The (R)-enantiomer of CE3F4 is a preferential inhibitor of human exchange protein directly activated by cyclic AMP isoform 1 (Epac1).

Isoform 1 and isoform 2 of exchange protein directly activated by cAMP (Epac1 and Epac2) contribute to cAMP signaling in numerous cellular processes. Their guanine-nucleotide exchange factor (GEF) activity toward the small GTP-binding protein Rap1 is stimulated by the agonist cAMP. CE3F4, a tetrahydroquinoline analog, prevents Epac1 activation in vitro and in living cultured cells by inhibiting the GEF activity of Epac1. However, the activity of the (R)- and (S)-enantiomers of CE3F4, as well as the ability of CE3F4 and its analogs to inhibit Epac2 GEF activity, have not yet been investigated. In this study, we report that (R)-CE3F4 is a more potent cAMP antagonist than racemic CE3F4 and (S)-CE3F4, inhibiting the GEF activity of Epac1 with 10-times more efficiency than (S)-CE3F4. Epac2, in contrast to Epac1, is activated more efficiently by cAMP than by 8-(4-chlorophenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (007), an Epac-selective cAMP analog. (R)-CE3F4 displays Epac isoform preference, with 10-fold selectivity for Epac1 over Epac2. Deletion of the N-terminal cyclic nucleotide-binding domain of Epac2 does not affect the characteristics of activation of Epac2 by cAMP and by 007, nor its inhibition by CE3F4. Finally, the evaluation of a series of CE3F4 structural analogs as GEF inhibitors allowed identifying structural features that are important for high Epac1 inhibitory activity of CE3F4. We conclude that the (R)-enantiomer of CE3F4 is a preferential inhibitor of Epac1 with high potency in the low micromolar range, and we suggest that this compound may be a useful pharmacological tool for investigating the functional role of Epac1 in cAMP signaling.

Courilleau D ，Bouyssou P ，Fischmeister R ，Lezoualc'h F ，Blondeau JP ... -  《-》

Identification of a tetrahydroquinoline analog as a pharmacological inhibitor of the cAMP-binding protein Epac.

Courilleau D ，Bisserier M ，Jullian JC ，Lucas A ，Bouyssou P ，Fischmeister R ，Blondeau JP ，Lezoualc'h F ... -  《-》

Novel Epac fluorescent ligand reveals distinct Epac1 vs. Epac2 distribution and function in cardiomyocytes.

Pereira L ，Rehmann H ，Lao DH ，Erickson JR ，Bossuyt J ，Chen J ，Bers DM ... -  《-》

Cyclic adenosine 3',5'-monophosphate (cAMP)-dependent protein kinases, but not exchange proteins directly activated by cAMP (Epac), mediate thyrotropin/cAMP-dependent regulation of thyroid cells.

Dremier S ，Milenkovic M ，Blancquaert S ，Dumont JE ，Døskeland SO ，Maenhaut C ，Roger PP ... -  《ENDOCRINOLOGY》

Characterization of the activation of the Rap-specific exchange factor Epac by cyclic nucleotides.

Rehmann H 《Methods in Enzymology》