{"gene":"FTCD","run_date":"2026-04-28T17:46:04","timeline":{"discoveries":[{"year":2000,"finding":"Human FTCD encodes a bifunctional enzyme (formiminotransferase cyclodeaminase) that links histidine catabolism to folate metabolism; the two enzymatic domains show high sequence similarity to two distinct bacterial open reading frames, indicating the eukaryotic protein arose by gene fusion.","method":"cDNA cloning, sequence analysis, domain homology comparison","journal":"Cytogenetics and cell genetics","confidence":"Medium","confidence_rationale":"Tier 2 — cloning and sequence-based domain characterization; single study but well-supported by structural inference","pmids":["10773664"],"is_preprint":false},{"year":2021,"finding":"FTCD was identified as a novel p47-binding protein; FTCD binds p47 and p97 via their polyglutamate motifs, forms a large FTCD–p97/p47–FTCD tethering complex, localizes to the Golgi complex, and is required for p97/p47-mediated Golgi membrane fusion and reassembly after mitosis. An in vivo tethering assay showed that mitochondria-targeted FTCD caused mitochondrial aggregation through endogenous p97/p47, confirming a membrane-tethering role.","method":"Co-immunoprecipitation, in vitro Golgi reassembly assay, in vivo tethering assay (mitochondria retargeting), pull-down, localization by fluorescence microscopy","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1–2 — multiple orthogonal methods (Co-IP, in vitro reconstitution assay, in vivo tethering assay) in a single study with strong mechanistic controls","pmids":["33555040"],"is_preprint":false},{"year":2019,"finding":"A missense variant (p.Val101Met, rs61735836) in FTCD is associated with reduced arsenic methylation efficiency; the major (Val) allele is human-specific and eliminates an upstream Kozak start codon, suggesting selection for a specific translation start site that affects FTCD activity and, through one-carbon/folate metabolism, methyl-group supply for arsenic methylation.","method":"Exome-wide association study in 1,660 Bangladeshi individuals; linkage disequilibrium analysis; Kozak sequence analysis","journal":"PLoS genetics","confidence":"Medium","confidence_rationale":"Tier 3 — human genetic association with functional annotation of start-codon variant; single cohort, no in vitro enzymatic validation","pmids":["30893314"],"is_preprint":false},{"year":2023,"finding":"Hepatocyte-specific knockout of FTCD in mice promoted both spontaneous and diethylnitrosamine-induced hepatocarcinogenesis; mechanistically, loss of FTCD upregulated PPARγ and SREBP2 via the PTEN/Akt/mTOR signalling axis, leading to lipid and cholesterol accumulation.","method":"Liver-specific Ftcd knockout mouse model, multi-omics (transcriptomics, metabolomics, proteomics), biochemical assays, diethylnitrosamine-induced HCC model","journal":"JHEP reports : innovation in hepatology","confidence":"High","confidence_rationale":"Tier 2 — genetic loss-of-function in vivo with multi-omics pathway validation and biochemical confirmation; single lab but multiple orthogonal methods","pmids":["37675273"],"is_preprint":false},{"year":2021,"finding":"Restoration of FTCD expression in HCC cells reduced intracellular tetrahydrofolate (THF) levels, inhibited NADPH/NADP+ and GSH/GSSG ratios, induced reactive oxygen species and mitochondrial oxidative stress, released cytochrome c, and activated caspase-dependent apoptosis, consistent with FTCD's enzymatic role in THF catabolism.","method":"In vitro FTCD plasmid overexpression in HCC cells; metabolite measurements (THF, NADPH/NADP+, GSH/GSSG); ROS assay; mitochondrial permeability transition pore assay; caspase activity; xenograft model","journal":"International journal of pharmaceutics","confidence":"Medium","confidence_rationale":"Tier 2 — multiple cellular assays linking FTCD enzymatic activity to metabolic and apoptotic outcomes; single lab study","pmids":["34774692"],"is_preprint":false}],"current_model":"FTCD is a bifunctional liver enzyme (formiminotransferase/cyclodeaminase) that arose by prokaryotic gene fusion and links histidine catabolism to one-carbon/folate metabolism; it also acts as a Golgi membrane tethering factor by forming a complex with p97 and p47 via polyglutamate motifs to drive post-mitotic Golgi reassembly, and in hepatocytes its loss activates the PTEN/Akt/mTOR–PPARγ/SREBP2 axis, promoting lipid accumulation and hepatocarcinogenesis."},"narrative":{"teleology":[{"year":2000,"claim":"Cloning of human FTCD resolved the domain architecture of the bifunctional enzyme, establishing that the formiminotransferase and cyclodeaminase activities reside in a single polypeptide produced by an ancient prokaryotic gene fusion event.","evidence":"cDNA cloning, sequence analysis, and domain homology comparison with bacterial ORFs","pmids":["10773664"],"confidence":"Medium","gaps":["No crystal structure of the human enzyme at that time","Enzymatic kinetics of each domain were not independently measured in this study"]},{"year":2019,"claim":"A human-specific missense variant (p.Val101Met) in FTCD was linked to altered arsenic methylation efficiency, connecting FTCD's one-carbon/folate metabolic role to methyl-group supply in a population context.","evidence":"Exome-wide association study in 1,660 Bangladeshi individuals with Kozak sequence analysis","pmids":["30893314"],"confidence":"Medium","gaps":["No in vitro enzymatic assay confirmed the variant's effect on FTCD catalytic activity","Single cohort; replication in independent populations not reported","Mechanism linking altered translation initiation to arsenic methylation not directly demonstrated"]},{"year":2021,"claim":"FTCD was discovered to have a non-enzymatic structural role as a Golgi membrane-tethering factor, forming a large FTCD–p97/p47–FTCD complex through polyglutamate motifs that is essential for post-mitotic Golgi reassembly.","evidence":"Co-immunoprecipitation, in vitro Golgi reassembly assay, in vivo mitochondria-retargeting tethering assay, and fluorescence microscopy","pmids":["33555040"],"confidence":"High","gaps":["Structural basis of FTCD–p47 interaction unresolved","Whether the enzymatic and tethering functions are coordinately regulated is unknown","Relevance of the tethering function in vivo (whole organism) not tested"]},{"year":2021,"claim":"Re-expression of FTCD in HCC cells demonstrated that its enzymatic activity depletes tetrahydrofolate, collapses NADPH and glutathione redox buffering, and triggers mitochondrial cytochrome c release and caspase-dependent apoptosis, linking FTCD loss to a survival advantage in liver cancer.","evidence":"Overexpression in HCC cell lines with metabolite quantification (THF, NADPH/NADP+, GSH/GSSG), ROS assays, mitochondrial permeability assays, and xenograft model","pmids":["34774692"],"confidence":"Medium","gaps":["Single-lab overexpression study; catalytic-dead mutant control not reported","Direct substrate channeling from formiminotransferase to cyclodeaminase domain not dissected"]},{"year":2023,"claim":"Hepatocyte-specific Ftcd knockout in mice established a causal tumor-suppressive role: loss of FTCD activated PTEN/Akt/mTOR signaling and upregulated PPARγ/SREBP2, leading to lipid/cholesterol accumulation and both spontaneous and carcinogen-induced hepatocarcinogenesis.","evidence":"Liver-specific Ftcd knockout mice, diethylnitrosamine-induced HCC model, multi-omics (transcriptomics, metabolomics, proteomics), biochemical assays","pmids":["37675273"],"confidence":"High","gaps":["Whether the Golgi-tethering function contributes to tumor suppression is unexplored","Direct molecular link between FTCD enzymatic product and PTEN regulation not identified","Human clinical validation of FTCD as a liver cancer biomarker or therapeutic target is lacking"]},{"year":null,"claim":"It remains unknown how FTCD's dual enzymatic and Golgi-tethering functions are coordinated, whether the two roles are independently regulated, and what the structural basis of the FTCD–p97/p47 tethering complex is.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of the FTCD–p97/p47 complex","No separation-of-function mutants distinguishing catalytic from tethering roles","Tissue-specific regulation of the two functions not characterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[0,2,4]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[1]}],"localization":[{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[1]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[0,2,4]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[4]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[3]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[3]}],"complexes":["FTCD–p97/p47 tethering complex"],"partners":["VCP","NSFL1C"],"other_free_text":[]},"mechanistic_narrative":"FTCD is a bifunctional enzyme (formiminotransferase-cyclodeaminase) that channels one-carbon units from histidine catabolism into folate metabolism; its two catalytic domains arose by fusion of distinct prokaryotic genes [PMID:10773664]. Beyond its metabolic role, FTCD localizes to the Golgi complex and functions as a membrane-tethering factor by forming a large FTCD–p97/p47–FTCD complex via polyglutamate motifs, which is required for p97/p47-mediated post-mitotic Golgi reassembly [PMID:33555040]. In hepatocytes, loss of FTCD depletes tetrahydrofolate and shifts the redox balance, and hepatocyte-specific knockout in mice activates the PTEN/Akt/mTOR–PPARγ/SREBP2 axis, promoting lipid accumulation and hepatocarcinogenesis [PMID:37675273, PMID:34774692]."},"prefetch_data":{"uniprot":{"accession":"O95954","full_name":"Formimidoyltransferase-cyclodeaminase","aliases":["Formiminotransferase-cyclodeaminase","FTCD","LCHC1"],"length_aa":541,"mass_kda":58.9,"function":"Folate-dependent enzyme, that displays both transferase and deaminase activity. Serves to channel one-carbon units from formiminoglutamate to the folate pool Binds and promotes bundling of vimentin filaments originating from the Golgi","subcellular_location":"Cytoplasm, cytosol; Golgi apparatus; Cytoplasm, cytoskeleton, microtubule organizing center, centrosome, centriole","url":"https://www.uniprot.org/uniprotkb/O95954/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/FTCD","classification":"Not Classified","n_dependent_lines":24,"n_total_lines":1208,"dependency_fraction":0.019867549668874173},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/FTCD","total_profiled":1310},"omim":[{"mim_id":"613065","title":"LEUKEMIA, ACUTE LYMPHOBLASTIC; ALL","url":"https://www.omim.org/entry/613065"},{"mim_id":"609457","title":"HISTIDINE AMMONIA-LYASE; HAL","url":"https://www.omim.org/entry/609457"},{"mim_id":"606806","title":"FORMIMINOTRANSFERASE CYCLODEAMINASE; FTCD","url":"https://www.omim.org/entry/606806"},{"mim_id":"606664","title":"GLYCINE N-METHYLTRANSFERASE DEFICIENCY","url":"https://www.omim.org/entry/606664"},{"mim_id":"606628","title":"GLYCINE N-METHYLTRANSFERASE; GNMT","url":"https://www.omim.org/entry/606628"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Cytosol","reliability":"Approved"},{"location":"Plasma membrane","reliability":"Additional"}],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"liver","ntpm":914.3}],"url":"https://www.proteinatlas.org/search/FTCD"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"O95954","domains":[{"cath_id":"3.30.990.10","chopping":"5-179","consensus_level":"high","plddt":96.7633,"start":5,"end":179},{"cath_id":"3.30.70.670","chopping":"183-273","consensus_level":"medium","plddt":96.9907,"start":183,"end":273},{"cath_id":"1.20.120.680","chopping":"339-539","consensus_level":"high","plddt":95.5114,"start":339,"end":539}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O95954","model_url":"https://alphafold.ebi.ac.uk/files/AF-O95954-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O95954-F1-predicted_aligned_error_v6.png","plddt_mean":95.31},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=FTCD","jax_strain_url":"https://www.jax.org/strain/search?query=FTCD"},"sequence":{"accession":"O95954","fasta_url":"https://rest.uniprot.org/uniprotkb/O95954.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O95954/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O95954"}},"corpus_meta":[{"pmid":"10773664","id":"PMC_10773664","title":"Cloning and characterization of human FTCD on 21q22.3, a candidate gene for glutamate formiminotransferase deficiency.","date":"2000","source":"Cytogenetics and cell genetics","url":"https://pubmed.ncbi.nlm.nih.gov/10773664","citation_count":34,"is_preprint":false},{"pmid":"37675273","id":"PMC_37675273","title":"Loss of hepatic FTCD promotes lipid accumulation and hepatocarcinogenesis by upregulating PPARγ and SREBP2.","date":"2023","source":"JHEP reports : innovation in hepatology","url":"https://pubmed.ncbi.nlm.nih.gov/37675273","citation_count":24,"is_preprint":false},{"pmid":"30893314","id":"PMC_30893314","title":"A missense variant in FTCD is associated with arsenic metabolism and toxicity phenotypes in Bangladesh.","date":"2019","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/30893314","citation_count":24,"is_preprint":false},{"pmid":"33555040","id":"PMC_33555040","title":"p97 and p47 function in membrane tethering in cooperation with FTCD during mitotic Golgi reassembly.","date":"2021","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/33555040","citation_count":16,"is_preprint":false},{"pmid":"30784016","id":"PMC_30784016","title":"The Diagnostic Value of Arginase-1, FTCD, and MOC-31 Expression in Early Detection of Hepatocellular Carcinoma (HCC) and in Differentiation Between HCC and Metastatic Adenocarcinoma to the Liver.","date":"2020","source":"Journal of gastrointestinal cancer","url":"https://pubmed.ncbi.nlm.nih.gov/30784016","citation_count":16,"is_preprint":false},{"pmid":"34774692","id":"PMC_34774692","title":"Hollow mesoporous organosilica nanotheranostics incorporating formimidoyltransferase cyclodeaminase (FTCD) plasmids for magnetic resonance imaging and tetrahydrofolate metabolism fission on hepatocellular carcinoma.","date":"2021","source":"International journal of pharmaceutics","url":"https://pubmed.ncbi.nlm.nih.gov/34774692","citation_count":9,"is_preprint":false},{"pmid":"38815631","id":"PMC_38815631","title":"Cabozantinib inhibits the growth of lenvatinib-resistant hepatoma cells restoring FTCD expression.","date":"2024","source":"Biochemical pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/38815631","citation_count":3,"is_preprint":false},{"pmid":"29927301","id":"PMC_29927301","title":"A functional promoter variant of the human formimidoyltransferase cyclodeaminase (FTCD) gene is associated with working memory performance in young but not older adults.","date":"2018","source":"Neuropsychology","url":"https://pubmed.ncbi.nlm.nih.gov/29927301","citation_count":3,"is_preprint":false},{"pmid":"38414493","id":"PMC_38414493","title":"Anodal transcranial direct current stimulation (atDCS) and functional transcranial Doppler sonography (fTCD) in healthy elderly and patients with MCI: modulation of age-related changes in word fluency and language lateralization.","date":"2024","source":"Frontiers in aging","url":"https://pubmed.ncbi.nlm.nih.gov/38414493","citation_count":3,"is_preprint":false},{"pmid":"39824452","id":"PMC_39824452","title":"AFB1 consolidates HBV harm to induce liver injury and carcinogenic risk by inactivating FTCD-AS1-PXR-MASP1 axis.","date":"2025","source":"Toxicology","url":"https://pubmed.ncbi.nlm.nih.gov/39824452","citation_count":2,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.07.20.665220","title":"Visual stimulus-evoked blood velocity responses in individual human posterior cerebral arteries measured with dynamic phase-contrast functional MR angiography","date":"2025-07-25","source":"bioRxiv","url":"https://doi.org/10.1101/2025.07.20.665220","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.09.15.613144","title":"Filter bank common spatial pattern and envelope-based features in multimodal EEG-fTCD brain-computer interfaces","date":"2024-09-19","source":"bioRxiv","url":"https://doi.org/10.1101/2024.09.15.613144","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":8301,"output_tokens":1396,"usd":0.022922},"stage2":{"model":"claude-opus-4-6","input_tokens":4632,"output_tokens":1781,"usd":0.101528},"total_usd":0.12445,"stage1_batch_id":"msgbatch_0118RScg3WGaGkaZRtWZbtce","stage2_batch_id":"msgbatch_01Cpfzvtbj42aqp5oYZ5Te2s","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2000,\n      \"finding\": \"Human FTCD encodes a bifunctional enzyme (formiminotransferase cyclodeaminase) that links histidine catabolism to folate metabolism; the two enzymatic domains show high sequence similarity to two distinct bacterial open reading frames, indicating the eukaryotic protein arose by gene fusion.\",\n      \"method\": \"cDNA cloning, sequence analysis, domain homology comparison\",\n      \"journal\": \"Cytogenetics and cell genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — cloning and sequence-based domain characterization; single study but well-supported by structural inference\",\n      \"pmids\": [\"10773664\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"FTCD was identified as a novel p47-binding protein; FTCD binds p47 and p97 via their polyglutamate motifs, forms a large FTCD–p97/p47–FTCD tethering complex, localizes to the Golgi complex, and is required for p97/p47-mediated Golgi membrane fusion and reassembly after mitosis. An in vivo tethering assay showed that mitochondria-targeted FTCD caused mitochondrial aggregation through endogenous p97/p47, confirming a membrane-tethering role.\",\n      \"method\": \"Co-immunoprecipitation, in vitro Golgi reassembly assay, in vivo tethering assay (mitochondria retargeting), pull-down, localization by fluorescence microscopy\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — multiple orthogonal methods (Co-IP, in vitro reconstitution assay, in vivo tethering assay) in a single study with strong mechanistic controls\",\n      \"pmids\": [\"33555040\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"A missense variant (p.Val101Met, rs61735836) in FTCD is associated with reduced arsenic methylation efficiency; the major (Val) allele is human-specific and eliminates an upstream Kozak start codon, suggesting selection for a specific translation start site that affects FTCD activity and, through one-carbon/folate metabolism, methyl-group supply for arsenic methylation.\",\n      \"method\": \"Exome-wide association study in 1,660 Bangladeshi individuals; linkage disequilibrium analysis; Kozak sequence analysis\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — human genetic association with functional annotation of start-codon variant; single cohort, no in vitro enzymatic validation\",\n      \"pmids\": [\"30893314\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Hepatocyte-specific knockout of FTCD in mice promoted both spontaneous and diethylnitrosamine-induced hepatocarcinogenesis; mechanistically, loss of FTCD upregulated PPARγ and SREBP2 via the PTEN/Akt/mTOR signalling axis, leading to lipid and cholesterol accumulation.\",\n      \"method\": \"Liver-specific Ftcd knockout mouse model, multi-omics (transcriptomics, metabolomics, proteomics), biochemical assays, diethylnitrosamine-induced HCC model\",\n      \"journal\": \"JHEP reports : innovation in hepatology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic loss-of-function in vivo with multi-omics pathway validation and biochemical confirmation; single lab but multiple orthogonal methods\",\n      \"pmids\": [\"37675273\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Restoration of FTCD expression in HCC cells reduced intracellular tetrahydrofolate (THF) levels, inhibited NADPH/NADP+ and GSH/GSSG ratios, induced reactive oxygen species and mitochondrial oxidative stress, released cytochrome c, and activated caspase-dependent apoptosis, consistent with FTCD's enzymatic role in THF catabolism.\",\n      \"method\": \"In vitro FTCD plasmid overexpression in HCC cells; metabolite measurements (THF, NADPH/NADP+, GSH/GSSG); ROS assay; mitochondrial permeability transition pore assay; caspase activity; xenograft model\",\n      \"journal\": \"International journal of pharmaceutics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple cellular assays linking FTCD enzymatic activity to metabolic and apoptotic outcomes; single lab study\",\n      \"pmids\": [\"34774692\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"FTCD is a bifunctional liver enzyme (formiminotransferase/cyclodeaminase) that arose by prokaryotic gene fusion and links histidine catabolism to one-carbon/folate metabolism; it also acts as a Golgi membrane tethering factor by forming a complex with p97 and p47 via polyglutamate motifs to drive post-mitotic Golgi reassembly, and in hepatocytes its loss activates the PTEN/Akt/mTOR–PPARγ/SREBP2 axis, promoting lipid accumulation and hepatocarcinogenesis.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"FTCD is a bifunctional enzyme (formiminotransferase-cyclodeaminase) that channels one-carbon units from histidine catabolism into folate metabolism; its two catalytic domains arose by fusion of distinct prokaryotic genes [PMID:10773664]. Beyond its metabolic role, FTCD localizes to the Golgi complex and functions as a membrane-tethering factor by forming a large FTCD–p97/p47–FTCD complex via polyglutamate motifs, which is required for p97/p47-mediated post-mitotic Golgi reassembly [PMID:33555040]. In hepatocytes, loss of FTCD depletes tetrahydrofolate and shifts the redox balance, and hepatocyte-specific knockout in mice activates the PTEN/Akt/mTOR–PPARγ/SREBP2 axis, promoting lipid accumulation and hepatocarcinogenesis [PMID:37675273, PMID:34774692].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Cloning of human FTCD resolved the domain architecture of the bifunctional enzyme, establishing that the formiminotransferase and cyclodeaminase activities reside in a single polypeptide produced by an ancient prokaryotic gene fusion event.\",\n      \"evidence\": \"cDNA cloning, sequence analysis, and domain homology comparison with bacterial ORFs\",\n      \"pmids\": [\"10773664\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No crystal structure of the human enzyme at that time\",\n        \"Enzymatic kinetics of each domain were not independently measured in this study\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"A human-specific missense variant (p.Val101Met) in FTCD was linked to altered arsenic methylation efficiency, connecting FTCD's one-carbon/folate metabolic role to methyl-group supply in a population context.\",\n      \"evidence\": \"Exome-wide association study in 1,660 Bangladeshi individuals with Kozak sequence analysis\",\n      \"pmids\": [\"30893314\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No in vitro enzymatic assay confirmed the variant's effect on FTCD catalytic activity\",\n        \"Single cohort; replication in independent populations not reported\",\n        \"Mechanism linking altered translation initiation to arsenic methylation not directly demonstrated\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"FTCD was discovered to have a non-enzymatic structural role as a Golgi membrane-tethering factor, forming a large FTCD–p97/p47–FTCD complex through polyglutamate motifs that is essential for post-mitotic Golgi reassembly.\",\n      \"evidence\": \"Co-immunoprecipitation, in vitro Golgi reassembly assay, in vivo mitochondria-retargeting tethering assay, and fluorescence microscopy\",\n      \"pmids\": [\"33555040\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis of FTCD–p47 interaction unresolved\",\n        \"Whether the enzymatic and tethering functions are coordinately regulated is unknown\",\n        \"Relevance of the tethering function in vivo (whole organism) not tested\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Re-expression of FTCD in HCC cells demonstrated that its enzymatic activity depletes tetrahydrofolate, collapses NADPH and glutathione redox buffering, and triggers mitochondrial cytochrome c release and caspase-dependent apoptosis, linking FTCD loss to a survival advantage in liver cancer.\",\n      \"evidence\": \"Overexpression in HCC cell lines with metabolite quantification (THF, NADPH/NADP+, GSH/GSSG), ROS assays, mitochondrial permeability assays, and xenograft model\",\n      \"pmids\": [\"34774692\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single-lab overexpression study; catalytic-dead mutant control not reported\",\n        \"Direct substrate channeling from formiminotransferase to cyclodeaminase domain not dissected\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Hepatocyte-specific Ftcd knockout in mice established a causal tumor-suppressive role: loss of FTCD activated PTEN/Akt/mTOR signaling and upregulated PPARγ/SREBP2, leading to lipid/cholesterol accumulation and both spontaneous and carcinogen-induced hepatocarcinogenesis.\",\n      \"evidence\": \"Liver-specific Ftcd knockout mice, diethylnitrosamine-induced HCC model, multi-omics (transcriptomics, metabolomics, proteomics), biochemical assays\",\n      \"pmids\": [\"37675273\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether the Golgi-tethering function contributes to tumor suppression is unexplored\",\n        \"Direct molecular link between FTCD enzymatic product and PTEN regulation not identified\",\n        \"Human clinical validation of FTCD as a liver cancer biomarker or therapeutic target is lacking\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unknown how FTCD's dual enzymatic and Golgi-tethering functions are coordinated, whether the two roles are independently regulated, and what the structural basis of the FTCD–p97/p47 tethering complex is.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No structural model of the FTCD–p97/p47 complex\",\n        \"No separation-of-function mutants distinguishing catalytic from tethering roles\",\n        \"Tissue-specific regulation of the two functions not characterized\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [0, 2, 4]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [0, 2, 4]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [4]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"complexes\": [\n      \"FTCD–p97/p47 tethering complex\"\n    ],\n    \"partners\": [\n      \"VCP\",\n      \"NSFL1C\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}