Guanine nucleotide exchange factor (GEF for RAP1A and RAP2A small GTPases that is activated by binding cAMP. Through simultaneous binding of PDE3B to RAPGEF3 and PIK3R6 is assembled in a signaling complex in which it activates the PI3K gamma complex and which is involved in angiogenesis. Plays a role in the modulation of the cAMP-induced dynamic control of endothelial barrier function through a pathway that is independent on Rho-mediated signaling. Required for the actin rearrangement at cell-cell junctions, such as stress fibers and junctional actin.,CAMP-GEFI, EPAC, EPAC1, HSU79275, bcm910,Endocrine & Metabolism,G protein signaling,G protein signaling_G-Protein-Coupled Receptors Signaling to MAPK/Erk,Immunology & Inflammation,MAPK-Erk Signaling Pathway,Signal Transduction,RAPGEF3