{"gene":"RNF19B","run_date":"2026-06-10T06:43:37","timeline":{"discoveries":[{"year":2000,"finding":"NKLAM (RNF19B) encodes a zinc finger protein that resides in NK cytolytic granules; antisense oligonucleotide-mediated knockdown of NKLAM inhibits cytotoxic function of NK cells and CTLs, establishing a direct role in cellular cytotoxicity. Two human isoforms (587 and 731 residue proteins) arise from alternative splicing, with the larger form predominant.","method":"Antisense oligonucleotide knockdown of NKLAM in NK cells/CTLs with cytotoxicity assays; cDNA cloning, genomic structure analysis, and expression profiling","journal":"Immunogenetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional knockdown with defined phenotype, orthogonal structural and expression analyses; single lab","pmids":["10912506"],"is_preprint":false},{"year":2012,"finding":"NKLAM is a phagosomal E3 ubiquitin ligase in macrophages; it translocates to the phagosome early during maturation coinciding with elevated phagosomal ubiquitinated proteins, co-localizes with ingested E. coli, and NKLAM-deficient macrophages show reduced bacterial killing.","method":"Confocal microscopy (co-localization with E. coli and IgG-opsonized latex beads), subcellular fractionation, bacterial killing assays with NKLAM-KO bone marrow-derived macrophages vs. wild type","journal":"Cellular immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization with functional consequence, KO phenotype with defined readout; single lab, two orthogonal methods","pmids":["23085241"],"is_preprint":false},{"year":2014,"finding":"NKLAM positively regulates iNOS expression and NO production in LPS-stimulated macrophages by promoting STAT1 tyrosine phosphorylation, IFNβ production, and NFκB p65 nuclear translocation; NKLAM-KO macrophages show reduced p65 expression, defective p65 phosphorylation at S536, and diminished NFκB transcriptional activity independent of IKBα degradation.","method":"NKLAM-KO vs. WT bone marrow-derived macrophage comparisons: ELISA (NO, IFNβ), Western blot (iNOS, phospho-STAT1, p65, phospho-p65, IKBα), confocal microscopy (p65 nuclear translocation), NFκB luciferase reporter transfection assay","journal":"Immunobiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO with defined cellular phenotype, multiple orthogonal methods; single lab","pmids":["25182373"],"is_preprint":false},{"year":2016,"finding":"NKLAM mediates K63-linked ubiquitination of STAT1 in macrophages; NKLAM transiently localizes to the IFNγ receptor complex during IFNγ stimulation, binds STAT1, and this ubiquitination is required for STAT1 DNA-binding to gamma activation sequences and full STAT1-mediated transcription. Loss of NKLAM results in hyperphosphorylation of JAK1 and STAT1 but impaired STAT1–DNA binding, without affecting STAT1 nuclear translocation.","method":"Co-immunoprecipitation (NKLAM with IFNγ receptor complex and STAT1), ubiquitination assay (K63-linkage specificity), confocal microscopy (NKLAM localization), EMSA (STAT1-DNA binding), NKLAM-KO macrophage nucleofection with STAT1-driven luciferase reporter, RT-PCR (STAT1 target gene mRNA)","journal":"Cellular signalling","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, ubiquitination linkage assay, functional reporter, EMSA, and KO rescue; multiple orthogonal methods in single rigorous study","pmids":["27570112"],"is_preprint":false},{"year":2018,"finding":"In vivo, NKLAM-KO mice infected with S. pneumoniae show higher bacterial lung burden, reduced STAT1 and STAT3 phosphorylation, and impaired neutrophil and NK cell recruitment; NKLAM-KO neutrophils and macrophages are individually defective in killing S. pneumoniae, confirming NKLAM's positive regulatory role in bactericidal activity in multiple innate immune cell types.","method":"Inhalation infection model with NKLAM-KO and WT mice; bacterial CFU enumeration, flow cytometry (lung immune cell populations), Western blot (phospho-STAT1, phospho-STAT3), ELISA (cytokines), ex vivo killing assays with isolated neutrophils and macrophages","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo KO with defined mechanistic readouts and ex vivo cell killing assays; single lab, multiple methods","pmids":["29518136"],"is_preprint":false},{"year":2019,"finding":"NKLAM regulates antiviral innate immunity during Sendai virus infection: NKLAM-KO mice show reduced STAT1 and NFκB p65 phosphorylation, attenuated autophagy (reduced LC3 and p62/SQSTM1), fewer lung neutrophils and macrophages, diminished pro-inflammatory cytokine production, and paradoxically attenuated viral replication at low dose but increased susceptibility at high dose.","method":"In vivo Sendai virus infection model with NKLAM-KO vs. WT mice; weight monitoring, viral titer, flow cytometry, Western blot (phospho-STAT1, phospho-NFκB p65, LC3, p62), ELISA (cytokines)","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo KO with defined mechanistic signaling readouts; single lab, multiple orthogonal methods","pmids":["31539400"],"is_preprint":false},{"year":2023,"finding":"RNF19B acts as the E3 ubiquitin ligase that mediates polyubiquitination and proteasomal degradation of RAC1 in NSCLC cells; DIRAS3 promotes the physical interaction between RNF19B and RAC1, enhancing RAC1 degradation and suppressing cell migration via the DIRAS3–RNF19B–RAC1 axis.","method":"Co-immunoprecipitation (RNF19B–RAC1 interaction with and without DIRAS3), ubiquitination assay (polyubiquitination of RAC1), proteasome inhibitor rescue of RAC1 levels, cell migration assays, knockdown/overexpression of DIRAS3 and RNF19B","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP, ubiquitination assay, proteasome inhibitor rescue, and functional migration readout; single lab, multiple methods","pmids":["37485351"],"is_preprint":false},{"year":2025,"finding":"Cysteine 301 of NKLAM is the catalytic residue essential for its RBR E3 ubiquitin ligase activity; C301A and C301S mutations abrogate ligase activity. Wild-type but not C301A NKLAM inhibits cellular proliferation and facilitates proteasomal degradation of c-Myc (reducing c-Myc half-life from 27 to 12 min). Prolonged NKLAM expression induces apoptosis; the C301S mutant induces apoptosis comparably to wild-type despite lacking ligase activity, indicating an alternative, ligase-independent apoptotic pathway.","method":"Site-directed mutagenesis (C301A, C301S), inducible expression in HEK293 and K562 cells, cell proliferation assays, metabolic activity assays, cycloheximide chase (c-Myc half-life), proteasome inhibitor rescue, annexin-V staining, caspase activation assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — active-site mutagenesis combined with multiple orthogonal functional assays (half-life, proteasome rescue, apoptosis markers) in two independent cell lines","pmids":["40273985"],"is_preprint":false},{"year":2025,"finding":"RNF19B, whose expression is transcriptionally promoted by the zinc-finger transcription factor ZNF573, mediates ubiquitination of PIK3CA in prostate cancer cells; loss of ZNF573 (via promoter hypermethylation) reduces RNF19B expression and impairs PIK3CA ubiquitination, enhancing PCa proliferation and invasion.","method":"ZNF573 overexpression/knockdown in PCa cells in vitro and in vivo, chromatin immunoprecipitation or luciferase reporter (ZNF573 transactivation of RNF19B), co-immunoprecipitation and ubiquitination assay (RNF19B–PIK3CA), proliferation and invasion assays","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional epistasis (ZNF573→RNF19B→PIK3CA), ubiquitination assay, in vivo confirmation; single lab, findings not yet replicated","pmids":["40973794"],"is_preprint":false}],"current_model":"RNF19B/NKLAM is an RBR-family E3 ubiquitin ligase whose catalytic activity depends on cysteine 301; it localizes to NK cytolytic granules and macrophage phagosomes, mediates K63-linked ubiquitination of STAT1 to promote IFNγ-driven transcription, drives K48/proteasomal degradation of c-Myc and RAC1 (the latter enhanced by DIRAS3), ubiquitinates PIK3CA downstream of ZNF573, positively regulates NFκB p65 nuclear translocation and iNOS expression, and is required for maximal bactericidal and antiviral activity of macrophages and NK cells."},"narrative":{"mechanistic_narrative":"RNF19B (NKLAM) is an RBR-family E3 ubiquitin ligase that functions as a positive regulator of innate immune effector cells and as a context-dependent suppressor of cancer cell proliferation and migration [PMID:10912506, PMID:40273985]. Its catalytic activity depends on cysteine 301, whose mutation abolishes ligase function [PMID:40273985]. In immune cells the protein resides in NK cytolytic granules where it is required for cytotoxicity [PMID:10912506] and translocates to the maturing macrophage phagosome, where it co-localizes with ingested bacteria and supports bacterial killing [PMID:23085241]. RNF19B amplifies inflammatory signaling by mediating K63-linked ubiquitination of STAT1 at the IFNγ receptor complex, an event needed for STAT1 DNA binding to gamma-activation sequences and full target-gene transcription, and by promoting NFκB p65 phosphorylation and nuclear translocation to drive iNOS expression and NO production [PMID:25182373, PMID:27570112]. Consistent with these roles, loss of the gene impairs bactericidal activity against S. pneumoniae and alters antiviral responses to Sendai virus in vivo [PMID:29518136, PMID:31539400]. In cancer cells RNF19B directs K48/proteasomal degradation of c-Myc to restrain proliferation [PMID:40273985] and of RAC1—an interaction enhanced by DIRAS3—to suppress migration [PMID:37485351], and it ubiquitinates PIK3CA downstream of the transcription factor ZNF573 [PMID:40973794].","teleology":[{"year":2000,"claim":"Established that NKLAM is a granule-resident protein functionally required for lymphocyte cytotoxicity, defining its first biological role before any enzymatic activity was known.","evidence":"Antisense knockdown in NK cells/CTLs with cytotoxicity assays plus cDNA cloning and expression profiling","pmids":["10912506"],"confidence":"Medium","gaps":["Molecular mechanism of cytotoxicity contribution not defined","No ubiquitin ligase activity demonstrated at this stage","Substrates within granules unidentified"]},{"year":2012,"claim":"Showed NKLAM is a phagosomal E3 ubiquitin ligase that relocates to the maturing phagosome and supports bacterial killing, linking its enzymatic identity to antimicrobial defense.","evidence":"Confocal co-localization with E. coli, subcellular fractionation, and bacterial killing assays in KO macrophages","pmids":["23085241"],"confidence":"Medium","gaps":["Phagosomal ubiquitination substrates not identified","Mechanism of phagosome recruitment unknown"]},{"year":2014,"claim":"Connected NKLAM to inflammatory transcriptional output by demonstrating it drives iNOS/NO via STAT1 phosphorylation, IFNβ production, and NFκB p65 nuclear translocation independent of IkBα degradation.","evidence":"KO vs WT macrophage ELISA, Western blot, confocal microscopy, and NFκB luciferase reporter assays","pmids":["25182373"],"confidence":"Medium","gaps":["Direct ubiquitination targets in the NFκB pathway not defined","Mechanism linking ligase activity to p65 S536 phosphorylation unclear"]},{"year":2016,"claim":"Defined the molecular mechanism of STAT1 regulation: NKLAM mediates K63-linked ubiquitination of STAT1 at the IFNγ receptor, enabling STAT1 DNA binding without affecting nuclear translocation.","evidence":"Reciprocal Co-IP, K63-linkage ubiquitination assay, EMSA, KO macrophage STAT1 luciferase reporter and RT-PCR","pmids":["27570112"],"confidence":"High","gaps":["Ubiquitinated lysine residues on STAT1 not mapped","How K63 chains promote DNA binding mechanistically unresolved"]},{"year":2018,"claim":"Validated NKLAM's positive regulatory role in vivo, showing it is required for bacterial clearance and immune cell recruitment across multiple innate cell types.","evidence":"S. pneumoniae inhalation infection of KO vs WT mice with CFU, flow cytometry, phospho-STAT Western blots, and ex vivo killing assays","pmids":["29518136"],"confidence":"Medium","gaps":["Cell-intrinsic vs systemic contributions not fully separated","Direct substrate driving the phenotype not identified"]},{"year":2019,"claim":"Extended NKLAM's role to antiviral immunity and autophagy, revealing dose-dependent effects on viral replication.","evidence":"Sendai virus infection of KO vs WT mice with viral titers, flow cytometry, autophagy marker (LC3/p62) and phospho-signaling Western blots, and cytokine ELISA","pmids":["31539400"],"confidence":"Medium","gaps":["Mechanism of autophagy regulation undefined","Basis for the paradoxical dose-dependent viral phenotype unexplained"]},{"year":2023,"claim":"Identified RNF19B as the E3 ligase degrading RAC1 and established the DIRAS3–RNF19B–RAC1 axis that suppresses cancer cell migration, extending its substrate repertoire beyond immune signaling.","evidence":"Co-IP with/without DIRAS3, RAC1 ubiquitination assay, proteasome inhibitor rescue, and migration assays in NSCLC cells","pmids":["37485351"],"confidence":"Medium","gaps":["Ubiquitin linkage type on RAC1 not specified","Mechanism by which DIRAS3 bridges the interaction unresolved"]},{"year":2025,"claim":"Pinpointed cysteine 301 as the catalytic residue and demonstrated proteasomal degradation of c-Myc, while uncovering a ligase-independent apoptotic activity.","evidence":"C301A/C301S site-directed mutagenesis, inducible expression in HEK293/K562, cycloheximide chase of c-Myc, proteasome rescue, and apoptosis assays","pmids":["40273985"],"confidence":"High","gaps":["Effector of the ligase-independent apoptotic pathway unknown","c-Myc ubiquitination linkage not specified"]},{"year":2025,"claim":"Placed RNF19B downstream of ZNF573 transcriptional control and identified PIK3CA as a substrate in prostate cancer, linking its expression regulation to tumor suppression.","evidence":"ZNF573 overexpression/knockdown in vitro and in vivo, transactivation assay, RNF19B–PIK3CA Co-IP and ubiquitination assay, proliferation/invasion assays","pmids":["40973794"],"confidence":"Medium","gaps":["Findings not yet independently replicated","PIK3CA ubiquitin linkage and degradation fate not fully defined"]},{"year":null,"claim":"How RNF19B's substrate selection is governed across its disparate immune (STAT1) and oncogenic (c-Myc, RAC1, PIK3CA) contexts, and what unifies its K63-activating versus K48-degradative outputs, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of substrate engagement","Determinants of K63 vs K48 chain output unknown","Identity of ligase-independent apoptotic effector unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016874","term_label":"ligase activity","supporting_discovery_ids":[1,6,7,8]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[3,6,7,8]}],"localization":[{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[0,1]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[3]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[0,1,2,3,4,5]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[2,3,6,8]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[6,7,8]}],"complexes":[],"partners":["STAT1","RAC1","DIRAS3","PIK3CA","C-MYC","ZNF573"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q6ZMZ0","full_name":"E3 ubiquitin-protein ligase RNF19B","aliases":["IBR domain-containing protein 3","Natural killer lytic-associated molecule","RING finger protein 19B"],"length_aa":732,"mass_kda":77.9,"function":"E3 ubiquitin-protein ligase which accepts ubiquitin from E2 ubiquitin-conjugating enzymes UBE2L3 and UBE2L6 in the form of a thioester and then directly transfers the ubiquitin to targeted substrates, such as UCKL1 (PubMed:16709802, PubMed:27485036). Involved in the cytolytic activity of natural killer cells and cytotoxic T-cells (PubMed:10438909). Protects against staurosporin-induced cell death (PubMed:27485036)","subcellular_location":"Cytoplasmic granule membrane; Endoplasmic reticulum membrane","url":"https://www.uniprot.org/uniprotkb/Q6ZMZ0/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/RNF19B","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/RNF19B","total_profiled":1310},"omim":[{"mim_id":"610872","title":"RING FINGER PROTEIN 19B; RNF19B","url":"https://www.omim.org/entry/610872"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Cytosol","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"testis","ntpm":73.9}],"url":"https://www.proteinatlas.org/search/RNF19B"},"hgnc":{"alias_symbol":["FLJ90005","NKLAM"],"prev_symbol":["IBRDC3"]},"alphafold":{"accession":"Q6ZMZ0","domains":[{"cath_id":"3.30.40.10","chopping":"116-200","consensus_level":"medium","plddt":91.1127,"start":116,"end":200},{"cath_id":"-","chopping":"300-330","consensus_level":"medium","plddt":83.1361,"start":300,"end":330},{"cath_id":"-","chopping":"344-446","consensus_level":"high","plddt":86.465,"start":344,"end":446},{"cath_id":"2.20.28","chopping":"202-266","consensus_level":"medium","plddt":83.7822,"start":202,"end":266}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6ZMZ0","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q6ZMZ0-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q6ZMZ0-F1-predicted_aligned_error_v6.png","plddt_mean":58.0},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RNF19B","jax_strain_url":"https://www.jax.org/strain/search?query=RNF19B"},"sequence":{"accession":"Q6ZMZ0","fasta_url":"https://rest.uniprot.org/uniprotkb/Q6ZMZ0.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q6ZMZ0/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6ZMZ0"}},"corpus_meta":[{"pmid":"27570112","id":"PMC_27570112","title":"E3 ubiquitin ligase NKLAM ubiquitinates STAT1 and positively regulates STAT1-mediated transcriptional activity.","date":"2016","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/27570112","citation_count":23,"is_preprint":false},{"pmid":"33192571","id":"PMC_33192571","title":"Natural Killer Lytic-Associated Molecule (NKLAM): An E3 Ubiquitin Ligase With an Integral Role in Innate Immunity.","date":"2020","source":"Frontiers in physiology","url":"https://pubmed.ncbi.nlm.nih.gov/33192571","citation_count":19,"is_preprint":false},{"pmid":"23085241","id":"PMC_23085241","title":"E3 ubiquitin ligase NKLAM is a macrophage phagosome protein and plays a role in bacterial killing.","date":"2012","source":"Cellular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/23085241","citation_count":18,"is_preprint":false},{"pmid":"31539400","id":"PMC_31539400","title":"Mice deficient in NKLAM have attenuated inflammatory cytokine production in a Sendai virus pneumonia model.","date":"2019","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/31539400","citation_count":9,"is_preprint":false},{"pmid":"29518136","id":"PMC_29518136","title":"Reduced inflammation and cytokine production in NKLAM deficient mice during Streptococcus pneumoniae infection.","date":"2018","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/29518136","citation_count":8,"is_preprint":false},{"pmid":"34277811","id":"PMC_34277811","title":"RAB5C, SYNJ1, and RNF19B promote male ankylosing spondylitis by regulating immune cell infiltration.","date":"2021","source":"Annals of translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/34277811","citation_count":8,"is_preprint":false},{"pmid":"25182373","id":"PMC_25182373","title":"E3 ubiquitin ligase NKLAM positively regulates macrophage inducible nitric oxide synthase expression.","date":"2014","source":"Immunobiology","url":"https://pubmed.ncbi.nlm.nih.gov/25182373","citation_count":8,"is_preprint":false},{"pmid":"10912506","id":"PMC_10912506","title":"Gene structure of human and mouse NKLAM, a gene associated with cellular cytotoxicity.","date":"2000","source":"Immunogenetics","url":"https://pubmed.ncbi.nlm.nih.gov/10912506","citation_count":7,"is_preprint":false},{"pmid":"37485351","id":"PMC_37485351","title":"DIRAS3 enhances RNF19B-mediated RAC1 ubiquitination and degradation in non-small-cell lung cancer cells.","date":"2023","source":"iScience","url":"https://pubmed.ncbi.nlm.nih.gov/37485351","citation_count":3,"is_preprint":false},{"pmid":"40273985","id":"PMC_40273985","title":"The ubiquitin ligase NKLAM promotes apoptosis and suppression of cell growth.","date":"2025","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/40273985","citation_count":0,"is_preprint":false},{"pmid":"40973794","id":"PMC_40973794","title":"Aging-associated ZNF573 methylation regulates RNF19B-PIK3CA ubiquitination to promote prostate cancer.","date":"2025","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/40973794","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7421,"output_tokens":2865,"usd":0.032619,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":10147,"output_tokens":3289,"usd":0.06648,"stage2_stop_reason":"end_turn"},"total_usd":0.099099,"stage1_batch_id":"msgbatch_01CNoDbkChHEkgrJnL7BwtGJ","stage2_batch_id":"msgbatch_016Y4x9E9Wg5VQDANj9quSQD","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2000,\n      \"finding\": \"NKLAM (RNF19B) encodes a zinc finger protein that resides in NK cytolytic granules; antisense oligonucleotide-mediated knockdown of NKLAM inhibits cytotoxic function of NK cells and CTLs, establishing a direct role in cellular cytotoxicity. Two human isoforms (587 and 731 residue proteins) arise from alternative splicing, with the larger form predominant.\",\n      \"method\": \"Antisense oligonucleotide knockdown of NKLAM in NK cells/CTLs with cytotoxicity assays; cDNA cloning, genomic structure analysis, and expression profiling\",\n      \"journal\": \"Immunogenetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional knockdown with defined phenotype, orthogonal structural and expression analyses; single lab\",\n      \"pmids\": [\"10912506\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"NKLAM is a phagosomal E3 ubiquitin ligase in macrophages; it translocates to the phagosome early during maturation coinciding with elevated phagosomal ubiquitinated proteins, co-localizes with ingested E. coli, and NKLAM-deficient macrophages show reduced bacterial killing.\",\n      \"method\": \"Confocal microscopy (co-localization with E. coli and IgG-opsonized latex beads), subcellular fractionation, bacterial killing assays with NKLAM-KO bone marrow-derived macrophages vs. wild type\",\n      \"journal\": \"Cellular immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization with functional consequence, KO phenotype with defined readout; single lab, two orthogonal methods\",\n      \"pmids\": [\"23085241\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"NKLAM positively regulates iNOS expression and NO production in LPS-stimulated macrophages by promoting STAT1 tyrosine phosphorylation, IFNβ production, and NFκB p65 nuclear translocation; NKLAM-KO macrophages show reduced p65 expression, defective p65 phosphorylation at S536, and diminished NFκB transcriptional activity independent of IKBα degradation.\",\n      \"method\": \"NKLAM-KO vs. WT bone marrow-derived macrophage comparisons: ELISA (NO, IFNβ), Western blot (iNOS, phospho-STAT1, p65, phospho-p65, IKBα), confocal microscopy (p65 nuclear translocation), NFκB luciferase reporter transfection assay\",\n      \"journal\": \"Immunobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO with defined cellular phenotype, multiple orthogonal methods; single lab\",\n      \"pmids\": [\"25182373\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"NKLAM mediates K63-linked ubiquitination of STAT1 in macrophages; NKLAM transiently localizes to the IFNγ receptor complex during IFNγ stimulation, binds STAT1, and this ubiquitination is required for STAT1 DNA-binding to gamma activation sequences and full STAT1-mediated transcription. Loss of NKLAM results in hyperphosphorylation of JAK1 and STAT1 but impaired STAT1–DNA binding, without affecting STAT1 nuclear translocation.\",\n      \"method\": \"Co-immunoprecipitation (NKLAM with IFNγ receptor complex and STAT1), ubiquitination assay (K63-linkage specificity), confocal microscopy (NKLAM localization), EMSA (STAT1-DNA binding), NKLAM-KO macrophage nucleofection with STAT1-driven luciferase reporter, RT-PCR (STAT1 target gene mRNA)\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, ubiquitination linkage assay, functional reporter, EMSA, and KO rescue; multiple orthogonal methods in single rigorous study\",\n      \"pmids\": [\"27570112\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"In vivo, NKLAM-KO mice infected with S. pneumoniae show higher bacterial lung burden, reduced STAT1 and STAT3 phosphorylation, and impaired neutrophil and NK cell recruitment; NKLAM-KO neutrophils and macrophages are individually defective in killing S. pneumoniae, confirming NKLAM's positive regulatory role in bactericidal activity in multiple innate immune cell types.\",\n      \"method\": \"Inhalation infection model with NKLAM-KO and WT mice; bacterial CFU enumeration, flow cytometry (lung immune cell populations), Western blot (phospho-STAT1, phospho-STAT3), ELISA (cytokines), ex vivo killing assays with isolated neutrophils and macrophages\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo KO with defined mechanistic readouts and ex vivo cell killing assays; single lab, multiple methods\",\n      \"pmids\": [\"29518136\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"NKLAM regulates antiviral innate immunity during Sendai virus infection: NKLAM-KO mice show reduced STAT1 and NFκB p65 phosphorylation, attenuated autophagy (reduced LC3 and p62/SQSTM1), fewer lung neutrophils and macrophages, diminished pro-inflammatory cytokine production, and paradoxically attenuated viral replication at low dose but increased susceptibility at high dose.\",\n      \"method\": \"In vivo Sendai virus infection model with NKLAM-KO vs. WT mice; weight monitoring, viral titer, flow cytometry, Western blot (phospho-STAT1, phospho-NFκB p65, LC3, p62), ELISA (cytokines)\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo KO with defined mechanistic signaling readouts; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"31539400\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"RNF19B acts as the E3 ubiquitin ligase that mediates polyubiquitination and proteasomal degradation of RAC1 in NSCLC cells; DIRAS3 promotes the physical interaction between RNF19B and RAC1, enhancing RAC1 degradation and suppressing cell migration via the DIRAS3–RNF19B–RAC1 axis.\",\n      \"method\": \"Co-immunoprecipitation (RNF19B–RAC1 interaction with and without DIRAS3), ubiquitination assay (polyubiquitination of RAC1), proteasome inhibitor rescue of RAC1 levels, cell migration assays, knockdown/overexpression of DIRAS3 and RNF19B\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP, ubiquitination assay, proteasome inhibitor rescue, and functional migration readout; single lab, multiple methods\",\n      \"pmids\": [\"37485351\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Cysteine 301 of NKLAM is the catalytic residue essential for its RBR E3 ubiquitin ligase activity; C301A and C301S mutations abrogate ligase activity. Wild-type but not C301A NKLAM inhibits cellular proliferation and facilitates proteasomal degradation of c-Myc (reducing c-Myc half-life from 27 to 12 min). Prolonged NKLAM expression induces apoptosis; the C301S mutant induces apoptosis comparably to wild-type despite lacking ligase activity, indicating an alternative, ligase-independent apoptotic pathway.\",\n      \"method\": \"Site-directed mutagenesis (C301A, C301S), inducible expression in HEK293 and K562 cells, cell proliferation assays, metabolic activity assays, cycloheximide chase (c-Myc half-life), proteasome inhibitor rescue, annexin-V staining, caspase activation assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — active-site mutagenesis combined with multiple orthogonal functional assays (half-life, proteasome rescue, apoptosis markers) in two independent cell lines\",\n      \"pmids\": [\"40273985\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"RNF19B, whose expression is transcriptionally promoted by the zinc-finger transcription factor ZNF573, mediates ubiquitination of PIK3CA in prostate cancer cells; loss of ZNF573 (via promoter hypermethylation) reduces RNF19B expression and impairs PIK3CA ubiquitination, enhancing PCa proliferation and invasion.\",\n      \"method\": \"ZNF573 overexpression/knockdown in PCa cells in vitro and in vivo, chromatin immunoprecipitation or luciferase reporter (ZNF573 transactivation of RNF19B), co-immunoprecipitation and ubiquitination assay (RNF19B–PIK3CA), proliferation and invasion assays\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional epistasis (ZNF573→RNF19B→PIK3CA), ubiquitination assay, in vivo confirmation; single lab, findings not yet replicated\",\n      \"pmids\": [\"40973794\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RNF19B/NKLAM is an RBR-family E3 ubiquitin ligase whose catalytic activity depends on cysteine 301; it localizes to NK cytolytic granules and macrophage phagosomes, mediates K63-linked ubiquitination of STAT1 to promote IFNγ-driven transcription, drives K48/proteasomal degradation of c-Myc and RAC1 (the latter enhanced by DIRAS3), ubiquitinates PIK3CA downstream of ZNF573, positively regulates NFκB p65 nuclear translocation and iNOS expression, and is required for maximal bactericidal and antiviral activity of macrophages and NK cells.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RNF19B (NKLAM) is an RBR-family E3 ubiquitin ligase that functions as a positive regulator of innate immune effector cells and as a context-dependent suppressor of cancer cell proliferation and migration [#0, #7]. Its catalytic activity depends on cysteine 301, whose mutation abolishes ligase function [#7]. In immune cells the protein resides in NK cytolytic granules where it is required for cytotoxicity [#0] and translocates to the maturing macrophage phagosome, where it co-localizes with ingested bacteria and supports bacterial killing [#1]. RNF19B amplifies inflammatory signaling by mediating K63-linked ubiquitination of STAT1 at the IFN\\u03b3 receptor complex, an event needed for STAT1 DNA binding to gamma-activation sequences and full target-gene transcription, and by promoting NF\\u03baB p65 phosphorylation and nuclear translocation to drive iNOS expression and NO production [#2, #3]. Consistent with these roles, loss of the gene impairs bactericidal activity against S. pneumoniae and alters antiviral responses to Sendai virus in vivo [#4, #5]. In cancer cells RNF19B directs K48/proteasomal degradation of c-Myc to restrain proliferation [#7] and of RAC1\\u2014an interaction enhanced by DIRAS3\\u2014to suppress migration [#6], and it ubiquitinates PIK3CA downstream of the transcription factor ZNF573 [#8].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Established that NKLAM is a granule-resident protein functionally required for lymphocyte cytotoxicity, defining its first biological role before any enzymatic activity was known.\",\n      \"evidence\": \"Antisense knockdown in NK cells/CTLs with cytotoxicity assays plus cDNA cloning and expression profiling\",\n      \"pmids\": [\"10912506\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism of cytotoxicity contribution not defined\", \"No ubiquitin ligase activity demonstrated at this stage\", \"Substrates within granules unidentified\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Showed NKLAM is a phagosomal E3 ubiquitin ligase that relocates to the maturing phagosome and supports bacterial killing, linking its enzymatic identity to antimicrobial defense.\",\n      \"evidence\": \"Confocal co-localization with E. coli, subcellular fractionation, and bacterial killing assays in KO macrophages\",\n      \"pmids\": [\"23085241\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Phagosomal ubiquitination substrates not identified\", \"Mechanism of phagosome recruitment unknown\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Connected NKLAM to inflammatory transcriptional output by demonstrating it drives iNOS/NO via STAT1 phosphorylation, IFN\\u03b2 production, and NF\\u03baB p65 nuclear translocation independent of IkB\\u03b1 degradation.\",\n      \"evidence\": \"KO vs WT macrophage ELISA, Western blot, confocal microscopy, and NF\\u03baB luciferase reporter assays\",\n      \"pmids\": [\"25182373\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct ubiquitination targets in the NF\\u03baB pathway not defined\", \"Mechanism linking ligase activity to p65 S536 phosphorylation unclear\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Defined the molecular mechanism of STAT1 regulation: NKLAM mediates K63-linked ubiquitination of STAT1 at the IFN\\u03b3 receptor, enabling STAT1 DNA binding without affecting nuclear translocation.\",\n      \"evidence\": \"Reciprocal Co-IP, K63-linkage ubiquitination assay, EMSA, KO macrophage STAT1 luciferase reporter and RT-PCR\",\n      \"pmids\": [\"27570112\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Ubiquitinated lysine residues on STAT1 not mapped\", \"How K63 chains promote DNA binding mechanistically unresolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Validated NKLAM's positive regulatory role in vivo, showing it is required for bacterial clearance and immune cell recruitment across multiple innate cell types.\",\n      \"evidence\": \"S. pneumoniae inhalation infection of KO vs WT mice with CFU, flow cytometry, phospho-STAT Western blots, and ex vivo killing assays\",\n      \"pmids\": [\"29518136\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Cell-intrinsic vs systemic contributions not fully separated\", \"Direct substrate driving the phenotype not identified\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Extended NKLAM's role to antiviral immunity and autophagy, revealing dose-dependent effects on viral replication.\",\n      \"evidence\": \"Sendai virus infection of KO vs WT mice with viral titers, flow cytometry, autophagy marker (LC3/p62) and phospho-signaling Western blots, and cytokine ELISA\",\n      \"pmids\": [\"31539400\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of autophagy regulation undefined\", \"Basis for the paradoxical dose-dependent viral phenotype unexplained\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identified RNF19B as the E3 ligase degrading RAC1 and established the DIRAS3\\u2013RNF19B\\u2013RAC1 axis that suppresses cancer cell migration, extending its substrate repertoire beyond immune signaling.\",\n      \"evidence\": \"Co-IP with/without DIRAS3, RAC1 ubiquitination assay, proteasome inhibitor rescue, and migration assays in NSCLC cells\",\n      \"pmids\": [\"37485351\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Ubiquitin linkage type on RAC1 not specified\", \"Mechanism by which DIRAS3 bridges the interaction unresolved\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Pinpointed cysteine 301 as the catalytic residue and demonstrated proteasomal degradation of c-Myc, while uncovering a ligase-independent apoptotic activity.\",\n      \"evidence\": \"C301A/C301S site-directed mutagenesis, inducible expression in HEK293/K562, cycloheximide chase of c-Myc, proteasome rescue, and apoptosis assays\",\n      \"pmids\": [\"40273985\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Effector of the ligase-independent apoptotic pathway unknown\", \"c-Myc ubiquitination linkage not specified\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Placed RNF19B downstream of ZNF573 transcriptional control and identified PIK3CA as a substrate in prostate cancer, linking its expression regulation to tumor suppression.\",\n      \"evidence\": \"ZNF573 overexpression/knockdown in vitro and in vivo, transactivation assay, RNF19B\\u2013PIK3CA Co-IP and ubiquitination assay, proliferation/invasion assays\",\n      \"pmids\": [\"40973794\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Findings not yet independently replicated\", \"PIK3CA ubiquitin linkage and degradation fate not fully defined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How RNF19B's substrate selection is governed across its disparate immune (STAT1) and oncogenic (c-Myc, RAC1, PIK3CA) contexts, and what unifies its K63-activating versus K48-degradative outputs, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of substrate engagement\", \"Determinants of K63 vs K48 chain output unknown\", \"Identity of ligase-independent apoptotic effector unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016874\", \"supporting_discovery_ids\": [1, 6, 7, 8]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [3, 6, 7, 8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [0, 1, 2, 3, 4, 5]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2, 3, 6, 8]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [6, 7, 8]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"STAT1\", \"RAC1\", \"DIRAS3\", \"PIK3CA\", \"c-Myc\", \"ZNF573\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}