{"gene":"FRAT2","run_date":"2026-06-09T23:54:44","timeline":{"discoveries":[{"year":2001,"finding":"FRAT2 encodes a 233-amino-acid protein that positively regulates the WNT signaling pathway. Wild-type FRAT2 mRNA, but not a mutant lacking the acidic domain and proline-rich domain, induced secondary axis formation in Xenopus, demonstrating that these domains are required for WNT pathway activation. The GSK-3β binding domain of FRAT2 is 100% identical to that of FRAT1.","method":"Xenopus axis duplication assay, domain deletion mutagenesis, cDNA cloning and sequence analysis","journal":"Biochemical and biophysical research communications","confidence":"High","confidence_rationale":"Tier 1 / Moderate — functional in vivo assay (Xenopus axis duplication) combined with domain deletion mutagenesis establishing specific domain requirements","pmids":["11237732"],"is_preprint":false},{"year":2002,"finding":"Human FRAT2 protein binds to GSK-3 (glycogen synthase kinase-3) and Dishevelled, two proteins involved in Wnt signal transduction. When transiently overexpressed in COS-1 cells, FRAT2 protein localizes to the cytosol and is concentrated in the nucleus.","method":"Co-immunoprecipitation, transient transfection, subcellular fractionation/localization","journal":"Gene","confidence":"Medium","confidence_rationale":"Tier 2–3 / Weak — single lab, binding inferred from overexpression in COS-1 cells; localization established by direct experiment but without functional consequence dissection","pmids":["12095675"],"is_preprint":false},{"year":2004,"finding":"Murine Frat2 binds to GSK3β (demonstrated by side-by-side comparison with Frat1 and Frat3). Frat2 is phosphorylated (first evidence of post-translational modification of Frat proteins). However, Frat2 is a less potent activator of the canonical Wnt/β-catenin/TCF pathway than Frat1, suggesting it may function in a divergent GSK3β pathway rather than as a core canonical Wnt component.","method":"Co-immunoprecipitation (GSK3β binding), β-catenin/TCF reporter assay (side-by-side comparison), phosphorylation detection by transfection into 293T cells","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — multiple orthogonal assays (Co-IP, reporter assay, phosphorylation) in a single focused mechanistic study with direct side-by-side comparisons","pmids":["15073180"],"is_preprint":false},{"year":2004,"finding":"FRAT-2 selectively enhances GSK3β-mediated phosphorylation of primed substrates (including tau at a primed epitope) but does not significantly affect phosphorylation of unprimed substrates, both in cell-based assays and in vitro with recombinant proteins. Co-immunoprecipitation confirmed that FRAT-2 associates with GSK3β and that this association increases phosphorylation of primed but not unprimed substrates. Additionally, FRAT-2 is itself phosphorylated by GSK3β.","method":"In vitro kinase assay with recombinant proteins, co-immunoprecipitation, cell-based phosphorylation assays, site-specific phospho-antibodies","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with recombinant proteins plus co-IP and cell-based assays, multiple orthogonal methods in single study establishing a distinct substrate selectivity mechanism","pmids":["15522877"],"is_preprint":false},{"year":2012,"finding":"FRAT2 mediates MLL fusion oncogene-driven activation of Rac GTPases in leukemia. MLL fusions maintain leukemia-associated Rac activity by upregulating Frat2 expression. Modulation of FRAT2 levels causes concomitant changes in Rac activity. Transformation of Frat knockout hematopoietic progenitor cells by MLL fusions produces leukemias with reduced Rac activation and increased chemotherapy sensitivity. FRAT2 activates Rac through a mechanism requiring GSK3 and DVL (Dishevelled); disruption of this pathway abrogates MLL fusion leukemogenic activity.","method":"Genetic knockout (Frat KO mouse), retroviral transformation assay, Rac activity assays, epistasis analysis with GSK3/DVL pathway inhibition, in vivo leukemia model","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean genetic KO with defined cellular and in vivo phenotype, Rac activity measured directly, epistasis with GSK3/DVL establishes pathway position, multiple orthogonal approaches in one focused study","pmids":["23074275"],"is_preprint":false},{"year":2020,"finding":"TMEM98 physically interacts with FRAT2 (as interaction partner), reduces FRAT2 protein levels, and thereby inhibits FRAT2-mediated induction of β-catenin/TCF signaling, acting as a negative regulator of FRAT-mediated Wnt/β-catenin signaling. TMEM98 itself is recycled between the plasma membrane and the Golgi.","method":"Co-immunoprecipitation (interaction), β-catenin/TCF reporter assay (functional inhibition), protein level quantification, subcellular localization/trafficking assays","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2–3 / Weak — single lab, co-IP plus reporter assay establish interaction and functional consequence, but single study without independent replication","pmids":["31961879"],"is_preprint":false},{"year":2022,"finding":"FRAT1 and FRAT2 physically interact with each other. miR-3648 directly targets FRAT1 and FRAT2 mRNAs, suppressing their expression and consequently inactivating the Wnt/β-catenin signaling pathway. Overexpression of FRAT1 promotes gastric cancer cell invasion, and siRNA-mediated knockdown of FRAT2 in FRAT1-overexpressing cells reverses the invasive potential, indicating that FRAT2 is required for FRAT1-mediated invasion.","method":"Co-immunoprecipitation (FRAT1-FRAT2 interaction), luciferase reporter assay (miR-3648 direct targeting), siRNA knockdown, invasion assays in vitro and in vivo","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — reciprocal functional assays (Co-IP, reporter, KD rescue), single lab, multiple orthogonal methods","pmids":["36153370"],"is_preprint":false}],"current_model":"FRAT2 is a GSK3β-binding protein that positively regulates the Wnt/β-catenin signaling pathway by associating with GSK3β and Dishevelled; it selectively enhances GSK3β phosphorylation of primed substrates (including tau), is itself phosphorylated by GSK3β, physically interacts with FRAT1, and in the context of MLL fusion oncogenes activates Rac GTPases through a GSK3/DVL-dependent mechanism; its activity is negatively regulated by TMEM98, which reduces FRAT2 protein levels and inhibits β-catenin/TCF signaling."},"narrative":{"mechanistic_narrative":"FRAT2 is a positive regulator of Wnt/β-catenin signaling that acts as a GSK3β-binding adaptor, with its acidic and proline-rich domains required for pathway activation, as shown by its ability to induce secondary axis formation in Xenopus [PMID:11237732]. It binds GSK3β and Dishevelled and localizes to both cytosol and nucleus [PMID:12095675, PMID:15073180], and rather than simply inhibiting the kinase it selectively enhances GSK3β-mediated phosphorylation of primed substrates such as tau while sparing unprimed substrates; FRAT2 is itself a GSK3β substrate, defining a reciprocal kinase–adaptor relationship [PMID:15522877]. FRAT2 is a comparatively weak activator of canonical β-catenin/TCF signaling, consistent with a partly divergent GSK3β function [PMID:15073180], and in leukemia it links MLL fusion oncogenes to Rac GTPase activation through a GSK3- and DVL-dependent mechanism, where Frat2 loss reduces Rac activity and abrogates MLL-driven leukemogenesis [PMID:23074275]. FRAT2 physically associates with its paralog FRAT1 and is required for FRAT1-driven cancer cell invasion [PMID:36153370], while its activity is negatively constrained by TMEM98, which binds FRAT2 and lowers its protein levels to dampen β-catenin/TCF signaling [PMID:31961879].","teleology":[{"year":2001,"claim":"Established FRAT2 as a positive Wnt-pathway regulator and mapped the protein domains needed for that activity, addressing whether FRAT2 functions in Wnt signal transduction at all.","evidence":"Xenopus axis duplication assay with domain-deletion FRAT2 mutants and cDNA sequence analysis","pmids":["11237732"],"confidence":"High","gaps":["Did not identify the direct molecular partner mediating activation","Mechanism downstream of the acidic/proline-rich domains undefined"]},{"year":2002,"claim":"Identified the physical partners of FRAT2 within the Wnt machinery, answering which signaling proteins FRAT2 engages.","evidence":"Co-immunoprecipitation of GSK-3 and Dishevelled and subcellular localization in transfected COS-1 cells","pmids":["12095675"],"confidence":"Medium","gaps":["Binding inferred from overexpression without reciprocal endogenous validation","Functional consequence of nuclear localization not dissected"]},{"year":2004,"claim":"Resolved whether FRAT2 is a core canonical Wnt component or a divergent GSK3β effector, and revealed FRAT2 as a phosphoprotein.","evidence":"Co-IP for GSK3β binding, β-catenin/TCF reporter side-by-side with Frat1/Frat3, and phosphorylation detection in 293T cells","pmids":["15073180"],"confidence":"High","gaps":["Kinase responsible for Frat2 phosphorylation not pinned down here","Nature of the divergent GSK3β pathway unspecified"]},{"year":2004,"claim":"Defined the biochemical mechanism of FRAT2 action on GSK3β — substrate-priming-dependent enhancement — rather than simple kinase inhibition.","evidence":"In vitro kinase assays with recombinant proteins, co-IP, and primed/unprimed phospho-substrate (including tau) readouts with site-specific antibodies","pmids":["15522877"],"confidence":"High","gaps":["Physiological substrates beyond tau not enumerated","Structural basis of priming selectivity unresolved"]},{"year":2012,"claim":"Connected FRAT2 to oncogenic Rac signaling, establishing its requirement for MLL-fusion leukemogenesis through a GSK3/DVL-dependent route.","evidence":"Frat knockout mouse hematopoietic progenitors, retroviral MLL-fusion transformation, direct Rac activity assays, GSK3/DVL epistasis, and in vivo leukemia model","pmids":["23074275"],"confidence":"High","gaps":["Molecular link from FRAT2/GSK3/DVL to specific Rac GEFs unknown","Whether β-catenin is involved in the Rac arm not resolved"]},{"year":2020,"claim":"Identified a negative regulator of FRAT2, answering how FRAT2 protein levels and downstream Wnt output are constrained.","evidence":"Co-IP of TMEM98 with FRAT2, FRAT2 protein-level quantification, β-catenin/TCF reporter assay, and TMEM98 trafficking assays","pmids":["31961879"],"confidence":"Medium","gaps":["Mechanism by which TMEM98 lowers FRAT2 levels (degradation vs. stability) not defined","Single lab without independent replication"]},{"year":2022,"claim":"Demonstrated FRAT1–FRAT2 heteromeric interaction and a microRNA control point, placing FRAT2 as a required effector of FRAT1-driven cancer invasion.","evidence":"Co-IP of FRAT1 with FRAT2, miR-3648 luciferase targeting, siRNA knockdown rescue, and invasion assays in vitro and in vivo","pmids":["36153370"],"confidence":"Medium","gaps":["Whether the FRAT1–FRAT2 complex acts through GSK3β in this context not tested","Stoichiometry and functional role of the heterocomplex undefined"]},{"year":null,"claim":"How FRAT2 partitions between its canonical β-catenin/TCF, divergent GSK3β, and Rac-activating functions, and how these are coordinated by partner availability and post-translational control, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structure of FRAT2 bound to GSK3β or DVL","Endogenous regulation of FRAT2 phosphorylation not characterized","Determinants selecting canonical vs. Rac outputs unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[3]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[2,3]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[1,4]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[1]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,2,4]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[4,6]}],"complexes":[],"partners":["GSK3B","DVL","FRAT1","TMEM98"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O75474","full_name":"GSK-3-binding protein FRAT2","aliases":["Frequently rearranged in advanced T-cell lymphomas 2","FRAT-2"],"length_aa":233,"mass_kda":24.1,"function":"Positively regulates the Wnt signaling pathway by stabilizing beta-catenin through the association with GSK-3","subcellular_location":"","url":"https://www.uniprot.org/uniprotkb/O75474/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/FRAT2","classification":"Not Classified","n_dependent_lines":46,"n_total_lines":1208,"dependency_fraction":0.0380794701986755},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/FRAT2","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"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Mitochondria","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/FRAT2"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"O75474","domains":[{"cath_id":"-","chopping":"177-203","consensus_level":"medium","plddt":95.663,"start":177,"end":203}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O75474","model_url":"https://alphafold.ebi.ac.uk/files/AF-O75474-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O75474-F1-predicted_aligned_error_v6.png","plddt_mean":62.12},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=FRAT2","jax_strain_url":"https://www.jax.org/strain/search?query=FRAT2"},"sequence":{"accession":"O75474","fasta_url":"https://rest.uniprot.org/uniprotkb/O75474.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O75474/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O75474"}},"corpus_meta":[{"pmid":"17873379","id":"PMC_17873379","title":"Networking of WNT, FGF, Notch, BMP, and Hedgehog 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signaling pathway. Wild-type FRAT2 mRNA, but not a mutant lacking the acidic domain and proline-rich domain, induced secondary axis formation in Xenopus, demonstrating that these domains are required for WNT pathway activation. The GSK-3β binding domain of FRAT2 is 100% identical to that of FRAT1.\",\n      \"method\": \"Xenopus axis duplication assay, domain deletion mutagenesis, cDNA cloning and sequence analysis\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — functional in vivo assay (Xenopus axis duplication) combined with domain deletion mutagenesis establishing specific domain requirements\",\n      \"pmids\": [\"11237732\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Human FRAT2 protein binds to GSK-3 (glycogen synthase kinase-3) and Dishevelled, two proteins involved in Wnt signal transduction. When transiently overexpressed in COS-1 cells, FRAT2 protein localizes to the cytosol and is concentrated in the nucleus.\",\n      \"method\": \"Co-immunoprecipitation, transient transfection, subcellular fractionation/localization\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Weak — single lab, binding inferred from overexpression in COS-1 cells; localization established by direct experiment but without functional consequence dissection\",\n      \"pmids\": [\"12095675\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Murine Frat2 binds to GSK3β (demonstrated by side-by-side comparison with Frat1 and Frat3). Frat2 is phosphorylated (first evidence of post-translational modification of Frat proteins). However, Frat2 is a less potent activator of the canonical Wnt/β-catenin/TCF pathway than Frat1, suggesting it may function in a divergent GSK3β pathway rather than as a core canonical Wnt component.\",\n      \"method\": \"Co-immunoprecipitation (GSK3β binding), β-catenin/TCF reporter assay (side-by-side comparison), phosphorylation detection by transfection into 293T cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — multiple orthogonal assays (Co-IP, reporter assay, phosphorylation) in a single focused mechanistic study with direct side-by-side comparisons\",\n      \"pmids\": [\"15073180\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"FRAT-2 selectively enhances GSK3β-mediated phosphorylation of primed substrates (including tau at a primed epitope) but does not significantly affect phosphorylation of unprimed substrates, both in cell-based assays and in vitro with recombinant proteins. Co-immunoprecipitation confirmed that FRAT-2 associates with GSK3β and that this association increases phosphorylation of primed but not unprimed substrates. Additionally, FRAT-2 is itself phosphorylated by GSK3β.\",\n      \"method\": \"In vitro kinase assay with recombinant proteins, co-immunoprecipitation, cell-based phosphorylation assays, site-specific phospho-antibodies\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with recombinant proteins plus co-IP and cell-based assays, multiple orthogonal methods in single study establishing a distinct substrate selectivity mechanism\",\n      \"pmids\": [\"15522877\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"FRAT2 mediates MLL fusion oncogene-driven activation of Rac GTPases in leukemia. MLL fusions maintain leukemia-associated Rac activity by upregulating Frat2 expression. Modulation of FRAT2 levels causes concomitant changes in Rac activity. Transformation of Frat knockout hematopoietic progenitor cells by MLL fusions produces leukemias with reduced Rac activation and increased chemotherapy sensitivity. FRAT2 activates Rac through a mechanism requiring GSK3 and DVL (Dishevelled); disruption of this pathway abrogates MLL fusion leukemogenic activity.\",\n      \"method\": \"Genetic knockout (Frat KO mouse), retroviral transformation assay, Rac activity assays, epistasis analysis with GSK3/DVL pathway inhibition, in vivo leukemia model\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic KO with defined cellular and in vivo phenotype, Rac activity measured directly, epistasis with GSK3/DVL establishes pathway position, multiple orthogonal approaches in one focused study\",\n      \"pmids\": [\"23074275\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TMEM98 physically interacts with FRAT2 (as interaction partner), reduces FRAT2 protein levels, and thereby inhibits FRAT2-mediated induction of β-catenin/TCF signaling, acting as a negative regulator of FRAT-mediated Wnt/β-catenin signaling. TMEM98 itself is recycled between the plasma membrane and the Golgi.\",\n      \"method\": \"Co-immunoprecipitation (interaction), β-catenin/TCF reporter assay (functional inhibition), protein level quantification, subcellular localization/trafficking assays\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Weak — single lab, co-IP plus reporter assay establish interaction and functional consequence, but single study without independent replication\",\n      \"pmids\": [\"31961879\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"FRAT1 and FRAT2 physically interact with each other. miR-3648 directly targets FRAT1 and FRAT2 mRNAs, suppressing their expression and consequently inactivating the Wnt/β-catenin signaling pathway. Overexpression of FRAT1 promotes gastric cancer cell invasion, and siRNA-mediated knockdown of FRAT2 in FRAT1-overexpressing cells reverses the invasive potential, indicating that FRAT2 is required for FRAT1-mediated invasion.\",\n      \"method\": \"Co-immunoprecipitation (FRAT1-FRAT2 interaction), luciferase reporter assay (miR-3648 direct targeting), siRNA knockdown, invasion assays in vitro and in vivo\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — reciprocal functional assays (Co-IP, reporter, KD rescue), single lab, multiple orthogonal methods\",\n      \"pmids\": [\"36153370\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"FRAT2 is a GSK3β-binding protein that positively regulates the Wnt/β-catenin signaling pathway by associating with GSK3β and Dishevelled; it selectively enhances GSK3β phosphorylation of primed substrates (including tau), is itself phosphorylated by GSK3β, physically interacts with FRAT1, and in the context of MLL fusion oncogenes activates Rac GTPases through a GSK3/DVL-dependent mechanism; its activity is negatively regulated by TMEM98, which reduces FRAT2 protein levels and inhibits β-catenin/TCF signaling.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"FRAT2 is a positive regulator of Wnt/\\u03b2-catenin signaling that acts as a GSK3\\u03b2-binding adaptor, with its acidic and proline-rich domains required for pathway activation, as shown by its ability to induce secondary axis formation in Xenopus [#0]. It binds GSK3\\u03b2 and Dishevelled and localizes to both cytosol and nucleus [#1, #2], and rather than simply inhibiting the kinase it selectively enhances GSK3\\u03b2-mediated phosphorylation of primed substrates such as tau while sparing unprimed substrates; FRAT2 is itself a GSK3\\u03b2 substrate, defining a reciprocal kinase\\u2013adaptor relationship [#3]. FRAT2 is a comparatively weak activator of canonical \\u03b2-catenin/TCF signaling, consistent with a partly divergent GSK3\\u03b2 function [#2], and in leukemia it links MLL fusion oncogenes to Rac GTPase activation through a GSK3- and DVL-dependent mechanism, where Frat2 loss reduces Rac activity and abrogates MLL-driven leukemogenesis [#4]. FRAT2 physically associates with its paralog FRAT1 and is required for FRAT1-driven cancer cell invasion [#6], while its activity is negatively constrained by TMEM98, which binds FRAT2 and lowers its protein levels to dampen \\u03b2-catenin/TCF signaling [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Established FRAT2 as a positive Wnt-pathway regulator and mapped the protein domains needed for that activity, addressing whether FRAT2 functions in Wnt signal transduction at all.\",\n      \"evidence\": \"Xenopus axis duplication assay with domain-deletion FRAT2 mutants and cDNA sequence analysis\",\n      \"pmids\": [\"11237732\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify the direct molecular partner mediating activation\", \"Mechanism downstream of the acidic/proline-rich domains undefined\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Identified the physical partners of FRAT2 within the Wnt machinery, answering which signaling proteins FRAT2 engages.\",\n      \"evidence\": \"Co-immunoprecipitation of GSK-3 and Dishevelled and subcellular localization in transfected COS-1 cells\",\n      \"pmids\": [\"12095675\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Binding inferred from overexpression without reciprocal endogenous validation\", \"Functional consequence of nuclear localization not dissected\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Resolved whether FRAT2 is a core canonical Wnt component or a divergent GSK3\\u03b2 effector, and revealed FRAT2 as a phosphoprotein.\",\n      \"evidence\": \"Co-IP for GSK3\\u03b2 binding, \\u03b2-catenin/TCF reporter side-by-side with Frat1/Frat3, and phosphorylation detection in 293T cells\",\n      \"pmids\": [\"15073180\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinase responsible for Frat2 phosphorylation not pinned down here\", \"Nature of the divergent GSK3\\u03b2 pathway unspecified\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Defined the biochemical mechanism of FRAT2 action on GSK3\\u03b2 \\u2014 substrate-priming-dependent enhancement \\u2014 rather than simple kinase inhibition.\",\n      \"evidence\": \"In vitro kinase assays with recombinant proteins, co-IP, and primed/unprimed phospho-substrate (including tau) readouts with site-specific antibodies\",\n      \"pmids\": [\"15522877\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological substrates beyond tau not enumerated\", \"Structural basis of priming selectivity unresolved\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Connected FRAT2 to oncogenic Rac signaling, establishing its requirement for MLL-fusion leukemogenesis through a GSK3/DVL-dependent route.\",\n      \"evidence\": \"Frat knockout mouse hematopoietic progenitors, retroviral MLL-fusion transformation, direct Rac activity assays, GSK3/DVL epistasis, and in vivo leukemia model\",\n      \"pmids\": [\"23074275\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular link from FRAT2/GSK3/DVL to specific Rac GEFs unknown\", \"Whether \\u03b2-catenin is involved in the Rac arm not resolved\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Identified a negative regulator of FRAT2, answering how FRAT2 protein levels and downstream Wnt output are constrained.\",\n      \"evidence\": \"Co-IP of TMEM98 with FRAT2, FRAT2 protein-level quantification, \\u03b2-catenin/TCF reporter assay, and TMEM98 trafficking assays\",\n      \"pmids\": [\"31961879\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which TMEM98 lowers FRAT2 levels (degradation vs. stability) not defined\", \"Single lab without independent replication\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Demonstrated FRAT1\\u2013FRAT2 heteromeric interaction and a microRNA control point, placing FRAT2 as a required effector of FRAT1-driven cancer invasion.\",\n      \"evidence\": \"Co-IP of FRAT1 with FRAT2, miR-3648 luciferase targeting, siRNA knockdown rescue, and invasion assays in vitro and in vivo\",\n      \"pmids\": [\"36153370\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether the FRAT1\\u2013FRAT2 complex acts through GSK3\\u03b2 in this context not tested\", \"Stoichiometry and functional role of the heterocomplex undefined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How FRAT2 partitions between its canonical \\u03b2-catenin/TCF, divergent GSK3\\u03b2, and Rac-activating functions, and how these are coordinated by partner availability and post-translational control, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structure of FRAT2 bound to GSK3\\u03b2 or DVL\", \"Endogenous regulation of FRAT2 phosphorylation not characterized\", \"Determinants selecting canonical vs. Rac outputs unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [1, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 2, 4]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [4, 6]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"GSK3B\", \"DVL\", \"FRAT1\", \"TMEM98\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":4,"faith_total":4,"faith_pct":100.0}}