Exchange protein directly activated by cAMP (Epac)

Exchange protein directly activated by cAMP (Epac) refers to a family of intracellular proteins (primarily Epac1 and Epac2) that constitute a third class of cAMP effector, distinct from protein kinase A (PKA) and cyclic nucleotide-gated ion channels. Epac proteins are guanine nucleotide exchange factors (GEFs) that, upon binding cAMP, undergo structural rearrangements allowing activation of Rap1 and Rap2, small GTPases involved in numerous cellular processes, notably signal transduction, exocytosis, insulin secretion, and neuronal signaling. Epac function is critical for regulation of vascular tone, heart function, neuronal excitability, immune responses, and metabolic homeostasis. Dysregulation of Epac signaling is implicated in numerous diseases, including cancer, cardiovascular and neurodegenerative disease, inflammation, and diabetes. Selective modulation of Epac activity is therapeutically promising, but specificity and safety remain key considerations.

Other names

EpaccAMP-regulated guanine nucleotide exchange proteinExchange protein activated by cAMPcAMP-GEFI (Epac1)cAMP-GEFII (Epac2)Rap guanine nucleotide exchange factor

Agonism: Small molecule cAMP analogs (e.g., 8-pCPT-2'-O-Me-cAMP) selectively activate Epac, leading to Rap1/Rap2 activation. Antagonism: Small molecule inhibitors (ESI-05, ESI-07) bind and inhibit specific Epac isoforms, blocking downstream Rap signaling.