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Showing RNF19BNKLAM is a alias.

RNF19B

E3 ubiquitin-protein ligase RNF19B · UniProt Q6ZMZ0

Length
732 aa
Mass
77.9 kDa
Annotated
2026-06-10
11 papers in source corpus 9 papers cited in narrative 9 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

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).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 2000 Medium

    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

    PMID:10912506

    Open questions at the time
    • Molecular mechanism of cytotoxicity contribution not defined
    • No ubiquitin ligase activity demonstrated at this stage
    • Substrates within granules unidentified
  2. 2012 Medium

    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

    PMID:23085241

    Open questions at the time
    • Phagosomal ubiquitination substrates not identified
    • Mechanism of phagosome recruitment unknown
  3. 2014 Medium

    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

    PMID:25182373

    Open questions at the time
    • Direct ubiquitination targets in the NFκB pathway not defined
    • Mechanism linking ligase activity to p65 S536 phosphorylation unclear
  4. 2016 High

    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

    PMID:27570112

    Open questions at the time
    • Ubiquitinated lysine residues on STAT1 not mapped
    • How K63 chains promote DNA binding mechanistically unresolved
  5. 2018 Medium

    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

    PMID:29518136

    Open questions at the time
    • Cell-intrinsic vs systemic contributions not fully separated
    • Direct substrate driving the phenotype not identified
  6. 2019 Medium

    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

    PMID:31539400

    Open questions at the time
    • Mechanism of autophagy regulation undefined
    • Basis for the paradoxical dose-dependent viral phenotype unexplained
  7. 2023 Medium

    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

    PMID:37485351

    Open questions at the time
    • Ubiquitin linkage type on RAC1 not specified
    • Mechanism by which DIRAS3 bridges the interaction unresolved
  8. 2025 High

    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

    PMID:40273985

    Open questions at the time
    • Effector of the ligase-independent apoptotic pathway unknown
    • c-Myc ubiquitination linkage not specified
  9. 2025 Medium

    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

    PMID:40973794

    Open questions at the time
    • Findings not yet independently replicated
    • PIK3CA ubiquitin linkage and degradation fate not fully defined

Open questions

Synthesis pass · forward-looking unresolved questions
  • 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.
  • No structural model of substrate engagement
  • Determinants of K63 vs K48 chain output unknown
  • Identity of ligase-independent apoptotic effector unknown

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0016874 ligase activity 4 GO:0140096 catalytic activity, acting on a protein 4
Localization
GO:0031410 cytoplasmic vesicle 2 GO:0005886 plasma membrane 1
Pathway
R-HSA-168256 Immune System 6 R-HSA-162582 Signal Transduction 4 R-HSA-392499 Metabolism of proteins 3

Evidence

Reading pass · 9 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2000 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. Antisense oligonucleotide knockdown of NKLAM in NK cells/CTLs with cytotoxicity assays; cDNA cloning, genomic structure analysis, and expression profiling Immunogenetics Medium 10912506
2012 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. 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 Cellular immunology Medium 23085241
2014 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. 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 Immunobiology Medium 25182373
2016 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. 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) Cellular signalling High 27570112
2018 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. 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 PloS one Medium 29518136
2019 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. 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) PloS one Medium 31539400
2023 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. 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 iScience Medium 37485351
2025 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. 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 The Journal of biological chemistry High 40273985
2025 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. 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 Oncogene Medium 40973794

Source papers

Stage 0 corpus · 11 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2016 E3 ubiquitin ligase NKLAM ubiquitinates STAT1 and positively regulates STAT1-mediated transcriptional activity. Cellular signalling 23 27570112
2020 Natural Killer Lytic-Associated Molecule (NKLAM): An E3 Ubiquitin Ligase With an Integral Role in Innate Immunity. Frontiers in physiology 19 33192571
2012 E3 ubiquitin ligase NKLAM is a macrophage phagosome protein and plays a role in bacterial killing. Cellular immunology 18 23085241
2019 Mice deficient in NKLAM have attenuated inflammatory cytokine production in a Sendai virus pneumonia model. PloS one 9 31539400
2021 RAB5C, SYNJ1, and RNF19B promote male ankylosing spondylitis by regulating immune cell infiltration. Annals of translational medicine 8 34277811
2018 Reduced inflammation and cytokine production in NKLAM deficient mice during Streptococcus pneumoniae infection. PloS one 8 29518136
2014 E3 ubiquitin ligase NKLAM positively regulates macrophage inducible nitric oxide synthase expression. Immunobiology 8 25182373
2000 Gene structure of human and mouse NKLAM, a gene associated with cellular cytotoxicity. Immunogenetics 7 10912506
2023 DIRAS3 enhances RNF19B-mediated RAC1 ubiquitination and degradation in non-small-cell lung cancer cells. iScience 3 37485351
2025 The ubiquitin ligase NKLAM promotes apoptosis and suppression of cell growth. The Journal of biological chemistry 0 40273985
2025 Aging-associated ZNF573 methylation regulates RNF19B-PIK3CA ubiquitination to promote prostate cancer. Oncogene 0 40973794

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