Direct spatial control of Epac1 by cyclic AMP.
Epac1 is a guanine nucleotide exchange factor (GEF) for the small G protein Rap and is directly activated by cyclic AMP (cAMP). Upon cAMP binding, Epac1 undergoes a conformational change that allows the interaction of its GEF domain with Rap, resulting in Rap activation and subsequent downstream effects, including integrin-mediated cell adhesion and cell-cell junction formation. Here, we report that cAMP also induces the translocation of Epac1 toward the plasma membrane. Combining high-resolution confocal fluorescence microscopy with total internal reflection fluorescence and fluorescent resonance energy transfer assays, we observed that Epac1 translocation is a rapid and reversible process. This dynamic redistribution of Epac1 requires both the cAMP-induced conformational change as well as the DEP domain. In line with its translocation, Epac1 activation induces Rap activation predominantly at the plasma membrane. We further show that the translocation of Epac1 enhances its ability to induce Rap-mediated cell adhesion. Thus, the regulation of Epac1-Rap signaling by cAMP includes both the release of Epac1 from autoinhibition and its recruitment to the plasma membrane.
Ponsioen
Bas
B
Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands.
Gloerich
Martijn
M
Ritsma
Laila
L
Rehmann
Holger
H
Bos
Johannes L
JL
Jalink
Kees
K
D000318:Adrenergic beta-Agonists / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D005576:Colforsin / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism*; D005786:Gene Expression Regulation; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007545:Isoproterenol / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D020668:rap GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
D000318:Adrenergic beta-Agonists; D020662:Guanine Nucleotide Exchange Factors; C116122:RAPGEF3 protein, human; D011993:Recombinant Fusion Proteins; D005576:Colforsin; D000242:Cyclic AMP; D020668:rap GTP-Binding Proteins; D007545:Isoproterenol