Model of cAMP/Epac1-induced endothelial barrier function requiring integrins. cAMP activation of Epac1 triggers 2 pathways: Epac mediates GTP-loading of Rap GTPases, which promotes cortical actin and VE-cadherin-induced cell-cell adhesion, and Epac activation of AKAP9 promotes microtubule growth. This pathway drives integrin adhesion at cell-cell borders. The coordinated function of VE-cadherin and integrins at junctional sites enhances endothelial cell barrier properties in response to cAMP-mediated activation of Epac.