. "Authored: Akkerman, JW, 2009-06-03"^^ . "Reviewed: Heemskerk, JW, 2010-09-01"^^ . "Edited: Jupe, S, 2010-09-01"^^ . "EPACs (exchange proteins directly activated by cAMP) are Rap1 GEFs that are activated by direct binding of cAMP (cyclic adenosine monophosphate). cAMP-GEFI (EPAC1) is widely expressed, while cAMP-GEFII (EPAC2) is enriched in brain and adrenal tissue. Both are selective for Rap1. A role of EPACs has been proposed for Rap1-dependent cell adhesion to laminin in both epithelial and red blood cells, and in the regulation of vascular endothelial barrier function."^^ . . . . . . . "Activation of EPACs by cAMP"^^ . . . . .