{"gene":"GFRA2","run_date":"2026-06-10T01:55:21","timeline":{"discoveries":[{"year":1997,"finding":"TrnR2 (GFRA2) is a GPI-linked cell-surface receptor that mediates both neurturin (NTN) and GDNF signaling through the RET receptor tyrosine kinase; the TrnR2-RET complex is approximately 30-fold more sensitive to NTN than to GDNF, establishing TrnR2 as the preferred co-receptor for neurturin.","method":"In vitro cell signaling assays using fibroblasts co-expressing TrnR2 and RET; GPI-linkage characterization; comparison with TrnR1-expressing cells","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — direct functional reconstitution in vitro with defined receptor pairs, ligand dose-response comparison, GPI-linkage characterization; foundational paper replicated by subsequent work","pmids":["9182803"],"is_preprint":false},{"year":2018,"finding":"Crystal structure of the full-length neurturin–GFRα2 complex reveals that GFRα2 domain 1 does not contact neurturin directly but presents a conserved surface that may interact with RET and/or NCAM. A heparan sulfate-binding site was identified on neurturin and a putative site on GFRα2, implicating heparan sulfate in assembly of the signaling complex. Relative GFRα2 surface concentration modulates functional affinity of neurturin via avidity effects.","method":"X-ray crystallography of NRTN alone and in complex with GFRα2; biophysical binding assays; mutagenesis of heparan sulfate-binding site; in vivo pharmacokinetic experiments with heparan sulfate-binding mutant NRTN","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure with functional validation (mutagenesis, biophysical assays, in vivo), single lab but multiple orthogonal methods","pmids":["29414779"],"is_preprint":false},{"year":2016,"finding":"GFRA2 marks cardiac progenitor cells and mediates cardiomyocyte differentiation through a RET-independent signaling pathway, distinct from the canonical neurturin/GDNF-RET axis.","method":"FACS isolation of GFRA2+ cardiac progenitors from mouse and human pluripotent stem cells; Gfra2 genetic knockout with in vitro and in vivo cardiomyocyte differentiation phenotype readouts; pathway analysis distinguishing RET-dependent vs. RET-independent signaling","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean genetic KO with defined cellular phenotype, FACS-based isolation, in vitro and in vivo validation, single lab","pmids":["27396331"],"is_preprint":false},{"year":2025,"finding":"Neurturin binding to GFRA2 on pancreatic cancer cells induces RET kinase recruitment and heterodimer assembly; the resulting receptor tyrosine kinase complex phosphorylates hexokinase 2 (HK2) at Ser122, enhancing its enzymatic activity and driving aerobic glycolysis to fuel tumor growth.","method":"Integrated metabolomics; co-immunoprecipitation of GFRA2-RET complex; in vitro kinase assays showing HK2 Ser122 phosphorylation; HK2 activity assays; in vivo tumor models with neurturin blockade and RET inhibitor combination","journal":"Cancer letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP of receptor complex, in vitro kinase/activity assays, in vivo validation, single lab with multiple methods","pmids":["39988080"],"is_preprint":false}],"current_model":"GFRA2 is a GPI-anchored cell-surface co-receptor that preferentially binds neurturin (over GDNF) and recruits the RET receptor tyrosine kinase to activate downstream signaling; the crystal structure shows its three-domain architecture, with domain 1 not contacting neurturin but potentially engaging RET/NCAM, and heparan sulfate contributing to complex assembly. Beyond the canonical RET-dependent neurturin pathway, GFRA2 also signals through a RET-independent route to drive cardiomyocyte differentiation, and in pancreatic cancer cells the GFRA2-RET complex phosphorylates hexokinase 2 at Ser122 to enhance glycolysis."},"narrative":{"mechanistic_narrative":"GFRA2 is a GPI-anchored cell-surface co-receptor that mediates neurotrophic factor signaling by preferentially binding neurturin and recruiting the RET receptor tyrosine kinase to assemble an active signaling complex [PMID:9182803]. Reconstitution in cells co-expressing GFRA2 and RET shows the complex responds to both neurturin and GDNF but is roughly 30-fold more sensitive to neurturin, establishing GFRA2 as the preferred neurturin co-receptor [PMID:9182803]. The crystal structure of the neurturin–GFRA2 complex resolves a three-domain architecture in which domain 1 makes no direct contact with neurturin but presents a conserved surface positioned to engage RET and/or NCAM, and identifies heparan sulfate-binding sites on both neurturin and GFRA2 that contribute to assembly and to avidity-driven modulation of functional ligand affinity by GFRA2 surface concentration [PMID:29414779]. Beyond the canonical RET pathway, GFRA2 marks cardiac progenitor cells and drives cardiomyocyte differentiation through a RET-independent route [PMID:27396331], and in pancreatic cancer cells neurturin-bound GFRA2 recruits RET to form a heterodimer that phosphorylates hexokinase 2 at Ser122, boosting its activity to enhance aerobic glycolysis and fuel tumor growth [PMID:39988080].","teleology":[{"year":1997,"claim":"Established that GFRA2 is the molecular co-receptor that confers neurturin responsiveness on RET, resolving how this ligand activates the RET tyrosine kinase.","evidence":"In vitro signaling reconstitution in fibroblasts co-expressing TrnR2 (GFRA2) and RET, with ligand dose-response comparison and GPI-linkage characterization","pmids":["9182803"],"confidence":"High","gaps":["Structural basis of GFRA2-RET assembly not resolved here","Does not address GFRA2 signaling independent of RET","Downstream signaling effectors not identified"]},{"year":2016,"claim":"Revealed a RET-independent function for GFRA2, showing it marks cardiac progenitors and drives cardiomyocyte differentiation beyond the canonical neurturin/GDNF-RET axis.","evidence":"FACS isolation of GFRA2+ cardiac progenitors from mouse and human pluripotent stem cells with Gfra2 knockout and in vitro/in vivo differentiation readouts","pmids":["27396331"],"confidence":"Medium","gaps":["Identity of the RET-independent signaling partner/transducer unknown","Ligand driving this pathway not defined","Single lab; mechanism downstream of GFRA2 uncharacterized"]},{"year":2018,"claim":"Defined the structural architecture of the neurturin–GFRA2 complex and implicated heparan sulfate in complex assembly, explaining how GFRA2 surface density tunes functional ligand affinity.","evidence":"X-ray crystallography of NRTN alone and in complex with GFRA2, biophysical binding assays, heparan sulfate-binding mutagenesis, and in vivo pharmacokinetics with a binding mutant","pmids":["29414779"],"confidence":"High","gaps":["Direct domain 1 contact with RET/NCAM inferred but not structurally captured","Full ternary GFRA2-NRTN-RET complex structure not solved","Functional consequence of avidity tuning in vivo not fully mapped"]},{"year":2025,"claim":"Connected GFRA2-RET signaling to tumor metabolism by identifying hexokinase 2 Ser122 as a substrate, linking neurturin signaling to enhanced glycolysis in pancreatic cancer.","evidence":"Co-immunoprecipitation of the GFRA2-RET complex, in vitro kinase and HK2 activity assays, integrated metabolomics, and in vivo tumor models with neurturin blockade and RET inhibition","pmids":["39988080"],"confidence":"Medium","gaps":["Whether RET directly phosphorylates HK2 versus via an intermediary kinase not fully resolved","Single lab; generality across cancer types untested","Reciprocal validation of the receptor complex limited"]},{"year":null,"claim":"The molecular identity and mechanism of the RET-independent GFRA2 signaling route remain undefined.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No transducer identified for RET-independent signaling","Ligand requirement for the cardiac differentiation pathway unknown","No structure of the assembled GFRA2-NRTN-RET ternary complex"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[0,1]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[0,3]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,1]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,3]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[2]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[3]}],"complexes":["GFRA2-RET co-receptor complex"],"partners":["RET","NRTN","GDNF","HK2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O00451","full_name":"GDNF family receptor alpha-2","aliases":["GDNF receptor beta","GDNFR-beta","Neurturin receptor alpha","NRTNR-alpha","NTNR-alpha","RET ligand 2","TGF-beta-related neurotrophic factor receptor 2"],"length_aa":464,"mass_kda":51.5,"function":"Receptor for neurturin (NRTN), a growth factor that supports the survival of sympathetic neurons (PubMed:10829012, PubMed:29414779, PubMed:31535977, PubMed:9182803). NRTN-binding leads to autophosphorylation and activation of the RET receptor (PubMed:31535977). Also able to mediate GDNF signaling through the RET tyrosine kinase receptor (PubMed:9182803) Participates in NRTN-induced 'Ser-727' phosphorylation of STAT3","subcellular_location":"Cell membrane","url":"https://www.uniprot.org/uniprotkb/O00451/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/GFRA2","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/GFRA2","total_profiled":1310},"omim":[{"mim_id":"605710","title":"GDNF FAMILY RECEPTOR ALPHA-3; GFRA3","url":"https://www.omim.org/entry/605710"},{"mim_id":"601956","title":"GDNF FAMILY RECEPTOR ALPHA-2; GFRA2","url":"https://www.omim.org/entry/601956"},{"mim_id":"601496","title":"GDNF FAMILY RECEPTOR ALPHA-1; GFRA1","url":"https://www.omim.org/entry/601496"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Plasma membrane","reliability":"Approved"},{"location":"Vesicles","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"testis","ntpm":9.0},{"tissue":"thyroid gland","ntpm":8.2}],"url":"https://www.proteinatlas.org/search/GFRA2"},"hgnc":{"alias_symbol":["RETL2","GDNFRB","NTNRA","TRNR2"],"prev_symbol":[]},"alphafold":{"accession":"O00451","domains":[{"cath_id":"-","chopping":"41-118","consensus_level":"high","plddt":88.8301,"start":41,"end":118},{"cath_id":"1.10.220.110","chopping":"136-140_159-358","consensus_level":"medium","plddt":94.9121,"start":136,"end":358}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O00451","model_url":"https://alphafold.ebi.ac.uk/files/AF-O00451-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O00451-F1-predicted_aligned_error_v6.png","plddt_mean":75.0},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GFRA2","jax_strain_url":"https://www.jax.org/strain/search?query=GFRA2"},"sequence":{"accession":"O00451","fasta_url":"https://rest.uniprot.org/uniprotkb/O00451.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O00451/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O00451"}},"corpus_meta":[{"pmid":"9182803","id":"PMC_9182803","title":"TrnR2, a novel receptor that mediates neurturin and GDNF signaling through Ret.","date":"1997","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/9182803","citation_count":305,"is_preprint":false},{"pmid":"30250203","id":"PMC_30250203","title":"GWAS and eQTL analysis identifies a SNP associated with both residual feed intake and GFRA2 expression in beef cattle.","date":"2018","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/30250203","citation_count":47,"is_preprint":false},{"pmid":"29414779","id":"PMC_29414779","title":"Structure and biophysical characterization of the human full-length neurturin-GFRa2 complex: A role for heparan sulfate in signaling.","date":"2018","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/29414779","citation_count":30,"is_preprint":false},{"pmid":"27396331","id":"PMC_27396331","title":"GFRA2 Identifies Cardiac Progenitors and Mediates Cardiomyocyte Differentiation in a RET-Independent Signaling Pathway.","date":"2016","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/27396331","citation_count":24,"is_preprint":false},{"pmid":"11409869","id":"PMC_11409869","title":"Cloning and characterization of the human GFRA2 locus and investigation of the gene in Hirschsprung disease.","date":"2001","source":"Human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/11409869","citation_count":15,"is_preprint":false},{"pmid":"16140423","id":"PMC_16140423","title":"Age-related alteration of neurturin receptor GFRa2 and nNOS in pelvic ganglia.","date":"2005","source":"Neurobiology of aging","url":"https://pubmed.ncbi.nlm.nih.gov/16140423","citation_count":14,"is_preprint":false},{"pmid":"12490080","id":"PMC_12490080","title":"Evaluation of germline sequence variants of GFRA1, GFRA2, and GFRA3 genes in a cohort of Spanish patients with sporadic medullary thyroid cancer.","date":"2002","source":"Thyroid : official journal of the American Thyroid Association","url":"https://pubmed.ncbi.nlm.nih.gov/12490080","citation_count":14,"is_preprint":false},{"pmid":"20369355","id":"PMC_20369355","title":"Glial cell line-derived neurotrophic factor receptor alpha 2 (GFRA2) gene is associated with tardive dyskinesia.","date":"2010","source":"Psychopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/20369355","citation_count":7,"is_preprint":false},{"pmid":"39988080","id":"PMC_39988080","title":"Neurturin-induced activation of GFRA2-RET axis potentiates pancreatic cancer glycolysis via phosphorylated hexokinase 2.","date":"2025","source":"Cancer letters","url":"https://pubmed.ncbi.nlm.nih.gov/39988080","citation_count":4,"is_preprint":false},{"pmid":"41622043","id":"PMC_41622043","title":"Exploratory genome-wide analysis suggests potential associations of PPP1R12B, FSTL5, G5K3B, and GFRA2 loci with a derived HDL functionality score.","date":"2026","source":"Journal of clinical lipidology","url":"https://pubmed.ncbi.nlm.nih.gov/41622043","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7002,"output_tokens":1256,"usd":0.019923,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":7890,"output_tokens":2176,"usd":0.046925,"stage2_stop_reason":"end_turn"},"total_usd":0.066848,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1997,\n      \"finding\": \"TrnR2 (GFRA2) is a GPI-linked cell-surface receptor that mediates both neurturin (NTN) and GDNF signaling through the RET receptor tyrosine kinase; the TrnR2-RET complex is approximately 30-fold more sensitive to NTN than to GDNF, establishing TrnR2 as the preferred co-receptor for neurturin.\",\n      \"method\": \"In vitro cell signaling assays using fibroblasts co-expressing TrnR2 and RET; GPI-linkage characterization; comparison with TrnR1-expressing cells\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — direct functional reconstitution in vitro with defined receptor pairs, ligand dose-response comparison, GPI-linkage characterization; foundational paper replicated by subsequent work\",\n      \"pmids\": [\"9182803\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Crystal structure of the full-length neurturin–GFRα2 complex reveals that GFRα2 domain 1 does not contact neurturin directly but presents a conserved surface that may interact with RET and/or NCAM. A heparan sulfate-binding site was identified on neurturin and a putative site on GFRα2, implicating heparan sulfate in assembly of the signaling complex. Relative GFRα2 surface concentration modulates functional affinity of neurturin via avidity effects.\",\n      \"method\": \"X-ray crystallography of NRTN alone and in complex with GFRα2; biophysical binding assays; mutagenesis of heparan sulfate-binding site; in vivo pharmacokinetic experiments with heparan sulfate-binding mutant NRTN\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure with functional validation (mutagenesis, biophysical assays, in vivo), single lab but multiple orthogonal methods\",\n      \"pmids\": [\"29414779\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"GFRA2 marks cardiac progenitor cells and mediates cardiomyocyte differentiation through a RET-independent signaling pathway, distinct from the canonical neurturin/GDNF-RET axis.\",\n      \"method\": \"FACS isolation of GFRA2+ cardiac progenitors from mouse and human pluripotent stem cells; Gfra2 genetic knockout with in vitro and in vivo cardiomyocyte differentiation phenotype readouts; pathway analysis distinguishing RET-dependent vs. RET-independent signaling\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic KO with defined cellular phenotype, FACS-based isolation, in vitro and in vivo validation, single lab\",\n      \"pmids\": [\"27396331\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Neurturin binding to GFRA2 on pancreatic cancer cells induces RET kinase recruitment and heterodimer assembly; the resulting receptor tyrosine kinase complex phosphorylates hexokinase 2 (HK2) at Ser122, enhancing its enzymatic activity and driving aerobic glycolysis to fuel tumor growth.\",\n      \"method\": \"Integrated metabolomics; co-immunoprecipitation of GFRA2-RET complex; in vitro kinase assays showing HK2 Ser122 phosphorylation; HK2 activity assays; in vivo tumor models with neurturin blockade and RET inhibitor combination\",\n      \"journal\": \"Cancer letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP of receptor complex, in vitro kinase/activity assays, in vivo validation, single lab with multiple methods\",\n      \"pmids\": [\"39988080\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GFRA2 is a GPI-anchored cell-surface co-receptor that preferentially binds neurturin (over GDNF) and recruits the RET receptor tyrosine kinase to activate downstream signaling; the crystal structure shows its three-domain architecture, with domain 1 not contacting neurturin but potentially engaging RET/NCAM, and heparan sulfate contributing to complex assembly. Beyond the canonical RET-dependent neurturin pathway, GFRA2 also signals through a RET-independent route to drive cardiomyocyte differentiation, and in pancreatic cancer cells the GFRA2-RET complex phosphorylates hexokinase 2 at Ser122 to enhance glycolysis.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GFRA2 is a GPI-anchored cell-surface co-receptor that mediates neurotrophic factor signaling by preferentially binding neurturin and recruiting the RET receptor tyrosine kinase to assemble an active signaling complex [#0]. Reconstitution in cells co-expressing GFRA2 and RET shows the complex responds to both neurturin and GDNF but is roughly 30-fold more sensitive to neurturin, establishing GFRA2 as the preferred neurturin co-receptor [#0]. The crystal structure of the neurturin–GFRA2 complex resolves a three-domain architecture in which domain 1 makes no direct contact with neurturin but presents a conserved surface positioned to engage RET and/or NCAM, and identifies heparan sulfate-binding sites on both neurturin and GFRA2 that contribute to assembly and to avidity-driven modulation of functional ligand affinity by GFRA2 surface concentration [#1]. Beyond the canonical RET pathway, GFRA2 marks cardiac progenitor cells and drives cardiomyocyte differentiation through a RET-independent route [#2], and in pancreatic cancer cells neurturin-bound GFRA2 recruits RET to form a heterodimer that phosphorylates hexokinase 2 at Ser122, boosting its activity to enhance aerobic glycolysis and fuel tumor growth [#3].\",\n  \"teleology\": [\n    {\n      \"year\": 1997,\n      \"claim\": \"Established that GFRA2 is the molecular co-receptor that confers neurturin responsiveness on RET, resolving how this ligand activates the RET tyrosine kinase.\",\n      \"evidence\": \"In vitro signaling reconstitution in fibroblasts co-expressing TrnR2 (GFRA2) and RET, with ligand dose-response comparison and GPI-linkage characterization\",\n      \"pmids\": [\"9182803\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis of GFRA2-RET assembly not resolved here\",\n        \"Does not address GFRA2 signaling independent of RET\",\n        \"Downstream signaling effectors not identified\"\n      ]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Revealed a RET-independent function for GFRA2, showing it marks cardiac progenitors and drives cardiomyocyte differentiation beyond the canonical neurturin/GDNF-RET axis.\",\n      \"evidence\": \"FACS isolation of GFRA2+ cardiac progenitors from mouse and human pluripotent stem cells with Gfra2 knockout and in vitro/in vivo differentiation readouts\",\n      \"pmids\": [\"27396331\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Identity of the RET-independent signaling partner/transducer unknown\",\n        \"Ligand driving this pathway not defined\",\n        \"Single lab; mechanism downstream of GFRA2 uncharacterized\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Defined the structural architecture of the neurturin–GFRA2 complex and implicated heparan sulfate in complex assembly, explaining how GFRA2 surface density tunes functional ligand affinity.\",\n      \"evidence\": \"X-ray crystallography of NRTN alone and in complex with GFRA2, biophysical binding assays, heparan sulfate-binding mutagenesis, and in vivo pharmacokinetics with a binding mutant\",\n      \"pmids\": [\"29414779\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Direct domain 1 contact with RET/NCAM inferred but not structurally captured\",\n        \"Full ternary GFRA2-NRTN-RET complex structure not solved\",\n        \"Functional consequence of avidity tuning in vivo not fully mapped\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Connected GFRA2-RET signaling to tumor metabolism by identifying hexokinase 2 Ser122 as a substrate, linking neurturin signaling to enhanced glycolysis in pancreatic cancer.\",\n      \"evidence\": \"Co-immunoprecipitation of the GFRA2-RET complex, in vitro kinase and HK2 activity assays, integrated metabolomics, and in vivo tumor models with neurturin blockade and RET inhibition\",\n      \"pmids\": [\"39988080\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether RET directly phosphorylates HK2 versus via an intermediary kinase not fully resolved\",\n        \"Single lab; generality across cancer types untested\",\n        \"Reciprocal validation of the receptor complex limited\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular identity and mechanism of the RET-independent GFRA2 signaling route remain undefined.\",\n      \"evidence\": null,\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No transducer identified for RET-independent signaling\",\n        \"Ligand requirement for the cardiac differentiation pathway unknown\",\n        \"No structure of the assembled GFRA2-NRTN-RET ternary complex\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"complexes\": [\n      \"GFRA2-RET co-receptor complex\"\n    ],\n    \"partners\": [\n      \"RET\",\n      \"NRTN\",\n      \"GDNF\",\n      \"HK2\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":4,"faith_pct":100.0}}