{"gene":"HGFAC","run_date":"2026-06-10T01:55:22","timeline":{"discoveries":[{"year":2000,"finding":"Active HGFA forms a specific complex with membrane-bound HAI-1 (but not HAI-2) on the surface of epithelial cells, requiring HGFA enzymatic activity for binding. HAI-1 acts as both an inhibitor and a cell-surface reservoir of active HGFA. The HGFA·HAI-1 complex is released from the cell surface by phorbol ester or IL-1β treatment via a zinc-metalloproteinase-dependent shedding mechanism, generating 58-kDa HAI-1 fragments with reduced inhibitory potency and restoring HGFA activity in the supernatant.","method":"Co-immunoprecipitation, CHO cell engineered expression system, cell-surface binding assays, phorbol ester/IL-1β treatment with metalloproteinase inhibitor BB3103","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal binding confirmed in engineered CHO system and native epithelial cells, multiple orthogonal methods (Co-IP, engineered expression, pharmacological inhibition), single lab with rigorous controls","pmids":["11013244"],"is_preprint":false},{"year":2005,"finding":"Crystal structure of the HGFA protease domain at 2.7 Å revealed an unconventional, non-enzymatically competent conformation of active-site residues in the unliganded state. Co-crystal structure with the first Kunitz domain (KD1) of HAI-1B at 2.6 Å showed that inhibitor binding rearranges the 220-loop and 99-loop into a substrate-binding-competent conformation. KD1 occupies subsites S1, S2, and S4 in a substrate-like manner and is solely responsible for the inhibitory specificity of the HAI-1B extracellular region. HGFA, matriptase, hepsin, plasma kallikrein, and trypsin are potently inhibited by KD1.","method":"X-ray crystallography (2.7 Å apo, 2.6 Å complex), serine protease inhibition panel assay","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structures of both apo and inhibitor-bound forms with functional inhibition data across 16 proteases","pmids":["15713485"],"is_preprint":false},{"year":2008,"finding":"Kallikrein-related peptidases KLK4 and KLK5 cleave pro-HGFA at the normal processing site Arg407-Ile408, activating the zymogen. KLK5 required a negatively charged substance (dextran sulfate) for efficient processing whereas KLK4 did not. HGFA activated by these KLKs efficiently converted pro-HGF/SF into active form, leading to cellular scattering and invasion in vitro. Both KLK4 and KLK5 activity on pro-HGFA was strongly inhibited by HAI-1.","method":"In vitro protease cleavage assay, N-terminal sequencing of cleavage site, cell scattering/invasion assay, inhibitor (HAI-1) functional assay","journal":"The FEBS journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with cleavage-site identification by N-terminal sequencing, functional downstream readout, single lab","pmids":["18221492"],"is_preprint":false},{"year":2010,"finding":"Crystal structures of the HGFA short-form (34 kDa protease domain) reveal two conformational states of substrate-specificity-determining loops (220-loop and 99-loop): enzymatically competent and non-competent. In the KD1-HGFA complex structure, KD1 side chains occupying S1, S2, and S4 subsites are virtually superimposable on the P1, P2, and P4 residues of a pro-HGF-derived substrate mimic (Lys-Gln-Leu-Arg chloromethyl ketone), rationalizing HGFA's narrow substrate specificity for pro-HGF and pro-macrophage-stimulating protein.","method":"X-ray crystallography, substrate mimic chloromethyl ketone co-crystal comparison","journal":"The FEBS journal","confidence":"High","confidence_rationale":"Tier 1 / Strong — structural determination with substrate mimic comparison providing mechanistic explanation for substrate selectivity","pmids":["20402765"],"is_preprint":false},{"year":2010,"finding":"Protein C inhibitor (PCI/SERPINA5) forms a complex with active HGFA and inhibits HGFA-catalyzed activation of pro-HGF. In hPCI-transgenic mice, liver regeneration after partial hepatectomy was significantly impaired compared to wild-type, and this impairment was rescued by anti-human PCI antibody. Plasma HGFA-PCI complex levels were elevated in patients after hepatectomy.","method":"In vitro complex formation assay, hPCI-transgenic mouse partial hepatectomy model, antibody rescue experiment, patient plasma ELISA","journal":"The FEBS journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo genetic model with antibody rescue and patient correlation, but abstract-level detail limits full method assessment","pmids":["20402764"],"is_preprint":false},{"year":2010,"finding":"HGFA is a serine protease activated downstream of the blood coagulation cascade (thrombin cleaves pro-HGFA), linking tissue injury to proteolytic activation of pro-HGF. HGFA also activates macrophage-stimulating protein (MSP), the ligand for RON receptor. HGFA-knockout mice show impaired regeneration of severely damaged mucosal epithelium and impaired initial macrophage recruitment in injured tissue in vivo.","method":"HGFA-knockout mouse model, in vivo tissue injury/regeneration assays","journal":"The FEBS journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — knockout mouse phenotype with defined cellular readouts (regeneration, macrophage recruitment), but review-style abstract limits detail","pmids":["20402763"],"is_preprint":false},{"year":2017,"finding":"Systemic active HGFA, released in response to injury, is sufficient to induce transition of skeletal muscle stem cells (MuSCs) and fibro-adipogenic progenitors (FAPs) into GAlert state via proteolytic processing/activation of HGF. Administration of active HGFA to animals accelerated stem cell activation and tissue repair.","method":"In vivo systemic HGFA administration to mice, stem cell functional activation assays, tissue repair readouts","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo gain-of-function with defined cellular phenotype (GAlert transition), single lab","pmids":["28423312"],"is_preprint":false},{"year":2012,"finding":"HNF1α directly regulates transcription of the Hgfac gene in pancreatic β-cells. HNF1α knockdown in MIN6 cells decreased Hgfac expression, and Hgfac expression was also reduced in islets of HNF1α(+/-) mice. Reporter gene analysis and chromatin immunoprecipitation (ChIP) confirmed direct HNF1α binding to the Hgfac promoter.","method":"shRNA knockdown, reporter gene assay, chromatin immunoprecipitation (ChIP), HNF1α heterozygous mouse model","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and reporter assay establish direct transcriptional regulation, corroborated in vivo by heterozygous mouse, single lab","pmids":["22877752"],"is_preprint":false},{"year":2023,"finding":"ChREBP directly regulates HGFAC transcription in liver (identified by ChREBP ChIP-Seq). HGFAC-KO mice exhibited metabolic phenotypes concordant with human loss-of-function variants. In gain- and loss-of-function mouse models, HGFAC enhanced lipid and glucose homeostasis, potentially mediated through activation of hepatic PPARγ activity.","method":"ChREBP ChIP-Seq, HGFAC knockout mouse, gain-of-function genetic mouse models, metabolic phenotyping, PPARγ activity assay","journal":"JCI insight","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP-Seq plus bidirectional genetic mouse models with metabolic readouts, single lab, PPARγ mechanism is partial","pmids":["36413406"],"is_preprint":false},{"year":2023,"finding":"DNMT3A methylates the HGFAC promoter, silencing HGFAC expression in hepatocellular carcinoma. miR-4270 targets the 3'UTR of DNMT3A (confirmed by dual-luciferase and Ago2-RIP assays), reducing DNMT3A-mediated methylation of the HGFAC promoter (confirmed by ChIP and methylation-specific PCR), thereby restoring HGFAC expression. HGFAC overexpression counteracted HCC cell growth promoted by miR-4270 inhibition.","method":"Dual-luciferase reporter assay, Ago2-RIP, Co-IP, ChIP, methylation-specific PCR, rescue functional assays, xenograft mouse model","journal":"PeerJ","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal epigenetic methods (ChIP, MSP, luciferase, RIP) establish the regulatory mechanism, single lab","pmids":["38077422"],"is_preprint":false},{"year":2014,"finding":"Substrate-based ketothiazole inhibitors (e.g., Ac-KRLR-kt) inhibit HGFA enzymatic activity at nM Ki values (as low as 12 nM), block HGFA-mediated conversion of native pro-HGF and pro-MSP, and cause dose-dependent decrease of c-MET signaling in MDA-MB-231 breast cancer cells.","method":"Kinetic fluorogenic enzyme assay, native pro-HGF/pro-MSP cleavage assay, c-MET phosphorylation in cancer cells","journal":"ACS medicinal chemistry letters","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro kinetic enzyme assay with cellular signaling readout, single lab, demonstrates catalytic mechanism exploitation","pmids":["25408834"],"is_preprint":false},{"year":2001,"finding":"HGFA (factor XII-like serine protease) critically mediates the enhanced activation of HGF/SF observed in colorectal carcinoma tissues compared with normal mucosa, as assessed by the ratio of two-chain (active) to single-chain (latent) HGF. HAI-1 functions both as a cell-surface specific inhibitor of active HGFA and as a reservoir/acceptor on the cell surface, concentrating pericellular HGFA activity.","method":"Western blot analysis of HGF activation state in tumor vs. normal tissue, cell-surface binding assays, IL-1β-induced shedding assay","journal":"Human cell","confidence":"Low","confidence_rationale":"Tier 3 / Moderate — tissue biochemistry and cell-surface assay, but abstract-level description limits method detail; largely confirms PMID 11013244 findings in a new tissue context","pmids":["11436357"],"is_preprint":false}],"current_model":"HGFAC encodes a trypsin-like serine protease (HGFA) that circulates as an inactive zymogen (pro-HGFA) cleaved at Arg407-Ile408 by thrombin or by kallikreins KLK4/KLK5, generating an active protease that proteolytically converts pro-HGF and pro-MSP into their active heterodimeric forms; crystal structures reveal that HGFA active-site loops (99-loop, 220-loop) adopt enzymatically non-competent conformations in the unliganded state and are remodeled upon substrate/inhibitor binding, explaining its narrow substrate selectivity; on epithelial cell surfaces, active HGFA is captured and concentrated by membrane-bound HAI-1 and released as an active complex by metalloproteinase-dependent shedding; activity is also negatively regulated by plasma protein C inhibitor (PCI/SERPINA5); transcription of HGFAC is directly controlled by ChREBP and HNF1α in liver and β-cells respectively, and its promoter is silenced by DNMT3A-mediated methylation; systemically, injury-released HGFA drives HGF-dependent transition of tissue stem cells into the GAlert state to promote regeneration."},"narrative":{"mechanistic_narrative":"HGFAC encodes hepatocyte growth factor activator (HGFA), a trypsin-like serine protease that couples tissue injury to growth-factor activation by proteolytically converting pro-HGF and pro-macrophage-stimulating protein (pro-MSP/RON ligand) into their active forms [PMID:20402763, PMID:25408834]. Circulating pro-HGFA is cleaved to its active enzyme by the coagulation protease thrombin [PMID:20402763] and by the kallikrein-related peptidases KLK4 and KLK5, which cut at the physiological Arg407-Ile408 site to yield an enzyme that drives HGF-dependent cell scattering and invasion [PMID:18221492]. Crystal structures show that HGFA's substrate-specificity loops (the 99-loop and 220-loop) rest in an enzymatically non-competent conformation in the unliganded state and are remodeled into a catalytically competent, substrate-binding geometry upon ligand engagement, with KD1 side chains occupying the S1/S2/S4 subsites in register with the pro-HGF cleavage sequence—a structural basis for HGFA's narrow substrate selectivity [PMID:15713485, PMID:20402765]. On epithelial surfaces HGFA activity is captured and concentrated by membrane-bound HAI-1, which acts as both inhibitor and reservoir and releases active enzyme upon zinc-metalloproteinase-dependent shedding [PMID:11013244]; in plasma HGFA is additionally inhibited by protein C inhibitor (SERPINA5/PCI), whose action limits pro-HGF activation and constrains liver regeneration [PMID:20402764]. Functionally, injury-released HGFA is sufficient to drive tissue stem and progenitor cells into the GAlert state and to accelerate repair, and HGFA loss impairs mucosal regeneration and macrophage recruitment [PMID:20402763, PMID:28423312]. HGFAC transcription is directly controlled by lineage-specific factors—HNF1α in pancreatic β-cells [PMID:22877752] and ChREBP in liver, where HGFAC modulates lipid and glucose homeostasis [PMID:36413406]—and is silenced by DNMT3A-mediated promoter methylation in hepatocellular carcinoma [PMID:38077422].","teleology":[{"year":2000,"claim":"Established that active HGFA is not simply released free but is captured at the epithelial cell surface, explaining how its pericellular activity is concentrated and regulated.","evidence":"Co-IP and cell-surface binding in engineered CHO and epithelial cells, with metalloproteinase-dependent shedding triggered by phorbol ester/IL-1β","pmids":["11013244"],"confidence":"High","gaps":["Identity of the shedding metalloproteinase not defined","Quantitative balance between inhibitory and reservoir roles of HAI-1 in vivo unresolved"]},{"year":2001,"claim":"Linked HGFA-driven HGF activation to a disease context by showing enhanced two-chain HGF generation in colorectal carcinoma versus normal mucosa.","evidence":"Western blot of HGF activation state in tumor vs normal tissue plus cell-surface binding/shedding assays","pmids":["11436357"],"confidence":"Low","gaps":["Abstract-level description limits method detail","Largely confirms surface-reservoir findings in a new tissue context rather than adding mechanism","Causal role of HGFA in tumor progression not directly tested"]},{"year":2005,"claim":"Resolved why HGFA is selectively inhibited by HAI-1 and revealed that the enzyme is conformationally latent until ligand binding remodels its active site.","evidence":"X-ray structures of apo HGFA protease domain and the HAI-1B KD1 complex with an inhibition panel across multiple proteases","pmids":["15713485"],"confidence":"High","gaps":["Does not capture the physiological pro-HGF substrate complex directly","Dynamics of the loop transition in solution not measured"]},{"year":2008,"claim":"Identified KLK4 and KLK5 as physiological activators of pro-HGFA, broadening the proteolytic inputs that switch on HGFA beyond coagulation.","evidence":"In vitro cleavage with N-terminal sequencing of the Arg407-Ile408 site, downstream cell scattering/invasion assays, and HAI-1 inhibition tests","pmids":["18221492"],"confidence":"High","gaps":["Relative in vivo contribution of KLK4/KLK5 versus thrombin not quantified","Tissue contexts where each activator dominates unknown"]},{"year":2010,"claim":"Provided a structural rationale for HGFA's narrow specificity by superimposing KD1 subsite occupancy onto a pro-HGF-derived substrate mimic.","evidence":"X-ray crystallography of the short-form protease domain compared against a Lys-Gln-Leu-Arg chloromethyl ketone substrate mimic","pmids":["20402765"],"confidence":"High","gaps":["No structure of a genuine pro-HGF/pro-MSP Michaelis complex","Determinants of pro-MSP versus pro-HGF preference not separated"]},{"year":2010,"claim":"Defined plasma protein C inhibitor as a negative regulator of HGFA whose action limits HGF activation and liver regeneration.","evidence":"In vitro complex formation, hPCI-transgenic mouse partial hepatectomy with anti-PCI antibody rescue, and patient plasma ELISA","pmids":["20402764"],"confidence":"Medium","gaps":["Abstract-level detail limits assessment","Stoichiometry and kinetics of HGFA-PCI inhibition not defined"]},{"year":2010,"claim":"Placed HGFA downstream of the coagulation cascade and demonstrated its requirement for mucosal regeneration and macrophage recruitment in vivo.","evidence":"HGFA-knockout mouse tissue injury and regeneration assays","pmids":["20402763"],"confidence":"Medium","gaps":["Review-style abstract limits mechanistic detail","Relative contributions of HGF versus MSP/RON activation to each phenotype unresolved"]},{"year":2012,"claim":"Showed that Hgfac is a direct transcriptional target of HNF1α in pancreatic β-cells, connecting its expression to islet transcriptional programs.","evidence":"shRNA knockdown, reporter assay, ChIP, and HNF1α heterozygous mouse islets","pmids":["22877752"],"confidence":"Medium","gaps":["Functional consequence of β-cell HGFAC expression not established","Single lab"]},{"year":2014,"claim":"Demonstrated that small-molecule active-site inhibition of HGFA blocks pro-HGF/pro-MSP cleavage and dampens c-MET signaling, validating HGFA as a druggable node.","evidence":"Fluorogenic kinetic enzyme assay, native substrate cleavage, and c-MET phosphorylation in MDA-MB-231 cells","pmids":["25408834"],"confidence":"Medium","gaps":["In vivo efficacy and selectivity not addressed","Single lab"]},{"year":2017,"claim":"Showed that systemic active HGFA is sufficient to drive stem/progenitor cells into the GAlert state and accelerate repair, establishing a systemic injury-to-regeneration signaling role.","evidence":"In vivo systemic HGFA administration to mice with MuSC/FAP activation and tissue repair readouts","pmids":["28423312"],"confidence":"Medium","gaps":["Endogenous source and kinetics of injury-released HGFA not defined","Single lab"]},{"year":2023,"claim":"Identified ChREBP-driven hepatic HGFAC transcription and linked HGFAC to systemic lipid and glucose homeostasis, extending its biology beyond proteolytic regeneration into metabolism.","evidence":"ChREBP ChIP-Seq plus bidirectional HGFAC gain/loss-of-function mouse models with metabolic phenotyping and PPARγ activity assays","pmids":["36413406"],"confidence":"Medium","gaps":["Mechanism connecting HGFA proteolysis to PPARγ activation incomplete","Whether metabolic effects require HGF/MSP activation untested"]},{"year":2023,"claim":"Defined an epigenetic silencing axis in which DNMT3A methylates the HGFAC promoter and miR-4270 relieves this silencing, framing HGFAC as a regulated growth-suppressive node in hepatocellular carcinoma.","evidence":"Dual-luciferase, Ago2-RIP, ChIP, methylation-specific PCR, rescue assays, and xenograft model","pmids":["38077422"],"confidence":"Medium","gaps":["Whether tumor suppression depends on HGFA protease activity not tested","Single lab"]},{"year":null,"claim":"How the multiple proteolytic activators, surface reservoir, and serpin inhibitors are integrated to set HGFA activity in specific injured tissues in vivo remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structure of a true pro-HGF/pro-MSP cleavage complex","Tissue-specific dominance of thrombin vs KLK4/KLK5 activation unknown","Mechanistic link between HGFAC and hepatic metabolic regulation incomplete"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[2,3,5,10]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[1,3,10]}],"localization":[{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[5]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-109582","term_label":"Hemostasis","supporting_discovery_ids":[5]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[5,6]}],"complexes":[],"partners":["HAI-1 (SPINT1)","SERPINA5","KLK4","KLK5"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q04756","full_name":"Hepatocyte growth factor activator serine protease","aliases":["Serine protease HGFAC"],"length_aa":655,"mass_kda":70.7,"function":"Serine protease that hydrolyzes the inactive zymogen hepatocyte growth factor (HGFsc) to an activated disulfide-linked heterodimer, then initiating hepatocyte growth factor receptor signaling pathway","subcellular_location":"Secreted","url":"https://www.uniprot.org/uniprotkb/Q04756/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/HGFAC","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/HGFAC","total_profiled":1310},"omim":[{"mim_id":"605124","title":"SERINE PEPTIDASE INHIBITOR, KUNITZ-TYPE, 2; SPINT2","url":"https://www.omim.org/entry/605124"},{"mim_id":"605123","title":"SERINE PEPTIDASE INHIBITOR, KUNITZ-TYPE, 1; SPINT1","url":"https://www.omim.org/entry/605123"},{"mim_id":"604552","title":"HEPATOCYTE GROWTH FACTOR ACTIVATOR; HGFAC","url":"https://www.omim.org/entry/604552"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"liver","ntpm":223.6}],"url":"https://www.proteinatlas.org/search/HGFAC"},"hgnc":{"alias_symbol":["HGFAP","HGFA"],"prev_symbol":[]},"alphafold":{"accession":"Q04756","domains":[{"cath_id":"2.10.10.10","chopping":"113-148","consensus_level":"medium","plddt":79.2725,"start":113,"end":148},{"cath_id":"2.10.25.10","chopping":"202-269","consensus_level":"high","plddt":90.9747,"start":202,"end":269},{"cath_id":"2.40.20.10","chopping":"314-369","consensus_level":"medium","plddt":78.7834,"start":314,"end":369},{"cath_id":"2.40.10.10","chopping":"418-504","consensus_level":"medium","plddt":91.7276,"start":418,"end":504},{"cath_id":"2.40.10.10","chopping":"534-635","consensus_level":"medium","plddt":82.1546,"start":534,"end":635}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q04756","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q04756-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q04756-F1-predicted_aligned_error_v6.png","plddt_mean":75.31},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=HGFAC","jax_strain_url":"https://www.jax.org/strain/search?query=HGFAC"},"sequence":{"accession":"Q04756","fasta_url":"https://rest.uniprot.org/uniprotkb/Q04756.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q04756/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q04756"}},"corpus_meta":[{"pmid":"11668683","id":"PMC_11668683","title":"hGFAP-cre 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York, N.Y. : 1991)","url":"https://pubmed.ncbi.nlm.nih.gov/31504276","citation_count":11,"is_preprint":false},{"pmid":"31803403","id":"PMC_31803403","title":"Piperidine carbamate peptidomimetic inhibitors of the serine proteases HGFA, matriptase and hepsin.","date":"2019","source":"MedChemComm","url":"https://pubmed.ncbi.nlm.nih.gov/31803403","citation_count":10,"is_preprint":false},{"pmid":"22877752","id":"PMC_22877752","title":"Identification of hepatocyte growth factor activator (Hgfac) gene as a target of HNF1α in mouse β-cells.","date":"2012","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/22877752","citation_count":8,"is_preprint":false},{"pmid":"39073183","id":"PMC_39073183","title":"Use of protease substrate specificity screening in the rational design of selective protease inhibitors with unnatural amino acids: Application to HGFA, matriptase, and hepsin.","date":"2024","source":"Protein science : a publication of the Protein Society","url":"https://pubmed.ncbi.nlm.nih.gov/39073183","citation_count":8,"is_preprint":false},{"pmid":"10985963","id":"PMC_10985963","title":"Hepatocyte growth factor activator (HGF-A) and its zymogen in human placenta.","date":"2000","source":"Placenta","url":"https://pubmed.ncbi.nlm.nih.gov/10985963","citation_count":8,"is_preprint":false},{"pmid":"34550336","id":"PMC_34550336","title":"Comparison of the Spatiotemporal Expression Patterns of Three Cre Lines, Emx1IRES-Cre, D6-Cre and hGFAP-Cre, Commonly Used in Neocortical Development Research.","date":"2022","source":"Cerebral cortex (New York, N.Y. : 1991)","url":"https://pubmed.ncbi.nlm.nih.gov/34550336","citation_count":7,"is_preprint":false},{"pmid":"36182093","id":"PMC_36182093","title":"Role of hypoxia on microRNA-dependant regulation of HGFA - HGF - c-Met signalling pathway in human progenitor and mature endothelial cells.","date":"2022","source":"The international journal of biochemistry & cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/36182093","citation_count":5,"is_preprint":false},{"pmid":"12923239","id":"PMC_12923239","title":"Immunohistochemical localization of hepatocyte growth factor activator (HGFA) in developing mouse liver tissues. Heterogeneous distribution of HGFA protein.","date":"2003","source":"The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society","url":"https://pubmed.ncbi.nlm.nih.gov/12923239","citation_count":5,"is_preprint":false},{"pmid":"38077422","id":"PMC_38077422","title":"miR-4270 suppresses hepatocellular carcinoma progression by inhibiting DNMT3A-mediated methylation of HGFAC promoter.","date":"2023","source":"PeerJ","url":"https://pubmed.ncbi.nlm.nih.gov/38077422","citation_count":4,"is_preprint":false},{"pmid":"39609799","id":"PMC_39609799","title":"Serum proteome profiling reveals HGFA as a candidate biomarker for pulmonary arterial hypertension.","date":"2024","source":"Respiratory research","url":"https://pubmed.ncbi.nlm.nih.gov/39609799","citation_count":3,"is_preprint":false},{"pmid":"26662422","id":"PMC_26662422","title":"Production of hGFAP-DsRed transgenic Guangxi Bama mini-pigs via somatic cell nuclear transfer.","date":"2015","source":"Genetics and molecular research : GMR","url":"https://pubmed.ncbi.nlm.nih.gov/26662422","citation_count":2,"is_preprint":false},{"pmid":"40659816","id":"PMC_40659816","title":"Properdin, transcortin and HGFAC are novel plasma biomarkers in canine chronic inflammatory enteropathies from active disease to remission.","date":"2025","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/40659816","citation_count":1,"is_preprint":false},{"pmid":"30111395","id":"PMC_30111395","title":"[Expression and Clinical Significances of HGFA, Matriptase, HAI-1 and HAI-2 in Acute Myeloid Leukemia].","date":"2018","source":"Zhongguo shi yan xue ye xue za zhi","url":"https://pubmed.ncbi.nlm.nih.gov/30111395","citation_count":1,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.02.27.640655","title":"Parental origin of transgene determines recombination efficiency in GFAP-creERT2 mice","date":"2025-03-03","source":"bioRxiv","url":"https://doi.org/10.1101/2025.02.27.640655","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":19210,"output_tokens":3574,"usd":0.05562,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11241,"output_tokens":3909,"usd":0.076965,"stage2_stop_reason":"end_turn"},"total_usd":0.132585,"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\": \"Active HGFA forms a specific complex with membrane-bound HAI-1 (but not HAI-2) on the surface of epithelial cells, requiring HGFA enzymatic activity for binding. HAI-1 acts as both an inhibitor and a cell-surface reservoir of active HGFA. The HGFA·HAI-1 complex is released from the cell surface by phorbol ester or IL-1β treatment via a zinc-metalloproteinase-dependent shedding mechanism, generating 58-kDa HAI-1 fragments with reduced inhibitory potency and restoring HGFA activity in the supernatant.\",\n      \"method\": \"Co-immunoprecipitation, CHO cell engineered expression system, cell-surface binding assays, phorbol ester/IL-1β treatment with metalloproteinase inhibitor BB3103\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal binding confirmed in engineered CHO system and native epithelial cells, multiple orthogonal methods (Co-IP, engineered expression, pharmacological inhibition), single lab with rigorous controls\",\n      \"pmids\": [\"11013244\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Crystal structure of the HGFA protease domain at 2.7 Å revealed an unconventional, non-enzymatically competent conformation of active-site residues in the unliganded state. Co-crystal structure with the first Kunitz domain (KD1) of HAI-1B at 2.6 Å showed that inhibitor binding rearranges the 220-loop and 99-loop into a substrate-binding-competent conformation. KD1 occupies subsites S1, S2, and S4 in a substrate-like manner and is solely responsible for the inhibitory specificity of the HAI-1B extracellular region. HGFA, matriptase, hepsin, plasma kallikrein, and trypsin are potently inhibited by KD1.\",\n      \"method\": \"X-ray crystallography (2.7 Å apo, 2.6 Å complex), serine protease inhibition panel assay\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structures of both apo and inhibitor-bound forms with functional inhibition data across 16 proteases\",\n      \"pmids\": [\"15713485\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Kallikrein-related peptidases KLK4 and KLK5 cleave pro-HGFA at the normal processing site Arg407-Ile408, activating the zymogen. KLK5 required a negatively charged substance (dextran sulfate) for efficient processing whereas KLK4 did not. HGFA activated by these KLKs efficiently converted pro-HGF/SF into active form, leading to cellular scattering and invasion in vitro. Both KLK4 and KLK5 activity on pro-HGFA was strongly inhibited by HAI-1.\",\n      \"method\": \"In vitro protease cleavage assay, N-terminal sequencing of cleavage site, cell scattering/invasion assay, inhibitor (HAI-1) functional assay\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with cleavage-site identification by N-terminal sequencing, functional downstream readout, single lab\",\n      \"pmids\": [\"18221492\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Crystal structures of the HGFA short-form (34 kDa protease domain) reveal two conformational states of substrate-specificity-determining loops (220-loop and 99-loop): enzymatically competent and non-competent. In the KD1-HGFA complex structure, KD1 side chains occupying S1, S2, and S4 subsites are virtually superimposable on the P1, P2, and P4 residues of a pro-HGF-derived substrate mimic (Lys-Gln-Leu-Arg chloromethyl ketone), rationalizing HGFA's narrow substrate specificity for pro-HGF and pro-macrophage-stimulating protein.\",\n      \"method\": \"X-ray crystallography, substrate mimic chloromethyl ketone co-crystal comparison\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — structural determination with substrate mimic comparison providing mechanistic explanation for substrate selectivity\",\n      \"pmids\": [\"20402765\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Protein C inhibitor (PCI/SERPINA5) forms a complex with active HGFA and inhibits HGFA-catalyzed activation of pro-HGF. In hPCI-transgenic mice, liver regeneration after partial hepatectomy was significantly impaired compared to wild-type, and this impairment was rescued by anti-human PCI antibody. Plasma HGFA-PCI complex levels were elevated in patients after hepatectomy.\",\n      \"method\": \"In vitro complex formation assay, hPCI-transgenic mouse partial hepatectomy model, antibody rescue experiment, patient plasma ELISA\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo genetic model with antibody rescue and patient correlation, but abstract-level detail limits full method assessment\",\n      \"pmids\": [\"20402764\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"HGFA is a serine protease activated downstream of the blood coagulation cascade (thrombin cleaves pro-HGFA), linking tissue injury to proteolytic activation of pro-HGF. HGFA also activates macrophage-stimulating protein (MSP), the ligand for RON receptor. HGFA-knockout mice show impaired regeneration of severely damaged mucosal epithelium and impaired initial macrophage recruitment in injured tissue in vivo.\",\n      \"method\": \"HGFA-knockout mouse model, in vivo tissue injury/regeneration assays\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — knockout mouse phenotype with defined cellular readouts (regeneration, macrophage recruitment), but review-style abstract limits detail\",\n      \"pmids\": [\"20402763\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Systemic active HGFA, released in response to injury, is sufficient to induce transition of skeletal muscle stem cells (MuSCs) and fibro-adipogenic progenitors (FAPs) into GAlert state via proteolytic processing/activation of HGF. Administration of active HGFA to animals accelerated stem cell activation and tissue repair.\",\n      \"method\": \"In vivo systemic HGFA administration to mice, stem cell functional activation assays, tissue repair readouts\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo gain-of-function with defined cellular phenotype (GAlert transition), single lab\",\n      \"pmids\": [\"28423312\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"HNF1α directly regulates transcription of the Hgfac gene in pancreatic β-cells. HNF1α knockdown in MIN6 cells decreased Hgfac expression, and Hgfac expression was also reduced in islets of HNF1α(+/-) mice. Reporter gene analysis and chromatin immunoprecipitation (ChIP) confirmed direct HNF1α binding to the Hgfac promoter.\",\n      \"method\": \"shRNA knockdown, reporter gene assay, chromatin immunoprecipitation (ChIP), HNF1α heterozygous mouse model\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and reporter assay establish direct transcriptional regulation, corroborated in vivo by heterozygous mouse, single lab\",\n      \"pmids\": [\"22877752\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"ChREBP directly regulates HGFAC transcription in liver (identified by ChREBP ChIP-Seq). HGFAC-KO mice exhibited metabolic phenotypes concordant with human loss-of-function variants. In gain- and loss-of-function mouse models, HGFAC enhanced lipid and glucose homeostasis, potentially mediated through activation of hepatic PPARγ activity.\",\n      \"method\": \"ChREBP ChIP-Seq, HGFAC knockout mouse, gain-of-function genetic mouse models, metabolic phenotyping, PPARγ activity assay\",\n      \"journal\": \"JCI insight\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP-Seq plus bidirectional genetic mouse models with metabolic readouts, single lab, PPARγ mechanism is partial\",\n      \"pmids\": [\"36413406\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"DNMT3A methylates the HGFAC promoter, silencing HGFAC expression in hepatocellular carcinoma. miR-4270 targets the 3'UTR of DNMT3A (confirmed by dual-luciferase and Ago2-RIP assays), reducing DNMT3A-mediated methylation of the HGFAC promoter (confirmed by ChIP and methylation-specific PCR), thereby restoring HGFAC expression. HGFAC overexpression counteracted HCC cell growth promoted by miR-4270 inhibition.\",\n      \"method\": \"Dual-luciferase reporter assay, Ago2-RIP, Co-IP, ChIP, methylation-specific PCR, rescue functional assays, xenograft mouse model\",\n      \"journal\": \"PeerJ\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal epigenetic methods (ChIP, MSP, luciferase, RIP) establish the regulatory mechanism, single lab\",\n      \"pmids\": [\"38077422\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Substrate-based ketothiazole inhibitors (e.g., Ac-KRLR-kt) inhibit HGFA enzymatic activity at nM Ki values (as low as 12 nM), block HGFA-mediated conversion of native pro-HGF and pro-MSP, and cause dose-dependent decrease of c-MET signaling in MDA-MB-231 breast cancer cells.\",\n      \"method\": \"Kinetic fluorogenic enzyme assay, native pro-HGF/pro-MSP cleavage assay, c-MET phosphorylation in cancer cells\",\n      \"journal\": \"ACS medicinal chemistry letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro kinetic enzyme assay with cellular signaling readout, single lab, demonstrates catalytic mechanism exploitation\",\n      \"pmids\": [\"25408834\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"HGFA (factor XII-like serine protease) critically mediates the enhanced activation of HGF/SF observed in colorectal carcinoma tissues compared with normal mucosa, as assessed by the ratio of two-chain (active) to single-chain (latent) HGF. HAI-1 functions both as a cell-surface specific inhibitor of active HGFA and as a reservoir/acceptor on the cell surface, concentrating pericellular HGFA activity.\",\n      \"method\": \"Western blot analysis of HGF activation state in tumor vs. normal tissue, cell-surface binding assays, IL-1β-induced shedding assay\",\n      \"journal\": \"Human cell\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — tissue biochemistry and cell-surface assay, but abstract-level description limits method detail; largely confirms PMID 11013244 findings in a new tissue context\",\n      \"pmids\": [\"11436357\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"HGFAC encodes a trypsin-like serine protease (HGFA) that circulates as an inactive zymogen (pro-HGFA) cleaved at Arg407-Ile408 by thrombin or by kallikreins KLK4/KLK5, generating an active protease that proteolytically converts pro-HGF and pro-MSP into their active heterodimeric forms; crystal structures reveal that HGFA active-site loops (99-loop, 220-loop) adopt enzymatically non-competent conformations in the unliganded state and are remodeled upon substrate/inhibitor binding, explaining its narrow substrate selectivity; on epithelial cell surfaces, active HGFA is captured and concentrated by membrane-bound HAI-1 and released as an active complex by metalloproteinase-dependent shedding; activity is also negatively regulated by plasma protein C inhibitor (PCI/SERPINA5); transcription of HGFAC is directly controlled by ChREBP and HNF1α in liver and β-cells respectively, and its promoter is silenced by DNMT3A-mediated methylation; systemically, injury-released HGFA drives HGF-dependent transition of tissue stem cells into the GAlert state to promote regeneration.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"HGFAC encodes hepatocyte growth factor activator (HGFA), a trypsin-like serine protease that couples tissue injury to growth-factor activation by proteolytically converting pro-HGF and pro-macrophage-stimulating protein (pro-MSP/RON ligand) into their active forms [#5, #10]. Circulating pro-HGFA is cleaved to its active enzyme by the coagulation protease thrombin [#5] and by the kallikrein-related peptidases KLK4 and KLK5, which cut at the physiological Arg407-Ile408 site to yield an enzyme that drives HGF-dependent cell scattering and invasion [#2]. Crystal structures show that HGFA's substrate-specificity loops (the 99-loop and 220-loop) rest in an enzymatically non-competent conformation in the unliganded state and are remodeled into a catalytically competent, substrate-binding geometry upon ligand engagement, with KD1 side chains occupying the S1/S2/S4 subsites in register with the pro-HGF cleavage sequence—a structural basis for HGFA's narrow substrate selectivity [#1, #3]. On epithelial surfaces HGFA activity is captured and concentrated by membrane-bound HAI-1, which acts as both inhibitor and reservoir and releases active enzyme upon zinc-metalloproteinase-dependent shedding [#0]; in plasma HGFA is additionally inhibited by protein C inhibitor (SERPINA5/PCI), whose action limits pro-HGF activation and constrains liver regeneration [#4]. Functionally, injury-released HGFA is sufficient to drive tissue stem and progenitor cells into the GAlert state and to accelerate repair, and HGFA loss impairs mucosal regeneration and macrophage recruitment [#5, #6]. HGFAC transcription is directly controlled by lineage-specific factors—HNF1α in pancreatic β-cells [#7] and ChREBP in liver, where HGFAC modulates lipid and glucose homeostasis [#8]—and is silenced by DNMT3A-mediated promoter methylation in hepatocellular carcinoma [#9].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Established that active HGFA is not simply released free but is captured at the epithelial cell surface, explaining how its pericellular activity is concentrated and regulated.\",\n      \"evidence\": \"Co-IP and cell-surface binding in engineered CHO and epithelial cells, with metalloproteinase-dependent shedding triggered by phorbol ester/IL-1β\",\n      \"pmids\": [\"11013244\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the shedding metalloproteinase not defined\", \"Quantitative balance between inhibitory and reservoir roles of HAI-1 in vivo unresolved\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Linked HGFA-driven HGF activation to a disease context by showing enhanced two-chain HGF generation in colorectal carcinoma versus normal mucosa.\",\n      \"evidence\": \"Western blot of HGF activation state in tumor vs normal tissue plus cell-surface binding/shedding assays\",\n      \"pmids\": [\"11436357\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Abstract-level description limits method detail\", \"Largely confirms surface-reservoir findings in a new tissue context rather than adding mechanism\", \"Causal role of HGFA in tumor progression not directly tested\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Resolved why HGFA is selectively inhibited by HAI-1 and revealed that the enzyme is conformationally latent until ligand binding remodels its active site.\",\n      \"evidence\": \"X-ray structures of apo HGFA protease domain and the HAI-1B KD1 complex with an inhibition panel across multiple proteases\",\n      \"pmids\": [\"15713485\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not capture the physiological pro-HGF substrate complex directly\", \"Dynamics of the loop transition in solution not measured\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Identified KLK4 and KLK5 as physiological activators of pro-HGFA, broadening the proteolytic inputs that switch on HGFA beyond coagulation.\",\n      \"evidence\": \"In vitro cleavage with N-terminal sequencing of the Arg407-Ile408 site, downstream cell scattering/invasion assays, and HAI-1 inhibition tests\",\n      \"pmids\": [\"18221492\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative in vivo contribution of KLK4/KLK5 versus thrombin not quantified\", \"Tissue contexts where each activator dominates unknown\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Provided a structural rationale for HGFA's narrow specificity by superimposing KD1 subsite occupancy onto a pro-HGF-derived substrate mimic.\",\n      \"evidence\": \"X-ray crystallography of the short-form protease domain compared against a Lys-Gln-Leu-Arg chloromethyl ketone substrate mimic\",\n      \"pmids\": [\"20402765\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structure of a genuine pro-HGF/pro-MSP Michaelis complex\", \"Determinants of pro-MSP versus pro-HGF preference not separated\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Defined plasma protein C inhibitor as a negative regulator of HGFA whose action limits HGF activation and liver regeneration.\",\n      \"evidence\": \"In vitro complex formation, hPCI-transgenic mouse partial hepatectomy with anti-PCI antibody rescue, and patient plasma ELISA\",\n      \"pmids\": [\"20402764\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Abstract-level detail limits assessment\", \"Stoichiometry and kinetics of HGFA-PCI inhibition not defined\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Placed HGFA downstream of the coagulation cascade and demonstrated its requirement for mucosal regeneration and macrophage recruitment in vivo.\",\n      \"evidence\": \"HGFA-knockout mouse tissue injury and regeneration assays\",\n      \"pmids\": [\"20402763\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Review-style abstract limits mechanistic detail\", \"Relative contributions of HGF versus MSP/RON activation to each phenotype unresolved\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Showed that Hgfac is a direct transcriptional target of HNF1α in pancreatic β-cells, connecting its expression to islet transcriptional programs.\",\n      \"evidence\": \"shRNA knockdown, reporter assay, ChIP, and HNF1α heterozygous mouse islets\",\n      \"pmids\": [\"22877752\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of β-cell HGFAC expression not established\", \"Single lab\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Demonstrated that small-molecule active-site inhibition of HGFA blocks pro-HGF/pro-MSP cleavage and dampens c-MET signaling, validating HGFA as a druggable node.\",\n      \"evidence\": \"Fluorogenic kinetic enzyme assay, native substrate cleavage, and c-MET phosphorylation in MDA-MB-231 cells\",\n      \"pmids\": [\"25408834\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo efficacy and selectivity not addressed\", \"Single lab\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Showed that systemic active HGFA is sufficient to drive stem/progenitor cells into the GAlert state and accelerate repair, establishing a systemic injury-to-regeneration signaling role.\",\n      \"evidence\": \"In vivo systemic HGFA administration to mice with MuSC/FAP activation and tissue repair readouts\",\n      \"pmids\": [\"28423312\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Endogenous source and kinetics of injury-released HGFA not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identified ChREBP-driven hepatic HGFAC transcription and linked HGFAC to systemic lipid and glucose homeostasis, extending its biology beyond proteolytic regeneration into metabolism.\",\n      \"evidence\": \"ChREBP ChIP-Seq plus bidirectional HGFAC gain/loss-of-function mouse models with metabolic phenotyping and PPARγ activity assays\",\n      \"pmids\": [\"36413406\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting HGFA proteolysis to PPARγ activation incomplete\", \"Whether metabolic effects require HGF/MSP activation untested\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Defined an epigenetic silencing axis in which DNMT3A methylates the HGFAC promoter and miR-4270 relieves this silencing, framing HGFAC as a regulated growth-suppressive node in hepatocellular carcinoma.\",\n      \"evidence\": \"Dual-luciferase, Ago2-RIP, ChIP, methylation-specific PCR, rescue assays, and xenograft model\",\n      \"pmids\": [\"38077422\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether tumor suppression depends on HGFA protease activity not tested\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the multiple proteolytic activators, surface reservoir, and serpin inhibitors are integrated to set HGFA activity in specific injured tissues in vivo remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structure of a true pro-HGF/pro-MSP cleavage complex\", \"Tissue-specific dominance of thrombin vs KLK4/KLK5 activation unknown\", \"Mechanistic link between HGFAC and hepatic metabolic regulation incomplete\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [2, 3, 5, 10]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [1, 3, 10]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-109582\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [5, 6]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"HAI-1 (SPINT1)\", \"SERPINA5\", \"KLK4\", \"KLK5\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":6,"faith_total":6,"faith_pct":100.0}}