Affinage

RAD18

E3 ubiquitin-protein ligase RAD18 · UniProt Q9NS91

Length
495 aa
Mass
56.2 kDa
Annotated
2026-04-28
100 papers in source corpus 37 papers cited in narrative 35 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

RAD18 is a RING-finger E3 ubiquitin ligase that serves as the central regulatory node for DNA damage tolerance and repair pathway choice at stalled replication forks and double-strand breaks. RAD18 forms an asymmetric homodimer that heterodimerizes with the E2 ubiquitin-conjugating enzyme RAD6 (HHR6A/B); the complex is recruited to sites of replication stress through RPA-coated ssDNA binding via its SAP domain and RPA interactions, with additional targeting by NBS1 and SIVA1, and monoubiquitinates PCNA at K164, which is the key signal for recruiting Y-family translesion synthesis polymerases (Polη, Polκ) and activating the Fanconi anemia pathway through FANCD2/FANCI chromatin loading (PMID:15359278, PMID:16611994, PMID:20937699, PMID:18363965, PMID:19029798, PMID:24958773). Beyond translesion synthesis, RAD18 promotes homologous recombination at DSBs through interaction with RAD51C, monoubiquitinates 53BP1 to regulate its retention at DSBs in G1, displaces 53BP1 from ubiquitylated H2A nucleosomes, and independently promotes Polη SUMOylation via PIAS1 bridging to maintain replication fork integrity during unchallenged S phase (PMID:19396164, PMID:19228710, PMID:28506460, PMID:27811911). RAD18 activity is regulated by DDK-mediated phosphorylation controlling Polη association, autoubiquitination governing nuclear-cytoplasmic distribution, USP7-mediated deubiquitination stabilizing RAD18 protein levels, and a SUMO-interacting motif that stimulates ligase activity toward SUMOylated PCNA (PMID:21098111, PMID:15509568, PMID:25961918, PMID:23034805).

Mechanistic history

Synthesis pass · year-by-year structured walk · 14 steps
  1. 1994 High

    Establishing the core enzymatic partnership: the question of how Rad6 ubiquitin-conjugating activity is directed to DNA damage sites was answered by showing that Rad18 provides the DNA-binding specificity and physically recruits Rad6 to ssDNA substrates.

    Evidence Co-immunoprecipitation, DNA binding assays, and genetic complementation in yeast

    PMID:7926769

    Open questions at the time
    • No substrate for the Rad6-Rad18 complex identified
    • Mechanism of damage recognition unknown
    • Mammalian homolog not yet characterized
  2. 1997 High

    Biochemical reconstitution of the Rad6-Rad18 heterodimer revealed it possesses ubiquitin-conjugating, ssDNA-binding, and ssDNA-dependent ATPase activities as a unified complex, and defined the minimal interaction domains between the two proteins.

    Evidence Purification to homogeneity from yeast co-expression, in vitro ubiquitin conjugation, ATPase, and DNA binding assays; two-hybrid and deletion mapping

    PMID:9234711 PMID:9287349

    Open questions at the time
    • Physiological substrate of the E3 ligase unknown
    • ATPase function not assigned to a specific step
    • No structural information on the complex
  3. 2004 High

    The key substrate was identified: human RAD18/RAD6 monoubiquitinates PCNA, and this modification is required to recruit Polη to damage sites, establishing the central translesion synthesis signaling mechanism. Concurrently, autoubiquitination of RAD18 was shown to regulate its nuclear-cytoplasmic partitioning.

    Evidence In vitro ubiquitination with purified proteins, RAD18−/− cells lacking Polη foci, Co-IP of RAD18-Polη; mass spectrometry of autoubiquitination sites, subcellular fractionation with zinc finger mutant

    PMID:15359278 PMID:15509568

    Open questions at the time
    • Mechanism of RAD18 recruitment to stalled forks not defined
    • Specificity for K164 on PCNA not structurally explained
    • Regulation of autoubiquitination unclear
  4. 2006 High

    RAD18-mediated PCNA monoubiquitination was shown to recruit additional TLS polymerases (Polκ) and to depend on ATR/Chk1 checkpoint signaling, while domain dissection revealed separable replication-dependent (SAP domain) and replication-independent (zinc finger) recruitment mechanisms.

    Evidence siRNA knockdown, RAD18−/− mouse cells, checkpoint kinase inhibition, live cell imaging with UV microbeam and domain mutants

    PMID:16611994 PMID:16980296

    Open questions at the time
    • Molecular basis of checkpoint-dependent regulation of RAD18 unknown
    • How RAD18 distinguishes different damage types unclear
  5. 2008 High

    The SAP domain was identified as a fork-structure sensor: RAD18 preferentially binds forked DNA substrates resembling stalled forks, and yeast Rad18 was shown to ubiquitinate a second substrate (Rad17/9-1-1 clamp) to activate a checkpoint transcriptional response.

    Evidence In vitro DNA binding with defined substrates, SAP mutant complementation assays; in vitro Rad17 ubiquitination and K197R mutagenesis with genetic epistasis

    PMID:18363965 PMID:18485869

    Open questions at the time
    • Relative contribution of ssDNA vs. fork structure binding in vivo unresolved
    • Whether Rad17 ubiquitination occurs in mammalian cells unknown
  6. 2009 High

    RAD18's role expanded beyond TLS: it was shown to promote homologous recombination at DSBs via RAD51C interaction, monoubiquitinate 53BP1 for DSB retention in G1, initiate template switching through PCNA polyubiquitination (with Ubc13-Mms2), and be recruited to ssDNA via direct RPA interaction.

    Evidence Co-IP and epistasis with RNF8/RAD51C; in vitro 53BP1 ubiquitination at K1268 with mutagenesis; 2D gel analysis of SCJs in yeast; RPA-RAD18 in vitro recruitment assay

    PMID:19029798 PMID:19092928 PMID:19228710 PMID:19396164

    Open questions at the time
    • How RAD18 coordinates TLS, HR, and template switching pathway choice unknown
    • Whether 53BP1 monoubiquitination and HR promotion are competing or cooperative functions unclear
    • In vitro reconstitution of PCNA polyubiquitination chain not fully achieved with mammalian proteins
  7. 2010 High

    RAD18 was linked to the Fanconi anemia pathway: PCNA monoubiquitination by RAD18 promotes FANCL chromatin recruitment and FANCD2/FANCI monoubiquitination, while RAD18 also directly binds FANCD2 through its RING domain independently of PCNA; DDK kinase phosphorylation of RAD18 was identified as a regulatory switch for Polη association.

    Evidence siRNA knockdown with chromatin fractionation and PCNA-K164R mutant; RAD18-KO cells with RING mutant complementation; in vitro kinase assay with serine cluster mutagenesis

    PMID:20937699 PMID:21098111 PMID:21355096

    Open questions at the time
    • Whether RAD18-dependent and -independent FANCD2 ubiquitination pathways are redundant or context-specific
    • Full phosphorylation map of RAD18 not established
    • How DDK phosphorylation is temporally coordinated with fork stalling unknown
  8. 2011 High

    Structural understanding of the RAD18 homodimer emerged: crystallography and NMR revealed RING-RING dimerization with asymmetric RAD6 binding, where the R6BD inhibits RAD6 polyubiquitin chain formation; NBS1 was identified as a damage-dependent recruiter of RAD18 via a domain mimicking the RAD6-binding interface.

    Evidence X-ray crystallography, NMR spectroscopy, differential tagging of RAD18 subunits with in vitro reconstitution; Co-IP and domain mapping for NBS1-RAD18

    PMID:21422291 PMID:21549715 PMID:21884979 PMID:21967848

    Open questions at the time
    • Full-length RAD18 homodimer structure not solved
    • Structural basis for asymmetric RAD6 binding in the full-length complex unknown
    • Whether NBS1 and RPA recruitment are sequential or parallel not established
  9. 2012 High

    A SUMO-interacting motif in Rad18 was shown to stimulate its ubiquitin ligase activity specifically toward SUMOylated PCNA, providing a mechanistic link between S-phase PCNA SUMOylation and damage-induced ubiquitination.

    Evidence In vitro ubiquitination with SUMOylated PCNA, SIM mutagenesis, genetic analysis in yeast

    PMID:23034805

    Open questions at the time
    • Whether this SIM-dependent stimulation operates in mammalian cells not tested
    • Quantitative contribution of SUMO-dependent vs. SUMO-independent PCNA ubiquitination unknown
  10. 2014 High

    Targeting of RAD18 to PCNA was shown to require the adaptor protein SIVA1, the NMR structure of RAD18's UBZ4 domain bound to ubiquitin was solved, and Polη was found to non-catalytically promote PCNA monoubiquitination by bridging RAD18 and PCNA.

    Evidence AP-MS and Co-IP for SIVA1; NMR structure of UBZ4-ubiquitin complex; Co-IP with catalytically-inactive Polη mutant

    PMID:23345618 PMID:24958773 PMID:25162118

    Open questions at the time
    • Whether SIVA1 and Polη scaffolding functions are redundant or additive unclear
    • Complete structural model of RAD18 on PCNA-loaded DNA lacking
  11. 2015 High

    USP7 was identified as a deubiquitinase that stabilizes RAD18 by counteracting its autoubiquitination-driven degradation, and RAD18 was revealed as a maternal limiting factor in Xenopus embryos whose titration activates the DNA damage checkpoint at the midblastula transition.

    Evidence In vitro deubiquitylation assay, Co-IP, siRNA knockdown affecting PCNA ubiquitination; Xenopus cell-free extract immunodepletion with checkpoint readout

    PMID:25961918 PMID:26212134

    Open questions at the time
    • Whether other DUBs regulate RAD18 unknown
    • Relevance of the embryonic checkpoint-suppression function to mammalian development not established
  12. 2016 High

    RAD18 was shown to promote Polη SUMOylation at K163 via PIAS1 bridging independently of its E3 ligase activity, targeting Polη to unchallenged replication forks; separately, REV1 was found to regulate RAD18 activity by disrupting inhibitory ubiquitinated-RAD18 self-complexes.

    Evidence Co-IP with K163R Polη mutant, chromosomal fragility analysis; Co-IP with ubiquitylated RAD18 forms and chromatin fractionation

    PMID:26795561 PMID:27811911

    Open questions at the time
    • Structural basis for RAD18-PIAS1 interaction unknown
    • Whether REV1-mediated RAD18 activation is damage-type specific not tested
  13. 2017 High

    NMR and biochemistry demonstrated that RAD18 binds mono-ubiquitylated H2A nucleosomes at DSBs through a bipartite interface contacting both ubiquitin and the nucleosome, competitively displacing 53BP1 and thereby influencing DSB repair pathway choice.

    Evidence NMR spectroscopy and competitive displacement assays with nucleosome substrates

    PMID:28506460

    Open questions at the time
    • In vivo quantitative contribution of RAD18-mediated 53BP1 displacement vs. RNF169 not resolved
    • Whether this function is cell-cycle regulated unknown
  14. 2020 High

    Single-molecule imaging revealed that Rad6/Rad18 is recruited to and translocates along RPA filaments in an ATP-independent manner, with RPA dramatically enhancing the efficiency and specificity of PCNA monoubiquitination.

    Evidence Single-molecule FRET microscopy and in vitro kinetic ubiquitination assays with purified proteins

    PMID:33242956

    Open questions at the time
    • Role of RAD18's ATPase activity (identified biochemically in 1997) remains unexplained
    • Whether RPA filament scanning is regulated by post-translational modifications unknown

Open questions

Synthesis pass · forward-looking unresolved questions
  • Key unresolved questions include: the full-length structural basis for RAD18 homodimer asymmetry on DNA-loaded PCNA; how RAD18 integrates signals from multiple recruiting factors (RPA, NBS1, SIVA1, Polη) to make pathway decisions among TLS, template switching, HR, and FA repair; and the physiological role of RAD18's ATPase activity.
  • No full-length structure of RAD18 on substrate
  • Pathway choice mechanism not reconstituted
  • ATPase function unassigned after >20 years

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140096 catalytic activity, acting on a protein 7 GO:0003677 DNA binding 3 GO:0016874 ligase activity 3 GO:0060090 molecular adaptor activity 2 GO:0140657 ATP-dependent activity 1
Localization
GO:0005694 chromosome 3 GO:0005634 nucleus 2
Pathway
R-HSA-73894 DNA Repair 7 R-HSA-69306 DNA Replication 4 R-HSA-1643685 Disease 2
Partners
NBS1PCNAPOLHRPA1SIVA1UBE2AUBE2BUSP7
Complex memberships
RAD18 homodimerRAD6-RAD18 heterodimer

Evidence

Reading pass · 35 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1994 Yeast Rad18 forms a specific complex with Rad6 (ubiquitin-conjugating enzyme) and provides DNA-binding activity (single-stranded DNA) to target Rad6 ubiquitin-conjugating activity to damage sites; Rad6 alone has no affinity for DNA but RAD18 binds ssDNA, and the two proteins form separate complexes with RAD18 and UBR1. Co-immunoprecipitation, DNA binding assays, genetic complementation with ubiquitin-conjugating-defective Rad6 mutant Genes & development High 7926769
1997 The purified yeast Rad6-Rad18 heterodimer has ubiquitin-conjugating activity, binds single-stranded DNA, and possesses ssDNA-dependent ATPase activity, representing the first ubiquitin-conjugating activity physically associated with DNA binding and ATPase activities. Co-overexpression and purification to near-homogeneity, in vitro ubiquitin conjugation assay, DNA binding assay, ATPase assay The Journal of biological chemistry High 9287349
1997 A 40-amino-acid region near the C-terminus of Rad18 (residues 371–410) is sufficient for interaction with Rad6; residues 141–149 at the C-terminus and 10–22 at the N-terminus of Rad6 are required for Rad18 binding, each forming amphipathic helices. Deletion mapping by two-hybrid and in vitro binding assays, site-directed mutagenesis Molecular and cellular biology High 9234711
2004 Human Rad18/Rad6B monoubiquitinates PCNA in vitro; RAD18-/- cells fail to form polymerase eta (Polη) nuclear foci after UV irradiation; Rad18 associates with Polη through C-terminal domains; Polη interacts preferentially with monoubiquitinated PCNA, whereas Polδ does not. In vitro ubiquitination assay with purified proteins, immunofluorescence focus formation in RAD18-/- cells, co-immunoprecipitation, UV irradiation The EMBO journal High 15359278
2000 Human RAD18 binds to HHR6A and HHR6B (human Rad6 homologs) in vivo; stable hRAD18-HHR6A and hRAD18-HHR6B complexes were purified from yeast co-expression; the RING-finger motif of hRad18 is required for interaction with hHR6 and for postreplication repair function. Co-immunoprecipitation, yeast co-expression and purification, stable transfection with RING-finger mutant Nucleic acids research High 10884424 10908344
2006 Rad18 regulates DNA polymerase kappa (Polκ) recruitment to stalled replication forks via PCNA monoubiquitination; siRNA-mediated Rad18 knockdown inhibits BPDE-induced PCNA ubiquitination and PCNA-Polκ interaction; overexpressed Rad18 induces PCNA ubiquitination and PCNA-Polκ association in a damage-independent manner; ATR/Chk1 signaling is required for Rad18-mediated PCNA monoubiquitination. siRNA knockdown, overexpression, co-immunoprecipitation, RAD18-/- mouse cells, checkpoint kinase inhibition Molecular and cellular biology High 16611994
2007 The SAP domain of human RAD18 (residues 248–282) mediates binding to DNA; the C2HC zinc finger domain mediates interaction with ubiquitin (analogous to UBZ/UBM domains); the RING domain and C-terminal region both contribute to Rad6 interaction; the C-terminus is not required for PCNA interaction; and Rad6/Rad18 forms stable dimers in vitro. Domain deletion/mutation analysis, in vitro binding assays, mass spectrometry Nucleic acids research High 17720710
2008 Human RAD18 complexed with RAD6B preferentially binds forked and single-stranded DNA structures (present at stalled replication forks) via its SAP domain (residues 248–282); SAP domain mutant RAD18 fails to accumulate at DNA damage sites in vivo and fails to guide Polη to stalled forks or efficiently monoubiquitinate PCNA. In vitro DNA binding assay with defined substrates, immunofluorescence in cells, UV sensitivity complementation Genes to cells High 18363965
2008 In budding yeast, Rad6-Rad18 mediates a eukaryotic SOS-like response by monoubiquitinating the Rad17 subunit of the 9-1-1 checkpoint clamp at K197, thereby promoting Rad53 phosphorylation and DNA-damage-induced transcription. In vitro ubiquitination assay, site-directed mutagenesis (K197R), genetic epistasis, checkpoint assays Cell High 18485869
2009 RAD18 promotes homologous recombination repair (HRR) downstream of RNF8-mediated DNA damage signaling; RAD18 is recruited to DSB sites via a pathway dependent on RNF8; RAD18 facilitates HRR through direct interaction with the recombinase RAD51C. Co-immunoprecipitation, immunofluorescence, siRNA knockdown, epistasis with RNF8 and RAD51C Nature cell biology High 19396164
2009 RAD18 promotes DSB repair during G1 phase by associating with 53BP1, monoubiquitinating 53BP1 at K1268 in vitro, and enhancing 53BP1 retention at chromatin near DSBs; a K1268R mutant 53BP1 is not efficiently retained at DSB sites; Rad18-null cells show impaired 53BP1 foci retention and DSB repair. Co-immunoprecipitation, in vitro ubiquitination assay, immunofluorescence, Rad18-null cells, site-directed mutagenesis (K1268R) Nucleic acids research High 19228710
2009 In budding yeast, Rad18 is required for formation of X-shaped sister chromatid junctions (SCJs) at damaged replication forks through PCNA polyubiquitylation involving Mms2 and Ubc13; this template switch pathway requires SUMOylated PCNA and Ubc9, and is coordinated with Rad51-dependent recombination. 2D gel electrophoresis to detect SCJs, genetic epistasis with rad18Δ, mms2Δ, ubc13Δ, siz1Δ, rad51Δ, physical analysis of replication intermediates Nature High 19092928
2009 Replication protein A (RPA) physically interacts with RAD18 in both yeast and mammalian cells; purified RPA can recruit RAD18 to ssDNA in vitro; RPA is required for PCNA ubiquitylation by Rad18; RAD18 chromatin association correlates with RPA. Co-immunoprecipitation, in vitro ssDNA recruitment assay with purified proteins, genetic analysis of RPA mutants Cell cycle Medium 19029798
2010 RAD18 is a substrate of Cdc7 kinase (DDK); DDK phosphorylates a serine cluster in the Polη-binding motif of RAD18; this phosphorylation is required for efficient RAD18-Polη association and redistribution of Polη to stalled replication forks. In vitro kinase assay, site-directed mutagenesis of serine cluster, co-immunoprecipitation, immunofluorescence The Journal of cell biology High 21098111
2010 RAD18-mediated PCNA monoubiquitination at K164 is required for FANCL recruitment to chromatin, and monoubiquitinated PCNA stimulates FANCL-catalyzed FANCD2 and FANCI monoubiquitination, linking RAD18 to Fanconi anemia pathway activation. siRNA knockdown of RAD18, chromatin fractionation, in vitro ubiquitination assay, PCNA-K164R mutant cells The Journal of cell biology High 20937699
2010 RAD18 binds FANCD2 directly (RING domain required) and is required for efficient monoubiquitylation and chromatin localization of both FANCD2 and FANCI; this activity is independent of PCNA ubiquitylation. Co-immunoprecipitation, RAD18-knockout cells, chromatin fractionation, RING-domain mutant RAD18 Blood High 21355096
2010 RAD18-dependent PCNA monoubiquitination promotes recruitment of SNM1A (a nuclease for ICL repair) to ICL lesions through SNM1A's UBZ (ubiquitin-binding zinc finger); SNM1A nuclear focus formation requires RAD18. Immunofluorescence, Co-IP, RAD18 siRNA knockdown, UBZ domain mutation The Journal of biological chemistry Medium 20385554
2011 Human RAD18 forms a homodimer through RING-RING interactions; the homodimeric RING domain can recruit two Rad6b molecules, but full-length RAD18 homodimer binds only one Rad6b; NMR and mutagenesis define the Rad6b binding interface on the RING domain; the RAD6-binding domain (R6BD) of RAD18 inhibits Rad6b ubiquitin chain-forming activity by competing with ubiquitin for the 'backside' binding site on Rad6. X-ray crystallography of RING domain, NMR spectroscopy, site-directed mutagenesis, in vitro ubiquitination assay Proceedings of the National Academy of Sciences / Journal of molecular biology High 21422291 21549715
2011 RAD18 forms a ternary complex with RAD6A as RAD6A-(RAD18)2; only one R6BD in the RAD18 dimer is sufficient for ternary complex formation and ligase activity; mutations in both subunits of either RING or SAP domains strongly reduce ligase activity, but inactivation in only one subunit is without effect, demonstrating asymmetry of the two RAD18 subunits. Differential tagging of RAD18 subunits, co-immunoprecipitation, in vitro ubiquitination assay, mutant analysis Nucleic acids research High 21967848
2011 NBS1 binds to RAD18 after UV irradiation via a C-terminal domain that shares structural/functional similarity with the RAD18-binding domain of RAD6; NBS1 mediates RAD18 recruitment to DNA damage sites; disruption of NBS1 abolishes RAD18-dependent PCNA ubiquitination and Polη focus formation. Co-immunoprecipitation, siRNA knockdown, immunofluorescence, domain mapping Molecular cell High 21884979
2004 Human Rad18 is monoubiquitinated at multiple sites by autoubiquitination via Rad6 in vitro; Rad18 self-association (dependent on zinc finger C207) is required for its monoubiquitination in vivo; monoubiquitinated Rad18 localizes mainly to the cytoplasm while non-ubiquitinated Rad18 is predominantly nuclear; Rad18 can also be polyubiquitinated and degraded by the proteasome. Mass spectrometry identification, in vitro ubiquitination, zinc finger mutant (C207F), subcellular fractionation, proteasome inhibitor treatment The Journal of biological chemistry High 15509568
2006 Human RAD18 accumulates rapidly at diverse DNA damage sites (UVC, X-ray, laser-induced SSBs) in a replication-independent manner requiring a zinc finger motif in the middle of RAD18; the SAP motif is additionally required for UV-induced Polη focus formation in a replication-dependent manner; these two functions are mechanistically separable. Live cell imaging, domain deletion/mutation, UV microbeam and laser irradiation, replication inhibition by aphidicolin The Journal of biological chemistry High 16980296
2009 In budding yeast, PCNA polyubiquitination by Rad6-Rad18 (initiation) and Ubc13-Mms2-Rad5 (chain extension) act sequentially and independently; loading of PCNA onto DNA is essential for recognition by Rad6-Rad18 for the initiation step, while chain extension by Ubc13-Mms2-Rad5 is only slightly enhanced by loading. In vitro reconstituted ubiquitination assays with purified components, PCNA loading assays The EMBO journal High 19851286
2012 In budding yeast, Rad18 contains a SUMO-interacting motif (SIM) that stimulates its ubiquitin ligase activity toward sumoylated PCNA; SUMO on PCNA strongly enhances Rad18-mediated ubiquitination; this SIM also mediates sumoylation of Rad18 itself, providing a mechanism for the transition from S-phase-associated PCNA sumoylation to damage-induced ubiquitination. In vitro ubiquitination assay with SUMOylated PCNA substrate, SIM mutation, genetic analysis Nucleic acids research High 23034805
2013 DNA polymerase eta (Polη) promotes PCNA monoubiquitination through a non-catalytic mechanism: the C-terminal domain of Polη binds both RAD18 and PCNA and facilitates PCNA monoubiquitination; this function is unique to Polη among Y-family TLS polymerases and is dissociable from catalytic activity. Co-immunoprecipitation, siRNA knockdown/complementation, catalytically-inactive Polη mutant, PCNA ubiquitination assays Nucleic acids research High 23345618
2014 SIVA1 constitutively interacts with PCNA via a PIP motif and also interacts with RAD18, serving as a molecular bridge that targets RAD18's E3 ligase activity to PCNA; SIVA1 knockdown compromises RAD18-dependent PCNA monoubiquitination and Polη focus formation. Affinity purification/mass spectrometry, co-immunoprecipitation, siRNA knockdown, immunofluorescence The Journal of cell biology High 24958773
2014 The monoubiquitinated form of RAD18 does not interact with SHPRH or HLTF (downstream E3 ligases for error-free bypass); ubiquitinated RAD18 preferentially interacts with the zinc finger domain of non-ubiquitinated RAD18 and inhibits RAD18 function in trans; deubiquitination of RAD18 (e.g., by treatment with MMS or H2O2) promotes a switch to Rad18-SHPRH complexes needed for error-free bypass. Co-immunoprecipitation, site-directed mutagenesis, immunofluorescence, PCNA ubiquitination assay The Journal of cell biology Medium 25023518
2014 NMR structure of the human RAD18 C2HC (type 4) UBZ domain in complex with ubiquitin reveals a β1-β2-α fold; RAD18-UBZ4 binds ubiquitin via its α-helix and strand β1, in a mode distinct from the Polη UBZ3 domain that uses only the α-helix. NMR spectroscopy, structure determination of UBZ-ubiquitin complex Biochemistry High 25162118
2015 USP7 (deubiquitylase) directly associates with RAD18 via a consensus USP7-binding motif and stabilizes RAD18 protein levels; loss of USP7 destabilizes RAD18, compromises UV-induced PCNA monoubiquitylation and Polη recruitment to stalled forks; USP7 can disassemble RAD18-dependent poly-ubiquitin chains in vitro and in vivo. Co-immunoprecipitation, siRNA knockdown, in vitro deubiquitylation assay, immunofluorescence Oncogene High 25961918
2016 Rad18 promotes SUMOylation of DNA polymerase eta (Polη) at K163 independently of its ubiquitin ligase activity, acting as a molecular bridge between Polη and the PIAS1 SUMO ligase; this SUMOylation targets Polη to replication forks during unchallenged S phase to prevent under-replicated DNA. Co-immunoprecipitation, SUMO-deficient mutant (K163R), replication stress assays, chromosomal fragility analysis Nature communications High 27811911
2017 RAD18 binds tightly to mono-ubiquitylated H2A nucleosomes (NCP-ubme) through a ubiquitin-binding domain that contacts both ubiquitin and nucleosome surfaces, displacing 53BP1 from DSB-associated chromatin; this mechanism is structurally distinct from RNF169. NMR spectroscopy, biochemical binding assays, competitive displacement assays Molecular cell High 28506460
2016 REV1 promotes PCNA monoubiquitylation by interacting with ubiquitylated RAD18, facilitating the release of non-ubiquitylated RAD18 from ubiquitylated RAD18 complexes, thereby freeing RAD18 to be recruited to chromatin for TLS function. Co-immunoprecipitation, siRNA knockdown, PCNA ubiquitination assay, chromatin fractionation Journal of cell science Medium 26795561
2020 Rad6/Rad18 complex is recruited to RPA filaments via Rad18•RPA interactions and randomly translocates along RPA filaments (ATP-independently), promoting productive PCNA monoubiquitination; RPA dramatically enhances the efficiency and specificity of PCNA monoubiquitination. Single-molecule FRET microscopy, in vitro kinetic ubiquitination assays with purified proteins Biochemistry High 33242956
2015 In Xenopus embryos, RAD18 functions as a maternal limiting factor that suppresses the DNA damage checkpoint by maintaining PCNA monoubiquitylation; increasing DNA template abundance near MBT titrates RAD18, reducing PCNA monoubiquitylation and derepressing CHK1 phosphorylation; ectopic RAD18 in somatic mammalian cells confers resistance to DNA damage by re-establishing this embryonic-like regulation. Xenopus cell-free extract, CHK1 phosphorylation as checkpoint readout, RAD18 immunodepletion, ectopic expression in somatic cells Developmental cell High 26212134
2019 An engineered RAD18 variant (e18) stimulates CRISPR-mediated HDR by suppressing the localization of the NHEJ-promoting factor 53BP1 to DSBs; RAD18 domain mapping identified the regions required for HDR promotion. CRISPR HDR reporter assays in human cells, 53BP1 immunofluorescence, domain deletion analysis Nature communications Medium 31363085

Source papers

Stage 0 corpus · 100 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2004 Rad18 guides poleta to replication stalling sites through physical interaction and PCNA monoubiquitination. The EMBO journal 479 15359278
1994 Specific complex formation between yeast RAD6 and RAD18 proteins: a potential mechanism for targeting RAD6 ubiquitin-conjugating activity to DNA damage sites. Genes & development 271 7926769
2009 RAD18 transmits DNA damage signalling to elicit homologous recombination repair. Nature cell biology 262 19396164
1997 Yeast DNA repair proteins Rad6 and Rad18 form a heterodimer that has ubiquitin conjugating, DNA binding, and ATP hydrolytic activities. The Journal of biological chemistry 253 9287349
1981 Characterization of postreplication repair in Saccharomyces cerevisiae and effects of rad6, rad18, rev3 and rad52 mutations. Molecular & general genetics : MGG 236 7038396
2008 SUMOylation regulates Rad18-mediated template switch. Nature 222 19092928
1995 The rad18 gene of Schizosaccharomyces pombe defines a new subgroup of the SMC superfamily involved in DNA repair. Molecular and cellular biology 184 8524274
2005 The error-free component of the RAD6/RAD18 DNA damage tolerance pathway of budding yeast employs sister-strand recombination. Proceedings of the National Academy of Sciences of the United States of America 157 16247017
2006 Rad18 regulates DNA polymerase kappa and is required for recovery from S-phase checkpoint-mediated arrest. Molecular and cellular biology 149 16611994
1988 The Saccharomyces cerevisiae RAD18 gene encodes a protein that contains potential zinc finger domains for nucleic acid binding and a putative nucleotide binding sequence. Nucleic acids research 129 2970061
2000 Dysfunction of human Rad18 results in defective postreplication repair and hypersensitivity to multiple mutagens. Proceedings of the National Academy of Sciences of the United States of America 124 10884424
1999 Rad18 is required for DNA repair and checkpoint responses in fission yeast. Molecular biology of the cell 119 10473635
2000 A novel SMC protein complex in Schizosaccharomyces pombe contains the Rad18 DNA repair protein. The EMBO journal 115 10747036
2011 E3 ligase Rad18 promotes monoubiquitination rather than ubiquitin chain formation by E2 enzyme Rad6. Proceedings of the National Academy of Sciences of the United States of America 113 21422291
2002 RAD18 and RAD54 cooperatively contribute to maintenance of genomic stability in vertebrate cells. The EMBO journal 113 12374756
2003 Enhanced genomic instability and defective postreplication repair in RAD18 knockout mouse embryonic stem cells. Molecular and cellular biology 106 12509447
2015 Regulation of Rad6/Rad18 Activity During DNA Damage Tolerance. Annual review of biophysics 98 26098514
2005 Composition and architecture of the Schizosaccharomyces pombe Rad18 (Smc5-6) complex. Molecular and cellular biology 97 15601840
2019 Stimulation of CRISPR-mediated homology-directed repair by an engineered RAD18 variant. Nature communications 94 31363085
1997 Domains required for dimerization of yeast Rad6 ubiquitin-conjugating enzyme and Rad18 DNA binding protein. Molecular and cellular biology 90 9234711
2007 Functional characterization of Rad18 domains for Rad6, ubiquitin, DNA binding and PCNA modification. Nucleic acids research 87 17720710
2010 RAD18-mediated ubiquitination of PCNA activates the Fanconi anemia DNA repair network. The Journal of cell biology 85 20937699
2002 Involvement of vertebrate polkappa in Rad18-independent postreplication repair of UV damage. The Journal of biological chemistry 82 12356753
2009 Mechanistic analysis of PCNA poly-ubiquitylation by the ubiquitin protein ligases Rad18 and Rad5. The EMBO journal 80 19851286
2018 Long non-coding RNA ROR promotes radioresistance in hepatocelluar carcinoma cells by acting as a ceRNA for microRNA-145 to regulate RAD18 expression. Archives of biochemistry and biophysics 78 29559320
2013 A non-catalytic role of DNA polymerase η in recruiting Rad18 and promoting PCNA monoubiquitination at stalled replication forks. Nucleic acids research 78 23345618
2017 Mechanisms of Ubiquitin-Nucleosome Recognition and Regulation of 53BP1 Chromatin Recruitment by RNF168/169 and RAD18. Molecular cell 76 28506460
2015 Tumor suppressor miR-145 reverses drug resistance by directly targeting DNA damage-related gene RAD18 in colorectal cancer. Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine 71 25913620
2011 The E3 ubiquitin ligase RAD18 regulates ubiquitylation and chromatin loading of FANCD2 and FANCI. Blood 70 21355096
2006 RAD18-independent ubiquitination of proliferating-cell nuclear antigen in the avian cell line DT40. EMBO reports 70 16888649
2007 A natural antisense transcript against Rad18, specifically expressed in neurons and upregulated during beta-amyloid-induced apoptosis. The European journal of neuroscience 69 17970741
2012 A SUMO-interacting motif activates budding yeast ubiquitin ligase Rad18 towards SUMO-modified PCNA. Nucleic acids research 68 23034805
2008 RAD6-RAD18-RAD5-pathway-dependent tolerance to chronic low-dose ultraviolet light. Nature 67 19079240
2007 RAD18 and poly(ADP-ribose) polymerase independently suppress the access of nonhomologous end joining to double-strand breaks and facilitate homologous recombination-mediated repair. Molecular and cellular biology 67 17242200
2016 Rad18-dependent SUMOylation of human specialized DNA polymerase eta is required to prevent under-replicated DNA. Nature communications 66 27811911
2001 Characterization of a novel human SMC heterodimer homologous to the Schizosaccharomyces pombe Rad18/Spr18 complex. Molecular biology of the cell 66 11408570
2004 Differential regulation of Rad18 through Rad6-dependent mono- and polyubiquitination. The Journal of biological chemistry 65 15509568
2017 DNA repair factor RAD18 and DNA polymerase Polκ confer tolerance of oncogenic DNA replication stress. The Journal of cell biology 64 28835467
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