Exchange of GDP for GTP by Rap1A 'Epac1:cAMP Complex [plasma membrane]' positively regulates 'Exchange of GTP for GDP by Rap1A' ACTIVATION Epac1 and Epac2 are activated by binding cAMP and positively regulate the exchange of GDP for GTP by the small GTPase Rap1A. The downstream effects of Rap1A:GTP in beta cells are uncertain but may involve increasing the number of "restless newcomer" secretory granules near the plasma membrane and thereby increasing secretion of insulin.<br> Other effects of Rap1A :GTP may include regulating beta cell proliferation through activation of the Raf/MEK/ERK mitogenic cascade and activation of the PI3 Kinase/PDK/PKC cell growth pathway. Pubmed15569269 Pubmed16973695 Pubmed17306374 Reactome Database ID Release 43422328 Reactome, http://www.reactome.org ReactomeREACT_19102 Epac1:cAMP Complex