Exchange factor directly activated by cAMP 1 (EPAC1) (EPAC1)

Exchange factor directly activated by cAMP 1 (EPAC1), encoded by the RAPGEF3 gene, is a major intracellular receptor for the second messenger cyclic adenosine monophosphate (cAMP). It functions as a guanine nucleotide exchange factor (GEF) that activates the small GTPases Rap1 and Rap2, operating independently of the classical protein kinase A (PKA) pathway. EPAC1 is ubiquitously expressed and regulates essential cellular processes such as cell adhesion, migration, endothelial barrier integrity, and cardiac calcium handling. In disease states, EPAC1 is often dysregulated; for instance, its overexpression is linked to cancer metastasis and poor prognosis, while its activation contributes to cardiac hypertrophy and heart failure. As a result, EPAC1 is considered a high-value therapeutic target, with various small-molecule inhibitors like ESI-09 and CE3F4 being developed to treat malignancies and cardiovascular disorders. Additionally, circulating EPAC1 levels have shown potential as biomarkers for coronary artery disease severity and therapeutic response to GLP-1 receptor agonists.

Other names

Rap Guanine Nucleotide Exchange Factor 3RAPGEF3cAMP-regulated guanine nucleotide exchange factor IcAMP-GEFIEPACH-EPAC

EPAC1 acts as a guanine nucleotide exchange factor (GEF) for the small GTPases Rap1 and Rap2. Upon binding of cAMP to its cyclic nucleotide-binding domain (CNBD), EPAC1 undergoes a conformational change that releases the catalytic CDC25-homology domain from autoinhibition. This allows the domain to facilitate the exchange of GDP for GTP on Rap proteins, thereby initiating downstream signaling cascades involved in cell adhesion, migration, and calcium handling.