{"gene":"CARD19","run_date":"2026-06-09T22:57:17","timeline":{"discoveries":[{"year":2004,"finding":"BinCARD (CARD19) interacts with Bcl10 through its CARD domain, and this interaction suppresses Bcl10-induced NF-κB activation and Bcl10 phosphorylation. Mutations at conserved CARD residues Leu17 or Leu65 abolished both the inhibitory effect on NF-κB and on Bcl10 phosphorylation.","method":"Co-immunoprecipitation, in vitro binding, mammalian two-hybrid, immunostaining, and CARD domain mutagenesis","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP plus multiple orthogonal binding assays and mutagenesis in single lab; later work showed overexpression artifact in primary cells","pmids":["15637807"],"is_preprint":false},{"year":2013,"finding":"Crystal structures of the BinCARD (CARD19) CARD domain were solved to 1.58 Å (native) and 1.40 Å (selenomethionine double mutant), revealing a canonical CARD fold, a cis-peptide bond between Tyr39 and Pro40, and oxidation of all three cysteines, suggesting a potential redox-regulatory role consistent with mitochondrial localization of BinCARD-2.","method":"X-ray crystallography (MAD phasing with selenomethionine-substituted double mutant; space group P1)","journal":"Acta crystallographica. Section D, Biological crystallography","confidence":"High","confidence_rationale":"Tier 1 / Strong — high-resolution crystal structures of native and mutant with direct structural validation","pmids":["23633586"],"is_preprint":false},{"year":2019,"finding":"BinCARD2 (CARD19) associates with MAVS and promotes MAVS oligomerization downstream of RIG-I, positively regulating RLR-mediated IFN-β production. Knockdown of BinCARD2 impaired MAVS oligomerization and reduced IFN-β and IL-6 induction after VSV infection, without affecting RIG-I/MAVS binding.","method":"Co-immunoprecipitation, siRNA knockdown, IFNB promoter reporter assay, VSV infection of A549 cells","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP plus functional KD with defined phenotypic readouts (oligomerization, IFN-β induction), single lab","pmids":["30795865"],"is_preprint":false},{"year":2020,"finding":"The only detectable translated product of C9orf89 is CARD19 (BinCARD-2, the properly spliced isoform); endogenous CARD19 localizes to mitochondria in primary cells. Loss of endogenous CARD19 had no discernible effect on Bcl10-dependent NF-κB activation, Malt1 protease function, or Bcl10 degradation after TCR engagement in primary murine CD8+ T cells, demonstrating that the previously reported NF-κB regulatory function reflects an overexpression artifact.","method":"Immunoblotting, confocal microscopy of endogenous CARD19, CARD19 knockout in primary murine CD8+ T cells, NF-κB reporter assays, Malt1 substrate cleavage assays","journal":"Cellular immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — endogenous localization by microscopy combined with clean KO in primary cells using multiple orthogonal functional readouts","pmids":["32763502"],"is_preprint":false},{"year":2021,"finding":"A Card19-deficient mouse line (Card19lxcn) showed impaired macrophage cell lysis downstream of gasdermin D cleavage and increased susceptibility to Yersinia infection, but an independently generated CRISPR/Cas9 Card19Null mouse showed no such defect. RNA-seq and western blotting revealed that Card19lxcn macrophages have severely reduced NINJ1 expression due to off-target disruption of the adjacent Ninj1 locus; reconstitution of Ninj1 rescued cell lysis, demonstrating that CARD19 itself is not required for pyroptotic plasma membrane rupture.","method":"Two independent KO mouse lines, RNA-seq, western blotting, NINJ1 reconstitution experiments, Yersinia infection survival assays","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Strong — two independent KO lines plus reconstitution experiment with multiple orthogonal methods ruling out direct CARD19 function in cell lysis","pmids":["34648590"],"is_preprint":false},{"year":2022,"finding":"CARD19 is specifically localized to the outer mitochondrial membrane (OMM); both the distal C-terminus and transmembrane domain are required for mitochondrial targeting, whereas the CARD domain is not. Mass spectrometry of CARD19 immunoprecipitates identified interactions with MICOS components MIC19, MIC25, and MIC60, and MICOS-interacting proteins SAMM50 and MTX2. These interactions are partly dependent on a properly folded CARD. Loss of CARD19 correlates with irregular cristae morphology, phenocopying silencing of MICOS subunits.","method":"SIM, TEM, confocal microscopy, proteinase K protection assay, deletion mutagenesis, mass spectrometry of immunoprecipitates, siRNA knockdown","journal":"Cells","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — multiple orthogonal structural/localization methods, proteomics-based interaction identification with domain mutagenesis, and defined ultrastructural phenotype","pmids":["35406738"],"is_preprint":false},{"year":2022,"finding":"IAV leverages BinCARD1 (an incompletely spliced isoform of CARD19) to promote nuclear import of the viral ribonucleoprotein (vRNP) complex: BinCARD1 interacts with viral NP and facilitates its binding to importin α7. Concurrently, BinCARD1 is polyubiquitinated at K103 via Lys63-linked chains, which are recognized by the TBK1-p62 axis for autophagic degradation, limiting its pro-viral activity.","method":"Co-immunoprecipitation, ubiquitination assays, autophagy/degradation assays, mutagenesis (K103), siRNA knockdown, IAV infection models","journal":"Cellular & molecular immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP with mutagenesis and functional infection readouts in a single lab; BinCARD1 is an incompletely spliced isoform not the canonical CARD19 protein","pmids":["36056146"],"is_preprint":false},{"year":2023,"finding":"CARD19 interacts with TAK1 and inhibits TAB2-mediated TAK1 ubiquitination and activation. In self-reactive B cells, CARD19 deficiency increases BCR/TAK1-mediated NF-κB activation, leading to elevated expression of Egr2/3 and E3 ubiquitin ligases c-Cbl/Cbl-b, which enhance B cell tolerance. CARD19 deficiency enhanced clonal deletion, receptor editing, and anergy of self-reactive B cells and prevented experimental SLE in a Bm12 model.","method":"Co-immunoprecipitation (CARD19-TAK1), ubiquitination assays (TAB2-mediated TAK1 ubiquitination), CARD19 knockout mice, BCR signaling assays, RNA sequencing, Bm12-induced SLE model","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP interaction with TAK1, functional ubiquitination assay, and KO mouse with multiple readouts in single lab","pmids":["36961449"],"is_preprint":false}],"current_model":"CARD19 (BinCARD-2) is a mitochondrial outer membrane protein that interacts with the MICOS subcomplex (MIC19/MIC25/MIC60) and associated proteins SAMM50/MTX2 to regulate cristae morphology; its CARD domain can interact with BCL10, TAK1, and MAVS to modulate NF-κB and innate immune signaling, though the endogenous protein's role in TCR-dependent NF-κB/BCL10 signaling has been refuted in primary T cells, while its functions in B cell tolerance via TAK1 inhibition and in RLR-mediated IFN-β production via MAVS oligomerization have been established experimentally."},"narrative":{"mechanistic_narrative":"CARD19 (BinCARD-2) is the only detectable translated product of the C9orf89 locus and is an outer mitochondrial membrane protein that contributes to cristae architecture while modulating innate immune and tolerance signaling through its CARD domain [PMID:32763502, PMID:35406738]. Mitochondrial targeting depends on its distal C-terminus and transmembrane domain rather than its CARD; at the OMM it interacts with the MICOS components MIC19, MIC25, and MIC60 and the associated proteins SAMM50 and MTX2, and its loss produces irregular cristae that phenocopy MICOS subunit depletion [PMID:35406738]. The isolated CARD domain adopts a canonical fold with a cis-peptide bond and oxidized cysteines consistent with a redox-sensitive, membrane-localized protein [PMID:23633586]. Functionally, CARD19 associates with MAVS to promote its oligomerization downstream of RIG-I, positively regulating RLR-driven IFN-β and IL-6 production [PMID:30795865], and it binds TAK1 to inhibit TAB2-mediated TAK1 ubiquitination, thereby restraining BCR/NF-κB signaling and shaping self-reactive B cell tolerance and lupus-like autoimmunity [PMID:36961449]. An earlier model in which CARD19 binds BCL10 to suppress NF-κB activation reflects an overexpression artifact: endogenous CARD19 loss has no effect on BCL10-dependent NF-κB activation or MALT1 protease function in primary T cells [PMID:15637807, PMID:32763502], and a reported role in pyroptotic membrane rupture was likewise attributable to off-target disruption of the adjacent Ninj1 locus rather than to CARD19 itself [PMID:34648590].","teleology":[{"year":2004,"claim":"The first functional hypothesis cast CARD19 as a CARD-dependent inhibitor of BCL10, addressing whether it tunes NF-κB signaling.","evidence":"Co-IP, mammalian two-hybrid, in vitro binding, and CARD residue mutagenesis in overexpression systems","pmids":["15637807"],"confidence":"Medium","gaps":["Based on overexpression, not endogenous protein","No demonstration of endogenous BCL10 complex","Later refuted in primary T cells"]},{"year":2013,"claim":"Solving the CARD domain structure established its fold and revealed oxidized cysteines and a cis-peptide bond, hinting at redox sensitivity tied to subcellular environment.","evidence":"X-ray crystallography of native and selenomethionine double-mutant CARD domain at 1.4–1.58 Å","pmids":["23633586"],"confidence":"High","gaps":["Structure of full-length membrane protein not determined","Functional consequence of cysteine oxidation not tested","No partner co-structure"]},{"year":2019,"claim":"CARD19 was assigned a positive role in antiviral signaling by promoting MAVS oligomerization, distinct from the inhibitory NF-κB model.","evidence":"Reciprocal Co-IP, siRNA knockdown, IFNB reporter, and VSV infection in A549 cells","pmids":["30795865"],"confidence":"Medium","gaps":["Mechanism of how CARD19 drives MAVS oligomerization unresolved","Single lab/cell type","Not validated in primary cells or knockout"]},{"year":2020,"claim":"Endogenous-level analysis showed CARD19 is mitochondrial and dispensable for BCL10/NF-κB/MALT1 signaling, overturning the original overexpression-based model.","evidence":"Endogenous immunoblotting and confocal microscopy plus CARD19 KO in primary murine CD8+ T cells with NF-κB and MALT1 cleavage readouts","pmids":["32763502"],"confidence":"High","gaps":["Did not define the actual mitochondrial function","Restricted to T cells","Mechanism of mitochondrial targeting not addressed"]},{"year":2021,"claim":"Two independent knockout lines resolved a contested role in pyroptosis, showing the lysis phenotype arose from off-target Ninj1 disruption, not CARD19.","evidence":"Comparison of Card19lxcn vs CRISPR Card19Null mice, RNA-seq, western blot, NINJ1 reconstitution, and Yersinia survival assays","pmids":["34648590"],"confidence":"High","gaps":["Does not assign CARD19 a positive function","Cautions that prior gene-trap line is confounded"]},{"year":2022,"claim":"Localization and proteomics established CARD19's core cell-biological function as an OMM protein in the MICOS interactome required for normal cristae morphology.","evidence":"SIM/TEM/confocal, proteinase K protection, deletion mutagenesis, mass spectrometry of immunoprecipitates, and siRNA knockdown","pmids":["35406738"],"confidence":"High","gaps":["Molecular role within MICOS (structural vs regulatory) unresolved","How cristae role connects to immune signaling unclear","Direct vs indirect MICOS contacts not dissected"]},{"year":2022,"claim":"An incompletely spliced isoform (BinCARD1) was implicated in IAV vRNP nuclear import and counter-regulated by ubiquitin-driven autophagic degradation, distinguishing isoform-specific functions.","evidence":"Co-IP, K103 ubiquitination and autophagy/degradation assays, mutagenesis, and IAV infection models","pmids":["36056146"],"confidence":"Medium","gaps":["Pertains to a non-canonical isoform, not CARD19/BinCARD-2","Single lab","Endogenous isoform abundance unclear"]},{"year":2023,"claim":"CARD19 was shown to restrain TAK1 activation, linking it to B cell tolerance and protection from lupus-like autoimmunity.","evidence":"CARD19-TAK1 Co-IP, TAB2-mediated TAK1 ubiquitination assays, CARD19 KO mice, BCR signaling, RNA-seq, and a Bm12 SLE model","pmids":["36961449"],"confidence":"Medium","gaps":["Mechanistic link between mitochondrial localization and TAK1 inhibition unresolved","Single lab","Direct vs indirect TAK1 regulation not fully defined"]},{"year":null,"claim":"How CARD19's outer-membrane MICOS/cristae role mechanistically connects to its CARD-mediated effects on MAVS-driven IFN-β and TAK1-dependent tolerance signaling remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified model linking cristae architecture to immune signaling","Whether MAVS and TAK1 effects require mitochondrial localization untested","Redox regulation of CARD function not functionally validated"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[5]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[2,7]}],"localization":[{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[3,5]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[2,7]},{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[5]}],"complexes":["MICOS"],"partners":["MIC19","MIC25","MIC60","SAMM50","MTX2","MAVS","TAK1","BCL10"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q96LW7","full_name":"Caspase recruitment domain-containing protein 19","aliases":["Bcl10-interacting CARD protein","BinCARD"],"length_aa":228,"mass_kda":25.6,"function":"Plays a role in inhibiting the effects of BCL10-induced activation of NF-kappa-B. May inhibit the phosphorylation of BCL10 in a CARD-dependent manner","subcellular_location":"Endoplasmic reticulum membrane; Mitochondrion membrane","url":"https://www.uniprot.org/uniprotkb/Q96LW7/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CARD19","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/CARD19","total_profiled":1310},"omim":[{"mim_id":"617726","title":"CASPASE RECRUITMENT DOMAIN-CONTAINING PROTEIN 19; CARD19","url":"https://www.omim.org/entry/617726"},{"mim_id":"603517","title":"BCL10 IMMUNE SIGNALING ADAPTOR; BCL10","url":"https://www.omim.org/entry/603517"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Mitochondria","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in many","driving_tissues":[],"url":"https://www.proteinatlas.org/search/CARD19"},"hgnc":{"alias_symbol":["MGC11115","bA370F5.1","BinCARD"],"prev_symbol":["C9orf89"]},"alphafold":{"accession":"Q96LW7","domains":[{"cath_id":"1.10.533.10","chopping":"7-104","consensus_level":"high","plddt":91.0439,"start":7,"end":104}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96LW7","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96LW7-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96LW7-F1-predicted_aligned_error_v6.png","plddt_mean":63.12},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CARD19","jax_strain_url":"https://www.jax.org/strain/search?query=CARD19"},"sequence":{"accession":"Q96LW7","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96LW7.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96LW7/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96LW7"}},"corpus_meta":[{"pmid":"36056146","id":"PMC_36056146","title":"Influenza A virus use of BinCARD1 to facilitate the binding of viral NP to importin α7 is counteracted by TBK1-p62 axis-mediated autophagy.","date":"2022","source":"Cellular & molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/36056146","citation_count":37,"is_preprint":false},{"pmid":"34648590","id":"PMC_34648590","title":"Genetic targeting of Card19 is linked to disrupted NINJ1 expression, impaired cell lysis, and increased susceptibility to Yersinia infection.","date":"2021","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/34648590","citation_count":35,"is_preprint":false},{"pmid":"15637807","id":"PMC_15637807","title":"Inhibition of Bcl10-mediated activation of NF-kappa B by BinCARD, a Bcl10-interacting CARD protein.","date":"2004","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/15637807","citation_count":17,"is_preprint":false},{"pmid":"23633586","id":"PMC_23633586","title":"The structure of the caspase recruitment domain of BinCARD reveals that all three cysteines can be oxidized.","date":"2013","source":"Acta crystallographica. Section D, Biological crystallography","url":"https://pubmed.ncbi.nlm.nih.gov/23633586","citation_count":12,"is_preprint":false},{"pmid":"30795865","id":"PMC_30795865","title":"BinCARD2 as a positive regulator of interferon response in innate immunity.","date":"2019","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/30795865","citation_count":9,"is_preprint":false},{"pmid":"35406738","id":"PMC_35406738","title":"CARD19 Interacts with Mitochondrial Contact Site and Cristae Organizing System Constituent Proteins and Regulates Cristae Morphology.","date":"2022","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/35406738","citation_count":8,"is_preprint":false},{"pmid":"32763502","id":"PMC_32763502","title":"CARD19, the protein formerly known as BinCARD, is a mitochondrial protein that does not regulate Bcl10-dependent NF-κB activation after TCR engagement.","date":"2020","source":"Cellular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/32763502","citation_count":6,"is_preprint":false},{"pmid":"37264057","id":"PMC_37264057","title":"Indirect CRISPR screening with photoconversion revealed key factors of drug resistance with cell-cell interactions.","date":"2023","source":"Communications biology","url":"https://pubmed.ncbi.nlm.nih.gov/37264057","citation_count":5,"is_preprint":false},{"pmid":"35523843","id":"PMC_35523843","title":"A Bayesian network structure learning approach to identify genes associated with stress in spleens of chickens.","date":"2022","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/35523843","citation_count":4,"is_preprint":false},{"pmid":"36961449","id":"PMC_36961449","title":"CARD19, a Novel Regulator of the TAK1/NF-κB Pathway in Self-Reactive B Cells.","date":"2023","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/36961449","citation_count":2,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7124,"output_tokens":2461,"usd":0.029143,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9570,"output_tokens":2962,"usd":0.06095,"stage2_stop_reason":"end_turn"},"total_usd":0.090093,"stage1_batch_id":"msgbatch_01ACAxJQabDsht39JXeWG22d","stage2_batch_id":"msgbatch_01QEU22A9U5sbPTgsMzTmvSf","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2004,\n      \"finding\": \"BinCARD (CARD19) interacts with Bcl10 through its CARD domain, and this interaction suppresses Bcl10-induced NF-κB activation and Bcl10 phosphorylation. Mutations at conserved CARD residues Leu17 or Leu65 abolished both the inhibitory effect on NF-κB and on Bcl10 phosphorylation.\",\n      \"method\": \"Co-immunoprecipitation, in vitro binding, mammalian two-hybrid, immunostaining, and CARD domain mutagenesis\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP plus multiple orthogonal binding assays and mutagenesis in single lab; later work showed overexpression artifact in primary cells\",\n      \"pmids\": [\"15637807\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Crystal structures of the BinCARD (CARD19) CARD domain were solved to 1.58 Å (native) and 1.40 Å (selenomethionine double mutant), revealing a canonical CARD fold, a cis-peptide bond between Tyr39 and Pro40, and oxidation of all three cysteines, suggesting a potential redox-regulatory role consistent with mitochondrial localization of BinCARD-2.\",\n      \"method\": \"X-ray crystallography (MAD phasing with selenomethionine-substituted double mutant; space group P1)\",\n      \"journal\": \"Acta crystallographica. Section D, Biological crystallography\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — high-resolution crystal structures of native and mutant with direct structural validation\",\n      \"pmids\": [\"23633586\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"BinCARD2 (CARD19) associates with MAVS and promotes MAVS oligomerization downstream of RIG-I, positively regulating RLR-mediated IFN-β production. Knockdown of BinCARD2 impaired MAVS oligomerization and reduced IFN-β and IL-6 induction after VSV infection, without affecting RIG-I/MAVS binding.\",\n      \"method\": \"Co-immunoprecipitation, siRNA knockdown, IFNB promoter reporter assay, VSV infection of A549 cells\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP plus functional KD with defined phenotypic readouts (oligomerization, IFN-β induction), single lab\",\n      \"pmids\": [\"30795865\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"The only detectable translated product of C9orf89 is CARD19 (BinCARD-2, the properly spliced isoform); endogenous CARD19 localizes to mitochondria in primary cells. Loss of endogenous CARD19 had no discernible effect on Bcl10-dependent NF-κB activation, Malt1 protease function, or Bcl10 degradation after TCR engagement in primary murine CD8+ T cells, demonstrating that the previously reported NF-κB regulatory function reflects an overexpression artifact.\",\n      \"method\": \"Immunoblotting, confocal microscopy of endogenous CARD19, CARD19 knockout in primary murine CD8+ T cells, NF-κB reporter assays, Malt1 substrate cleavage assays\",\n      \"journal\": \"Cellular immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — endogenous localization by microscopy combined with clean KO in primary cells using multiple orthogonal functional readouts\",\n      \"pmids\": [\"32763502\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"A Card19-deficient mouse line (Card19lxcn) showed impaired macrophage cell lysis downstream of gasdermin D cleavage and increased susceptibility to Yersinia infection, but an independently generated CRISPR/Cas9 Card19Null mouse showed no such defect. RNA-seq and western blotting revealed that Card19lxcn macrophages have severely reduced NINJ1 expression due to off-target disruption of the adjacent Ninj1 locus; reconstitution of Ninj1 rescued cell lysis, demonstrating that CARD19 itself is not required for pyroptotic plasma membrane rupture.\",\n      \"method\": \"Two independent KO mouse lines, RNA-seq, western blotting, NINJ1 reconstitution experiments, Yersinia infection survival assays\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — two independent KO lines plus reconstitution experiment with multiple orthogonal methods ruling out direct CARD19 function in cell lysis\",\n      \"pmids\": [\"34648590\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"CARD19 is specifically localized to the outer mitochondrial membrane (OMM); both the distal C-terminus and transmembrane domain are required for mitochondrial targeting, whereas the CARD domain is not. Mass spectrometry of CARD19 immunoprecipitates identified interactions with MICOS components MIC19, MIC25, and MIC60, and MICOS-interacting proteins SAMM50 and MTX2. These interactions are partly dependent on a properly folded CARD. Loss of CARD19 correlates with irregular cristae morphology, phenocopying silencing of MICOS subunits.\",\n      \"method\": \"SIM, TEM, confocal microscopy, proteinase K protection assay, deletion mutagenesis, mass spectrometry of immunoprecipitates, siRNA knockdown\",\n      \"journal\": \"Cells\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — multiple orthogonal structural/localization methods, proteomics-based interaction identification with domain mutagenesis, and defined ultrastructural phenotype\",\n      \"pmids\": [\"35406738\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"IAV leverages BinCARD1 (an incompletely spliced isoform of CARD19) to promote nuclear import of the viral ribonucleoprotein (vRNP) complex: BinCARD1 interacts with viral NP and facilitates its binding to importin α7. Concurrently, BinCARD1 is polyubiquitinated at K103 via Lys63-linked chains, which are recognized by the TBK1-p62 axis for autophagic degradation, limiting its pro-viral activity.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, autophagy/degradation assays, mutagenesis (K103), siRNA knockdown, IAV infection models\",\n      \"journal\": \"Cellular & molecular immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP with mutagenesis and functional infection readouts in a single lab; BinCARD1 is an incompletely spliced isoform not the canonical CARD19 protein\",\n      \"pmids\": [\"36056146\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CARD19 interacts with TAK1 and inhibits TAB2-mediated TAK1 ubiquitination and activation. In self-reactive B cells, CARD19 deficiency increases BCR/TAK1-mediated NF-κB activation, leading to elevated expression of Egr2/3 and E3 ubiquitin ligases c-Cbl/Cbl-b, which enhance B cell tolerance. CARD19 deficiency enhanced clonal deletion, receptor editing, and anergy of self-reactive B cells and prevented experimental SLE in a Bm12 model.\",\n      \"method\": \"Co-immunoprecipitation (CARD19-TAK1), ubiquitination assays (TAB2-mediated TAK1 ubiquitination), CARD19 knockout mice, BCR signaling assays, RNA sequencing, Bm12-induced SLE model\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP interaction with TAK1, functional ubiquitination assay, and KO mouse with multiple readouts in single lab\",\n      \"pmids\": [\"36961449\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CARD19 (BinCARD-2) is a mitochondrial outer membrane protein that interacts with the MICOS subcomplex (MIC19/MIC25/MIC60) and associated proteins SAMM50/MTX2 to regulate cristae morphology; its CARD domain can interact with BCL10, TAK1, and MAVS to modulate NF-κB and innate immune signaling, though the endogenous protein's role in TCR-dependent NF-κB/BCL10 signaling has been refuted in primary T cells, while its functions in B cell tolerance via TAK1 inhibition and in RLR-mediated IFN-β production via MAVS oligomerization have been established experimentally.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CARD19 (BinCARD-2) is the only detectable translated product of the C9orf89 locus and is an outer mitochondrial membrane protein that contributes to cristae architecture while modulating innate immune and tolerance signaling through its CARD domain [#3, #5]. Mitochondrial targeting depends on its distal C-terminus and transmembrane domain rather than its CARD; at the OMM it interacts with the MICOS components MIC19, MIC25, and MIC60 and the associated proteins SAMM50 and MTX2, and its loss produces irregular cristae that phenocopy MICOS subunit depletion [#5]. The isolated CARD domain adopts a canonical fold with a cis-peptide bond and oxidized cysteines consistent with a redox-sensitive, membrane-localized protein [#1]. Functionally, CARD19 associates with MAVS to promote its oligomerization downstream of RIG-I, positively regulating RLR-driven IFN-\\u03b2 and IL-6 production [#2], and it binds TAK1 to inhibit TAB2-mediated TAK1 ubiquitination, thereby restraining BCR/NF-\\u03baB signaling and shaping self-reactive B cell tolerance and lupus-like autoimmunity [#7]. An earlier model in which CARD19 binds BCL10 to suppress NF-\\u03baB activation reflects an overexpression artifact: endogenous CARD19 loss has no effect on BCL10-dependent NF-\\u03baB activation or MALT1 protease function in primary T cells [#0, #3], and a reported role in pyroptotic membrane rupture was likewise attributable to off-target disruption of the adjacent Ninj1 locus rather than to CARD19 itself [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 2004,\n      \"claim\": \"The first functional hypothesis cast CARD19 as a CARD-dependent inhibitor of BCL10, addressing whether it tunes NF-\\u03baB signaling.\",\n      \"evidence\": \"Co-IP, mammalian two-hybrid, in vitro binding, and CARD residue mutagenesis in overexpression systems\",\n      \"pmids\": [\"15637807\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Based on overexpression, not endogenous protein\", \"No demonstration of endogenous BCL10 complex\", \"Later refuted in primary T cells\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Solving the CARD domain structure established its fold and revealed oxidized cysteines and a cis-peptide bond, hinting at redox sensitivity tied to subcellular environment.\",\n      \"evidence\": \"X-ray crystallography of native and selenomethionine double-mutant CARD domain at 1.4\\u20131.58 \\u00c5\",\n      \"pmids\": [\"23633586\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure of full-length membrane protein not determined\", \"Functional consequence of cysteine oxidation not tested\", \"No partner co-structure\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"CARD19 was assigned a positive role in antiviral signaling by promoting MAVS oligomerization, distinct from the inhibitory NF-\\u03baB model.\",\n      \"evidence\": \"Reciprocal Co-IP, siRNA knockdown, IFNB reporter, and VSV infection in A549 cells\",\n      \"pmids\": [\"30795865\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of how CARD19 drives MAVS oligomerization unresolved\", \"Single lab/cell type\", \"Not validated in primary cells or knockout\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Endogenous-level analysis showed CARD19 is mitochondrial and dispensable for BCL10/NF-\\u03baB/MALT1 signaling, overturning the original overexpression-based model.\",\n      \"evidence\": \"Endogenous immunoblotting and confocal microscopy plus CARD19 KO in primary murine CD8+ T cells with NF-\\u03baB and MALT1 cleavage readouts\",\n      \"pmids\": [\"32763502\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define the actual mitochondrial function\", \"Restricted to T cells\", \"Mechanism of mitochondrial targeting not addressed\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Two independent knockout lines resolved a contested role in pyroptosis, showing the lysis phenotype arose from off-target Ninj1 disruption, not CARD19.\",\n      \"evidence\": \"Comparison of Card19lxcn vs CRISPR Card19Null mice, RNA-seq, western blot, NINJ1 reconstitution, and Yersinia survival assays\",\n      \"pmids\": [\"34648590\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not assign CARD19 a positive function\", \"Cautions that prior gene-trap line is confounded\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Localization and proteomics established CARD19's core cell-biological function as an OMM protein in the MICOS interactome required for normal cristae morphology.\",\n      \"evidence\": \"SIM/TEM/confocal, proteinase K protection, deletion mutagenesis, mass spectrometry of immunoprecipitates, and siRNA knockdown\",\n      \"pmids\": [\"35406738\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular role within MICOS (structural vs regulatory) unresolved\", \"How cristae role connects to immune signaling unclear\", \"Direct vs indirect MICOS contacts not dissected\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"An incompletely spliced isoform (BinCARD1) was implicated in IAV vRNP nuclear import and counter-regulated by ubiquitin-driven autophagic degradation, distinguishing isoform-specific functions.\",\n      \"evidence\": \"Co-IP, K103 ubiquitination and autophagy/degradation assays, mutagenesis, and IAV infection models\",\n      \"pmids\": [\"36056146\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Pertains to a non-canonical isoform, not CARD19/BinCARD-2\", \"Single lab\", \"Endogenous isoform abundance unclear\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"CARD19 was shown to restrain TAK1 activation, linking it to B cell tolerance and protection from lupus-like autoimmunity.\",\n      \"evidence\": \"CARD19-TAK1 Co-IP, TAB2-mediated TAK1 ubiquitination assays, CARD19 KO mice, BCR signaling, RNA-seq, and a Bm12 SLE model\",\n      \"pmids\": [\"36961449\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanistic link between mitochondrial localization and TAK1 inhibition unresolved\", \"Single lab\", \"Direct vs indirect TAK1 regulation not fully defined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How CARD19's outer-membrane MICOS/cristae role mechanistically connects to its CARD-mediated effects on MAVS-driven IFN-\\u03b2 and TAK1-dependent tolerance signaling remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model linking cristae architecture to immune signaling\", \"Whether MAVS and TAK1 effects require mitochondrial localization untested\", \"Redox regulation of CARD function not functionally validated\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [2, 7]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [3, 5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [2, 7]},\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"complexes\": [\"MICOS\"],\n    \"partners\": [\"MIC19\", \"MIC25\", \"MIC60\", \"SAMM50\", \"MTX2\", \"MAVS\", \"TAK1\", \"BCL10\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}