{"gene":"FRAT1","run_date":"2026-04-28T17:46:04","timeline":{"discoveries":[{"year":1997,"finding":"Frat1 was identified as a proto-oncogene that collaborates with Pim1 and Myc in lymphoma progression; retroviral insertion near Frat1 conferred selective advantage to tumor cells in vivo, and a Frat1-IRES-lacZ retrovirus accelerated lymphomagenesis in Myc/Pim1-expressing tumor cell lines.","method":"Retroviral insertional mutagenesis, proviral tagging, retroviral overexpression in transgenic mouse models","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 — clean in vivo gain-of-function with defined phenotypic readout, replicated across transgenic backgrounds","pmids":["9034327"],"is_preprint":false},{"year":1999,"finding":"FRAT1 interacts with both Dishevelled (Dvl) and GSK-3, and Axin also interacts with both Dvl and GSK-3; Dvl, Axin, GSK-3, and Frat1 can form a quaternary complex in which Dvl bridges Axin and recruits Frat1, leading to Frat1-mediated dissociation of GSK-3 from Axin. Wnt-1 promotes disintegration of this complex. Dominant-negative Dvl-binding domains of Frat1 or Axin block Wnt-1-induced LEF-1 activation.","method":"Co-immunoprecipitation, dominant-negative domain overexpression, Xenopus axis duplication, LEF-1 reporter assays in mammalian cells","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 — reciprocal co-IP of quaternary complex, multiple orthogonal functional assays, highly cited foundational study","pmids":["10428961"],"is_preprint":false},{"year":1999,"finding":"A peptide from FRAT1 (residues 188–226, 'FRATtide') binds GSK-3, competitively prevents GSK-3 from interacting with Axin, and selectively blocks GSK-3-catalysed phosphorylation of Axin and beta-catenin without suppressing GSK-3 activity toward glycogen synthase or eIF2B (substrates requiring priming phosphorylation).","method":"In vitro GSK-3 kinase assays with FRATtide peptide, competitive binding assays, substrate selectivity profiling","journal":"FEBS letters","confidence":"High","confidence_rationale":"Tier 1 — in vitro reconstitution with defined peptide and multiple substrate comparisons","pmids":["10481074"],"is_preprint":false},{"year":1999,"finding":"Frat1-knockout mice are viable and fertile with no overt developmental defects, attributable to functional redundancy with the closely related Frat3 gene; both Frat1 and Frat3 proteins can induce a secondary axis in Xenopus embryos, demonstrating conserved GSK-3 inhibitory/Wnt-activating function.","method":"Gene targeting (knockout mice), LacZ reporter for expression pattern, Xenopus axis duplication assay","journal":"Mechanisms of development","confidence":"High","confidence_rationale":"Tier 2 — loss-of-function mouse model plus functional rescue assay in Xenopus","pmids":["10534617"],"is_preprint":false},{"year":1999,"finding":"Transgenic overexpression of Frat1 leads to focal glomerulosclerosis and nephrotic syndrome, and accelerates M-MuLV-induced lymphomagenesis when combined with Pim1, providing direct in vivo evidence for Frat1's role in tumor progression.","method":"Transgenic mouse overexpression, tumor incidence monitoring, bitransgenic crosses","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 — clean gain-of-function in vivo with defined pathological phenotypes","pmids":["10557087"],"is_preprint":false},{"year":2001,"finding":"Adenoviral overexpression of FRAT1 in PC12 cells is sufficient for neuroprotection and correlates with inhibition of GSK-3 activity toward Tau and beta-catenin but not glycogen synthase, demonstrating that FRAT1 selectively inhibits the Axin-dependent arm of GSK-3 in a cellular context.","method":"Adenoviral FRAT1 overexpression, GSK-3 substrate phosphorylation assays (Tau, beta-catenin, glycogen synthase), cell viability assay","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 — clean cellular gain-of-function with defined substrate-specific readouts, single lab","pmids":["11696357"],"is_preprint":false},{"year":2002,"finding":"FRAT1 and FRAT2 proteins, when transiently overexpressed in COS-1 cells, localize to the cytosol and concentrate in the nucleus, establishing their subcellular distribution.","method":"Transient transfection and subcellular fractionation/immunofluorescence in COS-1 cells","journal":"Gene","confidence":"Low","confidence_rationale":"Tier 3 — single localization experiment without functional consequence linked","pmids":["12095675"],"is_preprint":false},{"year":2003,"finding":"CKI epsilon phosphorylates Dvl-1 and thereby enhances the binding of Dvl-1 to Frat-1 (requiring residues 228–250 of Dvl-1); depletion of CKI epsilon by RNAi reduces Wnt-3a-induced Dvl phosphorylation, impairs Dvl-1/Frat-1 complex formation, and attenuates Wnt-3a-induced beta-catenin accumulation.","method":"Co-immunoprecipitation, deletion mutagenesis of Dvl-1, RNAi knockdown of CKI epsilon, beta-catenin accumulation assay, TCF-4 reporter assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (CoIP, mutagenesis, RNAi, reporter) in single study establishing CKIε as the upstream kinase regulating Dvl/Frat1 interaction","pmids":["12556519"],"is_preprint":false},{"year":2003,"finding":"Expression of a FRAT1 peptide in swAPP(751) cells increases GSK-3alpha/beta phosphorylation on Ser21/Ser9 (inhibitory sites), inhibits kinase activity of both isoforms, and significantly decreases production of total Abeta and Abeta(1-42).","method":"FRAT1 peptide expression in swAPP cells, GSK-3 kinase activity assay, ELISA for Abeta production","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 — cellular gain-of-function with kinase activity and Abeta readouts, single lab","pmids":["14572648"],"is_preprint":false},{"year":2005,"finding":"FRAT1 interacts with the cytoplasmic domain of LRP5 (identified by yeast two-hybrid and confirmed by co-IP); Wnt3a or constitutively active LRP5 recruits Frat1 to the cell membrane; dominant-negative Dvl reduces LRP5/Frat1 interaction but not LRP5C/Frat1 interaction; Axin co-immunoprecipitates with Frat1 and LRP5, suggesting a membrane-recruited complex that leads to Axin degradation and Frat1-mediated GSK-3 inhibition and beta-catenin nuclear translocation.","method":"Yeast two-hybrid, co-immunoprecipitation, dominant-negative Dvl expression, beta-catenin localization assay, TCF-1 reporter assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — yeast two-hybrid plus reciprocal CoIP plus multiple functional assays identifying LRP5 as a new Frat1 partner","pmids":["15699046"],"is_preprint":false},{"year":2006,"finding":"Protein kinase A (PKA) phosphorylates FRAT1 at Ser188 in vitro and in intact cells; activation of endogenous beta-adrenergic receptors with norepinephrine stimulates Ser188 phosphorylation; PKA-mediated Ser188 phosphorylation inhibits FRAT1's ability to activate beta-catenin-dependent transcription. GSK-3 can also phosphorylate Ser188 in vitro or when overexpressed, but endogenous GSK-3 does not significantly phosphorylate FRAT1 in cells.","method":"In vitro kinase assay (PKA), phosphorylation site identification (mass spectrometry/mutagenesis), beta-adrenergic receptor stimulation, beta-catenin TCF reporter assay, site-directed mutagenesis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — in vitro kinase assay plus cellular phosphorylation plus functional consequence via mutagenesis","pmids":["16982607"],"is_preprint":false},{"year":2008,"finding":"FRAT1 overexpression in esophageal squamous cell carcinoma cells induces nuclear accumulation of beta-catenin and promotes beta-catenin/TCF transcriptional activity; these effects are reversed by co-expression of GSK-3beta or dominant-negative TCF4. Sustained c-Myc expression is necessary and sufficient for the growth state conferred by FRAT1. FRAT1 knockdown by RNAi inhibits cancer cell growth.","method":"Stable overexpression/RNAi knockdown, beta-catenin nuclear localization imaging, TCF reporter assay, dominant-negative rescue, c-Myc functional assays","journal":"International journal of cancer","confidence":"Medium","confidence_rationale":"Tier 2 — multiple functional assays with genetic rescue experiments, single lab","pmids":["18498136"],"is_preprint":false},{"year":2014,"finding":"NDRG1 upregulates FRAT1 expression, which prevents GSK-3beta from associating with the Axin1-APC-CK1 destruction complex, thereby inhibiting phosphorylation of beta-catenin at Ser33/37 and Thr41 and increasing non-phosphorylated beta-catenin at the plasma membrane. NDRG1 also reduces nuclear PAK4 to suppress beta-catenin nuclear translocation.","method":"Co-immunoprecipitation (GSK-3beta/Axin1 complex), siRNA knockdown of FRAT1 and NDRG1, Western blotting for beta-catenin phosphorylation status, subcellular fractionation","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 — CoIP plus siRNA knockdown with specific phosphorylation readouts, single lab","pmids":["24829151"],"is_preprint":false},{"year":2017,"finding":"FRAT1 is a direct target of miR-34a-3p; dual luciferase assays with the FRAT1 3'UTR confirmed direct binding, and mutation of the miR-34a-3p binding site abolished repression. miR-34a-3p overexpression decreases FRAT1 protein levels in meningioma cells and alters proliferation and apoptosis.","method":"Dual luciferase 3'UTR reporter assay, site-directed mutagenesis of miRNA binding site, Western blotting, cell proliferation and apoptosis assays","journal":"Aging","confidence":"Medium","confidence_rationale":"Tier 2 — luciferase assay with mutagenesis confirming direct miRNA targeting, single lab","pmids":["28340489"],"is_preprint":false},{"year":2022,"finding":"FRAT1 physically interacts with FRAT2; siRNA-mediated repression of FRAT2 in FRAT1-overexpressing gastric cancer cells reverses FRAT1-driven invasion. miR-3648 directly targets FRAT1 and FRAT2, inactivating Wnt/beta-catenin signaling and suppressing c-Myc; c-Myc in turn negatively regulates miR-3648 expression by binding its promoter, forming a negative feedback loop.","method":"Co-immunoprecipitation (FRAT1/FRAT2 interaction), siRNA knockdown, invasion assays, luciferase reporter, ChIP for c-Myc binding to miR-3648 promoter","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 — CoIP plus functional rescue plus ChIP, single lab","pmids":["36153370"],"is_preprint":false},{"year":2022,"finding":"FRAT1 knockdown in glioblastoma U251 cells decreases mRNA and protein levels of VEGFA and reduces secreted VEGFA in conditioned medium, suppressing tube formation (angiogenesis) by endothelial cells, placing FRAT1 upstream of VEGFA in the Wnt/beta-catenin pathway.","method":"siRNA knockdown, RT-qPCR, Western blot, ELISA for secreted VEGFA, tube formation assay","journal":"Molecular medicine reports","confidence":"Low","confidence_rationale":"Tier 3 — single-method knockdown with downstream readout, no direct mechanistic link established, single lab","pmids":["35059733"],"is_preprint":false}],"current_model":"FRAT1 is a GSK-3-binding protein that functions as a substrate-selective inhibitor of GSK-3 within the Wnt signaling pathway: it is recruited to the Dvl–Axin–GSK-3 quaternary complex (via a Dvl-dependent mechanism facilitated by CKI epsilon-mediated Dvl phosphorylation and also through LRP5 at the membrane), where it displaces GSK-3 from Axin through its GSK-3-binding domain (FRATtide), thereby selectively blocking GSK-3-catalysed phosphorylation of beta-catenin and Axin without affecting glycogen synthase or eIF2B phosphorylation, leading to beta-catenin stabilization, nuclear accumulation, and TCF/LEF-dependent transcription; FRAT1 activity is negatively regulated by PKA-mediated phosphorylation at Ser188, and FRAT1 itself is subject to post-transcriptional regulation by miRNAs including miR-34a-3p and miR-3648."},"narrative":{"teleology":[{"year":1997,"claim":"The initial discovery of Frat1 established it as a proto-oncogene that cooperates with Pim1 and Myc to accelerate lymphomagenesis, but its molecular mechanism was unknown.","evidence":"Retroviral insertional mutagenesis and proviral tagging in Eμ-Myc/Pim1 transgenic mice","pmids":["9034327"],"confidence":"High","gaps":["No molecular target or binding partner identified","Mechanism of oncogenic cooperation with Pim1/Myc undefined"]},{"year":1999,"claim":"Three concurrent studies revealed that FRAT1 functions within Wnt signaling by forming a quaternary complex with Dvl, Axin, and GSK-3, using a defined peptide domain (FRATtide) to competitively displace GSK-3 from Axin and selectively block β-catenin/Axin phosphorylation without affecting priming-dependent GSK-3 substrates—establishing FRAT1 as a substrate-selective GSK-3 inhibitor.","evidence":"Reciprocal co-immunoprecipitation of quaternary complex, FRATtide competitive binding and in vitro kinase assays with multiple GSK-3 substrates, Xenopus axis duplication assays, LEF-1 reporters","pmids":["10428961","10481074"],"confidence":"High","gaps":["Upstream signal connecting Wnt receptor activation to FRAT1 recruitment unresolved","Structural basis of FRATtide–GSK-3 interaction not yet determined"]},{"year":1999,"claim":"Loss-of-function and gain-of-function mouse models showed that Frat1 is dispensable for normal development due to redundancy with Frat3, but its overexpression causes glomerulosclerosis and accelerates lymphomagenesis, confirming its oncogenic potential in vivo.","evidence":"Frat1-knockout mice (gene targeting), Frat1-overexpressing transgenics, bitransgenic crosses with Pim1","pmids":["10534617","10557087"],"confidence":"High","gaps":["Frat1/Frat3 double knockout not yet generated to test pathway-level requirement","Tissue-specific contributions of Frat family members unclear"]},{"year":2003,"claim":"CKIε was identified as the kinase that phosphorylates Dvl-1 to enhance Dvl–Frat1 complex formation, linking Wnt3a receptor activation to the mechanism by which FRAT1 is recruited into the destruction complex.","evidence":"Co-immunoprecipitation with Dvl-1 deletion mutants, CKIε RNAi knockdown, Wnt3a-stimulated β-catenin accumulation assays","pmids":["12556519"],"confidence":"High","gaps":["Whether CKIε is the sole kinase regulating this interaction not excluded","Quantitative contribution of CKIε-dependent FRAT1 recruitment versus other Wnt-induced events unknown"]},{"year":2005,"claim":"The Wnt co-receptor LRP5 was identified as an additional FRAT1-binding partner that recruits FRAT1 to the plasma membrane upon Wnt3a stimulation, placing FRAT1 at the receptor complex and linking it to Axin degradation.","evidence":"Yeast two-hybrid screen with LRP5 cytoplasmic domain, reciprocal co-IP, dominant-negative Dvl rescue, TCF reporter assays","pmids":["15699046"],"confidence":"High","gaps":["Whether LRP6 similarly recruits FRAT1 not tested","Relative importance of LRP5- versus Dvl-mediated FRAT1 recruitment not quantified"]},{"year":2006,"claim":"PKA was shown to phosphorylate FRAT1 at Ser188 downstream of β-adrenergic receptor signaling, identifying the first negative regulatory modification of FRAT1 that inhibits its ability to activate β-catenin-dependent transcription.","evidence":"In vitro PKA kinase assay, Ser188 mutagenesis, norepinephrine stimulation of endogenous β-adrenergic receptors, TCF reporter assays","pmids":["16982607"],"confidence":"High","gaps":["How Ser188 phosphorylation mechanistically disrupts FRAT1 function (altered GSK-3 binding vs. localization vs. stability) not resolved","Physiological contexts where PKA–FRAT1 crosstalk operates in vivo not defined"]},{"year":2008,"claim":"FRAT1 was shown to drive nuclear β-catenin accumulation and cancer cell growth through TCF-dependent c-Myc expression, directly linking FRAT1's GSK-3 inhibitory mechanism to a specific transcriptional output in human cancer cells.","evidence":"Stable FRAT1 overexpression and RNAi in esophageal squamous cell carcinoma cells, GSK-3β and dominant-negative TCF4 rescue, c-Myc functional assays","pmids":["18498136"],"confidence":"Medium","gaps":["Whether c-Myc is the critical or sole effector of FRAT1-driven proliferation not established genome-wide","Contribution of FRAT1 to Wnt-independent GSK-3 functions in cancer unexplored"]},{"year":2014,"claim":"NDRG1 was identified as an upstream positive regulator of FRAT1 expression that prevents GSK-3β from joining the Axin1–APC–CK1 destruction complex, revealing a regulatory input that tunes FRAT1-dependent β-catenin stabilization at the plasma membrane.","evidence":"NDRG1/FRAT1 siRNA knockdown, co-IP of GSK-3β–Axin1, Western blotting for phospho-β-catenin, subcellular fractionation","pmids":["24829151"],"confidence":"Medium","gaps":["Mechanism by which NDRG1 upregulates FRAT1 (transcriptional vs. post-translational) not determined","Single-lab finding not independently replicated"]},{"year":2017,"claim":"miR-34a-3p was validated as a direct post-transcriptional repressor of FRAT1, establishing a microRNA-mediated regulatory layer on FRAT1 expression.","evidence":"Dual luciferase 3′UTR reporter with binding-site mutagenesis in meningioma cells","pmids":["28340489"],"confidence":"Medium","gaps":["Physiological relevance of miR-34a-3p–FRAT1 axis beyond meningioma not shown","Whether miR-34a-3p regulation of FRAT1 is sufficient to modulate Wnt output in vivo untested"]},{"year":2022,"claim":"FRAT1 was found to physically interact with FRAT2 and to be co-targeted with FRAT2 by miR-3648, which forms a negative feedback loop with c-Myc, revealing coordinated regulation of FRAT family members and a Wnt–c-Myc–miRNA circuit.","evidence":"Co-immunoprecipitation of FRAT1–FRAT2, siRNA rescue of FRAT1-driven invasion, luciferase reporter for miR-3648 targeting, ChIP for c-Myc at miR-3648 promoter in gastric cancer cells","pmids":["36153370"],"confidence":"Medium","gaps":["Functional significance of FRAT1–FRAT2 heterodimerization for GSK-3 inhibition not tested biochemically","Single-lab finding in gastric cancer; generalizability to other tissues unknown"]},{"year":null,"claim":"Key unresolved questions include the structural basis of FRATtide–GSK-3 selectivity, the in vivo requirement for the entire FRAT gene family in Wnt signaling (no Frat1/Frat3 double knockout reported), and the relative contributions of LRP5-, Dvl-, and NDRG1-mediated FRAT1 recruitment in physiological Wnt activation.","evidence":"","pmids":[],"confidence":"High","gaps":["No high-resolution structure of full-length FRAT1 in complex with GSK-3 or Axin","Frat1/Frat3 double knockout mouse not reported","Quantitative modeling of FRAT1's contribution relative to other GSK-3 inhibitory mechanisms in the Wnt pathway lacking"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[1,2,5,12]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[6]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[6]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[9]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,2,7,9,11,12,14]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[0,4,11,14]}],"complexes":[],"partners":["GSK3B","DVL1","AXIN1","LRP5","FRAT2","CSNK1E"],"other_free_text":[]},"mechanistic_narrative":"FRAT1 is a positive regulator of canonical Wnt/β-catenin signaling that acts as a substrate-selective inhibitor of GSK-3. FRAT1 is recruited to a quaternary complex with Dishevelled, Axin, and GSK-3β—a process facilitated by CKIε-mediated phosphorylation of Dvl and by LRP5 at the plasma membrane—where its GSK-3-binding domain (FRATtide) competitively displaces GSK-3 from Axin, selectively blocking phosphorylation of β-catenin and Axin without affecting priming-dependent substrates such as glycogen synthase [PMID:10428961, PMID:10481074, PMID:12556519, PMID:15699046]. This leads to β-catenin stabilization, nuclear accumulation, and TCF/LEF-dependent transcription of targets including c-Myc; FRAT1 activity is negatively regulated by PKA phosphorylation at Ser188 and post-transcriptionally by miR-34a-3p and miR-3648 [PMID:16982607, PMID:18498136, PMID:28340489, PMID:36153370]. Originally identified as a proto-oncogene cooperating with Pim1 and Myc in murine lymphomagenesis, FRAT1 overexpression promotes tumor progression in multiple cancer contexts, while single-gene knockout mice are viable due to functional redundancy with Frat3 [PMID:9034327, PMID:10534617, PMID:10557087]."},"prefetch_data":{"uniprot":{"accession":"Q92837","full_name":"Proto-oncogene FRAT1","aliases":["Frequently rearranged in advanced T-cell lymphomas 1","FRAT-1"],"length_aa":279,"mass_kda":29.1,"function":"Positively regulates the Wnt signaling pathway by stabilizing beta-catenin through the association with GSK-3. May play a role in tumor progression and collaborate with PIM1 and MYC in lymphomagenesis","subcellular_location":"Cytoplasm","url":"https://www.uniprot.org/uniprotkb/Q92837/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/FRAT1","classification":"Not Classified","n_dependent_lines":27,"n_total_lines":1208,"dependency_fraction":0.022350993377483443},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/FRAT1","total_profiled":1310},"omim":[{"mim_id":"606784","title":"GLYCOGEN SYNTHASE KINASE 3-ALPHA; GSK3A","url":"https://www.omim.org/entry/606784"},{"mim_id":"605006","title":"FREQUENTLY REARRANGED IN ADVANCED T-CELL LYMPHOMAS 2; FRAT2","url":"https://www.omim.org/entry/605006"},{"mim_id":"602503","title":"FREQUENTLY REARRANGED IN ADVANCED T-CELL LYMPHOMAS; FRAT1","url":"https://www.omim.org/entry/602503"},{"mim_id":"600982","title":"MITOGEN-ACTIVATED PROTEIN KINASE KINASE KINASE 1; MAP3K1","url":"https://www.omim.org/entry/600982"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Vesicles","reliability":"Approved"},{"location":"Cytosol","reliability":"Approved"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in many","driving_tissues":[],"url":"https://www.proteinatlas.org/search/FRAT1"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q92837","domains":[{"cath_id":"-","chopping":"200-230","consensus_level":"medium","plddt":91.9835,"start":200,"end":230}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q92837","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q92837-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q92837-F1-predicted_aligned_error_v6.png","plddt_mean":59.81},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=FRAT1","jax_strain_url":"https://www.jax.org/strain/search?query=FRAT1"},"sequence":{"accession":"Q92837","fasta_url":"https://rest.uniprot.org/uniprotkb/Q92837.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q92837/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q92837"}},"corpus_meta":[{"pmid":"10428961","id":"PMC_10428961","title":"Axin and Frat1 interact with dvl and GSK, bridging Dvl to GSK in Wnt-mediated regulation of LEF-1.","date":"1999","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/10428961","citation_count":342,"is_preprint":false},{"pmid":"10481074","id":"PMC_10481074","title":"A GSK3-binding peptide from FRAT1 selectively inhibits the GSK3-catalysed phosphorylation of axin and beta-catenin.","date":"1999","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/10481074","citation_count":200,"is_preprint":false},{"pmid":"9034327","id":"PMC_9034327","title":"Activation of a novel proto-oncogene, Frat1, contributes to progression of mouse T-cell lymphomas.","date":"1997","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/9034327","citation_count":123,"is_preprint":false},{"pmid":"24829151","id":"PMC_24829151","title":"The metastasis suppressor NDRG1 modulates the phosphorylation and nuclear translocation of β-catenin through mechanisms involving FRAT1 and PAK4.","date":"2014","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/24829151","citation_count":98,"is_preprint":false},{"pmid":"12556519","id":"PMC_12556519","title":"Casein kinase I epsilon enhances the binding of Dvl-1 to Frat-1 and is essential for Wnt-3a-induced accumulation of beta-catenin.","date":"2003","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12556519","citation_count":96,"is_preprint":false},{"pmid":"11696357","id":"PMC_11696357","title":"GSK-3 inhibition by adenoviral FRAT1 overexpression is neuroprotective and induces Tau dephosphorylation and beta-catenin stabilisation without elevation of glycogen synthase activity.","date":"2001","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/11696357","citation_count":82,"is_preprint":false},{"pmid":"11894125","id":"PMC_11894125","title":"Molecular cloning and expression of proto-oncogene FRAT1 in human cancer.","date":"2002","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/11894125","citation_count":76,"is_preprint":false},{"pmid":"11445844","id":"PMC_11445844","title":"FRAT1 and FRAT2, clustered in human chromosome 10q24.1 region, are up-regulated in gastric cancer.","date":"2001","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/11445844","citation_count":76,"is_preprint":false},{"pmid":"15699046","id":"PMC_15699046","title":"Interaction between LRP5 and Frat1 mediates the activation of the Wnt canonical pathway.","date":"2005","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/15699046","citation_count":62,"is_preprint":false},{"pmid":"28340489","id":"PMC_28340489","title":"MiR-34a-3p alters proliferation and apoptosis of meningioma cells in vitro and is directly targeting SMAD4, FRAT1 and BCL2.","date":"2017","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/28340489","citation_count":41,"is_preprint":false},{"pmid":"18498136","id":"PMC_18498136","title":"FRAT1 overexpression leads to aberrant activation of beta-catenin/TCF pathway in esophageal squamous cell carcinoma.","date":"2008","source":"International journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/18498136","citation_count":33,"is_preprint":false},{"pmid":"10534617","id":"PMC_10534617","title":"In vivo analysis of Frat1 deficiency suggests compensatory activity of Frat3.","date":"1999","source":"Mechanisms of development","url":"https://pubmed.ncbi.nlm.nih.gov/10534617","citation_count":31,"is_preprint":false},{"pmid":"31788970","id":"PMC_31788970","title":"LncRNA SNHG1 influences cell proliferation, migration, invasion, and apoptosis of non-small cell lung cancer cells via the miR-361-3p/FRAT1 axis.","date":"2019","source":"Thoracic cancer","url":"https://pubmed.ncbi.nlm.nih.gov/31788970","citation_count":30,"is_preprint":false},{"pmid":"10557087","id":"PMC_10557087","title":"Overexpression of Frat1 in transgenic mice leads to glomerulosclerosis and nephrotic syndrome, and provides direct evidence for the involvement of Frat1 in lymphoma progression.","date":"1999","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/10557087","citation_count":26,"is_preprint":false},{"pmid":"22528942","id":"PMC_22528942","title":"Expression of Frat1 correlates with expression of β-catenin and is associated with a poor clinical outcome in human SCC and AC.","date":"2012","source":"Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/22528942","citation_count":25,"is_preprint":false},{"pmid":"12095675","id":"PMC_12095675","title":"Characterization and tissue-specific expression of human GSK-3-binding proteins FRAT1 and FRAT2.","date":"2002","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/12095675","citation_count":25,"is_preprint":false},{"pmid":"20041315","id":"PMC_20041315","title":"FRAT1 expression and its correlation with pathologic grade, proliferation, and apoptosis in human astrocytomas.","date":"2009","source":"Medical oncology (Northwood, London, England)","url":"https://pubmed.ncbi.nlm.nih.gov/20041315","citation_count":24,"is_preprint":false},{"pmid":"23613813","id":"PMC_23613813","title":"Knockdown of FRAT1 expression by RNA interference inhibits human glioblastoma cell growth, migration and invasion.","date":"2013","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23613813","citation_count":24,"is_preprint":false},{"pmid":"21818639","id":"PMC_21818639","title":"Overexpression of Frat1 correlates with malignant phenotype and advanced stage in human non-small cell lung cancer.","date":"2011","source":"Virchows Archiv : an international journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/21818639","citation_count":21,"is_preprint":false},{"pmid":"26178481","id":"PMC_26178481","title":"The clinical significance of FRAT1 and ABCG2 expression in pancreatic ductal adenocarcinoma.","date":"2015","source":"Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/26178481","citation_count":19,"is_preprint":false},{"pmid":"36153370","id":"PMC_36153370","title":"The miR-3648/FRAT1-FRAT2/c-Myc negative feedback loop modulates the metastasis and invasion of gastric cancer cells.","date":"2022","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/36153370","citation_count":19,"is_preprint":false},{"pmid":"16982607","id":"PMC_16982607","title":"FRAT1, a substrate-specific regulator of glycogen synthase kinase-3 activity, is a cellular substrate of protein kinase A.","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16982607","citation_count":15,"is_preprint":false},{"pmid":"27666874","id":"PMC_27666874","title":"Knockdown of FRAT1 inhibits hypoxia-induced epithelial-to-mesenchymal transition via suppression of the Wnt/β-catenin pathway in hepatocellular carcinoma cells.","date":"2016","source":"Oncology reports","url":"https://pubmed.ncbi.nlm.nih.gov/27666874","citation_count":13,"is_preprint":false},{"pmid":"32201513","id":"PMC_32201513","title":"FRAT1 Enhances the Proliferation and Tumorigenesis of CD133+Nestin+ Glioma Stem Cells In Vitro and In Vivo.","date":"2020","source":"Journal of Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/32201513","citation_count":12,"is_preprint":false},{"pmid":"14572648","id":"PMC_14572648","title":"FRAT1 peptide decreases Abeta production in swAPP(751) cells.","date":"2003","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/14572648","citation_count":12,"is_preprint":false},{"pmid":"34319909","id":"PMC_34319909","title":"LncRNA CCAT1 promotes prostate cancer cells proliferation, migration, and invasion through regulation of miR-490-3p/FRAT1 axis.","date":"2021","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/34319909","citation_count":10,"is_preprint":false},{"pmid":"33131270","id":"PMC_33131270","title":"Swertiamarin suppresses proliferation, migration, and invasion of hepatocellular carcinoma cells <em>via</em> negative regulation of FRAT1.","date":"2020","source":"European journal of histochemistry : EJH","url":"https://pubmed.ncbi.nlm.nih.gov/33131270","citation_count":10,"is_preprint":false},{"pmid":"25387569","id":"PMC_25387569","title":"The clinical pathological significance of FRAT1 and ROR2 expression in cartilage tumors.","date":"2014","source":"Clinical & translational oncology : official publication of the Federation of Spanish Oncology Societies and of the National Cancer Institute of Mexico","url":"https://pubmed.ncbi.nlm.nih.gov/25387569","citation_count":9,"is_preprint":false},{"pmid":"1561099","id":"PMC_1561099","title":"Molecular cloning and sequencing of the attachment site and integrase gene of the temperate mycobacteriophage FRAT1.","date":"1992","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/1561099","citation_count":9,"is_preprint":false},{"pmid":"26893843","id":"PMC_26893843","title":"Silencing of FRAT1 by siRNA inhibits the proliferation of SGC7901 human gastric adenocarcinoma cells.","date":"2016","source":"Biomedical reports","url":"https://pubmed.ncbi.nlm.nih.gov/26893843","citation_count":7,"is_preprint":false},{"pmid":"35059733","id":"PMC_35059733","title":"FRAT1 promotes the angiogenic properties of human glioblastoma cells via VEGFA.","date":"2022","source":"Molecular medicine 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Cancer","date":"2025-03-29","source":"bioRxiv","url":"https://doi.org/10.1101/2025.03.25.645248","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":18171,"output_tokens":4179,"usd":0.058599},"stage2":{"model":"claude-opus-4-6","input_tokens":7611,"output_tokens":3050,"usd":0.171458},"total_usd":0.230057,"stage1_batch_id":"msgbatch_0118RScg3WGaGkaZRtWZbtce","stage2_batch_id":"msgbatch_01Cpfzvtbj42aqp5oYZ5Te2s","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1997,\n      \"finding\": \"Frat1 was identified as a proto-oncogene that collaborates with Pim1 and Myc in lymphoma progression; retroviral insertion near Frat1 conferred selective advantage to tumor cells in vivo, and a Frat1-IRES-lacZ retrovirus accelerated lymphomagenesis in Myc/Pim1-expressing tumor cell lines.\",\n      \"method\": \"Retroviral insertional mutagenesis, proviral tagging, retroviral overexpression in transgenic mouse models\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean in vivo gain-of-function with defined phenotypic readout, replicated across transgenic backgrounds\",\n      \"pmids\": [\"9034327\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"FRAT1 interacts with both Dishevelled (Dvl) and GSK-3, and Axin also interacts with both Dvl and GSK-3; Dvl, Axin, GSK-3, and Frat1 can form a quaternary complex in which Dvl bridges Axin and recruits Frat1, leading to Frat1-mediated dissociation of GSK-3 from Axin. Wnt-1 promotes disintegration of this complex. Dominant-negative Dvl-binding domains of Frat1 or Axin block Wnt-1-induced LEF-1 activation.\",\n      \"method\": \"Co-immunoprecipitation, dominant-negative domain overexpression, Xenopus axis duplication, LEF-1 reporter assays in mammalian cells\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-IP of quaternary complex, multiple orthogonal functional assays, highly cited foundational study\",\n      \"pmids\": [\"10428961\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"A peptide from FRAT1 (residues 188–226, 'FRATtide') binds GSK-3, competitively prevents GSK-3 from interacting with Axin, and selectively blocks GSK-3-catalysed phosphorylation of Axin and beta-catenin without suppressing GSK-3 activity toward glycogen synthase or eIF2B (substrates requiring priming phosphorylation).\",\n      \"method\": \"In vitro GSK-3 kinase assays with FRATtide peptide, competitive binding assays, substrate selectivity profiling\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro reconstitution with defined peptide and multiple substrate comparisons\",\n      \"pmids\": [\"10481074\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Frat1-knockout mice are viable and fertile with no overt developmental defects, attributable to functional redundancy with the closely related Frat3 gene; both Frat1 and Frat3 proteins can induce a secondary axis in Xenopus embryos, demonstrating conserved GSK-3 inhibitory/Wnt-activating function.\",\n      \"method\": \"Gene targeting (knockout mice), LacZ reporter for expression pattern, Xenopus axis duplication assay\",\n      \"journal\": \"Mechanisms of development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function mouse model plus functional rescue assay in Xenopus\",\n      \"pmids\": [\"10534617\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Transgenic overexpression of Frat1 leads to focal glomerulosclerosis and nephrotic syndrome, and accelerates M-MuLV-induced lymphomagenesis when combined with Pim1, providing direct in vivo evidence for Frat1's role in tumor progression.\",\n      \"method\": \"Transgenic mouse overexpression, tumor incidence monitoring, bitransgenic crosses\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean gain-of-function in vivo with defined pathological phenotypes\",\n      \"pmids\": [\"10557087\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Adenoviral overexpression of FRAT1 in PC12 cells is sufficient for neuroprotection and correlates with inhibition of GSK-3 activity toward Tau and beta-catenin but not glycogen synthase, demonstrating that FRAT1 selectively inhibits the Axin-dependent arm of GSK-3 in a cellular context.\",\n      \"method\": \"Adenoviral FRAT1 overexpression, GSK-3 substrate phosphorylation assays (Tau, beta-catenin, glycogen synthase), cell viability assay\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean cellular gain-of-function with defined substrate-specific readouts, single lab\",\n      \"pmids\": [\"11696357\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"FRAT1 and FRAT2 proteins, when transiently overexpressed in COS-1 cells, localize to the cytosol and concentrate in the nucleus, establishing their subcellular distribution.\",\n      \"method\": \"Transient transfection and subcellular fractionation/immunofluorescence in COS-1 cells\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single localization experiment without functional consequence linked\",\n      \"pmids\": [\"12095675\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"CKI epsilon phosphorylates Dvl-1 and thereby enhances the binding of Dvl-1 to Frat-1 (requiring residues 228–250 of Dvl-1); depletion of CKI epsilon by RNAi reduces Wnt-3a-induced Dvl phosphorylation, impairs Dvl-1/Frat-1 complex formation, and attenuates Wnt-3a-induced beta-catenin accumulation.\",\n      \"method\": \"Co-immunoprecipitation, deletion mutagenesis of Dvl-1, RNAi knockdown of CKI epsilon, beta-catenin accumulation assay, TCF-4 reporter assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (CoIP, mutagenesis, RNAi, reporter) in single study establishing CKIε as the upstream kinase regulating Dvl/Frat1 interaction\",\n      \"pmids\": [\"12556519\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Expression of a FRAT1 peptide in swAPP(751) cells increases GSK-3alpha/beta phosphorylation on Ser21/Ser9 (inhibitory sites), inhibits kinase activity of both isoforms, and significantly decreases production of total Abeta and Abeta(1-42).\",\n      \"method\": \"FRAT1 peptide expression in swAPP cells, GSK-3 kinase activity assay, ELISA for Abeta production\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — cellular gain-of-function with kinase activity and Abeta readouts, single lab\",\n      \"pmids\": [\"14572648\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"FRAT1 interacts with the cytoplasmic domain of LRP5 (identified by yeast two-hybrid and confirmed by co-IP); Wnt3a or constitutively active LRP5 recruits Frat1 to the cell membrane; dominant-negative Dvl reduces LRP5/Frat1 interaction but not LRP5C/Frat1 interaction; Axin co-immunoprecipitates with Frat1 and LRP5, suggesting a membrane-recruited complex that leads to Axin degradation and Frat1-mediated GSK-3 inhibition and beta-catenin nuclear translocation.\",\n      \"method\": \"Yeast two-hybrid, co-immunoprecipitation, dominant-negative Dvl expression, beta-catenin localization assay, TCF-1 reporter assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — yeast two-hybrid plus reciprocal CoIP plus multiple functional assays identifying LRP5 as a new Frat1 partner\",\n      \"pmids\": [\"15699046\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Protein kinase A (PKA) phosphorylates FRAT1 at Ser188 in vitro and in intact cells; activation of endogenous beta-adrenergic receptors with norepinephrine stimulates Ser188 phosphorylation; PKA-mediated Ser188 phosphorylation inhibits FRAT1's ability to activate beta-catenin-dependent transcription. GSK-3 can also phosphorylate Ser188 in vitro or when overexpressed, but endogenous GSK-3 does not significantly phosphorylate FRAT1 in cells.\",\n      \"method\": \"In vitro kinase assay (PKA), phosphorylation site identification (mass spectrometry/mutagenesis), beta-adrenergic receptor stimulation, beta-catenin TCF reporter assay, site-directed mutagenesis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro kinase assay plus cellular phosphorylation plus functional consequence via mutagenesis\",\n      \"pmids\": [\"16982607\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"FRAT1 overexpression in esophageal squamous cell carcinoma cells induces nuclear accumulation of beta-catenin and promotes beta-catenin/TCF transcriptional activity; these effects are reversed by co-expression of GSK-3beta or dominant-negative TCF4. Sustained c-Myc expression is necessary and sufficient for the growth state conferred by FRAT1. FRAT1 knockdown by RNAi inhibits cancer cell growth.\",\n      \"method\": \"Stable overexpression/RNAi knockdown, beta-catenin nuclear localization imaging, TCF reporter assay, dominant-negative rescue, c-Myc functional assays\",\n      \"journal\": \"International journal of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple functional assays with genetic rescue experiments, single lab\",\n      \"pmids\": [\"18498136\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"NDRG1 upregulates FRAT1 expression, which prevents GSK-3beta from associating with the Axin1-APC-CK1 destruction complex, thereby inhibiting phosphorylation of beta-catenin at Ser33/37 and Thr41 and increasing non-phosphorylated beta-catenin at the plasma membrane. NDRG1 also reduces nuclear PAK4 to suppress beta-catenin nuclear translocation.\",\n      \"method\": \"Co-immunoprecipitation (GSK-3beta/Axin1 complex), siRNA knockdown of FRAT1 and NDRG1, Western blotting for beta-catenin phosphorylation status, subcellular fractionation\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — CoIP plus siRNA knockdown with specific phosphorylation readouts, single lab\",\n      \"pmids\": [\"24829151\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"FRAT1 is a direct target of miR-34a-3p; dual luciferase assays with the FRAT1 3'UTR confirmed direct binding, and mutation of the miR-34a-3p binding site abolished repression. miR-34a-3p overexpression decreases FRAT1 protein levels in meningioma cells and alters proliferation and apoptosis.\",\n      \"method\": \"Dual luciferase 3'UTR reporter assay, site-directed mutagenesis of miRNA binding site, Western blotting, cell proliferation and apoptosis assays\",\n      \"journal\": \"Aging\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — luciferase assay with mutagenesis confirming direct miRNA targeting, single lab\",\n      \"pmids\": [\"28340489\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"FRAT1 physically interacts with FRAT2; siRNA-mediated repression of FRAT2 in FRAT1-overexpressing gastric cancer cells reverses FRAT1-driven invasion. miR-3648 directly targets FRAT1 and FRAT2, inactivating Wnt/beta-catenin signaling and suppressing c-Myc; c-Myc in turn negatively regulates miR-3648 expression by binding its promoter, forming a negative feedback loop.\",\n      \"method\": \"Co-immunoprecipitation (FRAT1/FRAT2 interaction), siRNA knockdown, invasion assays, luciferase reporter, ChIP for c-Myc binding to miR-3648 promoter\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — CoIP plus functional rescue plus ChIP, single lab\",\n      \"pmids\": [\"36153370\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"FRAT1 knockdown in glioblastoma U251 cells decreases mRNA and protein levels of VEGFA and reduces secreted VEGFA in conditioned medium, suppressing tube formation (angiogenesis) by endothelial cells, placing FRAT1 upstream of VEGFA in the Wnt/beta-catenin pathway.\",\n      \"method\": \"siRNA knockdown, RT-qPCR, Western blot, ELISA for secreted VEGFA, tube formation assay\",\n      \"journal\": \"Molecular medicine reports\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single-method knockdown with downstream readout, no direct mechanistic link established, single lab\",\n      \"pmids\": [\"35059733\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"FRAT1 is a GSK-3-binding protein that functions as a substrate-selective inhibitor of GSK-3 within the Wnt signaling pathway: it is recruited to the Dvl–Axin–GSK-3 quaternary complex (via a Dvl-dependent mechanism facilitated by CKI epsilon-mediated Dvl phosphorylation and also through LRP5 at the membrane), where it displaces GSK-3 from Axin through its GSK-3-binding domain (FRATtide), thereby selectively blocking GSK-3-catalysed phosphorylation of beta-catenin and Axin without affecting glycogen synthase or eIF2B phosphorylation, leading to beta-catenin stabilization, nuclear accumulation, and TCF/LEF-dependent transcription; FRAT1 activity is negatively regulated by PKA-mediated phosphorylation at Ser188, and FRAT1 itself is subject to post-transcriptional regulation by miRNAs including miR-34a-3p and miR-3648.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"FRAT1 is a positive regulator of canonical Wnt/β-catenin signaling that acts as a substrate-selective inhibitor of GSK-3. FRAT1 is recruited to a quaternary complex with Dishevelled, Axin, and GSK-3β—a process facilitated by CKIε-mediated phosphorylation of Dvl and by LRP5 at the plasma membrane—where its GSK-3-binding domain (FRATtide) competitively displaces GSK-3 from Axin, selectively blocking phosphorylation of β-catenin and Axin without affecting priming-dependent substrates such as glycogen synthase [PMID:10428961, PMID:10481074, PMID:12556519, PMID:15699046]. This leads to β-catenin stabilization, nuclear accumulation, and TCF/LEF-dependent transcription of targets including c-Myc; FRAT1 activity is negatively regulated by PKA phosphorylation at Ser188 and post-transcriptionally by miR-34a-3p and miR-3648 [PMID:16982607, PMID:18498136, PMID:28340489, PMID:36153370]. Originally identified as a proto-oncogene cooperating with Pim1 and Myc in murine lymphomagenesis, FRAT1 overexpression promotes tumor progression in multiple cancer contexts, while single-gene knockout mice are viable due to functional redundancy with Frat3 [PMID:9034327, PMID:10534617, PMID:10557087].\",\n  \"teleology\": [\n    {\n      \"year\": 1997,\n      \"claim\": \"The initial discovery of Frat1 established it as a proto-oncogene that cooperates with Pim1 and Myc to accelerate lymphomagenesis, but its molecular mechanism was unknown.\",\n      \"evidence\": \"Retroviral insertional mutagenesis and proviral tagging in Eμ-Myc/Pim1 transgenic mice\",\n      \"pmids\": [\"9034327\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No molecular target or binding partner identified\", \"Mechanism of oncogenic cooperation with Pim1/Myc undefined\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Three concurrent studies revealed that FRAT1 functions within Wnt signaling by forming a quaternary complex with Dvl, Axin, and GSK-3, using a defined peptide domain (FRATtide) to competitively displace GSK-3 from Axin and selectively block β-catenin/Axin phosphorylation without affecting priming-dependent GSK-3 substrates—establishing FRAT1 as a substrate-selective GSK-3 inhibitor.\",\n      \"evidence\": \"Reciprocal co-immunoprecipitation of quaternary complex, FRATtide competitive binding and in vitro kinase assays with multiple GSK-3 substrates, Xenopus axis duplication assays, LEF-1 reporters\",\n      \"pmids\": [\"10428961\", \"10481074\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Upstream signal connecting Wnt receptor activation to FRAT1 recruitment unresolved\", \"Structural basis of FRATtide–GSK-3 interaction not yet determined\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Loss-of-function and gain-of-function mouse models showed that Frat1 is dispensable for normal development due to redundancy with Frat3, but its overexpression causes glomerulosclerosis and accelerates lymphomagenesis, confirming its oncogenic potential in vivo.\",\n      \"evidence\": \"Frat1-knockout mice (gene targeting), Frat1-overexpressing transgenics, bitransgenic crosses with Pim1\",\n      \"pmids\": [\"10534617\", \"10557087\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Frat1/Frat3 double knockout not yet generated to test pathway-level requirement\", \"Tissue-specific contributions of Frat family members unclear\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"CKIε was identified as the kinase that phosphorylates Dvl-1 to enhance Dvl–Frat1 complex formation, linking Wnt3a receptor activation to the mechanism by which FRAT1 is recruited into the destruction complex.\",\n      \"evidence\": \"Co-immunoprecipitation with Dvl-1 deletion mutants, CKIε RNAi knockdown, Wnt3a-stimulated β-catenin accumulation assays\",\n      \"pmids\": [\"12556519\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether CKIε is the sole kinase regulating this interaction not excluded\", \"Quantitative contribution of CKIε-dependent FRAT1 recruitment versus other Wnt-induced events unknown\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"The Wnt co-receptor LRP5 was identified as an additional FRAT1-binding partner that recruits FRAT1 to the plasma membrane upon Wnt3a stimulation, placing FRAT1 at the receptor complex and linking it to Axin degradation.\",\n      \"evidence\": \"Yeast two-hybrid screen with LRP5 cytoplasmic domain, reciprocal co-IP, dominant-negative Dvl rescue, TCF reporter assays\",\n      \"pmids\": [\"15699046\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether LRP6 similarly recruits FRAT1 not tested\", \"Relative importance of LRP5- versus Dvl-mediated FRAT1 recruitment not quantified\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"PKA was shown to phosphorylate FRAT1 at Ser188 downstream of β-adrenergic receptor signaling, identifying the first negative regulatory modification of FRAT1 that inhibits its ability to activate β-catenin-dependent transcription.\",\n      \"evidence\": \"In vitro PKA kinase assay, Ser188 mutagenesis, norepinephrine stimulation of endogenous β-adrenergic receptors, TCF reporter assays\",\n      \"pmids\": [\"16982607\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How Ser188 phosphorylation mechanistically disrupts FRAT1 function (altered GSK-3 binding vs. localization vs. stability) not resolved\", \"Physiological contexts where PKA–FRAT1 crosstalk operates in vivo not defined\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"FRAT1 was shown to drive nuclear β-catenin accumulation and cancer cell growth through TCF-dependent c-Myc expression, directly linking FRAT1's GSK-3 inhibitory mechanism to a specific transcriptional output in human cancer cells.\",\n      \"evidence\": \"Stable FRAT1 overexpression and RNAi in esophageal squamous cell carcinoma cells, GSK-3β and dominant-negative TCF4 rescue, c-Myc functional assays\",\n      \"pmids\": [\"18498136\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether c-Myc is the critical or sole effector of FRAT1-driven proliferation not established genome-wide\", \"Contribution of FRAT1 to Wnt-independent GSK-3 functions in cancer unexplored\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"NDRG1 was identified as an upstream positive regulator of FRAT1 expression that prevents GSK-3β from joining the Axin1–APC–CK1 destruction complex, revealing a regulatory input that tunes FRAT1-dependent β-catenin stabilization at the plasma membrane.\",\n      \"evidence\": \"NDRG1/FRAT1 siRNA knockdown, co-IP of GSK-3β–Axin1, Western blotting for phospho-β-catenin, subcellular fractionation\",\n      \"pmids\": [\"24829151\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which NDRG1 upregulates FRAT1 (transcriptional vs. post-translational) not determined\", \"Single-lab finding not independently replicated\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"miR-34a-3p was validated as a direct post-transcriptional repressor of FRAT1, establishing a microRNA-mediated regulatory layer on FRAT1 expression.\",\n      \"evidence\": \"Dual luciferase 3′UTR reporter with binding-site mutagenesis in meningioma cells\",\n      \"pmids\": [\"28340489\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological relevance of miR-34a-3p–FRAT1 axis beyond meningioma not shown\", \"Whether miR-34a-3p regulation of FRAT1 is sufficient to modulate Wnt output in vivo untested\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"FRAT1 was found to physically interact with FRAT2 and to be co-targeted with FRAT2 by miR-3648, which forms a negative feedback loop with c-Myc, revealing coordinated regulation of FRAT family members and a Wnt–c-Myc–miRNA circuit.\",\n      \"evidence\": \"Co-immunoprecipitation of FRAT1–FRAT2, siRNA rescue of FRAT1-driven invasion, luciferase reporter for miR-3648 targeting, ChIP for c-Myc at miR-3648 promoter in gastric cancer cells\",\n      \"pmids\": [\"36153370\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional significance of FRAT1–FRAT2 heterodimerization for GSK-3 inhibition not tested biochemically\", \"Single-lab finding in gastric cancer; generalizability to other tissues unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis of FRATtide–GSK-3 selectivity, the in vivo requirement for the entire FRAT gene family in Wnt signaling (no Frat1/Frat3 double knockout reported), and the relative contributions of LRP5-, Dvl-, and NDRG1-mediated FRAT1 recruitment in physiological Wnt activation.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No high-resolution structure of full-length FRAT1 in complex with GSK-3 or Axin\", \"Frat1/Frat3 double knockout mouse not reported\", \"Quantitative modeling of FRAT1's contribution relative to other GSK-3 inhibitory mechanisms in the Wnt pathway lacking\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [1, 2, 5, 12]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [6]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [6]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [9]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 2, 7, 9, 11, 12, 14]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [0, 4, 11, 14]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"GSK3B\",\n      \"DVL1\",\n      \"AXIN1\",\n      \"LRP5\",\n      \"FRAT2\",\n      \"CSNK1E\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}