{"gene":"RAPGEF3","run_date":"2026-06-10T06:43:36","timeline":{"discoveries":[{"year":2002,"finding":"EPAC1 (RAPGEF3) functions as a cAMP-activated guanine nucleotide exchange factor (GEF) for Rap1; a selective cAMP analogue (8CPT-2Me-cAMP) was developed that activates EPAC but not PKA, demonstrating that cAMP-induced Rap1 activation and ERK regulation are independent processes.","method":"Rational drug design of selective cAMP analogue; in vitro and in vivo activation assays; cell-based ERK activity assays with PKA/Ras/Rap1 inhibitors","journal":"Nature cell biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro selectivity assay plus multiple cell-line epistasis experiments; replicated across multiple cell types","pmids":["12402047"],"is_preprint":false},{"year":2004,"finding":"EPAC1 undergoes a cAMP-induced conformational change (relief of autoinhibitory interaction between regulatory and catalytic domains) detectable as a FRET change in a CFP-Epac-YFP fusion; this in vivo conformational change serves as the molecular basis for cAMP-dependent activation.","method":"FRET imaging in mammalian cells using CFP-Epac1-YFP fusion; cAMP-binding mutant abolishes response; comparison with PKA-based sensor","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct in-cell FRET readout of conformational change, confirmed with binding-dead mutant, multiple orthogonal validations","pmids":["15550931"],"is_preprint":false},{"year":2004,"finding":"EPAC1 activation by cAMP occurs faster at the plasma membrane than in the cytoplasm or mitochondria; cAMP dynamics and effector activation are spatiotemporally compartmentalized in living cells.","method":"Targeted CFP-Epac1-YFP FRET reporters directed to plasma membrane, cytoplasm, mitochondria and nucleus; live-cell imaging with beta-adrenergic receptor stimulation","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — subcellular-targeted FRET biosensors with direct functional consequence (kinetics of Epac activation), multiple compartments compared","pmids":["15545605"],"is_preprint":false},{"year":2004,"finding":"EPAC1 activates the cAMP-Epac-Rap1 pathway to regulate cell adhesion and spreading on laminin-5 specifically through the alpha3beta1 integrin, but not the alpha6beta4 integrin, in a PKA-independent manner.","method":"PKA-independent cAMP analogue stimulation; dominant-negative Rap1; integrin-blocking antibodies; adhesion and spreading assays in multiple cell lines","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple cell lines, integrin-specific dissection, PKA independence confirmed with selective analogues and inhibitors","pmids":["15302884"],"is_preprint":false},{"year":2004,"finding":"EPAC1 signals via Rap2B to activate phospholipase C-epsilon (PLCε), increase intracellular Ca2+, and thereby activate H-Ras and ERK1/2 downstream of Gs-coupled receptors; a cAMP-binding-deficient EPAC1 mutant and dominant-negative Rap2B suppress this pathway.","method":"Dominant-negative and constitutively active Rap2B mutants; cAMP-binding-deficient EPAC1 mutant; Rap GTPase-activating protein II; Ca2+ measurements; ERK activity assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — multiple mutants, reconstitution-level pathway dissection with mechanistic mutants in a single study","pmids":["15319437"],"is_preprint":false},{"year":2005,"finding":"EPAC1 directly interacts with tubulin, co-purifies with cellular microtubules, and co-localizes with the mitotic spindle; association with microtubules suppresses EPAC-mediated Rap1 activation, while EPAC binding promotes microtubule formation.","method":"Co-purification with cellular microtubules; co-immunoprecipitation; co-localization (immunofluorescence); Rap1 activation assays in presence/absence of microtubule association","journal":"Molecular bioSystems","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — co-purification and co-localization support interaction, functional consequence shown but single lab","pmids":["16880999"],"is_preprint":false},{"year":2005,"finding":"EPAC1 activation induces cardiomyocyte hypertrophy through a Ca2+-dependent activation of Rac, calcineurin/NFAT signaling pathway; blockade of calcineurin or Rac blunts the hypertrophic response.","method":"Epac-selective cAMP analogue in primary cardiomyocytes; calcineurin inhibitor; dominant-negative Rac; NFAT reporter; hypertrophic marker expression","journal":"Circulation research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — selective agonist plus pathway inhibitors in primary cells; single lab","pmids":["16269655"],"is_preprint":false},{"year":2004,"finding":"EPAC1 interacts with the light chain 2 (LC2) of microtubule-associated protein MAP1A; the interaction is mediated by the cAMP-binding domain of EPAC1 (not the DEP or catalytic domains), and EPAC1 co-localizes with LC2 in the perinuclear region and filamentous structures.","method":"Yeast two-hybrid screen of brain libraries; co-immunoprecipitation in co-transfected HEK293 cells; GST pull-down with domain deletion mutants; immunolocalization","journal":"The Biochemical journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP confirmed interaction; domain mapping by GST pull-down; single lab","pmids":["15202935"],"is_preprint":false},{"year":2007,"finding":"EPAC1-dependent subcellular localization via its DEP domain is required for cAMP-mediated Rap1 activation and thyroid-stimulating hormone-induced mitogenesis; disruption of DEP-dependent targeting abolishes Epac-Rap1 activation and cell proliferation.","method":"Dominant-negative EPAC mutant; DEP domain deletion constructs; thyroid cell proliferation/DNA synthesis assays; Rap1 activation (pull-down) assays","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — domain-deletion and dominant-negative approach with functional cellular readout; single lab","pmids":["18063584"],"is_preprint":false},{"year":2008,"finding":"EPAC1 induces cardiomyocyte hypertrophy via the small GTPase Ras and activates calcineurin and CaMKII in a Rap1-independent, PKA-independent manner downstream of beta-adrenergic receptor stimulation; Epac1 knockdown reduces beta-AR-induced hypertrophy.","method":"siRNA knockdown of Epac1; Epac-selective cAMP analogue; dominant-negative Ras; calcineurin/CaMKII inhibitors; Ras activation assays; hypertrophic marker expression in primary cardiomyocytes","journal":"Circulation research","confidence":"High","confidence_rationale":"Tier 2 / Strong — siRNA loss-of-function plus pharmacologic pathway dissection; multiple orthogonal readouts; replicated with in vivo model (aortic constriction)","pmids":["18323524"],"is_preprint":false},{"year":2008,"finding":"EPAC is coupled to Rap2 in the nucleus and mediates cAMP-dependent nuclear export and activation of DNA-PK; PKA provides an opposing (inhibitory) input. Spatially discrete PDE-dependent cAMP degradation systems modulate the balance between EPAC and PKA arms, influencing DNA double-strand break repair and PKB/Akt Ser-473 phosphorylation.","method":"Epac-selective and PKA-selective cAMP analogues; nuclear/cytoplasmic fractionation; DNA-PK activity assays; etoposide-induced DSB repair assays; PKB/Akt phosphorylation (Western blot)","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — compartment fractionation + selective analogues + functional DSB repair assay; single lab","pmids":["18728186"],"is_preprint":false},{"year":2008,"finding":"EPAC1 forms a complex with Akt and PP2A; cAMP via both EPAC and PKA synergistically activates EPAC-associated PP2A phosphatase activity in a Rap1b-dependent manner, leading to Akt dephosphorylation and inhibition.","method":"Co-immunoprecipitation of EPAC-Akt-PP2A complex; dominant-negative EPAC and PP2A constructs; phosphatase activity assay; PKA- and EPAC-selective cAMP analogues; Akt phosphorylation assays","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — complex Co-IP plus in-complex phosphatase activity assay; dominant-negative validation; single lab","pmids":["18550542"],"is_preprint":false},{"year":2008,"finding":"EPAC activation in cardiomyocytes produces arrhythmias associated with altered Ca2+ homeostasis; the arrhythmogenic effect depends on CaMKII activity.","method":"Langendorff-perfused hearts with Epac-selective analogue; monophasic action potential recordings; CaMKII inhibitor KN-93; fluorescence Ca2+ imaging of isolated ventricular myocytes","journal":"Pflugers Archiv : European journal of physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — intact heart preparation plus cellular Ca2+ imaging with pharmacologic pathway dissection; single lab","pmids":["18600344"],"is_preprint":false},{"year":2008,"finding":"EPAC1 activation promotes fibroblast migration via Rap1, but inhibits collagen synthesis in a Rap1-independent manner; TGF-β1 transcriptionally downregulates Epac1 expression, and overexpression of Epac1 inhibits TGF-β1-induced collagen synthesis.","method":"Epac-selective cAMP analogue; Rap1 knockdown; Epac1 overexpression and siRNA; collagen synthesis assay; migration assay; multiple fibroblast cell types","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — selective agonist plus Rap1 knockdown; multiple cell types; overexpression rescue; single lab","pmids":["18434542"],"is_preprint":false},{"year":2008,"finding":"EPAC activation inhibits PAF-induced hyperpermeability in intact rat microvessels via stabilization of VE-cadherin at cell-cell junctions through the Epac/Rap1 pathway.","method":"Hydraulic conductivity measurement in rat venular microvessels; Epac-selective cAMP analogue; VE-cadherin immunofluorescence","journal":"American journal of physiology. Heart and circulatory physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — intact microvessel physiology combined with junction protein imaging; single lab","pmids":["18178724"],"is_preprint":false},{"year":2008,"finding":"EPAC activation inhibits epithelial cell migration by slowing focal adhesion dynamics and inhibiting polarized membrane protrusion; these effects extend beyond integrin affinity modulation.","method":"HGF/TGFβ-induced migration assays; forced integrin activation controls; live-cell focal adhesion dynamics imaging; Rap activation assays","journal":"Cellular signalling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — live imaging of focal adhesions plus forced integrin control distinguishes mechanism; single lab","pmids":["18346875"],"is_preprint":false},{"year":2009,"finding":"EPAC1 exists in a complex with vascular KATP channel subunits and inhibits KATP channel activity via a Ca2+-dependent mechanism requiring calcineurin (PP-2B) activation; this is PKA-independent.","method":"Co-immunoprecipitation of EPAC with KATP subunits; whole-cell patch clamp; Ca2+ imaging (Fura-2); calcineurin inhibitors cyclosporin A and ascomycin; BAPTA chelation","journal":"The Journal of physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — complex Co-IP plus electrophysiology plus Ca2+ imaging with pharmacologic dissection; single lab","pmids":["19491242"],"is_preprint":false},{"year":2009,"finding":"EPAC1 promotes DRG neurite outgrowth and mediates growth cone attraction to cAMP, netrin-1, and MAG gradients in embryonic neurons; siRNA knockdown of EPAC reduces outgrowth and prevents cAMP-dependent neurite regeneration on spinal cord tissue.","method":"Epac-selective cAMP analogue; siRNA knockdown; DRG neurite outgrowth assays; growth cone turning assays; spinal cord tissue substrate assays","journal":"Molecular and cellular neurosciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA loss-of-function plus pharmacologic gain-of-function with multiple functional readouts; single lab","pmids":["18583150"],"is_preprint":false},{"year":2009,"finding":"Embryonic growth cone attraction to cAMP, netrin-1, and MAG gradients is mediated by Epac, whereas repulsion in adult growth cones is mediated by PKA; FRET demonstrates netrin-1 activates Epac in embryonic but PKA in postnatal neurons, revealing a developmental switch in cAMP effector usage.","method":"FRET-based Epac and PKA biosensors in live neurons; growth cone turning assays with selective analogues; siRNA knockdown","journal":"The Journal of neuroscience : the official journal of the Society for Neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — FRET biosensors directly measure effector activation; functional turning assays with selective analogues; developmental comparison in same study","pmids":["20007468"],"is_preprint":false},{"year":2009,"finding":"EPAC1 activation increases cardiac myofilament Ca2+ sensitivity and phosphorylation of cardiac Troponin I and Myosin Binding Protein-C via PKC and CaMKII (not PKA); EPAC reduces Ca2+ transient amplitude while increasing cell shortening.","method":"Epac-selective cAMP analogue; constitutively active Epac in vivo infection; permeabilized cardiomyocyte Ca2+ sensitivity assay; PKC and CaMKII inhibitors; phosphoprotein detection","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution in permeabilized cells + in vivo constitutively active Epac + pharmacologic pathway dissection; multiple orthogonal methods","pmids":["19666481"],"is_preprint":false},{"year":2009,"finding":"EPAC1 activation triggers apoptosis specifically in cortical neurons (not cardiomyocytes) by transcriptionally upregulating Bim; EPAC1 knockout mice show reduced neuronal apoptosis in a 3-nitropropionic acid model.","method":"Epac-selective agonist; Epac1 genetic knockout mice; Bim siRNA knockdown; TUNEL and DNA fragmentation assays; qRT-PCR for Bim","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO in vivo plus pharmacologic/siRNA approach in vitro; replicated mechanistic pathway; cell-type specific comparison","pmids":["20516079"],"is_preprint":false},{"year":2009,"finding":"EPAC activation via the Epac/PI3K pathway promotes Akt and Foxo3a phosphorylation in skeletal muscle, mediating the antiproteolytic effect of epinephrine independently of PKA.","method":"Epac-selective cAMP analogue in isolated EDL muscles; PI3K inhibitor wortmannin; PKA agonist and inhibitor H89; Akt/Foxo3a phosphorylation (Western blot); proteolysis rate measurement","journal":"Molecular and cellular endocrinology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — selective agonist/antagonist plus PI3K inhibitor with phosphoprotein readouts; single lab","pmids":["19804812"],"is_preprint":false},{"year":2010,"finding":"EPAC and PKA synergize via a Rap1-independent mechanism to mediate cAMP-induced growth arrest in vascular smooth muscle cells; neither pathway alone is sufficient, and Rap1 inhibition does not negate the combined effect.","method":"Selective PKA and Epac cAMP analogues; constitutively active Epac; Rap1GAP overexpression; Rap1 siRNA; Rb phosphorylation; BrdU incorporation; ERK/JNK phosphorylation","journal":"Journal of molecular and cellular cardiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple approaches (selective analogues, dominant-negative, siRNA) with functional and biochemical readouts; single lab","pmids":["20971121"],"is_preprint":false},{"year":2011,"finding":"Taurocholate stimulates hepatocyte polarization and bile canalicular network formation through a cAMP-Epac-MEK-Rap1-LKB1-AMPK signaling cascade; inhibition of Epac, Rap1, or MEK blocks the effect.","method":"Rat hepatocyte sandwich cultures; adenylyl cyclase inhibitor; Epac-selective analogue; Rap1 and MEK inhibitors; kinase activation assays (LKB1, AMPK)","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ordered pathway dissection with selective inhibitors in primary cells; single lab","pmids":["21220320"],"is_preprint":false},{"year":2011,"finding":"EPAC/Rap1 pharmacological activation preserves tubular epithelial cell adhesion and barrier function during hypoxia in vitro and reduces renal failure in an ischemia-reperfusion mouse model in vivo.","method":"Epac-selective cAMP analogue (8-pCPT-2'-O-Me-cAMP); mouse IRI model; barrier function measurement; β-catenin and clusterin-α immunostaining","journal":"Journal of the American Society of Nephrology : JASN","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro and in vivo models with functional readout; single lab","pmids":["21493776"],"is_preprint":false},{"year":2012,"finding":"EPAC1 null mutation impairs LTP, spatial learning, and social interactions by promoting miR-124 transcription which suppresses Zif268 translation; knockdown of miR-124 restores Zif268 and reverses all EPAC-/- phenotypes.","method":"EPAC1/2 conditional forebrain knockout mice; LTP electrophysiology; behavioral tests; miR-124 knockdown and overexpression; Zif268 Western blot","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO combined with rescue by miR-124 knockdown; multiple epistatic experiments with mechanistic pathway; replicated behavioral and electrophysiological readouts","pmids":["22365550"],"is_preprint":false},{"year":2012,"finding":"EPAC1-mediated Rap1 activation and Akt phosphorylation are required for pancreatic cancer cell migration and invasion; ESI-09, a noncyclic nucleotide EPAC antagonist, blocks Epac-mediated Rap1 activation and Akt phosphorylation as well as insulin secretion.","method":"EPAC-specific inhibitor ESI-09; Rap1 activation assay; Akt phosphorylation (Western blot); migration and invasion assays; insulin secretion assay in β-cells","journal":"Molecular pharmacology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — selective inhibitor with multiple mechanistic and functional readouts; single lab","pmids":["23066090"],"is_preprint":false},{"year":2012,"finding":"EPAC1 coupled to Rap1 controls cAMP-dependent exocytosis of Weibel-Palade bodies (WPBs) in endothelial cells; siRNA knockdown of EPAC1 abolishes epinephrine-induced Rap1 activation and reduces WPB exocytosis.","method":"siRNA knockdown of EPAC1; Rap1 activation assay; Rap1GAP overexpression; WPB exocytosis assay (VWF release); epinephrine stimulation","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA knockdown plus Rap1GAP dominant-negative; functional exocytosis readout; single lab","pmids":["22511766"],"is_preprint":false},{"year":2012,"finding":"EPAC1 and Rap2b are recruited to the S. aureus-containing phagosome, and EPAC-Rap2b signaling through calpain activation regulates autophagic response to alpha-hemolysin in a PKA-independent manner.","method":"Immunofluorescence localization of EPAC and Rap2b to phagosomes; EPAC-selective analogue; calpain inhibitors; autophagy assays; siRNA knockdown","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct subcellular localization to phagosome with functional autophagy consequence; selective agonist/antagonist; single lab","pmids":["22654658"],"is_preprint":false},{"year":2012,"finding":"EPAC regulates SGLT expression and translocation to lipid rafts in renal proximal tubule cells via ERK, p38 MAPK, and NF-κB signaling, requiring caveolin-1 and F-actin organization.","method":"Epac-selective cAMP analogue; SGLT expression (Western blot); lipid raft fractionation; cytochalasin D (F-actin disruption); cav-1 siRNA; α-MG uptake assay","journal":"Biochimica et biophysica acta","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — selective agonist plus siRNA plus fractionation; multiple pathway inhibitors with functional transport readout; single lab","pmids":["22230192"],"is_preprint":false},{"year":2013,"finding":"Increased glucose uptake activates RAP1 via EPAC (exchange protein directly activated by cAMP) through pyruvate kinase M2 (PKM2) interaction with soluble adenylyl cyclase, contributing to oncogenic signaling and loss of epithelial polarity in a 3D culture model.","method":"3D mammary epithelial culture; GLUT3 overexpression; EPAC/RAP1 pathway inhibitors; PKM2 pulldown/interaction studies; soluble adenylyl cyclase inhibition","journal":"The Journal of clinical investigation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — mechanistic pathway dissection in physiologically relevant 3D model; PKM2-sAC interaction identified; single lab","pmids":["24316969"],"is_preprint":false},{"year":2013,"finding":"EPAC1 inhibition by CE3F4 (a tetrahydroquinoline analog) blocks EPAC1 GEF activity toward Rap1 via an uncompetitive inhibition mechanism; the formyl group at position 1 and bromine at position 5 are essential for activity; CE3F4 does not compete for cAMP binding.","method":"Cell-free GEF activity fluorescence assay; intact cell Rap1 activation assay; PKA holoenzyme activity assay (negative); structure-activity relationship analysis; kinetics of inhibition","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — cell-free enzymatic assay with kinetic characterization; SAR validation; single lab","pmids":["23139415"],"is_preprint":false},{"year":2014,"finding":"EPAC activation inhibits VEGF- and TNF-α-induced retinal vascular permeability and inhibits VEGFR signaling through the Ras/MEK/ERK pathway; Rap1B knockdown or EPAC antagonist increases endothelial permeability, and GTP-bound Rap1 promotes tight junction assembly.","method":"EPAC-selective analogue and antagonist; siRNA knockdown of Rap1B; Ras/MEK/ERK signaling (Western blot); permeability assays in vitro and in vivo; tight junction immunostaining","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro and in vivo permeability assays with siRNA knockdown and pharmacologic tools; single lab","pmids":["29158262"],"is_preprint":false},{"year":2015,"finding":"The cAMP-Epac-Rap1-PLCε-IP3 signaling module mobilizes intra-acrosomal calcium during sperm exocytosis; each step (cAMP, Epac, Rap1, PLCε) is required upstream of IP3-dependent calcium release from the acrosome.","method":"TAT-cAMP sponge to sequester cAMP; Epac-selective analogue; dominant-negative Rap1; PLCε inhibition; Rap1/Rab3/Rab27 GTP-loading assays; Ca2+ mobilization assay; acrosome reaction assay","journal":"Biochimica et biophysica acta","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstituted pathway with direct evidence for each step in a single study using multiple complementary tools including a novel engineered inhibitor","pmids":["26704387"],"is_preprint":false},{"year":2016,"finding":"EPAC-dependent vasorelaxation in mesenteric arteries occurs via activation of Kv7 channels; proximity ligation assay shows Kv7.4 co-localizes with Rap1a and Rap2 (EPAC downstream targets) upon isoproterenol stimulation specifically in mesenteric (not renal) arteries.","method":"Isometric tension recording; Kv7 channel inhibitor linopirdine; EPAC inhibitor; PKA inhibitor; proximity ligation assay for Kv7.4-AKAP and Kv7.4-Rap1a/Rap2 complexes; isolated myocytes","journal":"Arteriosclerosis, thrombosis, and vascular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional vascular assay plus proximity ligation assay for complex formation; vessel-type-specific comparison; single lab","pmids":["27789473"],"is_preprint":false},{"year":2013,"finding":"EPAC induces vascular relaxation in rat mesenteric arteries by increasing Ca2+ sparks from ryanodine receptors to activate BKCa channels in smooth muscle, and via endothelial SKCa/IKCa channels and NOS activation.","method":"Myography; iberiotoxin and apamin/TRAM-34 (K+ channel blockers); ryanodine; Ca2+ spark imaging (Fluo-4); NOS inhibitor L-NAME; endothelium denudation; patch clamp (STOCs and current clamp)","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple electrophysiology and Ca2+ imaging methods with pharmacologic dissection in intact vessels; comprehensive mechanism established","pmids":["23959673"],"is_preprint":false},{"year":2009,"finding":"EPAC1 mediates melanoma cell migration and metastasis via translocation of syndecan-2 to lipid rafts (through Epac/PI3K/tubulin polymerization) and via increased NDST-1-dependent heparan sulfate production; EPAC overexpression enhances lung colonization in mice.","method":"siRNA knockdown; Epac overexpression; lipid raft fractionation; syndecan-2 translocation imaging; PI3K inhibitor; migration assay; NDST-1 expression and translation rate; mouse lung colonization model","journal":"American journal of physiology. Cell physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA plus overexpression with in vivo metastasis model; multiple mechanistic readouts; single lab","pmids":["19657062"],"is_preprint":false},{"year":2007,"finding":"Anthrax edema toxin (an adenylyl cyclase) inhibits endothelial cell chemotaxis through downstream EPAC activation and Rap1; EPAC or activated Rap1 alone reproduces cytoskeletal changes and chemotaxis block; ET also induces transcription of EPAC2 (RapGEF4) and MR-GEF/RapGEF5.","method":"Anthrax ET treatment of HMVECs; Epac-selective analogue; constitutively active Rap1; cytoskeletal staining; chemotaxis assay; transcriptional profiling","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — selective agonist plus constitutively active Rap1 mimic; functional chemotaxis assay; single lab","pmids":["17491018"],"is_preprint":false},{"year":2011,"finding":"RAPGEF3 (EPAC1) localizes to the acrosome and subacrosomal ring in equine sperm; activation of RAPGEF3/RAPGEF4 induces acrosomal exocytosis in capacitated sperm and prevents membrane hyperpolarization during capacitation, supporting a role in Ca2+-dependent acrosome reaction via membrane depolarization.","method":"Indirect immunofluorescence localization; Epac-selective cAMP analogue stimulation; acrosomal exocytosis quantification; sperm membrane potential measurement","journal":"Biology of reproduction","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct immunolocalization plus functional exocytosis assay with membrane potential measurement; single lab","pmids":["21471298"],"is_preprint":false},{"year":2017,"finding":"hCG activates Erk1/2 in human endometrial stromal cells through the cAMP/EPAC pathway (not PKA, PKC, or PI3K); EPAC inhibition and siRNA knockdown prevent hCG-induced Erk1/2 phosphorylation and subsequent progesterone receptor upregulation.","method":"EPAC inhibitor; siRNA knockdown of EPAC; pathway inhibitors (PKA, PKC, PI3K); pErk1/2 Western blot; PR expression by immunofluorescence and qRT-PCR; primary human ESC cultures","journal":"Molecular human reproduction","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA knockdown plus selective inhibitors; pathway exclusion experiments; primary human cells; single lab","pmids":["28333280"],"is_preprint":false},{"year":2016,"finding":"EPAC-PKCα signaling mediates Epac-dependent sensitization of P2X3 receptors in DRG neurons after inflammation; PKCα is downstream of EPAC and mediates enhancement of P2X3R-dependent hyperalgesia via a distinct translocation pattern from PKCε.","method":"Epac agonist CPT; EPAC antagonists; classical PKC inhibitor Go6976; PKCα-siRNA; P2X3R current recordings; behavioral hyperalgesia assays; pPKCα immunostaining","journal":"Pain","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA plus pharmacologic epistasis with electrophysiological and behavioral readouts; single lab","pmids":["26963850"],"is_preprint":false},{"year":2018,"finding":"EPAC activation drives inflammation-induced sensitization of TRPV1 in DRG neurons via PKCα and PKCε; EPAC agonist increases membrane TRPV1 expression and pPKCα levels; PKCα and PKCε inhibitors block EPAC-mediated TRPV1 potentiation.","method":"Epac agonist CPT; EPAC antagonists; PKCα/PKCε inhibitors; patch clamp of TRPV1 currents; behavioral nociception assays; TRPV1 and pPKC immunostaining and colocalization","journal":"Pain","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — selective agonist/antagonist with electrophysiology and membrane trafficking assays; single lab","pmids":["30015706"],"is_preprint":false},{"year":2021,"finding":"Exendin-4 stimulates autophagic flux in pancreatic β-cells through the RAPGEF3/EPAC1-calcium-PPP3/calcineurin-TFEB axis, independent of AMPK and MTOR; RAPGEF4/EPAC2 is the primary mediator of this pathway identified by siRNA knockdown.","method":"siRNA knockdown of RAPGEF3/RAPGEF4; calcineurin inhibitors; TFEB overexpression; autophagy flux assays; Ca2+ signaling measurements; db/db mouse in vivo model","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA knockdown plus pharmacologic dissection plus in vivo model; ordered pathway established; single lab","pmids":["34338148"],"is_preprint":false},{"year":2021,"finding":"EPAC1 activation ameliorates tubulointerstitial inflammation in diabetic nephropathy through the C/EBP-β/SOCS3/STAT3 pathway; EPAC activation restores C/EBP-β, promotes its nuclear translocation, upregulates SOCS3, and inhibits STAT3 phosphorylation and MCP-1 expression.","method":"Epac-selective analogue in db/db mice and HK-2 cells; siRNA knockdown of C/EBP-β and SOCS3; SOCS3 overexpression; STAT3 phosphorylation (Western blot); macrophage migration assay","journal":"Acta pharmacologica Sinica","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA knockdown plus overexpression plus in vivo model; ordered pathway; single lab","pmids":["34103688"],"is_preprint":false},{"year":2019,"finding":"EPAC1 expression in left atrial fibroblasts is suppressed by HF/norepinephrine (via α-AR/Smad3) and upregulated by β2-AR activation; Epac1 activation reduces collagen expression and LA fibrosis post-MI, whereas Epac1 loss increases fibroblast collagen production.","method":"Epac-selective activator and antagonist ESI-09; β-AR subtype-selective agonists/antagonists; Smad3 inhibitor SIS3; collagen expression assays; in vivo MI mouse model with Sp-8-pCPT treatment; echocardiography","journal":"Cardiovascular research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — receptor subtype pharmacology with in vivo validation; Smad3-dependent transcriptional mechanism; single lab","pmids":["30016400"],"is_preprint":false},{"year":2014,"finding":"EPAC activation in pancreatic β-cells activates TRPM2 nonselective cation channels (NSCC) through a PKA-independent cAMP/EPAC pathway to facilitate membrane depolarization and insulin secretion; TRPM2-deficient mice lack this NSCC activation.","method":"GLP-1/exendin-4/glucose stimulation; PKA inhibitors; EPAC-selective analogue; TRPM2-knockout mice; patch clamp recordings of NSCC","journal":"Diabetes","confidence":"Medium","confidence_rationale":"Tier 2 / Strong — genetic KO mice plus pharmacologic PKA exclusion plus electrophysiology; replicated across GLP-1 analogues","pmids":["24824430"],"is_preprint":false}],"current_model":"RAPGEF3 (EPAC1) is a multidomain cAMP-binding guanine nucleotide exchange factor that, upon direct cAMP binding to its regulatory domain, undergoes a conformational change relieving autoinhibition to activate the small GTPases Rap1 and Rap2 in a PKA-independent manner; it is spatiotemporally compartmentalized through interactions with microtubules (via tubulin), KATP channels, MAP1A-LC2, and scaffold proteins (DEP domain-dependent membrane targeting), and controls diverse cellular functions including integrin-mediated adhesion, endothelial barrier maintenance via VE-cadherin and tight junctions, cardiomyocyte Ca2+ handling and hypertrophy (through Ras/calcineurin/CaMKII), growth cone guidance, neuronal apoptosis (via Bim upregulation), axon regeneration, sperm acrosomal exocytosis (via Rap1-PLCε-IP3-Ca2+ cascade), anti-fibrotic signaling in fibroblasts, and regulation of TRPM2 channel activity and insulin secretion in β-cells."},"narrative":{"mechanistic_narrative":"RAPGEF3 (EPAC1) is a cAMP-activated guanine nucleotide exchange factor that couples receptor-driven cAMP elevation to activation of the small GTPases Rap1 and Rap2 in a PKA-independent manner, thereby serving as a parallel cAMP effector arm controlling adhesion, barrier function, secretion, and cell-type-specific transcriptional and Ca2+ programs [PMID:12402047, PMID:15319437]. Direct cAMP binding to its regulatory domain relieves an autoinhibitory interaction with the catalytic domain — a conformational switch directly visualized in living cells by intramolecular FRET and abolished by cAMP-binding-dead mutants [PMID:15550931]. EPAC1 signaling is spatially compartmentalized: subcellular-targeted reporters show faster activation at the plasma membrane than in cytosol or mitochondria [PMID:15545605], DEP-domain-dependent membrane targeting is required for Rap1 activation and mitogenesis [PMID:18063584], and EPAC1 is positioned by direct interactions with tubulin/microtubules and with MAP1A light chain 2 [PMID:16880999, PMID:15202935]. Downstream of Rap, EPAC1 engages effector cascades including Rap2B–PLCε–Ca2+ to activate Ras/ERK [PMID:15319437], and controls integrin-α3β1-dependent adhesion and spreading [PMID:15302884]. Through these modules it stabilizes endothelial and epithelial junctions — preserving VE-cadherin and tight junctions to limit vascular permeability [PMID:18178724, PMID:29158262] — and drives regulated exocytosis, including Weibel-Palade body release in endothelium [PMID:22511766] and the cAMP–Epac–Rap1–PLCε–IP3–Ca2+ cascade that mobilizes acrosomal calcium during sperm exocytosis [PMID:26704387]. In cardiomyocytes EPAC1 activation produces hypertrophy and altered Ca2+ handling via Ras, Rac/calcineurin/NFAT, and CaMKII/PKC, increasing myofilament Ca2+ sensitivity and promoting arrhythmia, all independent of PKA [PMID:18323524, PMID:19666481, PMID:16269655]. EPAC1 also exerts cell-type-specific control of survival and plasticity, transcriptionally upregulating the pro-apoptotic factor Bim in cortical neurons [PMID:20516079] and, in forebrain neurons, driving miR-124-mediated suppression of Zif268 to support LTP, spatial learning, and social behavior [PMID:22365550]. In secretory and metabolic tissues EPAC1/EPAC2 activate TRPM2 cation channels to facilitate insulin secretion [PMID:24824430]. Selective cAMP analogues and the EPAC antagonists ESI-09 and CE3F4 provide pharmacological tools that confirm its GEF activity and PKA independence [PMID:12402047, PMID:23139415, PMID:23066090].","teleology":[{"year":2002,"claim":"Established that EPAC1 is a cAMP-activated GEF for Rap1 acting independently of PKA, defining a second cAMP effector arm distinct from the kinase pathway.","evidence":"Rational design of the PKA-sparing cAMP analogue 8CPT-2Me-cAMP with in vitro and cell-based Rap1/ERK activation assays","pmids":["12402047"],"confidence":"High","gaps":["Did not resolve the structural mechanism of cAMP-dependent activation","Physiological receptor contexts not yet mapped"]},{"year":2004,"claim":"Defined the activation mechanism as a cAMP-induced relief of autoinhibition between regulatory and catalytic domains, and showed this activation is spatially compartmentalized within the cell.","evidence":"Intramolecular CFP-Epac1-YFP FRET sensors in live cells with binding-dead mutants and subcellular-targeted reporters","pmids":["15550931","15545605"],"confidence":"High","gaps":["Identity of the scaffolds enforcing compartment-specific kinetics not fully defined","No atomic structure of the conformational transition"]},{"year":2004,"claim":"Connected EPAC1 to specific downstream physiology, linking Rap1 to integrin-α3β1 adhesion and Rap2B to a PLCε–Ca2+–Ras/ERK branch.","evidence":"Selective analogues, integrin-blocking antibodies, dominant-negative Rap1/Rap2B, and cAMP-binding-dead EPAC1 mutants in multiple cell lines","pmids":["15302884","15319437"],"confidence":"High","gaps":["Whether Rap1 vs Rap2 selectivity is intrinsic or context-driven not resolved","Direct PLCε binding not demonstrated"]},{"year":2004,"claim":"Identified protein partners that spatially position EPAC1, showing localization is achieved through cytoskeletal and scaffold interactions.","evidence":"Yeast two-hybrid, reciprocal Co-IP, and GST domain-mapping pull-downs identifying MAP1A-LC2 binding via the cAMP-binding domain; microtubule/tubulin co-purification","pmids":["15202935","16880999"],"confidence":"Medium","gaps":["Single-lab interactions without reciprocal validation across groups for tubulin","Functional impact of MAP1A-LC2 binding on signaling not quantified"]},{"year":2007,"claim":"Demonstrated that DEP-domain-dependent membrane targeting is functionally required for Rap1 activation and proliferative responses, establishing localization as obligatory for signaling output.","evidence":"DEP-deletion and dominant-negative constructs with Rap1 pull-down and thyroid mitogenesis assays","pmids":["18063584"],"confidence":"Medium","gaps":["Membrane lipid/protein anchor recognized by the DEP domain not identified","Single-lab, single cell-type result"]},{"year":2008,"claim":"Defined EPAC1 as a major driver of cardiomyocyte hypertrophy and altered Ca2+ handling through Ras, calcineurin and CaMKII, dissociating these effects from both Rap1 and PKA.","evidence":"siRNA knockdown, dominant-negative Ras, calcineurin/CaMKII inhibitors, and aortic constriction in vivo with hypertrophic markers and Ca2+ imaging","pmids":["18323524","16269655","18600344"],"confidence":"High","gaps":["How EPAC1 activates Ras independently of Rap not mechanistically resolved","Direct EPAC1-CaMKII coupling unclear"]},{"year":2008,"claim":"Showed EPAC1 modulates additional intracellular targets — Akt/PP2A complexes, nuclear DNA-PK, and barrier-junction proteins — placing it within survival, repair and permeability circuits.","evidence":"Co-IP of EPAC-Akt-PP2A complex with in-complex phosphatase assays; nuclear fractionation and DSB repair assays; intact microvessel permeability with VE-cadherin imaging","pmids":["18550542","18728186","18178724"],"confidence":"Medium","gaps":["These complexes documented by single-lab Co-IP without reciprocal/structural validation","Mechanism of EPAC1 nuclear targeting not defined"]},{"year":2009,"claim":"Revealed cell-type-specific outcomes, including a developmental switch in growth-cone cAMP effector usage and pro-apoptotic Bim induction in neurons versus contractile remodeling in heart.","evidence":"FRET biosensors and turning assays in embryonic vs postnatal neurons; Epac1 knockout mice and Bim siRNA; permeabilized cardiomyocyte Ca2+-sensitivity assays","pmids":["20007468","20516079","19666481","18583150"],"confidence":"High","gaps":["Molecular basis for cell-type-specific transcriptional outputs (e.g., Bim) not resolved","Determinants of Epac vs PKA developmental switch unknown"]},{"year":2012,"claim":"Linked EPAC1 to regulated secretion, phagosomal autophagy and neuronal plasticity, broadening its role in vesicle trafficking and gene-regulatory programs.","evidence":"siRNA/Rap1GAP for Weibel-Palade body exocytosis; phagosomal localization with calpain inhibitors for autophagy; forebrain knockout mice with miR-124/Zif268 rescue","pmids":["22511766","22654658","22365550"],"confidence":"Medium","gaps":["How EPAC1 controls miR-124 transcription mechanistically unclear","Phagosomal recruitment mechanism not defined"]},{"year":2013,"claim":"Characterized EPAC1 in vascular tone and channel regulation, showing it activates Kv7, BKCa and ryanodine-receptor-coupled Ca2+ signaling to drive vasorelaxation.","evidence":"Myography, Ca2+ spark imaging, patch clamp, and proximity ligation assays linking Rap1a/Rap2 to Kv7.4 in mesenteric vessels","pmids":["23959673","27789473","19491242"],"confidence":"High","gaps":["Vessel-bed specificity (mesenteric vs renal) mechanistically unexplained","Direct EPAC1-channel complexes not structurally defined"]},{"year":2015,"claim":"Reconstituted the full cAMP–Epac–Rap1–PLCε–IP3–Ca2+ module required for sperm acrosomal exocytosis, establishing EPAC1 in regulated calcium-dependent membrane fusion.","evidence":"TAT-cAMP sponge, Epac-selective analogue, dominant-negative Rap1, PLCε inhibition, and Ca2+/acrosome reaction assays; immunolocalization to the acrosome","pmids":["26704387","21471298"],"confidence":"High","gaps":["Spatial organization of the cascade on the acrosomal membrane not resolved","Relative contributions of EPAC1 vs EPAC2 not fully separated"]},{"year":2021,"claim":"Extended EPAC1 into metabolic and disease-relevant signaling, regulating TRPM2-dependent insulin secretion, β-cell autophagy via calcineurin/TFEB, and anti-inflammatory/anti-fibrotic pathways in kidney and heart.","evidence":"TRPM2-knockout mice and patch clamp; siRNA with calcineurin inhibitors and TFEB; in vivo db/db and MI models with C/EBP-β/SOCS3/STAT3 and Smad3 dissection","pmids":["24824430","34338148","34103688","30016400"],"confidence":"Medium","gaps":["Many disease pathways rest on single-lab in vivo models","Direct vs indirect engagement of TFEB and STAT3 circuits unresolved"]},{"year":null,"claim":"How a single cAMP-activated GEF achieves its highly cell-type- and compartment-specific outputs — selecting between Rap1, Rap2, Ras and non-canonical effectors — remains the central unresolved question.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unifying model linking scaffold/localization choice to effector selection","Endogenous receptor-to-EPAC1 coupling specificity poorly mapped","Structural basis of effector discrimination unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,4]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[2,8,16]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[5,7]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[10]},{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[5]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,4,33]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[27,33]},{"term_id":"R-HSA-397014","term_label":"Muscle contraction","supporting_discovery_ids":[9,19]}],"complexes":[],"partners":["RAP1A","RAP2B","TUBB","MAP1A","AKT1","PPP2CA","ABCC8","KCNQ4"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O95398","full_name":"Rap guanine nucleotide exchange factor 3","aliases":["Exchange factor directly activated by cAMP 1","Exchange protein directly activated by cAMP 1","EPAC 1","Rap1 guanine-nucleotide-exchange factor directly activated by cAMP","cAMP-regulated guanine nucleotide exchange factor I","cAMP-GEFI"],"length_aa":923,"mass_kda":103.8,"function":"Guanine nucleotide exchange factor (GEF) for RAP1A and RAP2A small GTPases that is activated by binding cAMP. Through simultaneous binding of PDE3B to RAPGEF3 and PIK3R6 is assembled in a signaling complex in which it activates the PI3K gamma complex and which is involved in angiogenesis. Plays a role in the modulation of the cAMP-induced dynamic control of endothelial barrier function through a pathway that is independent on Rho-mediated signaling. Required for the actin rearrangement at cell-cell junctions, such as stress fibers and junctional actin","subcellular_location":"Endomembrane system","url":"https://www.uniprot.org/uniprotkb/O95398/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/RAPGEF3","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/RAPGEF3","total_profiled":1310},"omim":[{"mim_id":"609527","title":"RAP GUANINE NUCLEOTIDE EXCHANGE FACTOR 5; RAPGEF5","url":"https://www.omim.org/entry/609527"},{"mim_id":"606057","title":"RAP GUANINE NUCLEOTIDE EXCHANGE FACTOR 3; RAPGEF3","url":"https://www.omim.org/entry/606057"},{"mim_id":"604990","title":"SOLUTE CARRIER FAMILY 9, MEMBER 3, REGULATOR 1; SLC9A3R1","url":"https://www.omim.org/entry/604990"},{"mim_id":"182307","title":"SOLUTE CARRIER FAMILY 9, MEMBER 3; SLC9A3","url":"https://www.omim.org/entry/182307"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Uncertain","locations":[{"location":"Cytosol","reliability":"Uncertain"},{"location":"Endoplasmic reticulum","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in many","driving_tissues":[],"url":"https://www.proteinatlas.org/search/RAPGEF3"},"hgnc":{"alias_symbol":["cAMP-GEFI","EPAC","bcm910"],"prev_symbol":[]},"alphafold":{"accession":"O95398","domains":[{"cath_id":"1.10.10.10","chopping":"88-223","consensus_level":"high","plddt":86.6309,"start":88,"end":223},{"cath_id":"2.60.120.10","chopping":"231-348","consensus_level":"high","plddt":92.7325,"start":231,"end":348},{"cath_id":"1.20.870.10","chopping":"360-372_385-518","consensus_level":"high","plddt":83.7563,"start":360,"end":518},{"cath_id":"3.10.20.90","chopping":"560-648","consensus_level":"high","plddt":91.6273,"start":560,"end":648},{"cath_id":"1.10.840.10","chopping":"655-862_894-919","consensus_level":"high","plddt":89.8106,"start":655,"end":919}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O95398","model_url":"https://alphafold.ebi.ac.uk/files/AF-O95398-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O95398-F1-predicted_aligned_error_v6.png","plddt_mean":77.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RAPGEF3","jax_strain_url":"https://www.jax.org/strain/search?query=RAPGEF3"},"sequence":{"accession":"O95398","fasta_url":"https://rest.uniprot.org/uniprotkb/O95398.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O95398/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O95398"}},"corpus_meta":[{"pmid":"12402047","id":"PMC_12402047","title":"A novel Epac-specific cAMP analogue demonstrates independent regulation of Rap1 and ERK.","date":"2002","source":"Nature cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/12402047","citation_count":618,"is_preprint":false},{"pmid":"17084085","id":"PMC_17084085","title":"Epac proteins: multi-purpose cAMP targets.","date":"2006","source":"Trends in biochemical sciences","url":"https://pubmed.ncbi.nlm.nih.gov/17084085","citation_count":438,"is_preprint":false},{"pmid":"15545605","id":"PMC_15545605","title":"Fluorescent indicators of cAMP and Epac activation reveal differential dynamics of cAMP signaling within discrete subcellular compartments.","date":"2004","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/15545605","citation_count":401,"is_preprint":false},{"pmid":"20055708","id":"PMC_20055708","title":"Epac: defining a new mechanism for cAMP action.","date":"2010","source":"Annual review of pharmacology and toxicology","url":"https://pubmed.ncbi.nlm.nih.gov/20055708","citation_count":395,"is_preprint":false},{"pmid":"15550931","id":"PMC_15550931","title":"Detecting cAMP-induced Epac activation by fluorescence resonance energy transfer: Epac as a novel cAMP indicator.","date":"2004","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/15550931","citation_count":354,"is_preprint":false},{"pmid":"14693691","id":"PMC_14693691","title":"Epac: A new cAMP-binding protein in support of glucagon-like peptide-1 receptor-mediated signal transduction in the pancreatic beta-cell.","date":"2004","source":"Diabetes","url":"https://pubmed.ncbi.nlm.nih.gov/14693691","citation_count":329,"is_preprint":false},{"pmid":"18604457","id":"PMC_18604457","title":"Epac and PKA: a tale of two intracellular cAMP receptors.","date":"2008","source":"Acta biochimica et biophysica Sinica","url":"https://pubmed.ncbi.nlm.nih.gov/18604457","citation_count":306,"is_preprint":false},{"pmid":"23447132","id":"PMC_23447132","title":"Exchange protein directly activated by cAMP (epac): a multidomain cAMP mediator in the regulation of diverse biological functions.","date":"2013","source":"Pharmacological reviews","url":"https://pubmed.ncbi.nlm.nih.gov/23447132","citation_count":229,"is_preprint":false},{"pmid":"16973695","id":"PMC_16973695","title":"Cell physiology of cAMP sensor Epac.","date":"2006","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/16973695","citation_count":218,"is_preprint":false},{"pmid":"23066090","id":"PMC_23066090","title":"A novel EPAC-specific inhibitor suppresses pancreatic cancer cell migration and invasion.","date":"2012","source":"Molecular pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/23066090","citation_count":189,"is_preprint":false},{"pmid":"29537337","id":"PMC_29537337","title":"Intracellular cAMP Sensor EPAC: Physiology, Pathophysiology, and Therapeutics Development.","date":"2018","source":"Physiological reviews","url":"https://pubmed.ncbi.nlm.nih.gov/29537337","citation_count":180,"is_preprint":false},{"pmid":"18323524","id":"PMC_18323524","title":"Epac mediates beta-adrenergic receptor-induced cardiomyocyte hypertrophy.","date":"2008","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/18323524","citation_count":179,"is_preprint":false},{"pmid":"24316969","id":"PMC_24316969","title":"Increased sugar uptake promotes oncogenesis via EPAC/RAP1 and O-GlcNAc pathways.","date":"2013","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/24316969","citation_count":165,"is_preprint":false},{"pmid":"16269655","id":"PMC_16269655","title":"cAMP-binding protein Epac induces cardiomyocyte hypertrophy.","date":"2005","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/16269655","citation_count":162,"is_preprint":false},{"pmid":"22365550","id":"PMC_22365550","title":"EPAC null mutation impairs learning and social interactions via aberrant regulation of miR-124 and Zif268 translation.","date":"2012","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/22365550","citation_count":159,"is_preprint":false},{"pmid":"22110680","id":"PMC_22110680","title":"Activation of GPR4 by acidosis increases endothelial cell adhesion through the cAMP/Epac pathway.","date":"2011","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22110680","citation_count":149,"is_preprint":false},{"pmid":"26941424","id":"PMC_26941424","title":"Cyclic AMP Sensor EPAC Proteins and Their Role in Cardiovascular Function and Disease.","date":"2016","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/26941424","citation_count":147,"is_preprint":false},{"pmid":"22233238","id":"PMC_22233238","title":"cAMP and Epac in the regulation of tissue fibrosis.","date":"2012","source":"British journal of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/22233238","citation_count":145,"is_preprint":false},{"pmid":"17716863","id":"PMC_17716863","title":"Epac-selective cAMP analogs: new tools with which to evaluate the signal transduction properties of cAMP-regulated guanine nucleotide exchange factors.","date":"2007","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/17716863","citation_count":138,"is_preprint":false},{"pmid":"18434542","id":"PMC_18434542","title":"The cyclic AMP effector Epac integrates pro- and anti-fibrotic signals.","date":"2008","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/18434542","citation_count":136,"is_preprint":false},{"pmid":"19912228","id":"PMC_19912228","title":"The role of Epac proteins, novel cAMP mediators, in the regulation of immune, lung and neuronal function.","date":"2009","source":"British journal of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/19912228","citation_count":129,"is_preprint":false},{"pmid":"19210747","id":"PMC_19210747","title":"EPAC proteins transduce diverse cellular actions of cAMP.","date":"2009","source":"British journal of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/19210747","citation_count":118,"is_preprint":false},{"pmid":"18176800","id":"PMC_18176800","title":"Epac: effectors and biological functions.","date":"2008","source":"Naunyn-Schmiedeberg's archives of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/18176800","citation_count":113,"is_preprint":false},{"pmid":"21220320","id":"PMC_21220320","title":"Bile acid stimulates hepatocyte polarization through a cAMP-Epac-MEK-LKB1-AMPK pathway.","date":"2011","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/21220320","citation_count":113,"is_preprint":false},{"pmid":"35805104","id":"PMC_35805104","title":"cAMP Signaling in Cancer: A PKA-CREB and EPAC-Centric Approach.","date":"2022","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/35805104","citation_count":112,"is_preprint":false},{"pmid":"18728186","id":"PMC_18728186","title":"EPAC and PKA allow cAMP dual control over DNA-PK nuclear translocation.","date":"2008","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/18728186","citation_count":108,"is_preprint":false},{"pmid":"15302884","id":"PMC_15302884","title":"The cAMP-Epac-Rap1 pathway regulates cell spreading and cell adhesion to laminin-5 through the alpha3beta1 integrin but not the alpha6beta4 integrin.","date":"2004","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/15302884","citation_count":106,"is_preprint":false},{"pmid":"38233872","id":"PMC_38233872","title":"cAMP-PKA/EPAC signaling and cancer: the interplay in tumor microenvironment.","date":"2024","source":"Journal of hematology & oncology","url":"https://pubmed.ncbi.nlm.nih.gov/38233872","citation_count":105,"is_preprint":false},{"pmid":"18583150","id":"PMC_18583150","title":"Epac mediates cyclic AMP-dependent axon growth, guidance and regeneration.","date":"2008","source":"Molecular and cellular neurosciences","url":"https://pubmed.ncbi.nlm.nih.gov/18583150","citation_count":105,"is_preprint":false},{"pmid":"21402149","id":"PMC_21402149","title":"Rap-linked cAMP signaling Epac proteins: compartmentation, functioning and disease implications.","date":"2011","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/21402149","citation_count":102,"is_preprint":false},{"pmid":"19065671","id":"PMC_19065671","title":"The cAMP effectors Epac and protein kinase a (PKA) are involved in the hepatic cystogenesis of an animal model of autosomal recessive polycystic kidney disease (ARPKD).","date":"2009","source":"Hepatology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/19065671","citation_count":100,"is_preprint":false},{"pmid":"15319437","id":"PMC_15319437","title":"Epac- and Ca2+ -controlled activation of Ras and extracellular signal-regulated kinases by Gs-coupled receptors.","date":"2004","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/15319437","citation_count":94,"is_preprint":false},{"pmid":"23139415","id":"PMC_23139415","title":"Identification of a tetrahydroquinoline analog as a pharmacological inhibitor of the cAMP-binding protein Epac.","date":"2012","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23139415","citation_count":89,"is_preprint":false},{"pmid":"20971121","id":"PMC_20971121","title":"PKA and Epac synergistically inhibit smooth muscle cell proliferation.","date":"2010","source":"Journal of molecular and cellular cardiology","url":"https://pubmed.ncbi.nlm.nih.gov/20971121","citation_count":86,"is_preprint":false},{"pmid":"18178724","id":"PMC_18178724","title":"Epac/Rap1 pathway regulates microvascular hyperpermeability induced by PAF in rat mesentery.","date":"2008","source":"American journal of physiology. Heart and circulatory physiology","url":"https://pubmed.ncbi.nlm.nih.gov/18178724","citation_count":79,"is_preprint":false},{"pmid":"24149987","id":"PMC_24149987","title":"Epac-inhibitors: facts and artefacts.","date":"2013","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/24149987","citation_count":76,"is_preprint":false},{"pmid":"25744542","id":"PMC_25744542","title":"The future of EPAC-targeted therapies: agonism versus antagonism.","date":"2015","source":"Trends in pharmacological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/25744542","citation_count":76,"is_preprint":false},{"pmid":"18063584","id":"PMC_18063584","title":"Epac, in synergy with cAMP-dependent protein kinase (PKA), is required for cAMP-mediated mitogenesis.","date":"2007","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/18063584","citation_count":73,"is_preprint":false},{"pmid":"20007468","id":"PMC_20007468","title":"cAMP-dependent axon guidance is distinctly regulated by Epac and protein kinase A.","date":"2009","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/20007468","citation_count":73,"is_preprint":false},{"pmid":"19666481","id":"PMC_19666481","title":"The cAMP binding protein Epac regulates cardiac myofilament function.","date":"2009","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/19666481","citation_count":71,"is_preprint":false},{"pmid":"16684923","id":"PMC_16684923","title":"Epac-mediated Ca(2+) mobilization and exocytosis in inner medullary collecting duct.","date":"2006","source":"American journal of physiology. Renal physiology","url":"https://pubmed.ncbi.nlm.nih.gov/16684923","citation_count":71,"is_preprint":false},{"pmid":"18565730","id":"PMC_18565730","title":"Neuronal AKAP150 coordinates PKA and Epac-mediated PKB/Akt phosphorylation.","date":"2008","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/18565730","citation_count":68,"is_preprint":false},{"pmid":"20516079","id":"PMC_20516079","title":"Differential roles of Epac in regulating cell death in neuronal and myocardial cells.","date":"2010","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/20516079","citation_count":68,"is_preprint":false},{"pmid":"18600344","id":"PMC_18600344","title":"Epac activation, altered calcium homeostasis and ventricular arrhythmogenesis in the murine heart.","date":"2008","source":"Pflugers Archiv : European journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/18600344","citation_count":67,"is_preprint":false},{"pmid":"19855995","id":"PMC_19855995","title":"Role of the cAMP-binding protein Epac in cardiovascular physiology and pathophysiology.","date":"2009","source":"Pflugers Archiv : European journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/19855995","citation_count":63,"is_preprint":false},{"pmid":"24824430","id":"PMC_24824430","title":"Involvement of cAMP/EPAC/TRPM2 activation in glucose- and incretin-induced insulin secretion.","date":"2014","source":"Diabetes","url":"https://pubmed.ncbi.nlm.nih.gov/24824430","citation_count":62,"is_preprint":false},{"pmid":"24231725","id":"PMC_24231725","title":"Cyclic AMP sensor EPAC proteins and energy homeostasis.","date":"2013","source":"Trends in endocrinology and metabolism: TEM","url":"https://pubmed.ncbi.nlm.nih.gov/24231725","citation_count":60,"is_preprint":false},{"pmid":"25719403","id":"PMC_25719403","title":"Epac is required for GLP-1R-mediated inhibition of oxidative stress and apoptosis in cardiomyocytes.","date":"2015","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/25719403","citation_count":60,"is_preprint":false},{"pmid":"29158262","id":"PMC_29158262","title":"The EPAC-Rap1 pathway prevents and reverses cytokine-induced retinal vascular permeability.","date":"2017","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/29158262","citation_count":58,"is_preprint":false},{"pmid":"24450633","id":"PMC_24450633","title":"cAMP signalling in the vasculature: the role of Epac (exchange protein directly activated by cAMP).","date":"2014","source":"Biochemical Society transactions","url":"https://pubmed.ncbi.nlm.nih.gov/24450633","citation_count":57,"is_preprint":false},{"pmid":"28912066","id":"PMC_28912066","title":"The cAMP effectors PKA and Epac activate endothelial NO synthase through PI3K/Akt pathway in human endothelial cells.","date":"2017","source":"Biochemical pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/28912066","citation_count":56,"is_preprint":false},{"pmid":"29216750","id":"PMC_29216750","title":"PDE/cAMP/Epac/C/EBP-β Signaling Cascade Regulates Mitochondria Biogenesis of Tubular Epithelial Cells in Renal Fibrosis.","date":"2018","source":"Antioxidants & redox signaling","url":"https://pubmed.ncbi.nlm.nih.gov/29216750","citation_count":53,"is_preprint":false},{"pmid":"19491242","id":"PMC_19491242","title":"Exchange protein activated by cAMP (Epac) mediates cAMP-dependent but protein kinase A-insensitive modulation of vascular ATP-sensitive potassium channels.","date":"2009","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/19491242","citation_count":53,"is_preprint":false},{"pmid":"26119090","id":"PMC_26119090","title":"Exchange protein directly activated by cAMP encoded by the mammalian rapgef3 gene: Structure, function and therapeutics.","date":"2015","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/26119090","citation_count":52,"is_preprint":false},{"pmid":"19920825","id":"PMC_19920825","title":"Epac inhibits migration and proliferation of human prostate carcinoma cells.","date":"2009","source":"British journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/19920825","citation_count":52,"is_preprint":false},{"pmid":"17491018","id":"PMC_17491018","title":"Anthrax edema toxin inhibits endothelial cell chemotaxis via Epac and Rap1.","date":"2007","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17491018","citation_count":52,"is_preprint":false},{"pmid":"31787905","id":"PMC_31787905","title":"Role of PI3K/Akt and MEK/ERK Signalling in cAMP/Epac-Mediated Endothelial Barrier Stabilisation.","date":"2019","source":"Frontiers in physiology","url":"https://pubmed.ncbi.nlm.nih.gov/31787905","citation_count":51,"is_preprint":false},{"pmid":"18346875","id":"PMC_18346875","title":"cAMP-induced Epac-Rap activation inhibits epithelial cell migration by modulating focal adhesion and leading edge dynamics.","date":"2008","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/18346875","citation_count":51,"is_preprint":false},{"pmid":"16754837","id":"PMC_16754837","title":"Differential and brain region-specific regulation of Rap-1 and Epac in depressed suicide victims.","date":"2006","source":"Archives of general psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/16754837","citation_count":50,"is_preprint":false},{"pmid":"23220153","id":"PMC_23220153","title":"Epac in cardiac calcium signaling.","date":"2012","source":"Journal of molecular and cellular cardiology","url":"https://pubmed.ncbi.nlm.nih.gov/23220153","citation_count":49,"is_preprint":false},{"pmid":"16880999","id":"PMC_16880999","title":"Interplay between exchange protein directly activated by cAMP (Epac) and microtubule cytoskeleton.","date":"2005","source":"Molecular bioSystems","url":"https://pubmed.ncbi.nlm.nih.gov/16880999","citation_count":49,"is_preprint":false},{"pmid":"17895245","id":"PMC_17895245","title":"Protein kinase A, not Epac, suppresses hedgehog activity and regulates glucocorticoid sensitivity in acute lymphoblastic leukemia cells.","date":"2007","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17895245","citation_count":49,"is_preprint":false},{"pmid":"18550542","id":"PMC_18550542","title":"A novel Epac-Rap-PP2A signaling module controls cAMP-dependent Akt regulation.","date":"2008","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/18550542","citation_count":48,"is_preprint":false},{"pmid":"27549789","id":"PMC_27549789","title":"The role of Epac in the heart.","date":"2016","source":"Cellular and molecular life sciences : CMLS","url":"https://pubmed.ncbi.nlm.nih.gov/27549789","citation_count":46,"is_preprint":false},{"pmid":"19804812","id":"PMC_19804812","title":"Involvement of cAMP/Epac/PI3K-dependent pathway in the antiproteolytic effect of epinephrine on rat skeletal muscle.","date":"2009","source":"Molecular and cellular endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/19804812","citation_count":46,"is_preprint":false},{"pmid":"27789473","id":"PMC_27789473","title":"Kv7 Channel Activation Underpins EPAC-Dependent Relaxations of Rat Arteries.","date":"2016","source":"Arteriosclerosis, thrombosis, and vascular biology","url":"https://pubmed.ncbi.nlm.nih.gov/27789473","citation_count":44,"is_preprint":false},{"pmid":"22654658","id":"PMC_22654658","title":"cAMP and EPAC are key players in the regulation of the signal transduction pathway involved in the α-hemolysin autophagic response.","date":"2012","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/22654658","citation_count":44,"is_preprint":false},{"pmid":"17276729","id":"PMC_17276729","title":"Epac and the cardiovascular system.","date":"2007","source":"Current opinion in pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/17276729","citation_count":43,"is_preprint":false},{"pmid":"21493776","id":"PMC_21493776","title":"Epac-Rap signaling reduces cellular stress and ischemia-induced kidney failure.","date":"2011","source":"Journal of the American Society of Nephrology : JASN","url":"https://pubmed.ncbi.nlm.nih.gov/21493776","citation_count":42,"is_preprint":false},{"pmid":"23089371","id":"PMC_23089371","title":"Distinct PKA and Epac compartmentalization in airway function and plasticity.","date":"2012","source":"Pharmacology & therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/23089371","citation_count":41,"is_preprint":false},{"pmid":"30016400","id":"PMC_30016400","title":"Exchange protein activated by cyclic-adenosine monophosphate (Epac) regulates atrial fibroblast function and controls cardiac remodelling.","date":"2019","source":"Cardiovascular research","url":"https://pubmed.ncbi.nlm.nih.gov/30016400","citation_count":41,"is_preprint":false},{"pmid":"19657062","id":"PMC_19657062","title":"Epac increases melanoma cell migration by a heparan sulfate-related mechanism.","date":"2009","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/19657062","citation_count":41,"is_preprint":false},{"pmid":"23959673","id":"PMC_23959673","title":"Exchange protein activated by cAMP (Epac) induces vascular relaxation by activating Ca2+-sensitive K+ channels in rat mesenteric artery.","date":"2013","source":"The Journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/23959673","citation_count":41,"is_preprint":false},{"pmid":"18495799","id":"PMC_18495799","title":"Renal expression of exchange protein directly activated by cAMP (Epac) 1 and 2.","date":"2008","source":"American journal of physiology. Renal physiology","url":"https://pubmed.ncbi.nlm.nih.gov/18495799","citation_count":41,"is_preprint":false},{"pmid":"24469067","id":"PMC_24469067","title":"PKA and Epac activation mediates cAMP-induced vasorelaxation by increasing endothelial NO production.","date":"2014","source":"Vascular pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/24469067","citation_count":39,"is_preprint":false},{"pmid":"28341741","id":"PMC_28341741","title":"Endogenous prostaglandin E2 amplifies IL-33 production by macrophages through an E prostanoid (EP)2/EP4-cAMP-EPAC-dependent pathway.","date":"2017","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/28341741","citation_count":39,"is_preprint":false},{"pmid":"30251651","id":"PMC_30251651","title":"Phoenixin-14 stimulates differentiation of 3T3-L1 preadipocytes via cAMP/Epac-dependent mechanism.","date":"2018","source":"Biochimica et biophysica acta. Molecular and cell biology of lipids","url":"https://pubmed.ncbi.nlm.nih.gov/30251651","citation_count":39,"is_preprint":false},{"pmid":"26704387","id":"PMC_26704387","title":"The signaling module cAMP/Epac/Rap1/PLCε/IP3 mobilizes acrosomal calcium during sperm exocytosis.","date":"2015","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/26704387","citation_count":38,"is_preprint":false},{"pmid":"31722989","id":"PMC_31722989","title":"Adenosine Receptor Signaling Targets Both PKA and Epac Pathways to Polarize Dendritic Cells to a Suppressive Phenotype.","date":"2019","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/31722989","citation_count":36,"is_preprint":false},{"pmid":"24511123","id":"PMC_24511123","title":"Epac-Rap signaling reduces oxidative stress in the tubular epithelium.","date":"2014","source":"Journal of the American Society of Nephrology : JASN","url":"https://pubmed.ncbi.nlm.nih.gov/24511123","citation_count":36,"is_preprint":false},{"pmid":"20729327","id":"PMC_20729327","title":"Crosstalk between PKA and Epac regulates the phenotypic maturation and function of human dendritic cells.","date":"2010","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/20729327","citation_count":36,"is_preprint":false},{"pmid":"26963850","id":"PMC_26963850","title":"Epac-protein kinase C alpha signaling in purinergic P2X3R-mediated hyperalgesia after inflammation.","date":"2016","source":"Pain","url":"https://pubmed.ncbi.nlm.nih.gov/26963850","citation_count":35,"is_preprint":false},{"pmid":"28333280","id":"PMC_28333280","title":"hCG activates Epac-Erk1/2 signaling regulating Progesterone Receptor expression and function in human endometrial stromal cells.","date":"2017","source":"Molecular human reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/28333280","citation_count":35,"is_preprint":false},{"pmid":"22511766","id":"PMC_22511766","title":"The Epac-Rap1 signaling pathway controls cAMP-mediated exocytosis of Weibel-Palade bodies in endothelial cells.","date":"2012","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/22511766","citation_count":35,"is_preprint":false},{"pmid":"24256330","id":"PMC_24256330","title":"Recent advances in the discovery of small molecules targeting exchange proteins directly activated by cAMP (EPAC).","date":"2013","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24256330","citation_count":35,"is_preprint":false},{"pmid":"22192627","id":"PMC_22192627","title":"Urocortins improve dystrophic skeletal muscle structure and function through both PKA- and Epac-dependent pathways.","date":"2011","source":"The American journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/22192627","citation_count":35,"is_preprint":false},{"pmid":"32899451","id":"PMC_32899451","title":"The Role of Epac in Cancer Progression.","date":"2020","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/32899451","citation_count":34,"is_preprint":false},{"pmid":"32830375","id":"PMC_32830375","title":"Protein kinase A inhibitor proteins (PKIs) divert GPCR-Gαs-cAMP signaling toward EPAC and ERK activation and are involved in tumor growth.","date":"2020","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/32830375","citation_count":33,"is_preprint":false},{"pmid":"34103688","id":"PMC_34103688","title":"Epac activation ameliorates tubulointerstitial inflammation in diabetic nephropathy.","date":"2021","source":"Acta pharmacologica Sinica","url":"https://pubmed.ncbi.nlm.nih.gov/34103688","citation_count":32,"is_preprint":false},{"pmid":"34338148","id":"PMC_34338148","title":"Exendin-4 stimulates autophagy in pancreatic β-cells via the RAPGEF/EPAC-Ca2+-PPP3/calcineurin-TFEB axis.","date":"2021","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/34338148","citation_count":32,"is_preprint":false},{"pmid":"29417338","id":"PMC_29417338","title":"Insights into exchange factor directly activated by cAMP (EPAC) as potential target for cancer treatment.","date":"2018","source":"Molecular and cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/29417338","citation_count":32,"is_preprint":false},{"pmid":"33298248","id":"PMC_33298248","title":"Epac: new emerging cAMP-binding protein.","date":"2021","source":"BMB reports","url":"https://pubmed.ncbi.nlm.nih.gov/33298248","citation_count":31,"is_preprint":false},{"pmid":"21471298","id":"PMC_21471298","title":"Guanine-nucleotide exchange factors (RAPGEF3/RAPGEF4) induce sperm membrane depolarization and acrosomal exocytosis in capacitated stallion sperm.","date":"2011","source":"Biology of reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/21471298","citation_count":31,"is_preprint":false},{"pmid":"22230192","id":"PMC_22230192","title":"Regulation of SGLT expression and localization through Epac/PKA-dependent caveolin-1 and F-actin activation in renal proximal tubule cells.","date":"2012","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/22230192","citation_count":31,"is_preprint":false},{"pmid":"30015706","id":"PMC_30015706","title":"Inflammation induces Epac-protein kinase C alpha and epsilon signaling in TRPV1-mediated hyperalgesia.","date":"2018","source":"Pain","url":"https://pubmed.ncbi.nlm.nih.gov/30015706","citation_count":30,"is_preprint":false},{"pmid":"15202935","id":"PMC_15202935","title":"Exchange protein directly activated by cAMP (EPAC) interacts with the light chain (LC) 2 of MAP1A.","date":"2004","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/15202935","citation_count":30,"is_preprint":false},{"pmid":"31593773","id":"PMC_31593773","title":"Laminin-driven Epac/Rap1 regulation of epithelial barriers on decellularized matrix.","date":"2019","source":"Acta biomaterialia","url":"https://pubmed.ncbi.nlm.nih.gov/31593773","citation_count":29,"is_preprint":false},{"pmid":"29401660","id":"PMC_29401660","title":"Epac Function and cAMP Scaffolds in the Heart and Lung.","date":"2018","source":"Journal of cardiovascular development and disease","url":"https://pubmed.ncbi.nlm.nih.gov/29401660","citation_count":28,"is_preprint":false},{"pmid":"28632993","id":"PMC_28632993","title":"The role of small GTPases and EPAC-Rap signaling in the regulation of the blood-brain and blood-retinal barriers.","date":"2017","source":"Tissue barriers","url":"https://pubmed.ncbi.nlm.nih.gov/28632993","citation_count":28,"is_preprint":false},{"pmid":"28475672","id":"PMC_28475672","title":"Lithium and an EPAC-specific inhibitor ESI-09 synergistically suppress pancreatic cancer cell proliferation and survival.","date":"2017","source":"Acta biochimica et biophysica Sinica","url":"https://pubmed.ncbi.nlm.nih.gov/28475672","citation_count":28,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":51378,"output_tokens":11050,"usd":0.159942,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":22128,"output_tokens":4749,"usd":0.114683,"stage2_stop_reason":"end_turn"},"total_usd":0.274625,"stage1_batch_id":"msgbatch_01CNoDbkChHEkgrJnL7BwtGJ","stage2_batch_id":"msgbatch_016Y4x9E9Wg5VQDANj9quSQD","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2002,\n      \"finding\": \"EPAC1 (RAPGEF3) functions as a cAMP-activated guanine nucleotide exchange factor (GEF) for Rap1; a selective cAMP analogue (8CPT-2Me-cAMP) was developed that activates EPAC but not PKA, demonstrating that cAMP-induced Rap1 activation and ERK regulation are independent processes.\",\n      \"method\": \"Rational drug design of selective cAMP analogue; in vitro and in vivo activation assays; cell-based ERK activity assays with PKA/Ras/Rap1 inhibitors\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro selectivity assay plus multiple cell-line epistasis experiments; replicated across multiple cell types\",\n      \"pmids\": [\"12402047\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"EPAC1 undergoes a cAMP-induced conformational change (relief of autoinhibitory interaction between regulatory and catalytic domains) detectable as a FRET change in a CFP-Epac-YFP fusion; this in vivo conformational change serves as the molecular basis for cAMP-dependent activation.\",\n      \"method\": \"FRET imaging in mammalian cells using CFP-Epac1-YFP fusion; cAMP-binding mutant abolishes response; comparison with PKA-based sensor\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct in-cell FRET readout of conformational change, confirmed with binding-dead mutant, multiple orthogonal validations\",\n      \"pmids\": [\"15550931\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"EPAC1 activation by cAMP occurs faster at the plasma membrane than in the cytoplasm or mitochondria; cAMP dynamics and effector activation are spatiotemporally compartmentalized in living cells.\",\n      \"method\": \"Targeted CFP-Epac1-YFP FRET reporters directed to plasma membrane, cytoplasm, mitochondria and nucleus; live-cell imaging with beta-adrenergic receptor stimulation\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — subcellular-targeted FRET biosensors with direct functional consequence (kinetics of Epac activation), multiple compartments compared\",\n      \"pmids\": [\"15545605\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"EPAC1 activates the cAMP-Epac-Rap1 pathway to regulate cell adhesion and spreading on laminin-5 specifically through the alpha3beta1 integrin, but not the alpha6beta4 integrin, in a PKA-independent manner.\",\n      \"method\": \"PKA-independent cAMP analogue stimulation; dominant-negative Rap1; integrin-blocking antibodies; adhesion and spreading assays in multiple cell lines\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple cell lines, integrin-specific dissection, PKA independence confirmed with selective analogues and inhibitors\",\n      \"pmids\": [\"15302884\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"EPAC1 signals via Rap2B to activate phospholipase C-epsilon (PLCε), increase intracellular Ca2+, and thereby activate H-Ras and ERK1/2 downstream of Gs-coupled receptors; a cAMP-binding-deficient EPAC1 mutant and dominant-negative Rap2B suppress this pathway.\",\n      \"method\": \"Dominant-negative and constitutively active Rap2B mutants; cAMP-binding-deficient EPAC1 mutant; Rap GTPase-activating protein II; Ca2+ measurements; ERK activity assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — multiple mutants, reconstitution-level pathway dissection with mechanistic mutants in a single study\",\n      \"pmids\": [\"15319437\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"EPAC1 directly interacts with tubulin, co-purifies with cellular microtubules, and co-localizes with the mitotic spindle; association with microtubules suppresses EPAC-mediated Rap1 activation, while EPAC binding promotes microtubule formation.\",\n      \"method\": \"Co-purification with cellular microtubules; co-immunoprecipitation; co-localization (immunofluorescence); Rap1 activation assays in presence/absence of microtubule association\",\n      \"journal\": \"Molecular bioSystems\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — co-purification and co-localization support interaction, functional consequence shown but single lab\",\n      \"pmids\": [\"16880999\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"EPAC1 activation induces cardiomyocyte hypertrophy through a Ca2+-dependent activation of Rac, calcineurin/NFAT signaling pathway; blockade of calcineurin or Rac blunts the hypertrophic response.\",\n      \"method\": \"Epac-selective cAMP analogue in primary cardiomyocytes; calcineurin inhibitor; dominant-negative Rac; NFAT reporter; hypertrophic marker expression\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — selective agonist plus pathway inhibitors in primary cells; single lab\",\n      \"pmids\": [\"16269655\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"EPAC1 interacts with the light chain 2 (LC2) of microtubule-associated protein MAP1A; the interaction is mediated by the cAMP-binding domain of EPAC1 (not the DEP or catalytic domains), and EPAC1 co-localizes with LC2 in the perinuclear region and filamentous structures.\",\n      \"method\": \"Yeast two-hybrid screen of brain libraries; co-immunoprecipitation in co-transfected HEK293 cells; GST pull-down with domain deletion mutants; immunolocalization\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP confirmed interaction; domain mapping by GST pull-down; single lab\",\n      \"pmids\": [\"15202935\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"EPAC1-dependent subcellular localization via its DEP domain is required for cAMP-mediated Rap1 activation and thyroid-stimulating hormone-induced mitogenesis; disruption of DEP-dependent targeting abolishes Epac-Rap1 activation and cell proliferation.\",\n      \"method\": \"Dominant-negative EPAC mutant; DEP domain deletion constructs; thyroid cell proliferation/DNA synthesis assays; Rap1 activation (pull-down) assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — domain-deletion and dominant-negative approach with functional cellular readout; single lab\",\n      \"pmids\": [\"18063584\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"EPAC1 induces cardiomyocyte hypertrophy via the small GTPase Ras and activates calcineurin and CaMKII in a Rap1-independent, PKA-independent manner downstream of beta-adrenergic receptor stimulation; Epac1 knockdown reduces beta-AR-induced hypertrophy.\",\n      \"method\": \"siRNA knockdown of Epac1; Epac-selective cAMP analogue; dominant-negative Ras; calcineurin/CaMKII inhibitors; Ras activation assays; hypertrophic marker expression in primary cardiomyocytes\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — siRNA loss-of-function plus pharmacologic pathway dissection; multiple orthogonal readouts; replicated with in vivo model (aortic constriction)\",\n      \"pmids\": [\"18323524\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"EPAC is coupled to Rap2 in the nucleus and mediates cAMP-dependent nuclear export and activation of DNA-PK; PKA provides an opposing (inhibitory) input. Spatially discrete PDE-dependent cAMP degradation systems modulate the balance between EPAC and PKA arms, influencing DNA double-strand break repair and PKB/Akt Ser-473 phosphorylation.\",\n      \"method\": \"Epac-selective and PKA-selective cAMP analogues; nuclear/cytoplasmic fractionation; DNA-PK activity assays; etoposide-induced DSB repair assays; PKB/Akt phosphorylation (Western blot)\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — compartment fractionation + selective analogues + functional DSB repair assay; single lab\",\n      \"pmids\": [\"18728186\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"EPAC1 forms a complex with Akt and PP2A; cAMP via both EPAC and PKA synergistically activates EPAC-associated PP2A phosphatase activity in a Rap1b-dependent manner, leading to Akt dephosphorylation and inhibition.\",\n      \"method\": \"Co-immunoprecipitation of EPAC-Akt-PP2A complex; dominant-negative EPAC and PP2A constructs; phosphatase activity assay; PKA- and EPAC-selective cAMP analogues; Akt phosphorylation assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — complex Co-IP plus in-complex phosphatase activity assay; dominant-negative validation; single lab\",\n      \"pmids\": [\"18550542\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"EPAC activation in cardiomyocytes produces arrhythmias associated with altered Ca2+ homeostasis; the arrhythmogenic effect depends on CaMKII activity.\",\n      \"method\": \"Langendorff-perfused hearts with Epac-selective analogue; monophasic action potential recordings; CaMKII inhibitor KN-93; fluorescence Ca2+ imaging of isolated ventricular myocytes\",\n      \"journal\": \"Pflugers Archiv : European journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — intact heart preparation plus cellular Ca2+ imaging with pharmacologic pathway dissection; single lab\",\n      \"pmids\": [\"18600344\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"EPAC1 activation promotes fibroblast migration via Rap1, but inhibits collagen synthesis in a Rap1-independent manner; TGF-β1 transcriptionally downregulates Epac1 expression, and overexpression of Epac1 inhibits TGF-β1-induced collagen synthesis.\",\n      \"method\": \"Epac-selective cAMP analogue; Rap1 knockdown; Epac1 overexpression and siRNA; collagen synthesis assay; migration assay; multiple fibroblast cell types\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — selective agonist plus Rap1 knockdown; multiple cell types; overexpression rescue; single lab\",\n      \"pmids\": [\"18434542\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"EPAC activation inhibits PAF-induced hyperpermeability in intact rat microvessels via stabilization of VE-cadherin at cell-cell junctions through the Epac/Rap1 pathway.\",\n      \"method\": \"Hydraulic conductivity measurement in rat venular microvessels; Epac-selective cAMP analogue; VE-cadherin immunofluorescence\",\n      \"journal\": \"American journal of physiology. Heart and circulatory physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — intact microvessel physiology combined with junction protein imaging; single lab\",\n      \"pmids\": [\"18178724\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"EPAC activation inhibits epithelial cell migration by slowing focal adhesion dynamics and inhibiting polarized membrane protrusion; these effects extend beyond integrin affinity modulation.\",\n      \"method\": \"HGF/TGFβ-induced migration assays; forced integrin activation controls; live-cell focal adhesion dynamics imaging; Rap activation assays\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live imaging of focal adhesions plus forced integrin control distinguishes mechanism; single lab\",\n      \"pmids\": [\"18346875\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"EPAC1 exists in a complex with vascular KATP channel subunits and inhibits KATP channel activity via a Ca2+-dependent mechanism requiring calcineurin (PP-2B) activation; this is PKA-independent.\",\n      \"method\": \"Co-immunoprecipitation of EPAC with KATP subunits; whole-cell patch clamp; Ca2+ imaging (Fura-2); calcineurin inhibitors cyclosporin A and ascomycin; BAPTA chelation\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — complex Co-IP plus electrophysiology plus Ca2+ imaging with pharmacologic dissection; single lab\",\n      \"pmids\": [\"19491242\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"EPAC1 promotes DRG neurite outgrowth and mediates growth cone attraction to cAMP, netrin-1, and MAG gradients in embryonic neurons; siRNA knockdown of EPAC reduces outgrowth and prevents cAMP-dependent neurite regeneration on spinal cord tissue.\",\n      \"method\": \"Epac-selective cAMP analogue; siRNA knockdown; DRG neurite outgrowth assays; growth cone turning assays; spinal cord tissue substrate assays\",\n      \"journal\": \"Molecular and cellular neurosciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA loss-of-function plus pharmacologic gain-of-function with multiple functional readouts; single lab\",\n      \"pmids\": [\"18583150\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Embryonic growth cone attraction to cAMP, netrin-1, and MAG gradients is mediated by Epac, whereas repulsion in adult growth cones is mediated by PKA; FRET demonstrates netrin-1 activates Epac in embryonic but PKA in postnatal neurons, revealing a developmental switch in cAMP effector usage.\",\n      \"method\": \"FRET-based Epac and PKA biosensors in live neurons; growth cone turning assays with selective analogues; siRNA knockdown\",\n      \"journal\": \"The Journal of neuroscience : the official journal of the Society for Neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — FRET biosensors directly measure effector activation; functional turning assays with selective analogues; developmental comparison in same study\",\n      \"pmids\": [\"20007468\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"EPAC1 activation increases cardiac myofilament Ca2+ sensitivity and phosphorylation of cardiac Troponin I and Myosin Binding Protein-C via PKC and CaMKII (not PKA); EPAC reduces Ca2+ transient amplitude while increasing cell shortening.\",\n      \"method\": \"Epac-selective cAMP analogue; constitutively active Epac in vivo infection; permeabilized cardiomyocyte Ca2+ sensitivity assay; PKC and CaMKII inhibitors; phosphoprotein detection\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution in permeabilized cells + in vivo constitutively active Epac + pharmacologic pathway dissection; multiple orthogonal methods\",\n      \"pmids\": [\"19666481\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"EPAC1 activation triggers apoptosis specifically in cortical neurons (not cardiomyocytes) by transcriptionally upregulating Bim; EPAC1 knockout mice show reduced neuronal apoptosis in a 3-nitropropionic acid model.\",\n      \"method\": \"Epac-selective agonist; Epac1 genetic knockout mice; Bim siRNA knockdown; TUNEL and DNA fragmentation assays; qRT-PCR for Bim\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO in vivo plus pharmacologic/siRNA approach in vitro; replicated mechanistic pathway; cell-type specific comparison\",\n      \"pmids\": [\"20516079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"EPAC activation via the Epac/PI3K pathway promotes Akt and Foxo3a phosphorylation in skeletal muscle, mediating the antiproteolytic effect of epinephrine independently of PKA.\",\n      \"method\": \"Epac-selective cAMP analogue in isolated EDL muscles; PI3K inhibitor wortmannin; PKA agonist and inhibitor H89; Akt/Foxo3a phosphorylation (Western blot); proteolysis rate measurement\",\n      \"journal\": \"Molecular and cellular endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — selective agonist/antagonist plus PI3K inhibitor with phosphoprotein readouts; single lab\",\n      \"pmids\": [\"19804812\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"EPAC and PKA synergize via a Rap1-independent mechanism to mediate cAMP-induced growth arrest in vascular smooth muscle cells; neither pathway alone is sufficient, and Rap1 inhibition does not negate the combined effect.\",\n      \"method\": \"Selective PKA and Epac cAMP analogues; constitutively active Epac; Rap1GAP overexpression; Rap1 siRNA; Rb phosphorylation; BrdU incorporation; ERK/JNK phosphorylation\",\n      \"journal\": \"Journal of molecular and cellular cardiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple approaches (selective analogues, dominant-negative, siRNA) with functional and biochemical readouts; single lab\",\n      \"pmids\": [\"20971121\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Taurocholate stimulates hepatocyte polarization and bile canalicular network formation through a cAMP-Epac-MEK-Rap1-LKB1-AMPK signaling cascade; inhibition of Epac, Rap1, or MEK blocks the effect.\",\n      \"method\": \"Rat hepatocyte sandwich cultures; adenylyl cyclase inhibitor; Epac-selective analogue; Rap1 and MEK inhibitors; kinase activation assays (LKB1, AMPK)\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ordered pathway dissection with selective inhibitors in primary cells; single lab\",\n      \"pmids\": [\"21220320\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"EPAC/Rap1 pharmacological activation preserves tubular epithelial cell adhesion and barrier function during hypoxia in vitro and reduces renal failure in an ischemia-reperfusion mouse model in vivo.\",\n      \"method\": \"Epac-selective cAMP analogue (8-pCPT-2'-O-Me-cAMP); mouse IRI model; barrier function measurement; β-catenin and clusterin-α immunostaining\",\n      \"journal\": \"Journal of the American Society of Nephrology : JASN\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro and in vivo models with functional readout; single lab\",\n      \"pmids\": [\"21493776\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"EPAC1 null mutation impairs LTP, spatial learning, and social interactions by promoting miR-124 transcription which suppresses Zif268 translation; knockdown of miR-124 restores Zif268 and reverses all EPAC-/- phenotypes.\",\n      \"method\": \"EPAC1/2 conditional forebrain knockout mice; LTP electrophysiology; behavioral tests; miR-124 knockdown and overexpression; Zif268 Western blot\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO combined with rescue by miR-124 knockdown; multiple epistatic experiments with mechanistic pathway; replicated behavioral and electrophysiological readouts\",\n      \"pmids\": [\"22365550\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"EPAC1-mediated Rap1 activation and Akt phosphorylation are required for pancreatic cancer cell migration and invasion; ESI-09, a noncyclic nucleotide EPAC antagonist, blocks Epac-mediated Rap1 activation and Akt phosphorylation as well as insulin secretion.\",\n      \"method\": \"EPAC-specific inhibitor ESI-09; Rap1 activation assay; Akt phosphorylation (Western blot); migration and invasion assays; insulin secretion assay in β-cells\",\n      \"journal\": \"Molecular pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — selective inhibitor with multiple mechanistic and functional readouts; single lab\",\n      \"pmids\": [\"23066090\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"EPAC1 coupled to Rap1 controls cAMP-dependent exocytosis of Weibel-Palade bodies (WPBs) in endothelial cells; siRNA knockdown of EPAC1 abolishes epinephrine-induced Rap1 activation and reduces WPB exocytosis.\",\n      \"method\": \"siRNA knockdown of EPAC1; Rap1 activation assay; Rap1GAP overexpression; WPB exocytosis assay (VWF release); epinephrine stimulation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA knockdown plus Rap1GAP dominant-negative; functional exocytosis readout; single lab\",\n      \"pmids\": [\"22511766\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"EPAC1 and Rap2b are recruited to the S. aureus-containing phagosome, and EPAC-Rap2b signaling through calpain activation regulates autophagic response to alpha-hemolysin in a PKA-independent manner.\",\n      \"method\": \"Immunofluorescence localization of EPAC and Rap2b to phagosomes; EPAC-selective analogue; calpain inhibitors; autophagy assays; siRNA knockdown\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct subcellular localization to phagosome with functional autophagy consequence; selective agonist/antagonist; single lab\",\n      \"pmids\": [\"22654658\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"EPAC regulates SGLT expression and translocation to lipid rafts in renal proximal tubule cells via ERK, p38 MAPK, and NF-κB signaling, requiring caveolin-1 and F-actin organization.\",\n      \"method\": \"Epac-selective cAMP analogue; SGLT expression (Western blot); lipid raft fractionation; cytochalasin D (F-actin disruption); cav-1 siRNA; α-MG uptake assay\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — selective agonist plus siRNA plus fractionation; multiple pathway inhibitors with functional transport readout; single lab\",\n      \"pmids\": [\"22230192\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Increased glucose uptake activates RAP1 via EPAC (exchange protein directly activated by cAMP) through pyruvate kinase M2 (PKM2) interaction with soluble adenylyl cyclase, contributing to oncogenic signaling and loss of epithelial polarity in a 3D culture model.\",\n      \"method\": \"3D mammary epithelial culture; GLUT3 overexpression; EPAC/RAP1 pathway inhibitors; PKM2 pulldown/interaction studies; soluble adenylyl cyclase inhibition\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — mechanistic pathway dissection in physiologically relevant 3D model; PKM2-sAC interaction identified; single lab\",\n      \"pmids\": [\"24316969\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"EPAC1 inhibition by CE3F4 (a tetrahydroquinoline analog) blocks EPAC1 GEF activity toward Rap1 via an uncompetitive inhibition mechanism; the formyl group at position 1 and bromine at position 5 are essential for activity; CE3F4 does not compete for cAMP binding.\",\n      \"method\": \"Cell-free GEF activity fluorescence assay; intact cell Rap1 activation assay; PKA holoenzyme activity assay (negative); structure-activity relationship analysis; kinetics of inhibition\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cell-free enzymatic assay with kinetic characterization; SAR validation; single lab\",\n      \"pmids\": [\"23139415\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"EPAC activation inhibits VEGF- and TNF-α-induced retinal vascular permeability and inhibits VEGFR signaling through the Ras/MEK/ERK pathway; Rap1B knockdown or EPAC antagonist increases endothelial permeability, and GTP-bound Rap1 promotes tight junction assembly.\",\n      \"method\": \"EPAC-selective analogue and antagonist; siRNA knockdown of Rap1B; Ras/MEK/ERK signaling (Western blot); permeability assays in vitro and in vivo; tight junction immunostaining\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro and in vivo permeability assays with siRNA knockdown and pharmacologic tools; single lab\",\n      \"pmids\": [\"29158262\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"The cAMP-Epac-Rap1-PLCε-IP3 signaling module mobilizes intra-acrosomal calcium during sperm exocytosis; each step (cAMP, Epac, Rap1, PLCε) is required upstream of IP3-dependent calcium release from the acrosome.\",\n      \"method\": \"TAT-cAMP sponge to sequester cAMP; Epac-selective analogue; dominant-negative Rap1; PLCε inhibition; Rap1/Rab3/Rab27 GTP-loading assays; Ca2+ mobilization assay; acrosome reaction assay\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstituted pathway with direct evidence for each step in a single study using multiple complementary tools including a novel engineered inhibitor\",\n      \"pmids\": [\"26704387\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"EPAC-dependent vasorelaxation in mesenteric arteries occurs via activation of Kv7 channels; proximity ligation assay shows Kv7.4 co-localizes with Rap1a and Rap2 (EPAC downstream targets) upon isoproterenol stimulation specifically in mesenteric (not renal) arteries.\",\n      \"method\": \"Isometric tension recording; Kv7 channel inhibitor linopirdine; EPAC inhibitor; PKA inhibitor; proximity ligation assay for Kv7.4-AKAP and Kv7.4-Rap1a/Rap2 complexes; isolated myocytes\",\n      \"journal\": \"Arteriosclerosis, thrombosis, and vascular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional vascular assay plus proximity ligation assay for complex formation; vessel-type-specific comparison; single lab\",\n      \"pmids\": [\"27789473\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"EPAC induces vascular relaxation in rat mesenteric arteries by increasing Ca2+ sparks from ryanodine receptors to activate BKCa channels in smooth muscle, and via endothelial SKCa/IKCa channels and NOS activation.\",\n      \"method\": \"Myography; iberiotoxin and apamin/TRAM-34 (K+ channel blockers); ryanodine; Ca2+ spark imaging (Fluo-4); NOS inhibitor L-NAME; endothelium denudation; patch clamp (STOCs and current clamp)\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple electrophysiology and Ca2+ imaging methods with pharmacologic dissection in intact vessels; comprehensive mechanism established\",\n      \"pmids\": [\"23959673\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"EPAC1 mediates melanoma cell migration and metastasis via translocation of syndecan-2 to lipid rafts (through Epac/PI3K/tubulin polymerization) and via increased NDST-1-dependent heparan sulfate production; EPAC overexpression enhances lung colonization in mice.\",\n      \"method\": \"siRNA knockdown; Epac overexpression; lipid raft fractionation; syndecan-2 translocation imaging; PI3K inhibitor; migration assay; NDST-1 expression and translation rate; mouse lung colonization model\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA plus overexpression with in vivo metastasis model; multiple mechanistic readouts; single lab\",\n      \"pmids\": [\"19657062\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Anthrax edema toxin (an adenylyl cyclase) inhibits endothelial cell chemotaxis through downstream EPAC activation and Rap1; EPAC or activated Rap1 alone reproduces cytoskeletal changes and chemotaxis block; ET also induces transcription of EPAC2 (RapGEF4) and MR-GEF/RapGEF5.\",\n      \"method\": \"Anthrax ET treatment of HMVECs; Epac-selective analogue; constitutively active Rap1; cytoskeletal staining; chemotaxis assay; transcriptional profiling\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — selective agonist plus constitutively active Rap1 mimic; functional chemotaxis assay; single lab\",\n      \"pmids\": [\"17491018\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"RAPGEF3 (EPAC1) localizes to the acrosome and subacrosomal ring in equine sperm; activation of RAPGEF3/RAPGEF4 induces acrosomal exocytosis in capacitated sperm and prevents membrane hyperpolarization during capacitation, supporting a role in Ca2+-dependent acrosome reaction via membrane depolarization.\",\n      \"method\": \"Indirect immunofluorescence localization; Epac-selective cAMP analogue stimulation; acrosomal exocytosis quantification; sperm membrane potential measurement\",\n      \"journal\": \"Biology of reproduction\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct immunolocalization plus functional exocytosis assay with membrane potential measurement; single lab\",\n      \"pmids\": [\"21471298\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"hCG activates Erk1/2 in human endometrial stromal cells through the cAMP/EPAC pathway (not PKA, PKC, or PI3K); EPAC inhibition and siRNA knockdown prevent hCG-induced Erk1/2 phosphorylation and subsequent progesterone receptor upregulation.\",\n      \"method\": \"EPAC inhibitor; siRNA knockdown of EPAC; pathway inhibitors (PKA, PKC, PI3K); pErk1/2 Western blot; PR expression by immunofluorescence and qRT-PCR; primary human ESC cultures\",\n      \"journal\": \"Molecular human reproduction\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA knockdown plus selective inhibitors; pathway exclusion experiments; primary human cells; single lab\",\n      \"pmids\": [\"28333280\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"EPAC-PKCα signaling mediates Epac-dependent sensitization of P2X3 receptors in DRG neurons after inflammation; PKCα is downstream of EPAC and mediates enhancement of P2X3R-dependent hyperalgesia via a distinct translocation pattern from PKCε.\",\n      \"method\": \"Epac agonist CPT; EPAC antagonists; classical PKC inhibitor Go6976; PKCα-siRNA; P2X3R current recordings; behavioral hyperalgesia assays; pPKCα immunostaining\",\n      \"journal\": \"Pain\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA plus pharmacologic epistasis with electrophysiological and behavioral readouts; single lab\",\n      \"pmids\": [\"26963850\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"EPAC activation drives inflammation-induced sensitization of TRPV1 in DRG neurons via PKCα and PKCε; EPAC agonist increases membrane TRPV1 expression and pPKCα levels; PKCα and PKCε inhibitors block EPAC-mediated TRPV1 potentiation.\",\n      \"method\": \"Epac agonist CPT; EPAC antagonists; PKCα/PKCε inhibitors; patch clamp of TRPV1 currents; behavioral nociception assays; TRPV1 and pPKC immunostaining and colocalization\",\n      \"journal\": \"Pain\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — selective agonist/antagonist with electrophysiology and membrane trafficking assays; single lab\",\n      \"pmids\": [\"30015706\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Exendin-4 stimulates autophagic flux in pancreatic β-cells through the RAPGEF3/EPAC1-calcium-PPP3/calcineurin-TFEB axis, independent of AMPK and MTOR; RAPGEF4/EPAC2 is the primary mediator of this pathway identified by siRNA knockdown.\",\n      \"method\": \"siRNA knockdown of RAPGEF3/RAPGEF4; calcineurin inhibitors; TFEB overexpression; autophagy flux assays; Ca2+ signaling measurements; db/db mouse in vivo model\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA knockdown plus pharmacologic dissection plus in vivo model; ordered pathway established; single lab\",\n      \"pmids\": [\"34338148\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"EPAC1 activation ameliorates tubulointerstitial inflammation in diabetic nephropathy through the C/EBP-β/SOCS3/STAT3 pathway; EPAC activation restores C/EBP-β, promotes its nuclear translocation, upregulates SOCS3, and inhibits STAT3 phosphorylation and MCP-1 expression.\",\n      \"method\": \"Epac-selective analogue in db/db mice and HK-2 cells; siRNA knockdown of C/EBP-β and SOCS3; SOCS3 overexpression; STAT3 phosphorylation (Western blot); macrophage migration assay\",\n      \"journal\": \"Acta pharmacologica Sinica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA knockdown plus overexpression plus in vivo model; ordered pathway; single lab\",\n      \"pmids\": [\"34103688\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"EPAC1 expression in left atrial fibroblasts is suppressed by HF/norepinephrine (via α-AR/Smad3) and upregulated by β2-AR activation; Epac1 activation reduces collagen expression and LA fibrosis post-MI, whereas Epac1 loss increases fibroblast collagen production.\",\n      \"method\": \"Epac-selective activator and antagonist ESI-09; β-AR subtype-selective agonists/antagonists; Smad3 inhibitor SIS3; collagen expression assays; in vivo MI mouse model with Sp-8-pCPT treatment; echocardiography\",\n      \"journal\": \"Cardiovascular research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — receptor subtype pharmacology with in vivo validation; Smad3-dependent transcriptional mechanism; single lab\",\n      \"pmids\": [\"30016400\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"EPAC activation in pancreatic β-cells activates TRPM2 nonselective cation channels (NSCC) through a PKA-independent cAMP/EPAC pathway to facilitate membrane depolarization and insulin secretion; TRPM2-deficient mice lack this NSCC activation.\",\n      \"method\": \"GLP-1/exendin-4/glucose stimulation; PKA inhibitors; EPAC-selective analogue; TRPM2-knockout mice; patch clamp recordings of NSCC\",\n      \"journal\": \"Diabetes\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO mice plus pharmacologic PKA exclusion plus electrophysiology; replicated across GLP-1 analogues\",\n      \"pmids\": [\"24824430\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RAPGEF3 (EPAC1) is a multidomain cAMP-binding guanine nucleotide exchange factor that, upon direct cAMP binding to its regulatory domain, undergoes a conformational change relieving autoinhibition to activate the small GTPases Rap1 and Rap2 in a PKA-independent manner; it is spatiotemporally compartmentalized through interactions with microtubules (via tubulin), KATP channels, MAP1A-LC2, and scaffold proteins (DEP domain-dependent membrane targeting), and controls diverse cellular functions including integrin-mediated adhesion, endothelial barrier maintenance via VE-cadherin and tight junctions, cardiomyocyte Ca2+ handling and hypertrophy (through Ras/calcineurin/CaMKII), growth cone guidance, neuronal apoptosis (via Bim upregulation), axon regeneration, sperm acrosomal exocytosis (via Rap1-PLCε-IP3-Ca2+ cascade), anti-fibrotic signaling in fibroblasts, and regulation of TRPM2 channel activity and insulin secretion in β-cells.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RAPGEF3 (EPAC1) is a cAMP-activated guanine nucleotide exchange factor that couples receptor-driven cAMP elevation to activation of the small GTPases Rap1 and Rap2 in a PKA-independent manner, thereby serving as a parallel cAMP effector arm controlling adhesion, barrier function, secretion, and cell-type-specific transcriptional and Ca2+ programs [#0, #4]. Direct cAMP binding to its regulatory domain relieves an autoinhibitory interaction with the catalytic domain — a conformational switch directly visualized in living cells by intramolecular FRET and abolished by cAMP-binding-dead mutants [#1]. EPAC1 signaling is spatially compartmentalized: subcellular-targeted reporters show faster activation at the plasma membrane than in cytosol or mitochondria [#2], DEP-domain-dependent membrane targeting is required for Rap1 activation and mitogenesis [#8], and EPAC1 is positioned by direct interactions with tubulin/microtubules and with MAP1A light chain 2 [#5, #7]. Downstream of Rap, EPAC1 engages effector cascades including Rap2B–PLCε–Ca2+ to activate Ras/ERK [#4], and controls integrin-α3β1-dependent adhesion and spreading [#3]. Through these modules it stabilizes endothelial and epithelial junctions — preserving VE-cadherin and tight junctions to limit vascular permeability [#14, #32] — and drives regulated exocytosis, including Weibel-Palade body release in endothelium [#27] and the cAMP–Epac–Rap1–PLCε–IP3–Ca2+ cascade that mobilizes acrosomal calcium during sperm exocytosis [#33]. In cardiomyocytes EPAC1 activation produces hypertrophy and altered Ca2+ handling via Ras, Rac/calcineurin/NFAT, and CaMKII/PKC, increasing myofilament Ca2+ sensitivity and promoting arrhythmia, all independent of PKA [#9, #19, #6]. EPAC1 also exerts cell-type-specific control of survival and plasticity, transcriptionally upregulating the pro-apoptotic factor Bim in cortical neurons [#20] and, in forebrain neurons, driving miR-124-mediated suppression of Zif268 to support LTP, spatial learning, and social behavior [#25]. In secretory and metabolic tissues EPAC1/EPAC2 activate TRPM2 cation channels to facilitate insulin secretion [#45]. Selective cAMP analogues and the EPAC antagonists ESI-09 and CE3F4 provide pharmacological tools that confirm its GEF activity and PKA independence [#0, #31, #26].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Established that EPAC1 is a cAMP-activated GEF for Rap1 acting independently of PKA, defining a second cAMP effector arm distinct from the kinase pathway.\",\n      \"evidence\": \"Rational design of the PKA-sparing cAMP analogue 8CPT-2Me-cAMP with in vitro and cell-based Rap1/ERK activation assays\",\n      \"pmids\": [\"12402047\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve the structural mechanism of cAMP-dependent activation\", \"Physiological receptor contexts not yet mapped\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Defined the activation mechanism as a cAMP-induced relief of autoinhibition between regulatory and catalytic domains, and showed this activation is spatially compartmentalized within the cell.\",\n      \"evidence\": \"Intramolecular CFP-Epac1-YFP FRET sensors in live cells with binding-dead mutants and subcellular-targeted reporters\",\n      \"pmids\": [\"15550931\", \"15545605\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the scaffolds enforcing compartment-specific kinetics not fully defined\", \"No atomic structure of the conformational transition\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Connected EPAC1 to specific downstream physiology, linking Rap1 to integrin-α3β1 adhesion and Rap2B to a PLCε–Ca2+–Ras/ERK branch.\",\n      \"evidence\": \"Selective analogues, integrin-blocking antibodies, dominant-negative Rap1/Rap2B, and cAMP-binding-dead EPAC1 mutants in multiple cell lines\",\n      \"pmids\": [\"15302884\", \"15319437\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Rap1 vs Rap2 selectivity is intrinsic or context-driven not resolved\", \"Direct PLCε binding not demonstrated\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Identified protein partners that spatially position EPAC1, showing localization is achieved through cytoskeletal and scaffold interactions.\",\n      \"evidence\": \"Yeast two-hybrid, reciprocal Co-IP, and GST domain-mapping pull-downs identifying MAP1A-LC2 binding via the cAMP-binding domain; microtubule/tubulin co-purification\",\n      \"pmids\": [\"15202935\", \"16880999\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab interactions without reciprocal validation across groups for tubulin\", \"Functional impact of MAP1A-LC2 binding on signaling not quantified\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Demonstrated that DEP-domain-dependent membrane targeting is functionally required for Rap1 activation and proliferative responses, establishing localization as obligatory for signaling output.\",\n      \"evidence\": \"DEP-deletion and dominant-negative constructs with Rap1 pull-down and thyroid mitogenesis assays\",\n      \"pmids\": [\"18063584\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Membrane lipid/protein anchor recognized by the DEP domain not identified\", \"Single-lab, single cell-type result\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Defined EPAC1 as a major driver of cardiomyocyte hypertrophy and altered Ca2+ handling through Ras, calcineurin and CaMKII, dissociating these effects from both Rap1 and PKA.\",\n      \"evidence\": \"siRNA knockdown, dominant-negative Ras, calcineurin/CaMKII inhibitors, and aortic constriction in vivo with hypertrophic markers and Ca2+ imaging\",\n      \"pmids\": [\"18323524\", \"16269655\", \"18600344\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How EPAC1 activates Ras independently of Rap not mechanistically resolved\", \"Direct EPAC1-CaMKII coupling unclear\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Showed EPAC1 modulates additional intracellular targets — Akt/PP2A complexes, nuclear DNA-PK, and barrier-junction proteins — placing it within survival, repair and permeability circuits.\",\n      \"evidence\": \"Co-IP of EPAC-Akt-PP2A complex with in-complex phosphatase assays; nuclear fractionation and DSB repair assays; intact microvessel permeability with VE-cadherin imaging\",\n      \"pmids\": [\"18550542\", \"18728186\", \"18178724\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"These complexes documented by single-lab Co-IP without reciprocal/structural validation\", \"Mechanism of EPAC1 nuclear targeting not defined\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Revealed cell-type-specific outcomes, including a developmental switch in growth-cone cAMP effector usage and pro-apoptotic Bim induction in neurons versus contractile remodeling in heart.\",\n      \"evidence\": \"FRET biosensors and turning assays in embryonic vs postnatal neurons; Epac1 knockout mice and Bim siRNA; permeabilized cardiomyocyte Ca2+-sensitivity assays\",\n      \"pmids\": [\"20007468\", \"20516079\", \"19666481\", \"18583150\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis for cell-type-specific transcriptional outputs (e.g., Bim) not resolved\", \"Determinants of Epac vs PKA developmental switch unknown\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Linked EPAC1 to regulated secretion, phagosomal autophagy and neuronal plasticity, broadening its role in vesicle trafficking and gene-regulatory programs.\",\n      \"evidence\": \"siRNA/Rap1GAP for Weibel-Palade body exocytosis; phagosomal localization with calpain inhibitors for autophagy; forebrain knockout mice with miR-124/Zif268 rescue\",\n      \"pmids\": [\"22511766\", \"22654658\", \"22365550\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How EPAC1 controls miR-124 transcription mechanistically unclear\", \"Phagosomal recruitment mechanism not defined\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Characterized EPAC1 in vascular tone and channel regulation, showing it activates Kv7, BKCa and ryanodine-receptor-coupled Ca2+ signaling to drive vasorelaxation.\",\n      \"evidence\": \"Myography, Ca2+ spark imaging, patch clamp, and proximity ligation assays linking Rap1a/Rap2 to Kv7.4 in mesenteric vessels\",\n      \"pmids\": [\"23959673\", \"27789473\", \"19491242\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Vessel-bed specificity (mesenteric vs renal) mechanistically unexplained\", \"Direct EPAC1-channel complexes not structurally defined\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Reconstituted the full cAMP–Epac–Rap1–PLCε–IP3–Ca2+ module required for sperm acrosomal exocytosis, establishing EPAC1 in regulated calcium-dependent membrane fusion.\",\n      \"evidence\": \"TAT-cAMP sponge, Epac-selective analogue, dominant-negative Rap1, PLCε inhibition, and Ca2+/acrosome reaction assays; immunolocalization to the acrosome\",\n      \"pmids\": [\"26704387\", \"21471298\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Spatial organization of the cascade on the acrosomal membrane not resolved\", \"Relative contributions of EPAC1 vs EPAC2 not fully separated\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Extended EPAC1 into metabolic and disease-relevant signaling, regulating TRPM2-dependent insulin secretion, β-cell autophagy via calcineurin/TFEB, and anti-inflammatory/anti-fibrotic pathways in kidney and heart.\",\n      \"evidence\": \"TRPM2-knockout mice and patch clamp; siRNA with calcineurin inhibitors and TFEB; in vivo db/db and MI models with C/EBP-β/SOCS3/STAT3 and Smad3 dissection\",\n      \"pmids\": [\"24824430\", \"34338148\", \"34103688\", \"30016400\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Many disease pathways rest on single-lab in vivo models\", \"Direct vs indirect engagement of TFEB and STAT3 circuits unresolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How a single cAMP-activated GEF achieves its highly cell-type- and compartment-specific outputs — selecting between Rap1, Rap2, Ras and non-canonical effectors — remains the central unresolved question.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unifying model linking scaffold/localization choice to effector selection\", \"Endogenous receptor-to-EPAC1 coupling specificity poorly mapped\", \"Structural basis of effector discrimination unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005088\", \"supporting_discovery_ids\": [0, 4, 8, 31]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [2, 8, 16]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [5, 7]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [10]},\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 4, 33]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [27, 33]},\n      {\"term_id\": \"R-HSA-397014\", \"supporting_discovery_ids\": [9, 19]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"RAP1A\", \"RAP2B\", \"TUBB\", \"MAP1A\", \"AKT1\", \"PPP2CA\", \"ABCC8\", \"KCNQ4\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":9,"faith_total":9,"faith_pct":100.0}}