Affinage

RING1

E3 ubiquitin-protein ligase RING1 · UniProt Q06587

Length
406 aa
Mass
42.4 kDa
Annotated
2026-06-10
41 papers in source corpus 15 papers cited in narrative 15 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

RING1 (RNF1/Ring1A) is a RING-domain E3 ubiquitin ligase and core component of Polycomb Repressive Complex 1 (PRC1) that enforces transcriptional repression of developmental genes (PMID:9199346, PMID:18037880). It self-associates and binds multiple Polycomb-group proteins through distinct interaction domains, including BMI1 and HPH1 (PMID:9199346, PMID:9858531), HPC3 via its C-box (PMID:10825164), and YY1 with which it shares both physical and genetic interactions (PMID:16624538); targeting RING1 to a reporter confers repression, and its function is conserved to the Drosophila ortholog Sce, which murine Ring1 can functionally replace (PMID:9199346, PMID:15147763). Within PRC1, RING1 monoubiquitinates histone H2A (H2AK119ub1), and conditional loss of Ring1A/B in ES cells abolishes H2A ubiquitination, releases poised Ser5-phosphorylated RNA Pol II from bivalent promoters, and de-represses developmental genes (PMID:18037880). This activity underlies region-specific developmental patterning: RING1 represses BMP/Wnt loci to control telencephalic dorsoventral patterning (PMID:33177537) and represses Meis1/2 to specify the distal limb, the latter confirmed by genetic epistasis (PMID:26674308). A de novo catalytic-domain mutation (p.R95Q) selectively abolishes nucleosomal H2A ubiquitination and causes a neurodevelopmental disorder, with the orthologous lesion producing neuronal migration and axon-guidance defects in C. elegans (PMID:29386386); hypomorphic RING1 variants reduce H2AK119ub1 locally and delay DNA damage repair and cell-cycle progression in neural progenitors (PMID:39256363). Independently of PRC1, the RING domain mediates ubiquitination of non-histone substrates: K48-linked ubiquitination and proteasomal degradation of p53, restraining cell-cycle arrest, apoptosis, and senescence (PMID:29187402); K48-linked degradation of GSDMD at K51/K168 to suppress pyroptosis and limit sepsis (PMID:40369166); and K11-linked degradation of Integrin α5 to suppress FAK signaling, adhesion, and migration (PMID:42229736).

Mechanistic history

Synthesis pass · year-by-year structured walk · 14 steps
  1. 1997 High

    Established RING1 as a Polycomb-group protein, answering whether it physically and functionally participates in transcriptional repression.

    Evidence Co-IP and colocalization with BMI1/HPH1 plus reporter repression assay in human cells

    PMID:9199346

    Open questions at the time
    • Did not define a catalytic activity for RING1
    • Mechanism of repression at endogenous genes unaddressed
  2. 1999 High

    Showed RING1 self-associates and binds BMI1 through distinct domains and that its overexpression is oncogenic, linking PcG repression to growth control.

    Evidence Yeast two-hybrid, in vitro binding, anchorage-independent growth and nude-mouse tumor assays

    PMID:9858531

    Open questions at the time
    • Transformation mechanism via En-2/c-jun/c-fos not resolved at the molecular level
    • Catalytic basis not yet defined
  3. 2000 Medium

    Mapped a direct HPC3 interaction via the C-box, refining the protein-interaction architecture connecting RING1 to PRC1.

    Evidence Yeast two-hybrid, in vivo Co-IP, domain-deletion analysis in mammalian cells

    PMID:10825164

    Open questions at the time
    • Role of covalent RING1 modification in the interaction unexplained
    • RING-finger dependence only partial
  4. 2004 High

    Demonstrated cross-species functional conservation by rescuing the Drosophila Sce Polycomb phenotype with murine Ring1, and broadened the interaction repertoire to RBP-J/KyoT2 in Notch signaling.

    Evidence Genetic rescue and polytene immunostaining in Drosophila; yeast two-hybrid, Co-IP and reporter transactivation assays for KyoT2/RBP-J

    PMID:14999091 PMID:15147763

    Open questions at the time
    • Whether Notch repression requires RING1 catalytic activity untested
    • Endogenous relevance of the RBP-J/KyoT2/RING1 complex unconfirmed
  5. 2006 Medium

    Connected RING1 to YY1 genetically and physically, establishing it as a partner in PcG-mediated homeotic gene control.

    Evidence Genetic epistasis in compound mutant mice and GST pull-down

    PMID:16624538

    Open questions at the time
    • Direct vs indirect basis of the YY1 interaction not separated
    • Catalytic contribution not assessed
  6. 2007 High

    Defined the central mechanism: PRC1-mediated H2A ubiquitination maintains poised RNA Pol II at bivalent developmental genes in ES cells.

    Evidence Conditional Ring1A/B knockout with ChIP for histone marks and Pol II phospho-isoforms and expression analysis

    PMID:18037880

    Open questions at the time
    • Did not address PRC1-independent substrates
    • Recruitment logic to specific bivalent loci not fully resolved
  7. 2015 High

    Placed RING1 in a defined developmental pathway by showing it represses Meis1/2 to specify the distal limb.

    Evidence Conditional double knockout, Meis2-deletion epistasis rescue, and ChIP at Meis loci in mice

    PMID:26674308

    Open questions at the time
    • Whether repression requires H2A ubiquitination specifically not isolated
    • RING1A vs RING1B individual contributions not separated
  8. 2017 High

    Revealed a PRC1-independent role: RING1 directly ubiquitinates and degrades p53, restraining tumor-suppressor responses.

    Evidence Co-IP, in vitro ubiquitination with RING-domain mutagenesis, and RNAi with p53-rescue functional readouts

    PMID:29187402

    Open questions at the time
    • Ubiquitin chain linkage on p53 not characterized in this study
    • In vivo relevance of p53 degradation not tested
  9. 2017 Low

    Identified CD147 as an interactor whose pro-migratory activity RING1 antagonizes, extending RING1 to melanoma cell migration.

    Evidence Yeast two-hybrid, Co-IP and migration assay with RING1 overexpression

    PMID:28832687

    Open questions at the time
    • Single lab with limited functional follow-up
    • No demonstration that RING1 ubiquitinates CD147
    • Reciprocal validation absent
  10. 2018 High

    Linked RING1 to human disease by showing a de novo RING-domain mutation selectively impairs nucleosomal H2A ubiquitination, producing neurodevelopmental defects.

    Evidence In vitro ubiquitination of WT vs mutant, patient-cell H2Aub measurement, and CRISPR knock-in C. elegans neuronal phenotyping

    PMID:29386386

    Open questions at the time
    • How R95Q decouples generic chain formation from nucleosome targeting unresolved
    • Genotype-phenotype spectrum in humans not defined
  11. 2020 High

    Showed region-specific PcG repression of BMP/Wnt loci by RING1 governs telencephalic dorsoventral patterning.

    Evidence Conditional mouse knockout, ChIP for Ring1B binding and H3K27me3, and expression analysis

    PMID:33177537

    Open questions at the time
    • Mechanism of region-specific targeting not defined
    • Catalytic vs scaffold contribution not separated
  12. 2024 High

    Established an innate-immune role: RING1 ubiquitinates GSDMD via K48 chains to suppress pyroptosis and constrain sepsis.

    Evidence Co-IP, in vitro ubiquitination with K51/K168 mutagenesis, RING inhibition, and Ring1 knockout infection/sepsis models

    PMID:40369166

    Open questions at the time
    • Signals controlling RING1-GSDMD engagement unknown
    • Relationship to nuclear PRC1 pool unaddressed
  13. 2024 High

    Distinguished RING1 from RNF2 by showing hypomorphic RING1 reduces H2AK119ub1 locally to impair DNA repair and cell cycle without altering NPC differentiation transcriptomes.

    Evidence ChIP-seq, DNA damage and cell-cycle assays, transcriptomics with CRISPR hypomorphic variants in a neurodevelopment model

    PMID:39256363

    Open questions at the time
    • Mechanistic basis of locus-restricted effect not fully resolved
    • Direct role in DNA repair machinery undefined
  14. 2026 Medium

    Extended non-histone substrate scope by showing RING1 destabilizes Integrin α5 via K11-linked ubiquitination to suppress FAK signaling and migration.

    Evidence Co-IP, ubiquitination assay, catalytic-domain deletion, substrate re-expression rescue, and in vivo metastasis model in ESCC

    PMID:42229736

    Open questions at the time
    • Generality beyond ESCC not tested
    • How linkage specificity is determined unknown

Open questions

Synthesis pass · forward-looking unresolved questions
  • It remains unclear what governs the partitioning of RING1 between nuclear PRC1-dependent H2A ubiquitination and its diverse PRC1-independent substrates (p53, GSDMD, Integrin α5), and how ubiquitin chain-linkage selectivity is determined for each.
  • No unified model for substrate/linkage selection
  • Subcellular control of catalytic targeting undefined
  • Cross-talk between developmental and non-histone functions unexplored

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140096 catalytic activity, acting on a protein 5 GO:0016874 ligase activity 4 GO:0042393 histone binding 3 GO:0140110 transcription regulator activity 2
Localization
GO:0000228 nuclear chromosome 2 GO:0005634 nucleus 2
Pathway
R-HSA-1266738 Developmental Biology 3 R-HSA-392499 Metabolism of proteins 3 R-HSA-74160 Gene expression (Transcription) 3 R-HSA-4839726 Chromatin organization 2 R-HSA-168256 Immune System 1 R-HSA-5357801 Programmed Cell Death 1
Complex memberships
PRC1 (Polycomb Repressive Complex 1)

Evidence

Reading pass · 15 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1997 RING1 co-immunoprecipitates with human Polycomb homolog, BMI1, and HPH1, colocalizes with these PcG proteins in nuclear domains, and when targeted to a reporter gene acts as a transcriptional repressor. Co-immunoprecipitation, colocalization by immunofluorescence, reporter gene repression assay, yeast two-hybrid screen Molecular and cellular biology High 9199346
1999 RING1 self-associates and directly interacts with BMI1 through distinct domains; overexpression of RING1 represses En-2 (a Polycomb target gene) and deregulates c-jun and c-fos, leading to oncogenic transformation (anchorage-independent growth and tumor formation in athymic mice). Yeast two-hybrid, in vitro protein-protein interaction assay, mammalian overexpression, anchorage-independent growth assay, nude mouse tumor assay Molecular and cellular biology High 9858531
2000 HPC3 (human Polycomb 3) was identified as a direct binding partner of RING1 via the HPC3 C-box domain; this interaction in vivo required covalently modified forms of RING1 but only partially depended on the RING finger of RING1. Yeast two-hybrid screen using RING1 as bait, in vivo co-immunoprecipitation, domain-deletion analysis, reporter gene silencing assay The Journal of biological chemistry Medium 10825164
2004 RING1 interacts with the LIM domains of KyoT2 in yeast and mammalian cells; a three-molecule complex of RBP-J, KyoT2, and RING1 forms in cells (RING1 and RBP-J do not associate directly). Overexpression of RING1 together with KyoT2 inhibits RBP-J transactivation by Notch intracellular domain (NIC), and this suppression is dependent on RING1's association with KyoT2. Yeast two-hybrid, in vitro binding, co-immunoprecipitation, reporter transactivation assay with overexpression and competition Nucleic acids research Medium 14999091
2004 Drosophila Ring/Sce is the ortholog of mammalian Ring1/Ring1A; murine Ring1/Ring1A can rescue the extreme Polycomb phenotype caused by loss of maternal and zygotic Sce, demonstrating functional conservation. Drosophila Ring/Sce binds ~100 sites on polytene chromosomes, 70% overlapping with other PcG proteins, and directly interacts with PcG proteins. Genetic rescue (ectopic expression), polytene chromosome immunostaining, direct protein interaction assay Mechanisms of development High 15147763
2006 Genetic epistasis in mice shows that Ring1/Ring1A deficiency reduces penetrance of homeotic transformations caused by YY1 heterozygosity; YY1 forms complexes with Ring1 and other class II PcG proteins (Rnf2, Bmi1) in GST pull-down experiments, establishing a direct physical and genetic interaction. Genetic epistasis in compound mutant mice, GST pull-down in transfected cells Mechanisms of development Medium 16624538
2007 Conditional deletion of Ring1A and Ring1B (RING1 proteins) in mouse ES cells leads sequentially to loss of H2A ubiquitination, release of Ser5-phosphorylated (poised) RNAP II from bivalent developmental gene promoters, and subsequent gene de-repression, establishing that PRC1-mediated H2A ubiquitination enforces the poised RNAP II configuration at bivalent genes. Conditional genetic deletion (Ring1A/B knockout), ChIP for histone modifications and RNAP II phospho-isoforms, RT-PCR for gene expression Nature cell biology High 18037880
2017 RING1 acts as an E3 ubiquitin ligase that directly interacts with p53 and ubiquitinates it, targeting p53 for proteasome-dependent degradation; the RING domain of RING1 is required for this E3 Ub ligase activity. RING1 depletion in p53 wild-type cancer cells induces cell-cycle arrest, apoptosis, and senescence, and this growth-inhibitory effect is partially rescued by p53 silencing, establishing a PRC1-independent function. Co-immunoprecipitation, in vitro ubiquitination assay, domain mutagenesis (RING domain), RNAi knockdown with cell-cycle/apoptosis/senescence readouts, p53 rescue experiment Cancer research High 29187402
2018 A de novo RING1 missense mutation (p.R95Q) in the catalytic RING domain retains capacity to catalyze ubiquitin chain formation but is specifically defective in ubiquitylating histone H2A in nucleosomes; patient cells showed decreased H2A monoubiquitylation. In C. elegans, the equivalent missense or knockout of spat-3 (RING1 ortholog) abolished H2A monoubiquitylation and caused neuronal migration and axon guidance defects. In vitro ubiquitination assay (wild-type vs. mutant RING1), patient cell H2Aub measurement, CRISPR knock-in in C. elegans, neuronal phenotype analysis Proceedings of the National Academy of Sciences of the United States of America High 29386386
2020 RING1B (and RING1A+B together) binds BMP and Wnt ligand gene loci in the ventral telencephalon and is required for their repression; deletion of Ring1b (or Ring1a/b) in neuroepithelial cells causes ectopic dorsal gene expression and loss of Shh expression in the ventral region, establishing a role for RING1 in dorsoventral patterning through region-specific PcG-mediated repression of BMP/Wnt signaling. Conditional gene knockout in mice, ChIP for Ring1B binding and H3K27me3 at target loci, in situ hybridization/immunostaining for gene expression Nature communications High 33177537
2015 RING1 proteins (RING1A/RING1B) repress Meis2 (and Meis1) in the proximal forelimb bud; deletion of Ring1A/B causes failure to repress proximal Meis1/2 and defects in distal limb specification. Additional deletion of Meis2 partially restores distal gene expression and limb formation in Ring1A/B-deficient mice, establishing a genetic epistasis relationship (RING1 → Meis2 repression → distal specification). Conditional double knockout in mice, genetic epistasis (Meis2 deletion rescue), ChIP for Ring1B binding at Meis1/2 loci Development (Cambridge, England) High 26674308
2024 RING1 directly interacts with GSDMD and ubiquitinates it at K51 and K168 via K48-linked chains, promoting proteasomal degradation of GSDMD and thereby negatively regulating pyroptosis. Loss of Ring1 increased bacterial infectious load and exacerbated LPS-induced sepsis in vivo; inhibition of RING1 E3 ligase activity (by mutation or small molecule inhibitors) increased GSDMD levels and pyroptotic cell death. Co-immunoprecipitation, in vitro ubiquitination assay, site-directed mutagenesis (K51/K168), RING domain inhibition, Ring1 knockout mice with infection/sepsis models Cell death and differentiation High 40369166
2024 RING1 (harboring a hypomorphic missense variant) binds target loci but fails to catalyze H2AK119ub1, reducing H2AK119ub1 by preventing catalytically active complexes from accessing the locus. Reduced H2AK119ub1 due to hypomorphic RING1 delays DNA damage repair and cell cycle progression in neural progenitor cells (NPCs) but does not generate differential gene expression impacting NPC differentiation; in contrast hypomorphic RNF2 reduces H2AK119ub1 more broadly and affects both DNA repair and transcription. In vitro neurodevelopment model, ChIP-seq for H2AK119ub1, DNA damage repair assays, cell cycle analysis, transcriptome analysis; CRISPR-introduced hypomorphic variants Nature communications High 39256363
2017 CD147 interacts with RING1 through CD147's transmembrane domain (identified by yeast two-hybrid); RING1 inhibits CD147's ability to promote melanoma cell migration, and CD147 localizes to the nuclear envelope in melanoma cells. Yeast two-hybrid, co-immunoprecipitation, migration assay with RING1 overexpression PloS one Low 28832687
2026 RING1 acts as an E3 ubiquitin ligase for Integrin α5 in ESCC cells, binding and destabilizing Integrin α5 via K11-linked ubiquitination in a RING domain-dependent manner; overexpression of RING1 degrades Integrin α5 and suppresses FAK pathway activity, cell adhesion, spreading, and migration; re-expression of Integrin α5 rescues RING1-mediated suppression. Co-immunoprecipitation, ubiquitination assay, domain-deletion analysis (catalytic domain), Integrin α5 re-expression rescue, adhesion/migration assays, in vivo metastasis model Cellular signalling Medium 42229736

Source papers

Stage 0 corpus · 41 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2007 Ring1-mediated ubiquitination of H2A restrains poised RNA polymerase II at bivalent genes in mouse ES cells. Nature cell biology 513 18037880
1997 RING1 is associated with the polycomb group protein complex and acts as a transcriptional repressor. Molecular and cellular biology 165 9199346
2006 Polycomb-group oncogenes EZH2, BMI1, and RING1 are overexpressed in prostate cancer with adverse pathologic and clinical features. European urology 154 17134822
1999 RING1 interacts with multiple Polycomb-group proteins and displays tumorigenic activity. Molecular and cellular biology 106 9858531
2011 The pepper E3 ubiquitin ligase RING1 gene, CaRING1, is required for cell death and the salicylic acid-dependent defense response. Plant physiology 91 21628629
2018 Long non-coding RNA C5orf66-AS1 promotes cell proliferation in cervical cancer by targeting miR-637/RING1 axis. Cell death & disease 81 30518760
2012 A novel target of microRNA-29, Ring1 and YY1-binding protein (Rybp), negatively regulates skeletal myogenesis. The Journal of biological chemistry 81 22661705
2010 Molecular chaperone-mediated rescue of mitophagy by a Parkin RING1 domain mutant. Human molecular genetics 60 20889486
2000 HPC3 is a new human polycomb orthologue that interacts and associates with RING1 and Bmi1 and has transcriptional repression properties. The Journal of biological chemistry 60 10825164
2017 The E3 Ligase RING1 Targets p53 for Degradation and Promotes Cancer Cell Proliferation and Survival. Cancer research 56 29187402
2004 RING1 inhibits transactivation of RBP-J by Notch through interaction with LIM protein KyoT2. Nucleic acids research 55 14999091
2017 Structural Studies of HHARI/UbcH7∼Ub Reveal Unique E2∼Ub Conformational Restriction by RBR RING1. Structure (London, England : 1993) 48 28552575
2019 Down-regulation of lncRNA XIST inhibits cell proliferation via regulating miR-744/RING1 axis in non-small cell lung cancer. Clinical science (London, England : 1979) 39 31292221
2004 The Drosophila Polycomb group gene Sex combs extra encodes the ortholog of mammalian Ring1 proteins. Mechanisms of development 35 15147763
2018 De novo mutation in RING1 with epigenetic effects on neurodevelopment. Proceedings of the National Academy of Sciences of the United States of America 34 29386386
2020 The Polycomb group protein Ring1 regulates dorsoventral patterning of the mouse telencephalon. Nature communications 32 33177537
2016 RING1 and YY1 binding protein suppresses breast cancer growth and metastasis. International journal of oncology 26 27748911
1997 Physical mapping 220 kb centromeric of the human MHC and DNA sequence analysis of the 43-kb segment including the RING1, HKE6, and HKE4 genes. Genomics 26 9205114
2016 Versatile members of the DNAJ family show Hsp70 dependent anti-aggregation activity on RING1 mutant parkin C289G. Scientific reports 25 27713507
2015 Interaction between RING1 (R1) and the Ubiquitin-like (UBL) Domains Is Critical for the Regulation of Parkin Activity. The Journal of biological chemistry 24 26631732
2006 Homeotic transformations of the axial skeleton of YY1 mutant mice and genetic interaction with the Polycomb group gene Ring1/Ring1A. Mechanisms of development 23 16624538
1978 Apparently non-deleted ring-1 chromosome and extreme growth failure in a mentally retarded girl. Clinical genetics 21 679524
1996 Physical mapping of the Ring1, Ring2, Ke6, Ke4, Rxrb, Col11a2, and RT1.Hb genes in the rat major histocompatibility complex. Immunogenetics 17 8662089
2020 Identification of loci and candidate gene GmSPX-RING1 responsible for phosphorus efficiency in soybean via genome-wide association analysis. BMC genomics 15 33076835
2019 Ring1 promotes the transformation of hepatic progenitor cells into cancer stem cells through the Wnt/β-catenin signaling pathway. Journal of cellular biochemistry 15 31696964
2019 Evolving Role of RING1 and YY1 Binding Protein in the Regulation of Germ-Cell-Specific Transcription. Genes 15 31752312
2015 RING1 proteins contribute to early proximal-distal specification of the forelimb bud by restricting Meis2 expression. Development (Cambridge, England) 14 26674308
2024 Architecture of the RNF1 complex that drives biological nitrogen fixation. Nature chemical biology 13 38890433
2014 Polycomb group oncogene RING1 is over-expressed in non-small cell lung cancer. Pathology oncology research : POR 13 24414991
2022 Rnf1 is the primary electron source to nitrogenase in a high-ammonium-accumulating strain of Azotobacter vinelandii. Applied microbiology and biotechnology 12 35804159
2017 Nuclear envelope-distributed CD147 interacts with and inhibits the transcriptional function of RING1 and promotes melanoma cell motility. PloS one 7 28832687
2022 The E3 ubiquitin ligase RING1 interacts with COP9 Signalosome Subunit 4 to positively regulate resistance to root-knot nematodes in Solanum lycopersicum L. Plant science : an international journal of experimental plant biology 6 35659944
2024 RING1 missense variants reveal sensitivity of DNA damage repair to H2A monoubiquitination dosage during neurogenesis. Nature communications 5 39256363
2025 RING1 dictates GSDMD-mediated inflammatory response and host susceptibility to pathogen infection. Cell death and differentiation 4 40369166
2024 RING1 Inhibition Has a Cell-Specific Antitumoral Role by Promoting Autophagy in Endometrial Cancer Cells. Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology 2 38219048
2014 A RING to rule them all: RING1 as silencer and activator. Developmental cell 2 24434133
2026 RING1 and BMI1 catalytic activities play distinct roles in plant PcG-mediated gene regulation. The Plant cell 1 41460774
2016 Spatiotemporal Patterns of RING1 Expression after Rat Spinal Cord Injury. Neurochemical research 1 28032293
2026 RING1 is an Integrin α5 E3 ubiquitin ligase and inhibits esophageal squamous cell carcinoma cell migration and metastasis. Cellular signalling 0 42229736
2025 The RING1 subunit of Polycomb Repressive Complex 1 monoubiquitinates histone H2A and mediates repression independently of Polycomb Repressive Complex 2 in the model diatom Phaeodactylum tricornutum. The New phytologist 0 41346180
2022 Generation of an RNF1-deficient human pluripotent stem cell line using CRISPR/Cas9 technology. Stem cell research 0 35567848

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