{"gene":"HFE","run_date":"2026-06-10T01:55:22","timeline":{"discoveries":[{"year":2000,"finding":"Crystal structure of HFE complexed with the extracellular portion of transferrin receptor (TfR) at 2.8 Å resolution shows two HFE molecules binding each side of a twofold-symmetric TfR dimer. HFE lies parallel to the membrane with its helices (counterpart of the MHC peptide-binding groove) making extensive contacts with TfR dimerization-domain helices. The HFE–TfR complex differs from the TfR-alone structure in domain arrangement and dimer interface, providing a mechanism for communicating binding events between TfR chains.","method":"X-ray crystallography (2.8 Å crystal structure of HFE–TfR extracellular complex)","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1 / Strong — atomic-resolution crystal structure with structural validation of the binding interface","pmids":["10638746"],"is_preprint":false},{"year":1999,"finding":"HFE competes with diferric transferrin (Fe-Tf) for binding to TfR by binding at or near the Fe-Tf binding site on TfR. Inhibition assays show the Fe-Tf:TfR:HFE ternary complex contains one Fe-Tf and one HFE bound to a TfR homodimer, with HFE reducing the apparent affinity of TfR for Fe-Tf.","method":"Radioactivity-based and biosensor (surface plasmon resonance) binding/inhibition assays with soluble recombinant proteins","journal":"Journal of Molecular Biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with two orthogonal quantitative binding assays","pmids":["10556042"],"is_preprint":false},{"year":2004,"finding":"HFE and Fe-Tf compete directly for their overlapping binding sites on each TfR polypeptide chain without negative cooperativity between the two TfR chains. A heterodimeric TfR engineered so one chain binds only HFE and the other only Fe-Tf confirmed the absence of cooperativity. Cell-line experiments showed this competition alters HFE trafficking patterns, indicating physiological relevance.","method":"Heterodimeric mutant TfR binding studies (soluble proteins) combined with transfected cell-line localization experiments","journal":"The Journal of Biological Chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — reconstitution with engineered heterodimer plus cellular validation, single lab but two orthogonal methods","pmids":["15056661"],"is_preprint":false},{"year":1999,"finding":"HFE protein is physically associated with TfR and β2-microglobulin in crypt enterocytes of human duodenum (as in placenta). Crypt enterocytes showed dramatically higher transferrin-bound iron uptake than villus cells, consistent with HFE modulating transferrin-bound iron uptake to sense body iron stores.","method":"Immunocytochemistry, co-immunoprecipitation/Western blot of crypt enterocyte fractions, iron uptake assays with isolated crypt vs. villus cells","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP/Western blot showing physical association plus functional iron uptake assay in primary human tissue","pmids":["9990067"],"is_preprint":false},{"year":1999,"finding":"Stable overexpression of HFE in HeLa cells decreases iron uptake from diferric transferrin and activates iron-regulatory proteins (IRPs), implying HFE reduces the intracellular labile iron pool. This IRP activation is accompanied by downregulation of ferritin and upregulation of transferrin receptor.","method":"Stably transfected HeLa cell line (tetracycline-inducible HFE), iron uptake assays, IRP activity assays, Western blot for ferritin and TfR","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean inducible expression system with multiple downstream readouts, single lab","pmids":["10572108"],"is_preprint":false},{"year":1998,"finding":"Targeted disruption of the murine Hfe gene produces systemic iron overload (8-fold elevated hepatic iron at 10 weeks, elevated transferrin saturation) with iron predominantly in periportal hepatocytes, establishing that HFE is required for regulation of iron homeostasis in vivo.","method":"Gene knockout mouse model; hepatic iron quantification, transferrin saturation measurement, histochemical iron staining","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean knockout with quantitative iron phenotype, widely replicated","pmids":["9482913"],"is_preprint":false},{"year":2008,"finding":"Hfe regulates hepcidin expression as a component of the TfR1 sensing complex. Mutations forcing constitutive Hfe–TfR1 interaction caused iron overload with inappropriately low hepcidin; mutations preventing the interaction caused iron deficiency with inappropriately high hepcidin. Liver-specific Hfe overexpression in Hfe-null mice increased hepcidin and caused iron deficiency. Together these data indicate Hfe induces hepcidin expression when NOT bound to TfR1.","method":"Knock-in mouse strains with TfR1 mutations promoting or preventing Hfe interaction; liver-specific transgenic Hfe overexpression in Hfe-/- background; hepcidin mRNA quantification, iron parameter measurement","journal":"Cell Metabolism","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple complementary genetic mouse models, each with reciprocal phenotypes, single lab but highly convergent evidence","pmids":["18316026"],"is_preprint":false},{"year":2002,"finding":"Wild-type HFE raises cellular iron by inhibiting iron efflux from monocyte/macrophage cells (THP-1 and primary macrophages), independently of its competition with transferrin for TfR1. The HH-associated mutant H41D retains TfR1 binding but loses the ability to inhibit iron release, indicating these are separable functions of HFE.","method":"Iron efflux assays in THP-1 monocyte cell line and primary macrophages from healthy individuals and HH patients; H41D mutant functional comparison; transferrin competition assay","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean cell-based efflux assay with mutant controls and primary human cells, single lab","pmids":["12429850"],"is_preprint":false},{"year":2014,"finding":"HFE interacts with the BMP type I receptor ALK3, inhibiting ALK3 ubiquitination and proteasomal degradation, thereby increasing ALK3 protein levels and its accumulation at the cell surface. This stabilization of ALK3 by HFE increases Smad1/5/8 phosphorylation and hepcidin expression; BMP pathway inhibition abolishes HFE-induced hepcidin upregulation. Both C282Y and H63D HFE mutants fail to increase ALK3 cell-surface expression. Hfe deletion in mice reduces hepatic ALK3 protein.","method":"HFE overexpression in Hep3B cells; co-immunoprecipitation (HFE–ALK3 interaction); ubiquitination assays; flow cytometry (cell-surface ALK3); phospho-Smad Western blot; BMP inhibitor treatment; Hfe-/- mouse liver Western blot","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (co-IP, ubiquitination assay, cell-surface quantification, mouse KO validation) in single lab","pmids":["24904118"],"is_preprint":false},{"year":2010,"finding":"Hepatocyte-specific AAV-mediated expression of Hfe in Hfe-null mice increases hepcidin mRNA and lowers hepatic iron and transferrin saturation, while Hfe expression in Tfr2-deficient mice has no effect on iron levels (and vice versa). Co-IP of liver lysates did not detect physical interaction between Hfe and Tfr2 in vivo, suggesting Hfe is limiting in the Hfe/Tfr2 complex that regulates hepcidin, and that both proteins are required in hepatocytes for hepcidin regulation.","method":"Hepatocyte-specific AAV2/8 gene delivery; hepcidin mRNA quantification; liver and serum iron measurement; co-immunoprecipitation of endogenous liver lysates","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo rescue with negative co-IP result clarifying interaction requirement; single lab, two complementary methods","pmids":["20177050"],"is_preprint":false},{"year":2012,"finding":"Hepatocellular overexpression of Hfe induces hepcidin and causes iron deficiency even in Tfr2-null mice, demonstrating that Tfr2 is not required for Hfe-dependent hepcidin induction. Co-IP of liver lysates did not detect Hfe–Tfr2 physical interaction in vivo.","method":"Transgenic Hfe overexpression in Tfr2(Y245X/Y245X) mice; hepcidin mRNA measurement; blood iron parameters; co-immunoprecipitation of liver lysates","journal":"American Journal of Hematology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic rescue in Tfr2-null background with negative co-IP; single lab","pmids":["22460705"],"is_preprint":false},{"year":2015,"finding":"Genetic epistasis in mice demonstrates Hfe and Hjv operate in the same pathway for hepcidin regulation: Hfe(-/-)Hjv(-/-) double-knockout mice are indistinguishable from single Hjv(-/-) mice in hepcidin suppression, iron overload, and Smad signaling, indicating Hfe functions upstream of or requires HJV-dependent BMP-Smad signaling.","method":"Double-knockout mouse generation (Hfe-/-Hjv-/-); serum and hepatic iron quantification; hepcidin mRNA; Smad1/5/8 phosphorylation Western blot; dietary iron challenge","journal":"Journal of Molecular Medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean double-knockout epistasis with multiple iron and signaling readouts, convergent with complementary study (PMID 25608116)","pmids":["25609138"],"is_preprint":false},{"year":2015,"finding":"In Hfe(-/-)Hjv(-/-) double-knockout mice, iron-induced phosphorylation of Smad1/5/8 is absent (as in Hjv(-/-) alone), and hepcidin cannot be induced by acute iron delivery, confirming that HFE-dependent hepcidin regulation requires HJV-mediated BMP-Smad signaling.","method":"Double-knockout mice; acute iron gavage; Smad1/5/8 phosphorylation Western blot; hepcidin mRNA quantification","journal":"Antioxidants & Redox Signaling","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with mechanistic signaling readout, corroborated by independent lab (PMID 25609138)","pmids":["25608116"],"is_preprint":false},{"year":2006,"finding":"Hfe is required for establishment of basal hepcidin levels but is dispensable for hepcidin upregulation in response to iron loading or acute inflammation (LPS). In contrast, LPS-induced hepcidin regulation is TLR-4 dependent. Hepatic ferroportin regulation by iron and LPS is largely independent of Hfe.","method":"Hfe-/- and β2m-/- mice subjected to iron deprivation, iron loading, and LPS challenge; hepcidin mRNA quantification; ferroportin protein measurement; TLR-4 knockout comparison","journal":"American Journal of Physiology - Gastrointestinal and Liver Physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple genetic models and dietary/pharmacological challenges, single lab","pmids":["16565419"],"is_preprint":false},{"year":2004,"finding":"In HT29 colonic cells (a duodenal model), stable HFE expression increases ferritin by inhibiting iron efflux rather than by affecting TfR1-mediated uptake. This effect is independent of HFE's interaction with TfR1 (shown using the W81A mutant with greatly reduced TfR1 affinity) and is associated with decreased hephaestin mRNA.","method":"Stably transfected HT29 cells; ferritin Western blot; iron uptake and efflux assays; W81A TfR1-binding mutant comparison; hephaestin mRNA RT-PCR","journal":"The Journal of Biological Chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — stable cell model with TfR1-binding mutant control and efflux vs. uptake distinction; single lab","pmids":["15044462"],"is_preprint":false},{"year":2008,"finding":"In Hfe-knockout hepatocytes, Tfr1-mediated (low-concentration) transferrin-bound iron uptake is increased 40–70% compared to iron-loaded wild-type hepatocytes with similar Tfr1 expression, showing Hfe specifically regulates the Tfr1-mediated hepatocyte iron uptake pathway. The high-capacity Tfr1-independent (putative Tfr2) pathway is not affected by absence of Hfe.","method":"Primary hepatocytes from Hfe-/- and wild-type mice; dual-concentration 125I-Tf/59Fe uptake assays distinguishing Tfr1 and Tfr1-independent pathways; Tfr1 and Tfr2 mRNA/protein quantification","journal":"Hepatology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — primary cell functional assay with pathway-specific concentrations and molecular quantification; single lab","pmids":["18393371"],"is_preprint":false},{"year":2003,"finding":"Knock-in mice carrying H67D (murine equivalent of human H63D) show hepatic iron loading that is intermediate between wild-type and C294Y homozygotes. H67D/H67D, C294Y/C294Y, and H67D/C294Y compound heterozygotes all develop hepatic iron loading, establishing that the H67D allele causes partial loss of Hfe function.","method":"Knock-in mouse generation; hepatic iron quantification at 10 weeks on standard diet","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo knock-in models with allelic series showing dose-response relationship","pmids":["14673107"],"is_preprint":false},{"year":2005,"finding":"HFE cross-talks with the MHC class I antigen presentation pathway: PBMCs from HH patients with the C282Y mutation show enhanced endocytosis and premature dissociation of MHC class I–β2m–peptide complexes, producing low-stability heterotrimers and increased free class I heavy chains at the cell surface. Earlier peptide loading and ER maturation of MHC class I are also observed in C282Y cells.","method":"FACS analysis of MHC class I surface expression and endocytosis rate; biochemical thermostability assays of MHC class I complexes; comparison of patient (C282Y) PBMCs vs. normal PBMCs","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — primary human cell experiments with multiple orthogonal assays; single lab","pmids":["15840699"],"is_preprint":false},{"year":2014,"finding":"Wild-type HFE (but not C282Y-mutated HFE) inhibits CD8+ T-lymphocyte activation (MIP-1β secretion and 4-1BB expression) when expressed in antigen-presenting cells. This inhibition is independent of MHC class I surface levels, β2-microglobulin competition, or HFE–TfR interaction. The α1-α2 domains of HFE are responsible for this immunosuppressive activity.","method":"Transient HFE transfection in APC model cells; co-culture with antigen-specific CD8+ T lymphocytes; cytokine ELISA (MIP-1β); 4-1BB flow cytometry; domain deletion mutants; W81A (TfR1-binding) mutant control","journal":"European Journal of Immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-based functional assay with domain mutants and multiple readouts; single lab","pmids":["24643698"],"is_preprint":false},{"year":2020,"finding":"HFE acts as a negative regulator of RIG-I-like receptor (RLR)-mediated type I interferon signaling by binding to MAVS (mitochondrial antiviral signaling protein) and mediating its autophagic degradation via SQSTM1/p62. RNA virus infection inhibits the HFE–MAVS interaction, blocking MAVS autophagic degradation. Hfe depletion abrogates MAVS degradation and enhances antiviral immune responses.","method":"Co-immunoprecipitation (HFE–MAVS and HFE–SQSTM1 interactions); Hfe knockdown/knockout cells and mice; type I IFN and cytokine measurement; autophagy flux assays; viral infection models","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP of endogenous proteins with functional KO validation in vitro and in vivo; single lab","pmids":["32746697"],"is_preprint":false},{"year":2000,"finding":"HFE protein is expressed on the cell surface of gastric epithelial cells, tissue macrophages, and circulating monocytes/granulocytes. The C282Y mutation reduces but does not completely prevent cell-surface presentation of HFE in these primary human cell types.","method":"Immunocytochemistry of tissue sections; immunostaining of isolated leukocyte populations from normal subjects and HH patients; antisera against two distinct HFE peptides","journal":"Haematologica","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — direct immunolocalization in primary human tissues and cells with two independent antisera, single lab","pmids":["10756356"],"is_preprint":false},{"year":2006,"finding":"HFE mRNA is expressed almost exclusively in the retinal pigment epithelium (RPE) within the retina, and HFE protein localizes specifically to the basolateral membrane of RPE cells. HFE-interacting proteins TfR1, TfR2, and β2-microglobulin are co-expressed in the retina, consistent with HFE regulating iron homeostasis at the RPE basolateral membrane.","method":"RT-PCR; in situ hybridization; immunofluorescence; immunogold electron microscopy in mouse retina","journal":"Investigative Ophthalmology & Visual Science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple localization methods (in situ hybridization, immunofluorescence, immunogold EM) converging on basolateral RPE localization; single lab","pmids":["17003411"],"is_preprint":false},{"year":2023,"finding":"Hepatocyte-specific TfR1 knockout mice show inappropriately high hepcidin relative to serum/liver iron, and combined hepatocyte Tfrc/Hfe double knockout abolishes the iron phenotype seen in Tfrc-only knockout mice, establishing that the major non-redundant function of hepatocyte TfR1 in iron homeostasis is to interact with HFE to regulate hepcidin. This pathway is modulated by serum iron and contributes to hepcidin suppression and iron overload in murine β-thalassemia.","method":"Hepatocyte-specific Tfrc conditional knockout mice (Tfrcfl/fl;Alb-Cre); double knockout with Hfe and β-thalassemia models; hepcidin mRNA, serum/liver iron, erythropoietin, erythroferrone measurements; iron challenge experiments","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple complementary conditional knockout models with quantitative iron and hormonal phenotypes; epistasis cleanly assigns TfR1 function to HFE interaction","pmids":["36322932"],"is_preprint":false},{"year":2009,"finding":"Expression of H63D and C282Y HFE variants in neuroblastoma SH-SY5Y cells alters the labile iron pool and selectively increases secretion of MCP-1 (monocyte chemoattractant protein-1) compared to wild-type HFE. MCP-1 secretion is tightly correlated with intracellular iron status, but the HFE genotype also influences MCP-1 independently of iron level, and modifies the pharmacological effect of minocycline on MCP-1.","method":"Stably transfected neuroblastoma cells expressing HFE variants; multiplex cytokine immunoassay; iron manipulation (ferric ammonium citrate, DFO); labile iron pool measurement","journal":"Journal of Neuroinflammation","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single cell model, cytokine assay without mechanistic resolution of direct vs. iron-mediated HFE effect","pmids":["19228389"],"is_preprint":false},{"year":2003,"finding":"HFE gene is expressed in rat hepatocytes (parenchymal cells) in addition to non-parenchymal liver cells, with highest expression in liver among all tissues. This raises the possibility that HFE has a direct role in hepatocyte iron metabolism, not only in Kupffer cells.","method":"Northern blot (tissue expression); real-time PCR of fractionated liver cell populations (parenchymal vs. non-parenchymal); gene cloning and exon-intron structure determination","journal":"Journal of Hepatology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — localization by mRNA quantification only, no functional readout; single lab","pmids":["12927914"],"is_preprint":false}],"current_model":"HFE is an MHC class I-like protein that physically interacts with transferrin receptor 1 (TfR1) at an overlapping site with transferrin, directly competing for TfR1 binding and reducing cellular iron uptake; when free from TfR1 (displaced by high diferric-transferrin saturation), hepatocyte HFE signals through the BMP type I receptor ALK3 and the HJV-dependent BMP–Smad1/5/8 pathway to upregulate the iron-regulatory hormone hepcidin, which in turn suppresses intestinal iron absorption and macrophage iron release—thus acting as a hepatocyte iron sensor whose disruption (C282Y or H63D mutations) causes hereditary hemochromatosis through inappropriately low hepcidin; additionally, HFE inhibits iron efflux from macrophages independently of TfR1, inhibits MAVS autophagic degradation to modulate innate antiviral immunity, and suppresses CD8+ T-lymphocyte activation via its α1-α2 domains."},"narrative":{"mechanistic_narrative":"HFE is an MHC class I-like protein that functions as a hepatocyte iron sensor governing systemic iron homeostasis, and its disruption causes hereditary hemochromatosis through inappropriately low levels of the iron-regulatory hormone hepcidin [PMID:9482913, PMID:18316026, PMID:14673107]. HFE binds the extracellular dimerization domain of transferrin receptor 1 (TfR1) using the helices that correspond to the MHC peptide-binding groove, occupying a site that overlaps the diferric-transferrin (Fe-Tf) binding site, so that HFE and Fe-Tf compete directly for each TfR1 chain without negative cooperativity [PMID:10638746, PMID:10556042, PMID:15056661]. This competition reduces transferrin-mediated iron uptake and lowers the intracellular labile iron pool, activating iron-regulatory proteins [PMID:10572108, PMID:18393371]. The sensing logic is that HFE induces hepcidin when displaced from TfR1: forcing constitutive HFE–TfR1 interaction lowers hepcidin and causes iron overload, while preventing it raises hepcidin, and hepatocyte TfR1's principal non-redundant role in iron homeostasis is to sequester HFE [PMID:18316026, PMID:36322932]. Free HFE stabilizes the BMP type I receptor ALK3 by inhibiting its ubiquitination and proteasomal degradation, thereby increasing ALK3 surface levels and Smad1/5/8 phosphorylation, and this hepcidin induction is genetically dependent on the HJV-mediated BMP–Smad pathway [PMID:24904118, PMID:25609138, PMID:25608116]; the C282Y and H63D disease mutations fail to stabilize ALK3 [PMID:24904118]. Beyond hepcidin signaling, HFE inhibits iron efflux from macrophages independently of its TfR1 interaction [PMID:12429850, PMID:15044462], suppresses CD8+ T-lymphocyte activation through its α1–α2 domains [PMID:24643698], and negatively regulates RIG-I-like receptor antiviral signaling by binding MAVS and routing it to SQSTM1/p62-dependent autophagic degradation [PMID:10756356].","teleology":[{"year":1998,"claim":"Established that HFE is genuinely required for iron homeostasis in vivo, anchoring the gene's physiological role before any molecular mechanism was known.","evidence":"Targeted Hfe knockout mouse with hepatic iron quantification and histochemistry","pmids":["9482913"],"confidence":"High","gaps":["Does not identify the molecular partner or signaling output through which HFE regulates iron","Hepatocyte-versus-macrophage site of action not resolved"]},{"year":1999,"claim":"Defined the central molecular interaction by showing HFE competes with diferric transferrin for an overlapping site on TfR1, explaining how HFE could modulate iron uptake.","evidence":"SPR and radioligand inhibition assays with soluble recombinant HFE, TfR, and Fe-Tf; co-IP/Western in primary human duodenal enterocytes","pmids":["10556042","9990067"],"confidence":"High","gaps":["In vitro stoichiometry does not establish the downstream signaling consequence of competition","Tissue association does not prove which cells sense iron systemically"]},{"year":1999,"claim":"Connected HFE–TfR1 binding to a cellular outcome, showing HFE overexpression lowers the labile iron pool and activates IRPs.","evidence":"Tetracycline-inducible HFE HeLa line with iron uptake, IRP activity, and ferritin/TfR Western readouts","pmids":["10572108"],"confidence":"Medium","gaps":["HeLa is not a hepatocyte or enterocyte model","Does not link the labile iron change to hepcidin regulation"]},{"year":2000,"claim":"Provided the atomic-resolution architecture of the HFE–TfR complex, revealing the MHC-groove helices contact the TfR dimerization domain and that binding rearranges the TfR dimer interface.","evidence":"2.8 Å X-ray crystal structure of the HFE–TfR ectodomain complex","pmids":["10638746"],"confidence":"High","gaps":["Structure does not capture the membrane-bound signaling complex or HFE engagement with hepcidin machinery","Conformational link between TfR binding and HFE release is structural inference only"]},{"year":2002,"claim":"Separated HFE functions by showing it inhibits macrophage iron efflux independently of TfR1 competition, indicating more than one biochemical activity.","evidence":"Iron efflux assays in THP-1 and primary macrophages with the H41D mutant that retains TfR1 binding but loses efflux inhibition","pmids":["12429850"],"confidence":"Medium","gaps":["Molecular target mediating efflux inhibition not identified","Single-lab cell assay without in vivo confirmation"]},{"year":2003,"claim":"Demonstrated that the H63D-equivalent allele is a partial loss-of-function, ordering the disease alleles into a severity series.","evidence":"H67D and C294Y knock-in mice with hepatic iron quantification across an allelic series","pmids":["14673107"],"confidence":"High","gaps":["Does not define which molecular function each mutation disrupts","Diet- and age-dependent penetrance not characterized"]},{"year":2004,"claim":"Refined the binding mechanism by showing HFE–TfR1 and Fe-Tf–TfR1 competition occurs per chain without negative cooperativity, and that competition alters HFE trafficking.","evidence":"Engineered heterodimeric TfR binding studies plus transfected cell-line localization","pmids":["15056661","15044462"],"confidence":"High","gaps":["The trafficking outcome's relevance to systemic hepcidin control not yet established","TfR1-independent efflux mechanism still molecularly undefined"]},{"year":2008,"claim":"Established the sensing logic of the system: HFE induces hepcidin specifically when NOT bound to TfR1, defining displacement by Fe-Tf as the trigger.","evidence":"Knock-in TfR1 mutants forcing or preventing HFE interaction, plus liver-specific HFE transgenic rescue in Hfe-null mice; hepcidin and iron readouts","pmids":["18316026"],"confidence":"High","gaps":["Does not identify the receptor through which free HFE signals to hepcidin","Hepatocyte iron-uptake contribution versus signaling contribution unresolved"]},{"year":2008,"claim":"Localized HFE's iron-uptake control to the TfR1-mediated hepatocyte pathway specifically, sharpening the sensor model.","evidence":"Dual-concentration 125I-Tf/59Fe uptake assays in primary Hfe-/- versus wild-type hepatocytes","pmids":["18393371"],"confidence":"Medium","gaps":["Does not connect altered hepatocyte uptake to hepcidin output","Tfr1-independent pathway identity (Tfr2) inferred, not proven"]},{"year":2010,"claim":"Clarified the relationship to TfR2, showing both proteins are required in hepatocytes for hepcidin regulation while no stable Hfe–Tfr2 complex is detected in vivo, and HFE is limiting.","evidence":"Hepatocyte-specific AAV Hfe delivery in Hfe-null and Tfr2-deficient mice; co-IP of endogenous liver lysates","pmids":["20177050"],"confidence":"Medium","gaps":["Negative co-IP does not exclude a transient or low-affinity interaction","Mechanism by which Tfr2 contributes to the same pathway not defined"]},{"year":2012,"claim":"Showed Hfe can induce hepcidin even without Tfr2, indicating Tfr2 is not strictly required for HFE-dependent hepcidin induction.","evidence":"Transgenic Hfe overexpression in Tfr2-null mice; hepcidin mRNA and iron parameters; co-IP","pmids":["22460705"],"confidence":"Medium","gaps":["Apparent tension with the earlier co-requirement finding not fully reconciled","Single-lab genetic system"]},{"year":2014,"claim":"Identified the receptor mechanism for HFE-driven hepcidin: HFE stabilizes the BMP type I receptor ALK3 by blocking its degradation, increasing surface ALK3 and Smad signaling.","evidence":"HFE overexpression in Hep3B with co-IP, ubiquitination assays, surface ALK3 flow cytometry, phospho-Smad blots, BMP inhibitor, and Hfe-/- mouse liver","pmids":["24904118"],"confidence":"High","gaps":["Does not show how TfR1 displacement is coupled to ALK3 engagement","Structural basis of HFE–ALK3 interaction unknown"]},{"year":2014,"claim":"Defined an iron-independent immunoregulatory function, with HFE suppressing CD8+ T-cell activation via its α1–α2 domains.","evidence":"HFE transfection in APC model cells co-cultured with antigen-specific CD8+ T cells; domain-deletion and W81A mutants; MIP-1β and 4-1BB readouts","pmids":["24643698"],"confidence":"Medium","gaps":["Molecular target of the α1–α2-mediated suppression not identified","In vivo immunological relevance not established"]},{"year":2015,"claim":"Placed HFE genetically within the HJV-dependent BMP–Smad pathway, establishing that HFE-driven hepcidin regulation requires HJV-mediated signaling.","evidence":"Hfe-/-Hjv-/- double-knockout epistasis with iron, hepcidin, and acute-iron-induced Smad1/5/8 phosphorylation readouts (two independent studies)","pmids":["25609138","25608116"],"confidence":"High","gaps":["Whether HFE and HJV act on the same receptor complex molecularly not resolved here","Order of HFE relative to HJV in the pathway inferred from epistasis"]},{"year":2020,"claim":"Extended HFE into innate antiviral immunity, showing it binds MAVS and drives its SQSTM1/p62-dependent autophagic degradation to dampen type I interferon responses.","evidence":"Co-IP of HFE–MAVS and HFE–SQSTM1; Hfe knockdown/knockout cells and mice; 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rat.","date":"2003","source":"Journal of hepatology","url":"https://pubmed.ncbi.nlm.nih.gov/12927914","citation_count":23,"is_preprint":false},{"pmid":"17729389","id":"PMC_17729389","title":"HFE gene in primary and secondary hepatic iron overload.","date":"2007","source":"World journal of gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/17729389","citation_count":22,"is_preprint":false},{"pmid":"10660482","id":"PMC_10660482","title":"Mutations of the HFE gene and the risk of hepatocellular carcinoma.","date":"1999","source":"Blood cells, molecules & diseases","url":"https://pubmed.ncbi.nlm.nih.gov/10660482","citation_count":22,"is_preprint":false},{"pmid":"17284543","id":"PMC_17284543","title":"The H63D variant in the HFE gene predisposes to arthralgia, chondrocalcinosis and osteoarthritis.","date":"2007","source":"Annals of the rheumatic diseases","url":"https://pubmed.ncbi.nlm.nih.gov/17284543","citation_count":22,"is_preprint":false},{"pmid":"23657305","id":"PMC_23657305","title":"Hfe mutations and iron overload in patients with alcoholic liver disease.","date":"2013","source":"Arquivos de gastroenterologia","url":"https://pubmed.ncbi.nlm.nih.gov/23657305","citation_count":22,"is_preprint":false},{"pmid":"29315562","id":"PMC_29315562","title":"HFE Genotype Restricts the Response to Paraquat in a Mouse Model of Neurotoxicity.","date":"2018","source":"Journal of neurochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/29315562","citation_count":22,"is_preprint":false},{"pmid":"18393371","id":"PMC_18393371","title":"The role of Hfe in transferrin-bound iron uptake by hepatocytes.","date":"2008","source":"Hepatology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/18393371","citation_count":20,"is_preprint":false},{"pmid":"22908207","id":"PMC_22908207","title":"Hemochromatosis gene (HFE) polymorphisms and risk of type 2 diabetes mellitus: a meta-analysis.","date":"2012","source":"American journal of epidemiology","url":"https://pubmed.ncbi.nlm.nih.gov/22908207","citation_count":19,"is_preprint":false},{"pmid":"25608116","id":"PMC_25608116","title":"HJV and HFE Play Distinct Roles in Regulating Hepcidin.","date":"2015","source":"Antioxidants & redox signaling","url":"https://pubmed.ncbi.nlm.nih.gov/25608116","citation_count":19,"is_preprint":false},{"pmid":"28350201","id":"PMC_28350201","title":"A role for sex and a common HFE gene variant in brain iron uptake.","date":"2017","source":"Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/28350201","citation_count":19,"is_preprint":false},{"pmid":"24643698","id":"PMC_24643698","title":"The WT hemochromatosis protein HFE inhibits CD8⁺ T-lymphocyte activation.","date":"2014","source":"European journal of immunology","url":"https://pubmed.ncbi.nlm.nih.gov/24643698","citation_count":19,"is_preprint":false},{"pmid":"12445172","id":"PMC_12445172","title":"HFE gene mutations and iron metabolism in Wilson's disease.","date":"2002","source":"Liver","url":"https://pubmed.ncbi.nlm.nih.gov/12445172","citation_count":19,"is_preprint":false},{"pmid":"11051367","id":"PMC_11051367","title":"Prevalence and clinical significance of HFE gene mutations in patients with iron overload.","date":"2000","source":"The American journal of gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/11051367","citation_count":18,"is_preprint":false},{"pmid":"11929045","id":"PMC_11929045","title":"Hemochromatosis (HFE) and transferrin receptor-1 (TFRC1) genes in sporadic porphyria cutanea tarda (sPCT).","date":"2002","source":"Cellular and molecular biology (Noisy-le-Grand, France)","url":"https://pubmed.ncbi.nlm.nih.gov/11929045","citation_count":18,"is_preprint":false},{"pmid":"19711434","id":"PMC_19711434","title":"Hereditary hemochromatosis gene (HFE) variants are associated with birth weight and childhood leukemia risk.","date":"2009","source":"Pediatric blood & cancer","url":"https://pubmed.ncbi.nlm.nih.gov/19711434","citation_count":18,"is_preprint":false},{"pmid":"12416729","id":"PMC_12416729","title":"HFE and non-HFE hemochromatosis.","date":"2002","source":"International journal of hematology","url":"https://pubmed.ncbi.nlm.nih.gov/12416729","citation_count":17,"is_preprint":false},{"pmid":"10488796","id":"PMC_10488796","title":"Update on hereditary hemochromatosis and the HFE gene.","date":"1999","source":"Mayo Clinic proceedings","url":"https://pubmed.ncbi.nlm.nih.gov/10488796","citation_count":17,"is_preprint":false},{"pmid":"10878571","id":"PMC_10878571","title":"The structure and function of HFE.","date":"2000","source":"BioEssays : news and reviews in molecular, cellular and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/10878571","citation_count":16,"is_preprint":false},{"pmid":"18820912","id":"PMC_18820912","title":"Does the SLC40A1 gene modify HFE-related haemochromatosis phenotypes?","date":"2008","source":"Annals of hematology","url":"https://pubmed.ncbi.nlm.nih.gov/18820912","citation_count":16,"is_preprint":false},{"pmid":"15464655","id":"PMC_15464655","title":"Iron, the HFE gene, and hepatitis C.","date":"2004","source":"Clinics in liver disease","url":"https://pubmed.ncbi.nlm.nih.gov/15464655","citation_count":16,"is_preprint":false},{"pmid":"25064704","id":"PMC_25064704","title":"Diagnostic evaluation of hereditary hemochromatosis (HFE and non-HFE).","date":"2014","source":"Hematology/oncology clinics of North America","url":"https://pubmed.ncbi.nlm.nih.gov/25064704","citation_count":16,"is_preprint":false},{"pmid":"34829689","id":"PMC_34829689","title":"Dietary Iron Overload and Hfe Related Hemochromatosis Alter Hepatic Mitochondrial Function.","date":"2021","source":"Antioxidants (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/34829689","citation_count":16,"is_preprint":false},{"pmid":"15642540","id":"PMC_15642540","title":"Hereditary hemochromatosis gene (HFE) mutations C282Y, H63D and S65C in patients with idiopathic dilated cardiomyopathy.","date":"2005","source":"European journal of heart failure","url":"https://pubmed.ncbi.nlm.nih.gov/15642540","citation_count":16,"is_preprint":false},{"pmid":"11469076","id":"PMC_11469076","title":"C282Y and H63D mutations of HFE gene in patients with advanced alcoholic liver disease.","date":"2001","source":"Revista espanola de enfermedades digestivas","url":"https://pubmed.ncbi.nlm.nih.gov/11469076","citation_count":16,"is_preprint":false},{"pmid":"20027482","id":"PMC_20027482","title":"HFE gene mutations and iron status of Brazilian blood donors.","date":"2009","source":"Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas","url":"https://pubmed.ncbi.nlm.nih.gov/20027482","citation_count":16,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":47049,"output_tokens":6672,"usd":0.120613,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":15672,"output_tokens":5142,"usd":0.103455,"stage2_stop_reason":"end_turn"},"total_usd":0.224068,"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\": 2000,\n      \"finding\": \"Crystal structure of HFE complexed with the extracellular portion of transferrin receptor (TfR) at 2.8 Å resolution shows two HFE molecules binding each side of a twofold-symmetric TfR dimer. HFE lies parallel to the membrane with its helices (counterpart of the MHC peptide-binding groove) making extensive contacts with TfR dimerization-domain helices. The HFE–TfR complex differs from the TfR-alone structure in domain arrangement and dimer interface, providing a mechanism for communicating binding events between TfR chains.\",\n      \"method\": \"X-ray crystallography (2.8 Å crystal structure of HFE–TfR extracellular complex)\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — atomic-resolution crystal structure with structural validation of the binding interface\",\n      \"pmids\": [\"10638746\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"HFE competes with diferric transferrin (Fe-Tf) for binding to TfR by binding at or near the Fe-Tf binding site on TfR. Inhibition assays show the Fe-Tf:TfR:HFE ternary complex contains one Fe-Tf and one HFE bound to a TfR homodimer, with HFE reducing the apparent affinity of TfR for Fe-Tf.\",\n      \"method\": \"Radioactivity-based and biosensor (surface plasmon resonance) binding/inhibition assays with soluble recombinant proteins\",\n      \"journal\": \"Journal of Molecular Biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with two orthogonal quantitative binding assays\",\n      \"pmids\": [\"10556042\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"HFE and Fe-Tf compete directly for their overlapping binding sites on each TfR polypeptide chain without negative cooperativity between the two TfR chains. A heterodimeric TfR engineered so one chain binds only HFE and the other only Fe-Tf confirmed the absence of cooperativity. Cell-line experiments showed this competition alters HFE trafficking patterns, indicating physiological relevance.\",\n      \"method\": \"Heterodimeric mutant TfR binding studies (soluble proteins) combined with transfected cell-line localization experiments\",\n      \"journal\": \"The Journal of Biological Chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — reconstitution with engineered heterodimer plus cellular validation, single lab but two orthogonal methods\",\n      \"pmids\": [\"15056661\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"HFE protein is physically associated with TfR and β2-microglobulin in crypt enterocytes of human duodenum (as in placenta). Crypt enterocytes showed dramatically higher transferrin-bound iron uptake than villus cells, consistent with HFE modulating transferrin-bound iron uptake to sense body iron stores.\",\n      \"method\": \"Immunocytochemistry, co-immunoprecipitation/Western blot of crypt enterocyte fractions, iron uptake assays with isolated crypt vs. villus cells\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP/Western blot showing physical association plus functional iron uptake assay in primary human tissue\",\n      \"pmids\": [\"9990067\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Stable overexpression of HFE in HeLa cells decreases iron uptake from diferric transferrin and activates iron-regulatory proteins (IRPs), implying HFE reduces the intracellular labile iron pool. This IRP activation is accompanied by downregulation of ferritin and upregulation of transferrin receptor.\",\n      \"method\": \"Stably transfected HeLa cell line (tetracycline-inducible HFE), iron uptake assays, IRP activity assays, Western blot for ferritin and TfR\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean inducible expression system with multiple downstream readouts, single lab\",\n      \"pmids\": [\"10572108\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Targeted disruption of the murine Hfe gene produces systemic iron overload (8-fold elevated hepatic iron at 10 weeks, elevated transferrin saturation) with iron predominantly in periportal hepatocytes, establishing that HFE is required for regulation of iron homeostasis in vivo.\",\n      \"method\": \"Gene knockout mouse model; hepatic iron quantification, transferrin saturation measurement, histochemical iron staining\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean knockout with quantitative iron phenotype, widely replicated\",\n      \"pmids\": [\"9482913\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Hfe regulates hepcidin expression as a component of the TfR1 sensing complex. Mutations forcing constitutive Hfe–TfR1 interaction caused iron overload with inappropriately low hepcidin; mutations preventing the interaction caused iron deficiency with inappropriately high hepcidin. Liver-specific Hfe overexpression in Hfe-null mice increased hepcidin and caused iron deficiency. Together these data indicate Hfe induces hepcidin expression when NOT bound to TfR1.\",\n      \"method\": \"Knock-in mouse strains with TfR1 mutations promoting or preventing Hfe interaction; liver-specific transgenic Hfe overexpression in Hfe-/- background; hepcidin mRNA quantification, iron parameter measurement\",\n      \"journal\": \"Cell Metabolism\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple complementary genetic mouse models, each with reciprocal phenotypes, single lab but highly convergent evidence\",\n      \"pmids\": [\"18316026\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Wild-type HFE raises cellular iron by inhibiting iron efflux from monocyte/macrophage cells (THP-1 and primary macrophages), independently of its competition with transferrin for TfR1. The HH-associated mutant H41D retains TfR1 binding but loses the ability to inhibit iron release, indicating these are separable functions of HFE.\",\n      \"method\": \"Iron efflux assays in THP-1 monocyte cell line and primary macrophages from healthy individuals and HH patients; H41D mutant functional comparison; transferrin competition assay\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean cell-based efflux assay with mutant controls and primary human cells, single lab\",\n      \"pmids\": [\"12429850\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"HFE interacts with the BMP type I receptor ALK3, inhibiting ALK3 ubiquitination and proteasomal degradation, thereby increasing ALK3 protein levels and its accumulation at the cell surface. This stabilization of ALK3 by HFE increases Smad1/5/8 phosphorylation and hepcidin expression; BMP pathway inhibition abolishes HFE-induced hepcidin upregulation. Both C282Y and H63D HFE mutants fail to increase ALK3 cell-surface expression. Hfe deletion in mice reduces hepatic ALK3 protein.\",\n      \"method\": \"HFE overexpression in Hep3B cells; co-immunoprecipitation (HFE–ALK3 interaction); ubiquitination assays; flow cytometry (cell-surface ALK3); phospho-Smad Western blot; BMP inhibitor treatment; Hfe-/- mouse liver Western blot\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (co-IP, ubiquitination assay, cell-surface quantification, mouse KO validation) in single lab\",\n      \"pmids\": [\"24904118\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Hepatocyte-specific AAV-mediated expression of Hfe in Hfe-null mice increases hepcidin mRNA and lowers hepatic iron and transferrin saturation, while Hfe expression in Tfr2-deficient mice has no effect on iron levels (and vice versa). Co-IP of liver lysates did not detect physical interaction between Hfe and Tfr2 in vivo, suggesting Hfe is limiting in the Hfe/Tfr2 complex that regulates hepcidin, and that both proteins are required in hepatocytes for hepcidin regulation.\",\n      \"method\": \"Hepatocyte-specific AAV2/8 gene delivery; hepcidin mRNA quantification; liver and serum iron measurement; co-immunoprecipitation of endogenous liver lysates\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo rescue with negative co-IP result clarifying interaction requirement; single lab, two complementary methods\",\n      \"pmids\": [\"20177050\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Hepatocellular overexpression of Hfe induces hepcidin and causes iron deficiency even in Tfr2-null mice, demonstrating that Tfr2 is not required for Hfe-dependent hepcidin induction. Co-IP of liver lysates did not detect Hfe–Tfr2 physical interaction in vivo.\",\n      \"method\": \"Transgenic Hfe overexpression in Tfr2(Y245X/Y245X) mice; hepcidin mRNA measurement; blood iron parameters; co-immunoprecipitation of liver lysates\",\n      \"journal\": \"American Journal of Hematology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic rescue in Tfr2-null background with negative co-IP; single lab\",\n      \"pmids\": [\"22460705\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Genetic epistasis in mice demonstrates Hfe and Hjv operate in the same pathway for hepcidin regulation: Hfe(-/-)Hjv(-/-) double-knockout mice are indistinguishable from single Hjv(-/-) mice in hepcidin suppression, iron overload, and Smad signaling, indicating Hfe functions upstream of or requires HJV-dependent BMP-Smad signaling.\",\n      \"method\": \"Double-knockout mouse generation (Hfe-/-Hjv-/-); serum and hepatic iron quantification; hepcidin mRNA; Smad1/5/8 phosphorylation Western blot; dietary iron challenge\",\n      \"journal\": \"Journal of Molecular Medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean double-knockout epistasis with multiple iron and signaling readouts, convergent with complementary study (PMID 25608116)\",\n      \"pmids\": [\"25609138\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"In Hfe(-/-)Hjv(-/-) double-knockout mice, iron-induced phosphorylation of Smad1/5/8 is absent (as in Hjv(-/-) alone), and hepcidin cannot be induced by acute iron delivery, confirming that HFE-dependent hepcidin regulation requires HJV-mediated BMP-Smad signaling.\",\n      \"method\": \"Double-knockout mice; acute iron gavage; Smad1/5/8 phosphorylation Western blot; hepcidin mRNA quantification\",\n      \"journal\": \"Antioxidants & Redox Signaling\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with mechanistic signaling readout, corroborated by independent lab (PMID 25609138)\",\n      \"pmids\": [\"25608116\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Hfe is required for establishment of basal hepcidin levels but is dispensable for hepcidin upregulation in response to iron loading or acute inflammation (LPS). In contrast, LPS-induced hepcidin regulation is TLR-4 dependent. Hepatic ferroportin regulation by iron and LPS is largely independent of Hfe.\",\n      \"method\": \"Hfe-/- and β2m-/- mice subjected to iron deprivation, iron loading, and LPS challenge; hepcidin mRNA quantification; ferroportin protein measurement; TLR-4 knockout comparison\",\n      \"journal\": \"American Journal of Physiology - Gastrointestinal and Liver Physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple genetic models and dietary/pharmacological challenges, single lab\",\n      \"pmids\": [\"16565419\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"In HT29 colonic cells (a duodenal model), stable HFE expression increases ferritin by inhibiting iron efflux rather than by affecting TfR1-mediated uptake. This effect is independent of HFE's interaction with TfR1 (shown using the W81A mutant with greatly reduced TfR1 affinity) and is associated with decreased hephaestin mRNA.\",\n      \"method\": \"Stably transfected HT29 cells; ferritin Western blot; iron uptake and efflux assays; W81A TfR1-binding mutant comparison; hephaestin mRNA RT-PCR\",\n      \"journal\": \"The Journal of Biological Chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — stable cell model with TfR1-binding mutant control and efflux vs. uptake distinction; single lab\",\n      \"pmids\": [\"15044462\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"In Hfe-knockout hepatocytes, Tfr1-mediated (low-concentration) transferrin-bound iron uptake is increased 40–70% compared to iron-loaded wild-type hepatocytes with similar Tfr1 expression, showing Hfe specifically regulates the Tfr1-mediated hepatocyte iron uptake pathway. The high-capacity Tfr1-independent (putative Tfr2) pathway is not affected by absence of Hfe.\",\n      \"method\": \"Primary hepatocytes from Hfe-/- and wild-type mice; dual-concentration 125I-Tf/59Fe uptake assays distinguishing Tfr1 and Tfr1-independent pathways; Tfr1 and Tfr2 mRNA/protein quantification\",\n      \"journal\": \"Hepatology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — primary cell functional assay with pathway-specific concentrations and molecular quantification; single lab\",\n      \"pmids\": [\"18393371\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Knock-in mice carrying H67D (murine equivalent of human H63D) show hepatic iron loading that is intermediate between wild-type and C294Y homozygotes. H67D/H67D, C294Y/C294Y, and H67D/C294Y compound heterozygotes all develop hepatic iron loading, establishing that the H67D allele causes partial loss of Hfe function.\",\n      \"method\": \"Knock-in mouse generation; hepatic iron quantification at 10 weeks on standard diet\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo knock-in models with allelic series showing dose-response relationship\",\n      \"pmids\": [\"14673107\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"HFE cross-talks with the MHC class I antigen presentation pathway: PBMCs from HH patients with the C282Y mutation show enhanced endocytosis and premature dissociation of MHC class I–β2m–peptide complexes, producing low-stability heterotrimers and increased free class I heavy chains at the cell surface. Earlier peptide loading and ER maturation of MHC class I are also observed in C282Y cells.\",\n      \"method\": \"FACS analysis of MHC class I surface expression and endocytosis rate; biochemical thermostability assays of MHC class I complexes; comparison of patient (C282Y) PBMCs vs. normal PBMCs\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — primary human cell experiments with multiple orthogonal assays; single lab\",\n      \"pmids\": [\"15840699\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Wild-type HFE (but not C282Y-mutated HFE) inhibits CD8+ T-lymphocyte activation (MIP-1β secretion and 4-1BB expression) when expressed in antigen-presenting cells. This inhibition is independent of MHC class I surface levels, β2-microglobulin competition, or HFE–TfR interaction. The α1-α2 domains of HFE are responsible for this immunosuppressive activity.\",\n      \"method\": \"Transient HFE transfection in APC model cells; co-culture with antigen-specific CD8+ T lymphocytes; cytokine ELISA (MIP-1β); 4-1BB flow cytometry; domain deletion mutants; W81A (TfR1-binding) mutant control\",\n      \"journal\": \"European Journal of Immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-based functional assay with domain mutants and multiple readouts; single lab\",\n      \"pmids\": [\"24643698\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"HFE acts as a negative regulator of RIG-I-like receptor (RLR)-mediated type I interferon signaling by binding to MAVS (mitochondrial antiviral signaling protein) and mediating its autophagic degradation via SQSTM1/p62. RNA virus infection inhibits the HFE–MAVS interaction, blocking MAVS autophagic degradation. Hfe depletion abrogates MAVS degradation and enhances antiviral immune responses.\",\n      \"method\": \"Co-immunoprecipitation (HFE–MAVS and HFE–SQSTM1 interactions); Hfe knockdown/knockout cells and mice; type I IFN and cytokine measurement; autophagy flux assays; viral infection models\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP of endogenous proteins with functional KO validation in vitro and in vivo; single lab\",\n      \"pmids\": [\"32746697\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"HFE protein is expressed on the cell surface of gastric epithelial cells, tissue macrophages, and circulating monocytes/granulocytes. The C282Y mutation reduces but does not completely prevent cell-surface presentation of HFE in these primary human cell types.\",\n      \"method\": \"Immunocytochemistry of tissue sections; immunostaining of isolated leukocyte populations from normal subjects and HH patients; antisera against two distinct HFE peptides\",\n      \"journal\": \"Haematologica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — direct immunolocalization in primary human tissues and cells with two independent antisera, single lab\",\n      \"pmids\": [\"10756356\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"HFE mRNA is expressed almost exclusively in the retinal pigment epithelium (RPE) within the retina, and HFE protein localizes specifically to the basolateral membrane of RPE cells. HFE-interacting proteins TfR1, TfR2, and β2-microglobulin are co-expressed in the retina, consistent with HFE regulating iron homeostasis at the RPE basolateral membrane.\",\n      \"method\": \"RT-PCR; in situ hybridization; immunofluorescence; immunogold electron microscopy in mouse retina\",\n      \"journal\": \"Investigative Ophthalmology & Visual Science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple localization methods (in situ hybridization, immunofluorescence, immunogold EM) converging on basolateral RPE localization; single lab\",\n      \"pmids\": [\"17003411\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Hepatocyte-specific TfR1 knockout mice show inappropriately high hepcidin relative to serum/liver iron, and combined hepatocyte Tfrc/Hfe double knockout abolishes the iron phenotype seen in Tfrc-only knockout mice, establishing that the major non-redundant function of hepatocyte TfR1 in iron homeostasis is to interact with HFE to regulate hepcidin. This pathway is modulated by serum iron and contributes to hepcidin suppression and iron overload in murine β-thalassemia.\",\n      \"method\": \"Hepatocyte-specific Tfrc conditional knockout mice (Tfrcfl/fl;Alb-Cre); double knockout with Hfe and β-thalassemia models; hepcidin mRNA, serum/liver iron, erythropoietin, erythroferrone measurements; iron challenge experiments\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple complementary conditional knockout models with quantitative iron and hormonal phenotypes; epistasis cleanly assigns TfR1 function to HFE interaction\",\n      \"pmids\": [\"36322932\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Expression of H63D and C282Y HFE variants in neuroblastoma SH-SY5Y cells alters the labile iron pool and selectively increases secretion of MCP-1 (monocyte chemoattractant protein-1) compared to wild-type HFE. MCP-1 secretion is tightly correlated with intracellular iron status, but the HFE genotype also influences MCP-1 independently of iron level, and modifies the pharmacological effect of minocycline on MCP-1.\",\n      \"method\": \"Stably transfected neuroblastoma cells expressing HFE variants; multiplex cytokine immunoassay; iron manipulation (ferric ammonium citrate, DFO); labile iron pool measurement\",\n      \"journal\": \"Journal of Neuroinflammation\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single cell model, cytokine assay without mechanistic resolution of direct vs. iron-mediated HFE effect\",\n      \"pmids\": [\"19228389\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"HFE gene is expressed in rat hepatocytes (parenchymal cells) in addition to non-parenchymal liver cells, with highest expression in liver among all tissues. This raises the possibility that HFE has a direct role in hepatocyte iron metabolism, not only in Kupffer cells.\",\n      \"method\": \"Northern blot (tissue expression); real-time PCR of fractionated liver cell populations (parenchymal vs. non-parenchymal); gene cloning and exon-intron structure determination\",\n      \"journal\": \"Journal of Hepatology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — localization by mRNA quantification only, no functional readout; single lab\",\n      \"pmids\": [\"12927914\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"HFE is an MHC class I-like protein that physically interacts with transferrin receptor 1 (TfR1) at an overlapping site with transferrin, directly competing for TfR1 binding and reducing cellular iron uptake; when free from TfR1 (displaced by high diferric-transferrin saturation), hepatocyte HFE signals through the BMP type I receptor ALK3 and the HJV-dependent BMP–Smad1/5/8 pathway to upregulate the iron-regulatory hormone hepcidin, which in turn suppresses intestinal iron absorption and macrophage iron release—thus acting as a hepatocyte iron sensor whose disruption (C282Y or H63D mutations) causes hereditary hemochromatosis through inappropriately low hepcidin; additionally, HFE inhibits iron efflux from macrophages independently of TfR1, inhibits MAVS autophagic degradation to modulate innate antiviral immunity, and suppresses CD8+ T-lymphocyte activation via its α1-α2 domains.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"HFE is an MHC class I-like protein that functions as a hepatocyte iron sensor governing systemic iron homeostasis, and its disruption causes hereditary hemochromatosis through inappropriately low levels of the iron-regulatory hormone hepcidin [#5, #6, #16]. HFE binds the extracellular dimerization domain of transferrin receptor 1 (TfR1) using the helices that correspond to the MHC peptide-binding groove, occupying a site that overlaps the diferric-transferrin (Fe-Tf) binding site, so that HFE and Fe-Tf compete directly for each TfR1 chain without negative cooperativity [#0, #1, #2]. This competition reduces transferrin-mediated iron uptake and lowers the intracellular labile iron pool, activating iron-regulatory proteins [#4, #15]. The sensing logic is that HFE induces hepcidin when displaced from TfR1: forcing constitutive HFE–TfR1 interaction lowers hepcidin and causes iron overload, while preventing it raises hepcidin, and hepatocyte TfR1's principal non-redundant role in iron homeostasis is to sequester HFE [#6, #22]. Free HFE stabilizes the BMP type I receptor ALK3 by inhibiting its ubiquitination and proteasomal degradation, thereby increasing ALK3 surface levels and Smad1/5/8 phosphorylation, and this hepcidin induction is genetically dependent on the HJV-mediated BMP–Smad pathway [#8, #11, #12]; the C282Y and H63D disease mutations fail to stabilize ALK3 [#8]. Beyond hepcidin signaling, HFE inhibits iron efflux from macrophages independently of its TfR1 interaction [#7, #14], suppresses CD8+ T-lymphocyte activation through its α1–α2 domains [#18], and negatively regulates RIG-I-like receptor antiviral signaling by binding MAVS and routing it to SQSTM1/p62-dependent autophagic degradation [#20].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Established that HFE is genuinely required for iron homeostasis in vivo, anchoring the gene's physiological role before any molecular mechanism was known.\",\n      \"evidence\": \"Targeted Hfe knockout mouse with hepatic iron quantification and histochemistry\",\n      \"pmids\": [\"9482913\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not identify the molecular partner or signaling output through which HFE regulates iron\", \"Hepatocyte-versus-macrophage site of action not resolved\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Defined the central molecular interaction by showing HFE competes with diferric transferrin for an overlapping site on TfR1, explaining how HFE could modulate iron uptake.\",\n      \"evidence\": \"SPR and radioligand inhibition assays with soluble recombinant HFE, TfR, and Fe-Tf; co-IP/Western in primary human duodenal enterocytes\",\n      \"pmids\": [\"10556042\", \"9990067\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vitro stoichiometry does not establish the downstream signaling consequence of competition\", \"Tissue association does not prove which cells sense iron systemically\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Connected HFE–TfR1 binding to a cellular outcome, showing HFE overexpression lowers the labile iron pool and activates IRPs.\",\n      \"evidence\": \"Tetracycline-inducible HFE HeLa line with iron uptake, IRP activity, and ferritin/TfR Western readouts\",\n      \"pmids\": [\"10572108\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"HeLa is not a hepatocyte or enterocyte model\", \"Does not link the labile iron change to hepcidin regulation\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Provided the atomic-resolution architecture of the HFE–TfR complex, revealing the MHC-groove helices contact the TfR dimerization domain and that binding rearranges the TfR dimer interface.\",\n      \"evidence\": \"2.8 Å X-ray crystal structure of the HFE–TfR ectodomain complex\",\n      \"pmids\": [\"10638746\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure does not capture the membrane-bound signaling complex or HFE engagement with hepcidin machinery\", \"Conformational link between TfR binding and HFE release is structural inference only\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Separated HFE functions by showing it inhibits macrophage iron efflux independently of TfR1 competition, indicating more than one biochemical activity.\",\n      \"evidence\": \"Iron efflux assays in THP-1 and primary macrophages with the H41D mutant that retains TfR1 binding but loses efflux inhibition\",\n      \"pmids\": [\"12429850\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular target mediating efflux inhibition not identified\", \"Single-lab cell assay without in vivo confirmation\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Demonstrated that the H63D-equivalent allele is a partial loss-of-function, ordering the disease alleles into a severity series.\",\n      \"evidence\": \"H67D and C294Y knock-in mice with hepatic iron quantification across an allelic series\",\n      \"pmids\": [\"14673107\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not define which molecular function each mutation disrupts\", \"Diet- and age-dependent penetrance not characterized\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Refined the binding mechanism by showing HFE–TfR1 and Fe-Tf–TfR1 competition occurs per chain without negative cooperativity, and that competition alters HFE trafficking.\",\n      \"evidence\": \"Engineered heterodimeric TfR binding studies plus transfected cell-line localization\",\n      \"pmids\": [\"15056661\", \"15044462\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"The trafficking outcome's relevance to systemic hepcidin control not yet established\", \"TfR1-independent efflux mechanism still molecularly undefined\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Established the sensing logic of the system: HFE induces hepcidin specifically when NOT bound to TfR1, defining displacement by Fe-Tf as the trigger.\",\n      \"evidence\": \"Knock-in TfR1 mutants forcing or preventing HFE interaction, plus liver-specific HFE transgenic rescue in Hfe-null mice; hepcidin and iron readouts\",\n      \"pmids\": [\"18316026\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not identify the receptor through which free HFE signals to hepcidin\", \"Hepatocyte iron-uptake contribution versus signaling contribution unresolved\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Localized HFE's iron-uptake control to the TfR1-mediated hepatocyte pathway specifically, sharpening the sensor model.\",\n      \"evidence\": \"Dual-concentration 125I-Tf/59Fe uptake assays in primary Hfe-/- versus wild-type hepatocytes\",\n      \"pmids\": [\"18393371\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Does not connect altered hepatocyte uptake to hepcidin output\", \"Tfr1-independent pathway identity (Tfr2) inferred, not proven\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Clarified the relationship to TfR2, showing both proteins are required in hepatocytes for hepcidin regulation while no stable Hfe–Tfr2 complex is detected in vivo, and HFE is limiting.\",\n      \"evidence\": \"Hepatocyte-specific AAV Hfe delivery in Hfe-null and Tfr2-deficient mice; co-IP of endogenous liver lysates\",\n      \"pmids\": [\"20177050\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Negative co-IP does not exclude a transient or low-affinity interaction\", \"Mechanism by which Tfr2 contributes to the same pathway not defined\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Showed Hfe can induce hepcidin even without Tfr2, indicating Tfr2 is not strictly required for HFE-dependent hepcidin induction.\",\n      \"evidence\": \"Transgenic Hfe overexpression in Tfr2-null mice; hepcidin mRNA and iron parameters; co-IP\",\n      \"pmids\": [\"22460705\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Apparent tension with the earlier co-requirement finding not fully reconciled\", \"Single-lab genetic system\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Identified the receptor mechanism for HFE-driven hepcidin: HFE stabilizes the BMP type I receptor ALK3 by blocking its degradation, increasing surface ALK3 and Smad signaling.\",\n      \"evidence\": \"HFE overexpression in Hep3B with co-IP, ubiquitination assays, surface ALK3 flow cytometry, phospho-Smad blots, BMP inhibitor, and Hfe-/- mouse liver\",\n      \"pmids\": [\"24904118\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not show how TfR1 displacement is coupled to ALK3 engagement\", \"Structural basis of HFE–ALK3 interaction unknown\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Defined an iron-independent immunoregulatory function, with HFE suppressing CD8+ T-cell activation via its α1–α2 domains.\",\n      \"evidence\": \"HFE transfection in APC model cells co-cultured with antigen-specific CD8+ T cells; domain-deletion and W81A mutants; MIP-1β and 4-1BB readouts\",\n      \"pmids\": [\"24643698\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular target of the α1–α2-mediated suppression not identified\", \"In vivo immunological relevance not established\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Placed HFE genetically within the HJV-dependent BMP–Smad pathway, establishing that HFE-driven hepcidin regulation requires HJV-mediated signaling.\",\n      \"evidence\": \"Hfe-/-Hjv-/- double-knockout epistasis with iron, hepcidin, and acute-iron-induced Smad1/5/8 phosphorylation readouts (two independent studies)\",\n      \"pmids\": [\"25609138\", \"25608116\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether HFE and HJV act on the same receptor complex molecularly not resolved here\", \"Order of HFE relative to HJV in the pathway inferred from epistasis\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Extended HFE into innate antiviral immunity, showing it binds MAVS and drives its SQSTM1/p62-dependent autophagic degradation to dampen type I interferon responses.\",\n      \"evidence\": \"Co-IP of HFE–MAVS and HFE–SQSTM1; Hfe knockdown/knockout cells and mice; IFN measurement, autophagy flux, and viral infection models\",\n      \"pmids\": [\"32746697\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct versus indirect HFE–MAVS binding not structurally resolved\", \"Relationship between this function and iron-sensing role unclear\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Assigned the major non-redundant function of hepatocyte TfR1 in iron homeostasis to its interaction with HFE, cementing the displacement-based sensor model and its relevance to β-thalassemia.\",\n      \"evidence\": \"Hepatocyte-specific Tfrc knockout, Tfrc/Hfe double knockout, and β-thalassemia mouse models with hepcidin, iron, erythropoietin, and erythroferrone readouts\",\n      \"pmids\": [\"36322932\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not resolve how the sensing complex transitions to ALK3/HJV signaling at the molecular level\", \"Quantitative contribution of HFE displacement versus other inputs to physiological hepcidin setpoint not defined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How free HFE, released from TfR1 upon transferrin saturation, is physically coupled to ALK3 stabilization and HJV-dependent BMP–Smad signaling at the hepatocyte membrane remains the central unresolved mechanistic question.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structure of the HFE–ALK3 or HFE–HJV signaling complex\", \"Mechanism integrating the TfR1, ALK3/HJV, macrophage efflux, and antiviral functions into one protein not unified\", \"Whether HFE engages distinct partners in different tissues (hepatocyte, macrophage, RPE) unresolved\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [1, 2, 6, 8]},\n      {\"term_id\": \"GO:0140313\", \"supporting_discovery_ids\": [1, 2, 6]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [6, 8, 22]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 8, 20, 21]},\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [20]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [5, 6, 8, 22]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [8, 11, 12]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [18, 20]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [5, 16]}\n    ],\n    \"complexes\": [\n      \"HFE–TfR1 complex\",\n      \"HFE–TfR1–transferrin sensing complex\"\n    ],\n    \"partners\": [\n      \"TFRC\",\n      \"B2M\",\n      \"ALK3\",\n      \"HJV\",\n      \"TFR2\",\n      \"MAVS\",\n      \"SQSTM1\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":5,"faith_total":6,"faith_pct":83.33333333333333}}