RAP1A exchanges GDP for GTP

Stable Identifier
Reaction [transition]
Homo sapiens
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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.
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.

Literature References
PubMed ID Title Journal Year
15569269 Glucagon-like peptide-1: regulation of insulin secretion and therapeutic potential

Brock, B, Gromada, J, Rorsman, P, Schmitz, O

Basic Clin Pharmacol Toxicol 2004
16973695 Cell physiology of cAMP sensor Epac

Chepurny, OG, Harbeck, M, Holz, GG, Roe, MW, Kang, G

J Physiol 2006
15995848 The Rap-B-Raf signalling pathway is activated by glucose and glucagon-like peptide-1 in human islet cells

Göke, R, Trümper, J, Ross, D, Hörsch, D, Jahr, H, Brendel, MD

Diabetologia 2005
17306374 Mechanisms of action of glucagon-like peptide 1 in the pancreas

Egan, JM, Doyle, ME

Pharmacol Ther 2007
This event is regulated