pathway and the major route for channeling the cAMP signal. cAMP is regulated by adenylyl cyclases that produce it and phosphodiesterases that hydrolyze it. Compartmentalization of PKA signaling is mediated by the AKAP family of scaffold proteins that bring together the kinase, cAMP modulators and sometimes the targets. cAMP-dependent protein kinase A signaling pathway cAMP/PKA signaling pathway pathway protein kinase A signaling serine/threonine-specific kinase mediated signaling pathway