{"gene":"NHLRC2","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":2017,"finding":"NHLRC2 is cleaved by caspase-8 at Asp580 in vitro during ROS-induced apoptosis; the thioredoxin-like domain of NHLRC2 physically interacts with the proenzyme form of caspase-8, and siRNA knockdown of caspase-8 blocked ROS-induced decrease in NHLRC2 protein levels. Loss of NHLRC2 (shRNA or CRISPR-Cas9) increased susceptibility to ROS-induced apoptosis.","method":"In vitro cleavage assay identifying Asp580 as the caspase-8 cleavage site; co-immunoprecipitation of NHLRC2 thioredoxin-like domain with pro-caspase-8; siRNA knockdown; shRNA and CRISPR-Cas9 loss-of-function with apoptosis readout","journal":"Cell death & disease","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro cleavage assay with site-identification (Asp580), Co-IP, and genetic KD/KO each supporting the same mechanistic conclusion in a single focused study","pmids":["29242562"],"is_preprint":false},{"year":2018,"finding":"Crystal structure of the Trx-like and NHL repeat β-propeller domains of human NHLRC2 determined to 2.7 Å resolution, revealing two adjacent domains forming a cleft containing a conserved CCINC motif with an extended negative electrostatic surface proposed to form a ligand/partner binding site. SAXS of full-length NHLRC2 shows the non-conserved C-terminal domain does not pack against the N-terminal domains. The FINCA disease-associated Asp148Tyr mutation destabilizes the protein structure by 2°C.","method":"X-ray crystallography (2.7 Å) and SAXS for full-length protein; thermal stability assay for Asp148Tyr mutant","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure plus SAXS plus mutant stability measurement in a single rigorous structural study","pmids":["30138417"],"is_preprint":false},{"year":2018,"finding":"An insulin turbidity assay on recombinant human NHLRC2 showed NO thioredoxin reductase activity, despite the protein containing a thioredoxin-like domain.","method":"Insulin turbidity assay (in vitro enzymatic assay) with recombinant NHLRC2","journal":"Acta neuropathologica","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — direct in vitro enzymatic assay, single lab, single method; result is negative (no thioredoxin activity)","pmids":["29423877"],"is_preprint":false},{"year":2018,"finding":"Proximity-labeling mass spectrometry identified putative interacting partners for NHLRC2, and functional studies using FINCA patient-derived immortalized fibroblasts (carrying compound heterozygous mutations) showed multilamellar bodies, distinctly organized vimentin filaments, and features of myofibroblast differentiation. NHLRC2 knockdown and overexpression experiments placed NHLRC2 in regulation of cytoskeletal organization and vesicle transport; loss of NHLRC2 function enhanced fibroblast-to-myofibroblast differentiation.","method":"Proximity-labeling (BioID) mass spectrometry; transmission electron microscopy of patient-derived immortalized cells; NHLRC2 knockdown and overexpression in normal fibroblasts","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — proximity-labeling MS for interaction partners, TEM morphological phenotyping, and KD/OE functional studies in same paper; single lab","pmids":["30239752"],"is_preprint":false},{"year":2018,"finding":"Nhlrc2 null mouse embryos implanted and appeared normal at E6.5 but development arrested at E7.5, with only 6% of E8.5 embryos homozygous null; KO embryos showed failed gastrulation and amniotic folding. Embryonic stem cells from null blastocysts proliferated normally despite complete loss of NHLRC2 protein, indicating the essential role is post-implantation.","method":"Nhlrc2 knockout mouse (C57BL/6NCrl-Nhlrc2tm1a(KOMP)Wtsi/Oulu); timed matings with genotyping; in vitro fertilization; LacZ reporter for expression mapping","journal":"Genesis (New York, N.Y. : 2000)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — well-defined KO with timed developmental staging and reporter expression; single lab","pmids":["35258166"],"is_preprint":false},{"year":2020,"finding":"In a FINCA mouse model (compound heterozygote: Nhlrc2 p.Asp148Tyr knockin × Nhlrc2 knockout), 2D-DIGE proteomics of E13.5 cortical neuronal precursor cells identified 19 altered proteins, including significant upregulation of hnRNP C2 in both developing neurons and adult hippocampus. Several altered proteins are involved in vesicular transport pathways and actin dynamics, connecting NHLRC2 dysfunction to disrupted RNA metabolism and cytoskeletal regulation in neurons.","method":"CRISPR/Cas9 knockin mouse; 2D-DIGE comparative proteomics of embryonic cortical neuronal precursor cells; Western blot validation","journal":"Molecular medicine (Cambridge, Mass.)","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — in vivo genetic model with proteomics and validation; single lab; hnRNP C2 accumulation confirmed by orthogonal methods","pmids":["33297935"],"is_preprint":false},{"year":2023,"finding":"Expression of novel and previously published non-truncating NHLRC2 variants in HEK293 cells demonstrated that greater reduction in NHLRC2 protein expression is associated with a more severe disease phenotype, supporting a genotype-phenotype correlation based on residual protein levels.","method":"Cloning and expression of NHLRC2 variants in HEK293 cells with protein level quantification","journal":"European journal of human genetics : EJHG","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single overexpression assay measuring protein levels, single lab, no mechanistic dissection beyond quantification","pmids":["37188825"],"is_preprint":false},{"year":2025,"finding":"Proximity-labeling mass spectrometry comparing wild-type and p.Asp148Tyr NHLRC2 in HEK293 cells, combined with transcriptional profiling of mouse embryonic stem cells homozygous for p.Asp148Tyr or Nhlrc2 KO, identified Rho GTPase signalling as a pathway commonly affected by NHLRC2 dysfunction. FINCA mice showed altered innate immune response, particularly reduced interferon-γ production in splenocytes.","method":"Proximity-labeling (BioID) mass spectrometry with variant vs. wild-type comparison; transcriptomics of mESCs; T cell and cytokine profiling (interferon-γ) of FINCA compound heterozygous mice","journal":"Brain, behavior, & immunity - health","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — two orthogonal discovery approaches (proximity-labeling MS and transcriptomics) converging on Rho GTPase pathway, supported by in vivo immune phenotyping; single lab","pmids":["40510178"],"is_preprint":false}],"current_model":"NHLRC2 is an essential, ubiquitously expressed protein whose crystal structure reveals a thioredoxin-like domain and NHL-repeat β-propeller domain forming a conserved CCINC-containing cleft (with no thioredoxin reductase activity detected in vitro); it is cleaved by caspase-8 at Asp580 via an interaction between its thioredoxin-like domain and pro-caspase-8 during ROS-induced apoptosis, and its loss-of-function (via patient mutations, knockdown, or knockout) disrupts cytoskeletal organization (vimentin, actin/Rho GTPase signalling), vesicle transport, and RNA metabolism (hnRNP C2 accumulation), promoting fibroblast-to-myofibroblast differentiation and impairing immune responses, while complete loss causes embryonic lethality at gastrulation in mice."},"narrative":{"mechanistic_narrative":"NHLRC2 is an essential, ubiquitously required protein that integrates cytoskeletal organization, vesicle transport, and RNA metabolism, and whose complete loss arrests mouse embryonic development at gastrulation around E7.5 despite normal pre-implantation proliferation [PMID:35258166]. Structurally it comprises an N-terminal thioredoxin-like domain adjacent to an NHL-repeat β-propeller, together forming a cleft containing a conserved CCINC motif with an extended negative electrostatic surface that constitutes a likely ligand/partner-binding site, while the non-conserved C-terminal domain remains spatially separate; the FINCA-associated Asp148Tyr substitution destabilizes the fold [PMID:30138417]. Despite the thioredoxin-like domain, recombinant NHLRC2 lacks detectable thioredoxin reductase activity [PMID:29423877]. During ROS-induced apoptosis the thioredoxin-like domain binds pro-caspase-8 and NHLRC2 is cleaved at Asp580, and its depletion sensitizes cells to ROS-induced death [PMID:29242562]. Loss of NHLRC2 function disrupts vimentin filament organization, vesicle transport, and Rho GTPase signalling, promotes fibroblast-to-myofibroblast differentiation, perturbs RNA metabolism through accumulation of hnRNP C2, and impairs innate immune responses including interferon-γ production [PMID:30239752, PMID:33297935, PMID:40510178]. Biallelic non-truncating NHLRC2 variants cause the multisystem FINCA disease, with residual protein level correlating with phenotype severity [PMID:37188825]. Beyond these findings, the direct molecular substrate or enzymatic/scaffolding function executed through the CCINC cleft has not been defined in the available corpus.","teleology":[{"year":2017,"claim":"Established the first direct molecular handle on NHLRC2 by linking it to apoptotic signalling, showing it is a caspase-8 substrate whose loss sensitizes cells to oxidative stress.","evidence":"In vitro cleavage assay mapping Asp580, Co-IP of the Trx-like domain with pro-caspase-8, and siRNA/shRNA/CRISPR loss-of-function with ROS-apoptosis readout","pmids":["29242562"],"confidence":"High","gaps":["Does not define NHLRC2's baseline (non-apoptotic) molecular function","Functional consequence of the cleavage fragment unknown","No structural basis for the caspase-8 interaction"]},{"year":2018,"claim":"Solved the domain architecture, revealing a Trx-like plus NHL-repeat β-propeller arrangement forming a conserved CCINC cleft as the candidate functional surface and showing a disease mutation destabilizes the protein.","evidence":"X-ray crystallography to 2.7 Å, SAXS of full-length protein, and thermal stability assay of the Asp148Tyr mutant","pmids":["30138417"],"confidence":"High","gaps":["No ligand or partner bound in the CCINC cleft was identified","C-terminal domain structure unresolved","Catalytic role of the cleft unknown"]},{"year":2018,"claim":"Tested whether the thioredoxin-like domain confers redox enzymatic activity, finding none and arguing the domain serves a binding/structural rather than catalytic role.","evidence":"Insulin turbidity assay on recombinant NHLRC2","pmids":["29423877"],"confidence":"Medium","gaps":["Single in vitro assay and method","Negative result does not exclude other redox-related activities","No alternative function assigned to the Trx-like domain"]},{"year":2018,"claim":"Connected NHLRC2 to cellular physiology by showing FINCA patient cells display abnormal vimentin organization and myofibroblast features, placing the protein in cytoskeletal organization and vesicle transport.","evidence":"BioID proximity-labeling MS, TEM of patient-derived immortalized fibroblasts, and knockdown/overexpression in normal fibroblasts","pmids":["30239752"],"confidence":"Medium","gaps":["Direct vs. indirect partners not distinguished from BioID","Mechanism linking NHLRC2 to vimentin not defined","Single lab and patient-derived background"]},{"year":2018,"claim":"Defined the developmental window of NHLRC2 essentiality, showing it is dispensable pre-implantation but required for gastrulation.","evidence":"Nhlrc2 knockout mouse with timed staging, IVF, and LacZ expression mapping","pmids":["35258166"],"confidence":"Medium","gaps":["Molecular cause of gastrulation arrest unknown","Lethality precludes adult tissue analysis","Does not identify the essential downstream pathway"]},{"year":2020,"claim":"Linked NHLRC2 dysfunction to RNA metabolism in neural tissue by identifying hnRNP C2 accumulation alongside altered vesicular-transport and actin-dynamics proteins.","evidence":"FINCA knockin x KO mouse model with 2D-DIGE proteomics of E13.5 cortical neuronal precursors and Western validation","pmids":["33297935"],"confidence":"Medium","gaps":["Causal link between NHLRC2 and hnRNP C2 not mechanistically resolved","Whether RNA metabolism defect is primary or secondary unclear","Single lab"]},{"year":2023,"claim":"Established a genotype-phenotype rule for FINCA, showing residual NHLRC2 protein level scales with disease severity.","evidence":"Expression of non-truncating variants in HEK293 cells with protein-level quantification","pmids":["37188825"],"confidence":"Low","gaps":["Single overexpression assay with no mechanistic dissection","Protein level read out in non-native cell context","Does not address how reduced levels cause specific phenotypes"]},{"year":2025,"claim":"Converged multiple datasets on Rho GTPase signalling as a core affected pathway and extended NHLRC2 dysfunction to innate immunity via reduced interferon-γ.","evidence":"Variant-vs-WT BioID proximity-labeling MS, mESC transcriptomics, and FINCA mouse T cell/cytokine profiling","pmids":["40510178"],"confidence":"Medium","gaps":["Direct effector linking NHLRC2 to Rho GTPase signalling not identified","Mechanism of impaired interferon-γ production unresolved","Single lab"]},{"year":null,"claim":"The direct biochemical activity or binding partner engaged through the conserved CCINC cleft, and the molecular event that makes NHLRC2 essential for gastrulation, remain undefined.","evidence":"No discovery in the corpus assigns a substrate or catalytic/scaffolding mechanism to NHLRC2","pmids":[],"confidence":"Low","gaps":["No defined molecular substrate or ligand","Mechanism unifying cytoskeletal, vesicular, RNA, and immune phenotypes unknown","No structure-function link from the CCINC cleft to a cellular activity"]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[0]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[7]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[4]}],"complexes":[],"partners":["CASP8"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8NBF2","full_name":"NHL repeat-containing protein 2","aliases":[],"length_aa":726,"mass_kda":79.4,"function":"Required for normal embryonic development","subcellular_location":"Cytoplasm, cytosol","url":"https://www.uniprot.org/uniprotkb/Q8NBF2/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/NHLRC2","classification":"Not Classified","n_dependent_lines":840,"n_total_lines":1208,"dependency_fraction":0.695364238410596},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/NHLRC2","total_profiled":1310},"omim":[{"mim_id":"618278","title":"FIBROSIS, NEURODEGENERATION, AND CEREBRAL ANGIOMATOSIS; FINCA","url":"https://www.omim.org/entry/618278"},{"mim_id":"618277","title":"NHL REPEAT-CONTAINING PROTEIN 2; NHLRC2","url":"https://www.omim.org/entry/618277"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/NHLRC2"},"hgnc":{"alias_symbol":["FLJ25621","FLJ20147","FLJ33312","MGC45492","DKFZp779F115"],"prev_symbol":[]},"alphafold":{"accession":"Q8NBF2","domains":[{"cath_id":"3.40.30.10","chopping":"12-217","consensus_level":"high","plddt":96.2165,"start":12,"end":217},{"cath_id":"2.120.10.30","chopping":"227-570","consensus_level":"high","plddt":96.8877,"start":227,"end":570},{"cath_id":"2.60.40,2.60.40","chopping":"601-726","consensus_level":"high","plddt":87.7799,"start":601,"end":726}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NBF2","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NBF2-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NBF2-F1-predicted_aligned_error_v6.png","plddt_mean":92.69},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NHLRC2","jax_strain_url":"https://www.jax.org/strain/search?query=NHLRC2"},"sequence":{"accession":"Q8NBF2","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8NBF2.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8NBF2/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NBF2"}},"corpus_meta":[{"pmid":"29242562","id":"PMC_29242562","title":"ROS-induced cleavage of NHLRC2 by caspase-8 leads to apoptotic cell death in the HCT116 human colon cancer cell line.","date":"2017","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/29242562","citation_count":47,"is_preprint":false},{"pmid":"29423877","id":"PMC_29423877","title":"NHLRC2 variants identified in patients with fibrosis, neurodegeneration, and cerebral angiomatosis (FINCA): characterisation of a novel cerebropulmonary disease.","date":"2018","source":"Acta neuropathologica","url":"https://pubmed.ncbi.nlm.nih.gov/29423877","citation_count":26,"is_preprint":false},{"pmid":"30239752","id":"PMC_30239752","title":"Biallelic mutations in human NHLRC2 enhance myofibroblast differentiation in FINCA disease.","date":"2018","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/30239752","citation_count":19,"is_preprint":false},{"pmid":"30138417","id":"PMC_30138417","title":"Structural analysis of human NHLRC2, mutations of which are associated with FINCA disease.","date":"2018","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/30138417","citation_count":15,"is_preprint":false},{"pmid":"32435055","id":"PMC_32435055","title":"Novel compound heterozygous variants in NHLRC2 in a patient with FINCA syndrome.","date":"2020","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/32435055","citation_count":13,"is_preprint":false},{"pmid":"35258166","id":"PMC_35258166","title":"Nhlrc2 is crucial during mouse gastrulation.","date":"2022","source":"Genesis (New York, N.Y. : 2000)","url":"https://pubmed.ncbi.nlm.nih.gov/35258166","citation_count":8,"is_preprint":false},{"pmid":"33297935","id":"PMC_33297935","title":"Variant in NHLRC2 leads to increased hnRNP C2 in developing neurons and the hippocampus of a mouse model of FINCA disease.","date":"2020","source":"Molecular medicine (Cambridge, Mass.)","url":"https://pubmed.ncbi.nlm.nih.gov/33297935","citation_count":8,"is_preprint":false},{"pmid":"35964085","id":"PMC_35964085","title":"NHLRC2 expression is increased in idiopathic pulmonary fibrosis.","date":"2022","source":"Respiratory research","url":"https://pubmed.ncbi.nlm.nih.gov/35964085","citation_count":5,"is_preprint":false},{"pmid":"37188825","id":"PMC_37188825","title":"Broadening the phenotypic and molecular spectrum of FINCA syndrome: Biallelic NHLRC2 variants in 15 novel individuals.","date":"2023","source":"European journal of human genetics : EJHG","url":"https://pubmed.ncbi.nlm.nih.gov/37188825","citation_count":5,"is_preprint":false},{"pmid":"37179546","id":"PMC_37179546","title":"Novel patients with NHLRC2 variants expand the phenotypic spectrum of FINCA disease.","date":"2023","source":"Frontiers in neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/37179546","citation_count":5,"is_preprint":false},{"pmid":"35801790","id":"PMC_35801790","title":"Case report: novel mutations of NDUFS6 and NHLRC2 genes potentially cause the quick postnatal death of a Chinese Hani minority neonate with mitochondrial complex I deficiency and FINCA syndrome.","date":"2022","source":"Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/35801790","citation_count":5,"is_preprint":false},{"pmid":"37425408","id":"PMC_37425408","title":"High NHLRC2 expression is associated with shortened survival in lung adenocarcinoma.","date":"2023","source":"Translational lung cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/37425408","citation_count":3,"is_preprint":false},{"pmid":"40510178","id":"PMC_40510178","title":"Altered behaviour and immune response in mice with NHLRC2 p.Asp148Tyr variant.","date":"2025","source":"Brain, behavior, & immunity - health","url":"https://pubmed.ncbi.nlm.nih.gov/40510178","citation_count":0,"is_preprint":false},{"pmid":"39328589","id":"PMC_39328589","title":"Case Report: Clinical manifestations and treatment of two Chinese patients with FINCA syndrome carrying a novel variant of NHLRC2.","date":"2024","source":"Frontiers in pediatrics","url":"https://pubmed.ncbi.nlm.nih.gov/39328589","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9692,"output_tokens":2415,"usd":0.03265,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9542,"output_tokens":2904,"usd":0.060155,"stage2_stop_reason":"end_turn"},"total_usd":0.092805,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2017,\n      \"finding\": \"NHLRC2 is cleaved by caspase-8 at Asp580 in vitro during ROS-induced apoptosis; the thioredoxin-like domain of NHLRC2 physically interacts with the proenzyme form of caspase-8, and siRNA knockdown of caspase-8 blocked ROS-induced decrease in NHLRC2 protein levels. Loss of NHLRC2 (shRNA or CRISPR-Cas9) increased susceptibility to ROS-induced apoptosis.\",\n      \"method\": \"In vitro cleavage assay identifying Asp580 as the caspase-8 cleavage site; co-immunoprecipitation of NHLRC2 thioredoxin-like domain with pro-caspase-8; siRNA knockdown; shRNA and CRISPR-Cas9 loss-of-function with apoptosis readout\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro cleavage assay with site-identification (Asp580), Co-IP, and genetic KD/KO each supporting the same mechanistic conclusion in a single focused study\",\n      \"pmids\": [\"29242562\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Crystal structure of the Trx-like and NHL repeat β-propeller domains of human NHLRC2 determined to 2.7 Å resolution, revealing two adjacent domains forming a cleft containing a conserved CCINC motif with an extended negative electrostatic surface proposed to form a ligand/partner binding site. SAXS of full-length NHLRC2 shows the non-conserved C-terminal domain does not pack against the N-terminal domains. The FINCA disease-associated Asp148Tyr mutation destabilizes the protein structure by 2°C.\",\n      \"method\": \"X-ray crystallography (2.7 Å) and SAXS for full-length protein; thermal stability assay for Asp148Tyr mutant\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure plus SAXS plus mutant stability measurement in a single rigorous structural study\",\n      \"pmids\": [\"30138417\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"An insulin turbidity assay on recombinant human NHLRC2 showed NO thioredoxin reductase activity, despite the protein containing a thioredoxin-like domain.\",\n      \"method\": \"Insulin turbidity assay (in vitro enzymatic assay) with recombinant NHLRC2\",\n      \"journal\": \"Acta neuropathologica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — direct in vitro enzymatic assay, single lab, single method; result is negative (no thioredoxin activity)\",\n      \"pmids\": [\"29423877\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Proximity-labeling mass spectrometry identified putative interacting partners for NHLRC2, and functional studies using FINCA patient-derived immortalized fibroblasts (carrying compound heterozygous mutations) showed multilamellar bodies, distinctly organized vimentin filaments, and features of myofibroblast differentiation. NHLRC2 knockdown and overexpression experiments placed NHLRC2 in regulation of cytoskeletal organization and vesicle transport; loss of NHLRC2 function enhanced fibroblast-to-myofibroblast differentiation.\",\n      \"method\": \"Proximity-labeling (BioID) mass spectrometry; transmission electron microscopy of patient-derived immortalized cells; NHLRC2 knockdown and overexpression in normal fibroblasts\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — proximity-labeling MS for interaction partners, TEM morphological phenotyping, and KD/OE functional studies in same paper; single lab\",\n      \"pmids\": [\"30239752\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Nhlrc2 null mouse embryos implanted and appeared normal at E6.5 but development arrested at E7.5, with only 6% of E8.5 embryos homozygous null; KO embryos showed failed gastrulation and amniotic folding. Embryonic stem cells from null blastocysts proliferated normally despite complete loss of NHLRC2 protein, indicating the essential role is post-implantation.\",\n      \"method\": \"Nhlrc2 knockout mouse (C57BL/6NCrl-Nhlrc2tm1a(KOMP)Wtsi/Oulu); timed matings with genotyping; in vitro fertilization; LacZ reporter for expression mapping\",\n      \"journal\": \"Genesis (New York, N.Y. : 2000)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — well-defined KO with timed developmental staging and reporter expression; single lab\",\n      \"pmids\": [\"35258166\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"In a FINCA mouse model (compound heterozygote: Nhlrc2 p.Asp148Tyr knockin × Nhlrc2 knockout), 2D-DIGE proteomics of E13.5 cortical neuronal precursor cells identified 19 altered proteins, including significant upregulation of hnRNP C2 in both developing neurons and adult hippocampus. Several altered proteins are involved in vesicular transport pathways and actin dynamics, connecting NHLRC2 dysfunction to disrupted RNA metabolism and cytoskeletal regulation in neurons.\",\n      \"method\": \"CRISPR/Cas9 knockin mouse; 2D-DIGE comparative proteomics of embryonic cortical neuronal precursor cells; Western blot validation\",\n      \"journal\": \"Molecular medicine (Cambridge, Mass.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — in vivo genetic model with proteomics and validation; single lab; hnRNP C2 accumulation confirmed by orthogonal methods\",\n      \"pmids\": [\"33297935\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Expression of novel and previously published non-truncating NHLRC2 variants in HEK293 cells demonstrated that greater reduction in NHLRC2 protein expression is associated with a more severe disease phenotype, supporting a genotype-phenotype correlation based on residual protein levels.\",\n      \"method\": \"Cloning and expression of NHLRC2 variants in HEK293 cells with protein level quantification\",\n      \"journal\": \"European journal of human genetics : EJHG\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single overexpression assay measuring protein levels, single lab, no mechanistic dissection beyond quantification\",\n      \"pmids\": [\"37188825\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Proximity-labeling mass spectrometry comparing wild-type and p.Asp148Tyr NHLRC2 in HEK293 cells, combined with transcriptional profiling of mouse embryonic stem cells homozygous for p.Asp148Tyr or Nhlrc2 KO, identified Rho GTPase signalling as a pathway commonly affected by NHLRC2 dysfunction. FINCA mice showed altered innate immune response, particularly reduced interferon-γ production in splenocytes.\",\n      \"method\": \"Proximity-labeling (BioID) mass spectrometry with variant vs. wild-type comparison; transcriptomics of mESCs; T cell and cytokine profiling (interferon-γ) of FINCA compound heterozygous mice\",\n      \"journal\": \"Brain, behavior, & immunity - health\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — two orthogonal discovery approaches (proximity-labeling MS and transcriptomics) converging on Rho GTPase pathway, supported by in vivo immune phenotyping; single lab\",\n      \"pmids\": [\"40510178\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"NHLRC2 is an essential, ubiquitously expressed protein whose crystal structure reveals a thioredoxin-like domain and NHL-repeat β-propeller domain forming a conserved CCINC-containing cleft (with no thioredoxin reductase activity detected in vitro); it is cleaved by caspase-8 at Asp580 via an interaction between its thioredoxin-like domain and pro-caspase-8 during ROS-induced apoptosis, and its loss-of-function (via patient mutations, knockdown, or knockout) disrupts cytoskeletal organization (vimentin, actin/Rho GTPase signalling), vesicle transport, and RNA metabolism (hnRNP C2 accumulation), promoting fibroblast-to-myofibroblast differentiation and impairing immune responses, while complete loss causes embryonic lethality at gastrulation in mice.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"NHLRC2 is an essential, ubiquitously required protein that integrates cytoskeletal organization, vesicle transport, and RNA metabolism, and whose complete loss arrests mouse embryonic development at gastrulation around E7.5 despite normal pre-implantation proliferation [#4]. Structurally it comprises an N-terminal thioredoxin-like domain adjacent to an NHL-repeat \\u03b2-propeller, together forming a cleft containing a conserved CCINC motif with an extended negative electrostatic surface that constitutes a likely ligand/partner-binding site, while the non-conserved C-terminal domain remains spatially separate; the FINCA-associated Asp148Tyr substitution destabilizes the fold [#1]. Despite the thioredoxin-like domain, recombinant NHLRC2 lacks detectable thioredoxin reductase activity [#2]. During ROS-induced apoptosis the thioredoxin-like domain binds pro-caspase-8 and NHLRC2 is cleaved at Asp580, and its depletion sensitizes cells to ROS-induced death [#0]. Loss of NHLRC2 function disrupts vimentin filament organization, vesicle transport, and Rho GTPase signalling, promotes fibroblast-to-myofibroblast differentiation, perturbs RNA metabolism through accumulation of hnRNP C2, and impairs innate immune responses including interferon-\\u03b3 production [#3, #5, #7]. Biallelic non-truncating NHLRC2 variants cause the multisystem FINCA disease, with residual protein level correlating with phenotype severity [#6]. Beyond these findings, the direct molecular substrate or enzymatic/scaffolding function executed through the CCINC cleft has not been defined in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2017,\n      \"claim\": \"Established the first direct molecular handle on NHLRC2 by linking it to apoptotic signalling, showing it is a caspase-8 substrate whose loss sensitizes cells to oxidative stress.\",\n      \"evidence\": \"In vitro cleavage assay mapping Asp580, Co-IP of the Trx-like domain with pro-caspase-8, and siRNA/shRNA/CRISPR loss-of-function with ROS-apoptosis readout\",\n      \"pmids\": [\"29242562\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not define NHLRC2's baseline (non-apoptotic) molecular function\", \"Functional consequence of the cleavage fragment unknown\", \"No structural basis for the caspase-8 interaction\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Solved the domain architecture, revealing a Trx-like plus NHL-repeat \\u03b2-propeller arrangement forming a conserved CCINC cleft as the candidate functional surface and showing a disease mutation destabilizes the protein.\",\n      \"evidence\": \"X-ray crystallography to 2.7 \\u00c5, SAXS of full-length protein, and thermal stability assay of the Asp148Tyr mutant\",\n      \"pmids\": [\"30138417\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No ligand or partner bound in the CCINC cleft was identified\", \"C-terminal domain structure unresolved\", \"Catalytic role of the cleft unknown\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Tested whether the thioredoxin-like domain confers redox enzymatic activity, finding none and arguing the domain serves a binding/structural rather than catalytic role.\",\n      \"evidence\": \"Insulin turbidity assay on recombinant NHLRC2\",\n      \"pmids\": [\"29423877\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single in vitro assay and method\", \"Negative result does not exclude other redox-related activities\", \"No alternative function assigned to the Trx-like domain\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Connected NHLRC2 to cellular physiology by showing FINCA patient cells display abnormal vimentin organization and myofibroblast features, placing the protein in cytoskeletal organization and vesicle transport.\",\n      \"evidence\": \"BioID proximity-labeling MS, TEM of patient-derived immortalized fibroblasts, and knockdown/overexpression in normal fibroblasts\",\n      \"pmids\": [\"30239752\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct vs. indirect partners not distinguished from BioID\", \"Mechanism linking NHLRC2 to vimentin not defined\", \"Single lab and patient-derived background\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Defined the developmental window of NHLRC2 essentiality, showing it is dispensable pre-implantation but required for gastrulation.\",\n      \"evidence\": \"Nhlrc2 knockout mouse with timed staging, IVF, and LacZ expression mapping\",\n      \"pmids\": [\"35258166\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular cause of gastrulation arrest unknown\", \"Lethality precludes adult tissue analysis\", \"Does not identify the essential downstream pathway\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Linked NHLRC2 dysfunction to RNA metabolism in neural tissue by identifying hnRNP C2 accumulation alongside altered vesicular-transport and actin-dynamics proteins.\",\n      \"evidence\": \"FINCA knockin x KO mouse model with 2D-DIGE proteomics of E13.5 cortical neuronal precursors and Western validation\",\n      \"pmids\": [\"33297935\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Causal link between NHLRC2 and hnRNP C2 not mechanistically resolved\", \"Whether RNA metabolism defect is primary or secondary unclear\", \"Single lab\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Established a genotype-phenotype rule for FINCA, showing residual NHLRC2 protein level scales with disease severity.\",\n      \"evidence\": \"Expression of non-truncating variants in HEK293 cells with protein-level quantification\",\n      \"pmids\": [\"37188825\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single overexpression assay with no mechanistic dissection\", \"Protein level read out in non-native cell context\", \"Does not address how reduced levels cause specific phenotypes\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Converged multiple datasets on Rho GTPase signalling as a core affected pathway and extended NHLRC2 dysfunction to innate immunity via reduced interferon-\\u03b3.\",\n      \"evidence\": \"Variant-vs-WT BioID proximity-labeling MS, mESC transcriptomics, and FINCA mouse T cell/cytokine profiling\",\n      \"pmids\": [\"40510178\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct effector linking NHLRC2 to Rho GTPase signalling not identified\", \"Mechanism of impaired interferon-\\u03b3 production unresolved\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The direct biochemical activity or binding partner engaged through the conserved CCINC cleft, and the molecular event that makes NHLRC2 essential for gastrulation, remain undefined.\",\n      \"evidence\": \"No discovery in the corpus assigns a substrate or catalytic/scaffolding mechanism to NHLRC2\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No defined molecular substrate or ligand\", \"Mechanism unifying cytoskeletal, vesicular, RNA, and immune phenotypes unknown\", \"No structure-function link from the CCINC cleft to a cellular activity\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [7]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"CASP8\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"faith_supported":6,"faith_total":6,"faith_pct":100.0}}