The discovery of exchange protein activated by cAMP (Epac) as a guanine nucleotide exchange factor for Rap GTPases has shed light on protein kinase A (PKA)-independent functions of cAMP signaling in neural tissues.

As the name suggests, EPAC proteins (EPAC1 and EPAC2) are a family of intracellular sensors for cAMP, and function as nucleotide exchange factors for the Rap subfamily of RAS -like small GTPases.

Apr 1, 2018 · This review focuses on one family of the known cAMP receptors, the exchange proteins directly activated by cAMP (EPACs), also known as the cAMP-regulated guanine nucleotide exchange factors (cAMP-GEFs).

Like PKA, Epac contains an evolutionally conserved cAMP-binding domain that acts as a molecular switch for sensing intracellular second messenger cAMP levels to control diverse biological functions.

Mar 4, 2016 · Overview of key exchange protein directly activated by cAMP (EPAC) functions in the vasculature. In vascular endothelial cells, EPAC1 enhances endothelial barrier (EB) function through various mechanisms.

In eukaryotic cells, the effects of cAMP are mediated by two ubiquitously expressed intracellular cAMP receptors, the classic protein kinase A (PKA)/cAMP-dependent protein kinase and the recently discovered exchange protein directly activated by camp (Epac)/cAMP-regulated guanine nucleotide exchange factors.

Apr 15, 2017 · The excessive cAMP can be degraded into 5′-AMP by phosphodiesterases (PDEs). The binding of cAMP to inactive EPAC leads to the activation of EPAC, which facilitates the exchange of guanosine diphosphate (GDP) to guanosine triphosphate (GTP) and controls Rap-mediated biological functions.

Sep 1, 2003 · Five years ago, Epac — a guanine nucleotide exchange factor for the Ras-like small GTPases Rap1 and Rap2 — was found to be a new target of cyclic AMP, which opened up new avenues for cAMP...

Nov 19, 2004 · Epac1 is a guanine nucleotide exchange factor for Rap1 that is activated by direct binding of cAMP. In vitro studies suggest that cAMP relieves the interaction between the regulatory and catalytic domains of Epac. Here, we monitor Epac1 activation in vivo by using a CFP–Epac–YFP fusion construct.

This review focuses on one family of the known cAMP receptors, the exchange proteins directly activated by cAMP (EPACs), also known as the cAMP-regulated guanine nucleotide exchange factors (cAMP-GEFs).