{"gene":"RNF111","run_date":"2026-06-10T06:43:37","timeline":{"discoveries":[{"year":2001,"finding":"Arkadia (RNF111) is a nuclear RING domain-containing protein essential for node induction in the mammalian embryo; genetic interaction with Nodal revealed by chimera analysis showing Arkadia functions in extraembryonic tissues to induce the node and is required for HNF3beta expression in the anterior primitive streak.","method":"Gene-trap mutagenesis, chimeric embryo analysis, genetic epistasis with Nodal","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis and chimeric embryo analysis replicated across two independent back-to-back Nature papers (PMID:11298452, PMID:11298453)","pmids":["11298452","11298453"],"is_preprint":false},{"year":2001,"finding":"Arkadia specifically potentiates the mesendoderm-inducing activity of a subset of TGF-beta/Nodal family members in Xenopus; it functions as a nuclear protein that enhances Nodal signaling when co-expressed and can act in cells adjacent to those producing the Nodal signal.","method":"Xenopus overexpression, morpholino knockdown, genetic interaction with extracellular Nodal blockade","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — functional epistasis with Nodal, replicated alongside companion mouse paper, multiple assays","pmids":["11298453"],"is_preprint":false},{"year":2003,"finding":"Arkadia physically interacts with inhibitory Smad7, induces its poly-ubiquitination and proteasome-dependent degradation via its RING domain, thereby amplifying both TGF-beta and BMP signaling; unlike Smurf1, Arkadia does not associate with TGF-beta receptors.","method":"Co-immunoprecipitation, ubiquitination assay, siRNA knockdown, Western blot for Smad7 accumulation","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — Co-IP plus ubiquitination assay plus RNAi phenotype, independently replicated in multiple subsequent studies","pmids":["14657019"],"is_preprint":false},{"year":2006,"finding":"Axin acts as a scaffold protein that forms a multimeric complex with Smad7 and Arkadia, facilitating Arkadia-mediated Smad7 ubiquitination and degradation to activate TGF-beta signaling; Axin also induces nuclear export of Smad7.","method":"Co-immunoprecipitation, siRNA knockdown, pulse-chase experiment, nuclear export assay","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP, pulse-chase, and siRNA rescue, single lab but multiple orthogonal methods","pmids":["16601693"],"is_preprint":false},{"year":2007,"finding":"Arkadia is absolutely required for TGF-beta-induced Smad3/Smad4-dependent transcription; it activates this transcription by inducing signal-dependent degradation of transcriptional repressor SnoN. Arkadia interacts with SnoN and ubiquitinates it constitutively, but efficient degradation requires a complex of Arkadia, SnoN, and phosphorylated Smad2 or Smad3.","method":"siRNA library screen, dominant-negative mutant overexpression, luciferase reporter assay, Co-IP, ubiquitination assay, rescue experiment in SEG-1 cancer cells","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (reporter, Co-IP, ubiquitination, rescue), replicated by companion paper same year","pmids":["17591695"],"is_preprint":false},{"year":2007,"finding":"Arkadia induces ubiquitin-dependent degradation of SnoN and c-Ski (in addition to Smad7) via its C-terminal RING domain; Arkadia interacts with SnoN and c-Ski both in their free forms and when bound to Smad proteins.","method":"Co-immunoprecipitation, ubiquitination assay, Western blot for protein levels, RING domain mutant analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — Co-IP plus ubiquitination assay with RING mutant control, replicated by companion paper same year","pmids":["17510063"],"is_preprint":false},{"year":2007,"finding":"Arkadia interacts with and ubiquitinates phospho-Smad2/3 (P-Smad2/3), inducing their degradation; this is mediated by the same domains required for enhancing their transcriptional activity. Loss of Arkadia causes nuclear accumulation of hypoactive P-Smad2/3. Arkadia thus couples degradation of P-Smad2/3 with activation of target gene transcription, providing a signaling termination mechanism.","method":"Knockout embryonic stem cells, chimeric embryo analysis, Co-IP, ubiquitination assay, gene expression analysis, rescue by reintroduction of Arkadia","journal":"PLoS biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo genetic knockout, Co-IP, ubiquitination, transcriptional readout, multiple orthogonal approaches","pmids":["17341133"],"is_preprint":false},{"year":2008,"finding":"Arkadia RING-H2 domain was recombinantly expressed and shown by NMR to be a stably folded protein with a RING-H2 type architecture, suitable for structural studies of its E3 ubiquitin ligase activity.","method":"Recombinant protein expression, NMR spectroscopy","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — NMR structure determination of isolated domain, single lab, preliminary characterization only","pmids":["19032943"],"is_preprint":false},{"year":2008,"finding":"Arkadia regulates myoblast differentiation by inducing degradation of Ski and Ski-bound phospho-Smad2/3 complexes; it binds Smad2/3 via Ski to induce ubiquitination of the Smad2/3 complex, affecting myoblast differentiation through both Smad-dependent and Smad-independent pathways.","method":"siRNA knockdown, overexpression, Co-IP, ubiquitination assay, C2C12 differentiation assay","journal":"Bone","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP, ubiquitination, and differentiation phenotype in single lab with multiple methods","pmids":["18950738"],"is_preprint":false},{"year":2010,"finding":"Arkadia interacts with the mu2 subunit of the clathrin-adaptor AP2 complex through its N-terminal YALL motif binding to the YXXΦ-binding domain of mu2; Arkadia ubiquitylates mu2 at Lys130 and modifies EGFR endocytosis induced by EGF. Arkadia localizes to both nucleus and cytosol.","method":"Yeast-two-hybrid screening, Co-IP, ubiquitination assay, endocytosis assay, subcellular fractionation","journal":"Journal of biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast-two-hybrid, Co-IP, ubiquitination assay, and functional endocytosis readout in single lab","pmids":["20965945"],"is_preprint":false},{"year":2010,"finding":"The Arkadia RING-H2 domain requires two Zn(II) ions coordinated through a Cys3-His2-Cys3 motif; mutation of Cys955 to Arg (C955R) dramatically reduces zinc-binding affinity and disrupts global structural integrity of the RING domain.","method":"Site-directed mutagenesis, recombinant protein expression, atomic absorption spectroscopy, NMR","journal":"Bioinorganic chemistry and applications","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — mutagenesis plus atomic absorption and NMR, single lab, single study","pmids":["20689703"],"is_preprint":false},{"year":2012,"finding":"NMR solution structure of Arkadia's RING-H2 domain revealed a ββbα fold with cross-brace Zn(II) ligation; chemical shift perturbation showed that the RING-H2 domain interacts with the E2 enzyme UbcH5b.","method":"NMR spectroscopy, chemical shift perturbation mapping","journal":"Proteins","confidence":"High","confidence_rationale":"Tier 1 / Moderate — NMR structure determination with E2 interaction mapping, single lab but Tier 1 method","pmids":["22411132"],"is_preprint":false},{"year":2012,"finding":"FHL2 binds Arkadia and increases its half-life by inhibiting K27-linked polyubiquitination of Arkadia, thereby stabilizing Arkadia and enhancing TGF-beta signaling. Arkadia undergoes K63- and K27-linked polyubiquitination, partly via autocatalysis; K27-linked ubiquitination promotes its proteolytic turnover.","method":"Co-IP, ubiquitination assay with linkage-specific mutants, cycloheximide chase, siRNA knockdown, luciferase reporter assay","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP, ubiquitination linkage analysis, and half-life measurements in single lab with multiple orthogonal methods","pmids":["23212909"],"is_preprint":false},{"year":2011,"finding":"RB1CC1/FIP200 is a substrate-selective cofactor of Arkadia that enhances Arkadia E3 ligase activity specifically toward c-Ski but not SnoN, through direct physical interaction with c-Ski as a scaffold.","method":"Co-IP, ubiquitination assay, siRNA knockdown, overexpression, luciferase reporter assay","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP, ubiquitination, reporter, and KD phenotype, single lab with multiple methods","pmids":["21795712"],"is_preprint":false},{"year":2013,"finding":"RNF111/Arkadia is a SUMO-targeted ubiquitin ligase (STUbL) that uses three adjacent SUMO-interacting motifs (SIMs) for specific recognition of poly-SUMO2/3 chains. It uses Ubc13-Mms2 as cognate E2 to promote non-proteolytic K63-linked ubiquitylation of SUMOylated target proteins. RNF111 promotes K63-linked ubiquitylation of SUMOylated XPC and facilitates nucleotide excision repair by regulating XPC recruitment to UV-damaged DNA.","method":"SUMO-interaction assay, ubiquitination assay with linkage-specific antibodies, Co-IP, NER recruitment assay, UV damage response, siRNA knockdown","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — in vitro ubiquitination assay with chain linkage determination, SIM-deletion mutants, XPC functional recruitment assay; multiple orthogonal methods in single rigorous study","pmids":["23751493"],"is_preprint":false},{"year":2013,"finding":"Arkadia contains three successive SUMO-interacting motifs (SIMs) that mediate interaction with poly-SUMO2; the third SIM (VVDL) is most relevant. Arkadia functions as a STUbL by ubiquitinating SUMO chains. Arkadia's SIMs are required for its interaction with polysumoylated PML and for arsenic-induced degradation of polysumoylated PML. Arkadia homodimerizes but does not heterodimerize with RNF4.","method":"Co-IP, ubiquitination assay, siRNA knockdown, immunofluorescence for PML bodies, dimerization assay","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (Co-IP, ubiquitination, knockdown, localization), confirmed STUbL activity on PML substrate","pmids":["23530056"],"is_preprint":false},{"year":2013,"finding":"RNF111 promotes DNA damage-induced NEDD8 (neddylation) accumulation at DNA damage sites; this requires the E2 enzyme UBE2M. RNF111 catalyzes polyneddylation of histone H4 at N-terminal lysine residues in response to DNA damage. NEDD8 chains are recognized by the MIU domain of RNF168, and RNF111-dependent neddylation promotes RNF168 foci formation and downstream recruitment of 53BP1 and BRCA1.","method":"siRNA/shRNA knockdown, ubiquitin-like modification assay, mass spectrometry, Co-IP, immunofluorescence for damage foci","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo neddylation assay, MS identification of H4 neddylation sites, genetic knockdown with functional foci readout, multiple orthogonal methods","pmids":["23394999"],"is_preprint":false},{"year":2014,"finding":"Arkadia/RNF111 colocalizes with CBX4/Pc2 in Polycomb bodies; both the SUMO-interacting motifs (SIMs) and a unique M domain (absent in paralogs ARKL1/ARKL2 and RNF4) redundantly promote this colocalization and activation of a TGF-beta transcriptional reporter. Transcriptome profiling showed Arkadia can both promote and inhibit gene expression depending on epigenetic context.","method":"Immunofluorescence colocalization, domain-deletion mutant analysis, TGF-beta reporter assay, RNA-seq transcriptome profiling","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct colocalization, mutant analysis, and transcriptome profiling; single lab","pmids":["24912682"],"is_preprint":false},{"year":2015,"finding":"Arkadia ubiquitylates and induces proteasome-dependent degradation of Smad6 (a BMP-specific inhibitory Smad), as shown by activity of wild-type but not C937A RING-dead mutant Arkadia; elevated Smad6 protein was detected in Arkadia KO MEFs. Arkadia knockdown reduces BMP-induced osteoblast differentiation markers.","method":"Ubiquitination assay with RING mutant, Western blot in KO MEFs, siRNA knockdown, BMP differentiation reporter assay","journal":"Journal of biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ubiquitination assay with RING mutant control plus KO cell validation, single lab","pmids":["25762727"],"is_preprint":false},{"year":2015,"finding":"Arkadia physically interacts with ESRP2 (epithelial splicing regulatory protein 2), induces its polyubiquitination, and modulates its splicing function; Arkadia and ESRP2 cooperate to suppress ccRCC tumor growth.","method":"Co-IP, ubiquitination assay, tumor growth assay in vivo, RNA-seq splicing analysis","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP, ubiquitination, and in vivo tumor suppression, single lab","pmids":["26522722"],"is_preprint":false},{"year":2017,"finding":"NMR analysis of Arkadia RING-H2 W972 mutants showed that W972R (but not W972A) disrupts interaction with E2 enzyme UbcH5b, with structural changes in the C-terminal alpha-helix and increased distance between Zn(II) ions; W972R abolishes TGF-beta signaling enhancement while W972A retains full activity.","method":"NMR spectroscopy, E2 interaction assay, TGF-beta luciferase reporter assay, site-directed mutagenesis","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — NMR structure plus mutagenesis plus functional reporter assay; single lab but multiple orthogonal Tier 1–2 methods","pmids":["28647409"],"is_preprint":false},{"year":2018,"finding":"Arkadia/RNF111 ubiquitinates Nrf2 via K48-linked chains, paradoxically stabilizing Nrf2 (rather than degrading it) and promoting Nrf2-dependent gene transcription. This sumoylation-dependent stabilization occurs in PML-nuclear body-enriched fractions.","method":"Co-immunoprecipitation, K48-linkage-specific ubiquitin antibody, cycloheximide chase, ARE-luciferase reporter assay","journal":"Cellular physiology and biochemistry","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single Co-IP method, unusual mechanistic claim (K48 stabilization) not independently replicated","pmids":["29597191"],"is_preprint":false},{"year":2021,"finding":"RNF111 (Rnf111) is the Nedd8 E3 ligase for cGAS; it interacts with and polyneddylates cGAS at Lys231 and Lys421 (identified by mass spectrometry), which promotes cGAS dimerization and enhances its DNA-binding ability, leading to proper cGAS-STING pathway activation and antiviral innate immunity.","method":"Co-IP, mass spectrometry identification of neddylation sites, neddylation assay, cGAS dimerization assay, DNA-binding assay, Rnf111 knockout mice susceptibility to HSV-1","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Strong — Co-IP, MS site identification, functional neddylation assay, dimerization assay, in vivo KO phenotype; multiple orthogonal methods","pmids":["33720974"],"is_preprint":false},{"year":2021,"finding":"Arkadia-mediated degradation of SKI and SnoN is required for iTreg (but not Th17) cell differentiation; genetic ablation of SKI and SnoN rescues Arkadia-deficient iTreg differentiation both in vitro and in vivo, establishing SKI/SnoN as the functionally relevant Arkadia substrates in this context.","method":"Conditional knockout of Arkadia in CD4+ T cells, double-knockout of SKI and SnoN, in vitro differentiation assay, in vivo intestinal lamina propria analysis","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional KO with specific cellular phenotype plus genetic rescue by substrate ablation; in vitro and in vivo validation","pmids":["34473197"],"is_preprint":false},{"year":2021,"finding":"Quantitative ubiquitylome proteomics in CRISPR-engineered U2OS cells (expressing RING-truncated RNF111) demonstrated that SKI and SKIL/SnoN are the only substrates ubiquitylated and degraded by RNF111 upon TGF-beta signaling; lysine 343 in the SAND domain of SKIL is identified as the RNF111 ubiquitylation target site.","method":"CRISPR engineering, label-free quantitative proteomics, diGly immunoprecipitation, ubiquitin pan-nanobody immunoprecipitation, mass spectrometry","journal":"Molecular & cellular proteomics","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — systematic quantitative ubiquitylome by two orthogonal enrichment methods in CRISPR-engineered cells, single lab but highly rigorous","pmids":["34740826"],"is_preprint":false},{"year":2022,"finding":"Non-RING elements of Arkadia (including conserved NRGA and TIER motifs) are required for E2 (UbcH5B) interaction and for efficient auto-ubiquitination; Arkadia isoform-1 does not interact with free ubiquitin, unlike isoform-2 and its homolog Ark2C.","method":"NMR interaction studies, UBCH5B C85S oxyester hydrolysis assay, auto-ubiquitination assay, mutant analysis","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — NMR plus in vitro ubiquitination assay with mutants, single lab","pmids":["36142504"],"is_preprint":false},{"year":2023,"finding":"UBXN7 directly interacts with the RING domain of RNF111 through its UAS thioredoxin-like domain, inhibiting RNF111 auto-ubiquitination by preventing E2 conjugating enzyme binding; UBXN7 overexpression stabilizes RNF111, while UBXN7 depletion reduces RNF111 protein levels. This modulates TGF-beta-induced SKIL/SnoN degradation.","method":"Co-IP, direct binding assay, ubiquitination assay, siRNA knockdown, overexpression, interactome mass spectrometry","journal":"BMC biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct binding, Co-IP, ubiquitination assay with functional substrate degradation readout; single lab, multiple methods","pmids":["37024974"],"is_preprint":false},{"year":2023,"finding":"Arkadia RING domain interacts with E2 enzymes UbcH5B, UbcH13, and UbcH7 through a similar interaction surface; cooperation with different E2s results in distinct ubiquitin chain linkages (monoubiquitylation, K63, K48, or K11), determining substrate fate.","method":"NMR chemical shift perturbation, ubiquitination assay with linkage-specific E2 enzymes","journal":"Cancers","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — NMR interaction mapping plus in vitro ubiquitination chain-type assays; single lab","pmids":["36831384"],"is_preprint":false},{"year":2025,"finding":"Arkadia and the related E3 Ark2C promote substrate ubiquitylation with multiple E2 enzymes (including Ubc13 and Ube2K) that require a priming ubiquitin before subsequent chain assembly; substrates that bind Arkadia more tightly are more extensively modified, and prior substrate ubiquitylation enhances subsequent ubiquitylation.","method":"Crystal/structural analysis of RING-E2 complexes, binding assays, in vitro substrate ubiquitylation assays, activity assays with E2 panel","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — structural characterization of RING-E2 complexes plus in vitro reconstituted substrate ubiquitylation assays with mechanistic detail; single lab but multiple rigorous Tier 1 methods","pmids":["40451499"],"is_preprint":false},{"year":2025,"finding":"Arkadia interacts with Merlin (NF2) and the SKI family co-repressor SKOR2 in human Schwann cells (validated by Co-IP/MS in hiPSC-derived SCs); this Merlin-Arkadia-SKOR2 complex is required for proper Schwann cell proliferation control.","method":"Co-immunoprecipitation followed by mass spectrometry, hiPSC-derived Schwann cell model, NF2 mutant vs wild-type comparison","journal":"Stem cell research & therapy","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP/MS experiment in single lab, interaction validated but mechanism not fully characterized","pmids":["40188079"],"is_preprint":false},{"year":2025,"finding":"Rnf111 deficiency in zebrafish reduces phosphorylation of Smad2/3 in hematopoietic stem and progenitor cells (HSPC), impairing definitive hematopoiesis; restoration of TGF-beta/Smad2 signaling with IDE2 rescues HSPC development. Gcsfr/NO signaling is identified as a downstream target pathway of Smad2/3 in Rnf111-mediated HSPC development.","method":"CRISPR/Cas9 Rnf111 knockout zebrafish, phospho-Smad2/3 Western blot, pharmacological rescue with IDE2, genetic epistasis with Gcsfr/NO pathway","journal":"Haematologica","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — CRISPR KO with defined cellular phenotype plus pharmacological rescue and pathway epistasis; single lab in zebrafish model","pmids":["39363867"],"is_preprint":false},{"year":2025,"finding":"Arkadia (E3 ubiquitin ligase for SKI) overexpression reduces SKI protein levels in human Treg cells, enhancing Treg cell stability and immunosuppressive function under TGF-beta inhibition and inflammatory conditions.","method":"Lentiviral overexpression of ARKADIA in human Treg subsets, flow cytometry, Western blotting, transcriptomics, co-culture suppression assay","journal":"Frontiers in immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — gain-of-function with defined molecular (SKI degradation) and functional (Treg stability) readout; single lab","pmids":["40995370"],"is_preprint":false}],"current_model":"RNF111/Arkadia is a nuclear RING-H2 E3 ubiquitin ligase and SUMO-targeted ubiquitin ligase (STUbL) that amplifies TGF-β/Nodal/BMP signaling by targeting the transcriptional repressors SnoN/SKIL, c-SKI, and inhibitory Smads (Smad6, Smad7) for polyubiquitination and proteasomal degradation via its RING domain; it also promotes non-proteolytic K63-linked ubiquitylation of SUMOylated substrates (including XPC in NER), polyneddylation of cGAS to enhance antiviral immunity, and histone H4 neddylation in the DNA damage response, with its ubiquitin chain-type specificity tuned by the choice of E2 partner enzyme (UbcH5B for K48, Ubc13 for K63) and its activity regulated by scaffold proteins (Axin, RB1CC1), stabilizing partners (FHL2, UBXN7), and autocatalytic ubiquitination."},"narrative":{"mechanistic_narrative":"RNF111/Arkadia is a nuclear RING-H2 E3 ubiquitin ligase that amplifies TGF-β/Nodal/BMP signaling and was first defined genetically as an essential inducer of the embryonic node acting in extraembryonic tissue downstream of Nodal [PMID:11298452, PMID:11298453]. Its core function is to drive signal-dependent polyubiquitination and proteasomal degradation of negative regulators of the pathway: the inhibitory Smads (Smad7 in TGF-β/BMP signaling, the BMP-specific Smad6) and the transcriptional repressors SnoN/SKIL and c-SKI, thereby permitting Smad3/Smad4-dependent transcription [PMID:14657019, PMID:17591695, PMID:17510063, PMID:25762727]. Substrate engagement frequently occurs in complex with phosphorylated Smad2/3, and RNF111 also ubiquitinates phospho-Smad2/3 itself, coupling transcriptional activation to signal termination [PMID:17591695, PMID:17341133]; systematic ubiquitylome profiling confirms SKI and SKIL/SnoN as its principal degradative substrates upon TGF-β stimulation, with SKIL targeted at Lys343 [PMID:34740826]. The RING-H2 domain coordinates two Zn(II) ions in a cross-brace ββα fold and engages E2 enzymes via a defined surface, and the identity of the cooperating E2 dictates ubiquitin chain linkage and hence substrate fate—UbcH5B for proteolytic chains, Ubc13–Mms2 for non-proteolytic K63 chains [PMID:22411132, PMID:28647409, PMID:36831384]. Beyond TGF-β, RNF111 acts as a SUMO-targeted ubiquitin ligase: three tandem SUMO-interacting motifs recognize poly-SUMO2/3 chains, enabling K63-linked ubiquitylation of SUMOylated substrates including XPC during nucleotide excision repair and degradation of polysumoylated PML [PMID:23751493, PMID:23530056]. It additionally functions as a NEDD8 ligase, catalyzing DNA-damage-induced histone H4 polyneddylation that promotes RNF168, 53BP1 and BRCA1 recruitment, and polyneddylating cGAS at Lys231/Lys421 to enhance cGAS dimerization and antiviral cGAS-STING signaling [PMID:23394999, PMID:33720974]. RNF111 activity is tuned by scaffold and stabilizing partners—Axin and RB1CC1/FIP200 promote substrate selection, while FHL2 and UBXN7 stabilize RNF111 by limiting its auto-ubiquitination [PMID:16601693, PMID:21795712, PMID:23212909, PMID:37024974]. Physiologically these activities control iTreg/Treg differentiation through SKI/SnoN degradation and definitive hematopoiesis via Smad2/3 [PMID:34473197, PMID:40995370, PMID:39363867].","teleology":[{"year":2001,"claim":"Established Arkadia/RNF111 as a genetically required positive regulator of Nodal/TGF-β signaling in vivo, defining its biological role before any biochemical mechanism was known.","evidence":"Gene-trap mutagenesis and chimeric embryo analysis with Nodal epistasis in mouse, and overexpression/morpholino assays in Xenopus","pmids":["11298452","11298453"],"confidence":"High","gaps":["Molecular mechanism of signal potentiation not yet defined","Did not identify substrates or enzymatic activity"]},{"year":2003,"claim":"Defined the molecular mechanism of pathway amplification: Arkadia is a RING E3 ligase that degrades inhibitory Smad7, distinguishing it from receptor-associated Smurf1.","evidence":"Co-IP, ubiquitination assay, and siRNA knockdown with Smad7 accumulation readout","pmids":["14657019"],"confidence":"High","gaps":["E2 partner not identified","Chain linkage type not resolved"]},{"year":2007,"claim":"Expanded the substrate repertoire to the transcriptional repressors SnoN and c-SKI and to phospho-Smad2/3, showing degradation of repressors activates transcription while phospho-Smad turnover terminates the signal.","evidence":"siRNA screen, Co-IP, ubiquitination assays, reporter assays in cancer cells, and knockout ES cell/chimera analysis","pmids":["17591695","17510063","17341133"],"confidence":"High","gaps":["How efficient SnoN degradation requires phospho-Smad complex mechanistically unclear","Quantitative substrate hierarchy not established"]},{"year":2008,"claim":"Determined the structural basis of catalysis: the RING-H2 domain folds independently and binds the E2 UbcH5b, linking structure to E3 activity.","evidence":"Recombinant expression, NMR spectroscopy, and chemical shift perturbation E2 mapping","pmids":["19032943","22411132","20689703"],"confidence":"High","gaps":["Full-length structure with substrate not solved","Chain-type determinants not yet mapped"]},{"year":2012,"claim":"Revealed that Arkadia activity is itself regulated by partners and autoubiquitination, identifying Axin, RB1CC1/FIP200 and FHL2 as substrate-selective or stabilizing cofactors.","evidence":"Co-IP, linkage-specific ubiquitination assays, pulse-chase/cycloheximide, and reporter assays","pmids":["16601693","21795712","23212909"],"confidence":"Medium","gaps":["Single-lab characterization for each cofactor","Quantitative contribution to physiological substrate selection unclear"]},{"year":2013,"claim":"Reclassified RNF111 as a SUMO-targeted ubiquitin ligase and a NEDD8 ligase, dramatically broadening its function beyond TGF-β to DNA repair, PML turnover, and damage-response neddylation.","evidence":"SIM-deletion mutants, linkage-specific ubiquitination with Ubc13-Mms2, NER recruitment assays, MS identification of H4 neddylation, and damage foci readouts","pmids":["23751493","23530056","23394999"],"confidence":"High","gaps":["How RNF111 switches between ubiquitin and NEDD8 ligase modes unclear","Full SUMOylated substrate range not defined"]},{"year":2017,"claim":"Defined precise RING residues controlling E2 engagement, separating structural integrity from functional signaling output.","evidence":"NMR of W972 mutants, E2 interaction assays, and TGF-β reporter assays","pmids":["28647409"],"confidence":"High","gaps":["Effect of these residues on STUbL/neddylation activities not tested","No co-structure with E2 bound"]},{"year":2021,"claim":"Pinned down the physiologically relevant degradative substrates (SKI/SKIL) by systematic proteomics and genetic rescue, and demonstrated context-specific roles in iTreg differentiation, antiviral immunity, and hematopoiesis.","evidence":"Quantitative diGly ubiquitylome in CRISPR cells, conditional KO with SKI/SnoN double-KO rescue, cGAS neddylation with KO mice, and zebrafish Rnf111 KO with rescue","pmids":["34740826","34473197","33720974","39363867"],"confidence":"High","gaps":["Tissue-specific substrate selection mechanism not fully resolved","Relationship between cGAS neddylation and TGF-β functions unexplored"]},{"year":2023,"claim":"Established that E2 choice and non-RING elements dictate ubiquitin chain architecture and substrate fate, and identified UBXN7 as a regulator of RNF111 stability.","evidence":"NMR with E2 panel, linkage-specific ubiquitination assays, and Co-IP/binding with UBXN7","pmids":["36831384","37024974","36142504"],"confidence":"Medium","gaps":["In-cell relevance of each chain type to specific substrates not fully mapped","Single-lab structural assignments"]},{"year":2025,"claim":"Provided structural and mechanistic detail of priming-dependent processive chain assembly across multiple E2s, refining the model of how substrate affinity governs modification extent.","evidence":"Structural analysis of RING-E2 complexes and reconstituted in vitro ubiquitylation assays with an E2 panel","pmids":["40451499"],"confidence":"High","gaps":["In vivo validation of priming requirement lacking","How priming integrates with SUMO/NEDD8 targeting unclear"]},{"year":null,"claim":"It remains unresolved how RNF111 selects among its ubiquitin-, SUMO-, and NEDD8-directed activities in a given cellular context and how partner proteins coordinate this switch.","evidence":"No single study in the corpus integrates the STUbL, neddylation, and Smad-degradation modes mechanistically","pmids":[],"confidence":"Low","gaps":["No unified model of modifier-type and substrate selection","Schwann cell Merlin-SKOR2 complex and Nrf2 stabilization rest on single low-confidence reports"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016874","term_label":"ligase activity","supporting_discovery_ids":[2,5,14,16,22]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[2,4,5,6,18,24]},{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[16,22]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[4,6]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,1,9]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[9]},{"term_id":"GO:0005654","term_label":"nucleoplasm","supporting_discovery_ids":[15,17]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[2,4,5,6]},{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[14,16]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[22,23,31]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0,1,30]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[2,5,24]}],"complexes":["Merlin(NF2)-Arkadia-SKOR2 complex"],"partners":["SKIL/SNON","SKI","SMAD7","SMAD6","AXIN1","FHL2","UBXN7","RB1CC1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q6ZNA4","full_name":"E3 ubiquitin-protein ligase Arkadia","aliases":["RING finger protein 111","hRNF111","RING-type E3 ubiquitin transferase Arkadia"],"length_aa":994,"mass_kda":108.9,"function":"E3 ubiquitin-protein ligase (PubMed:26656854). Required for mesoderm patterning during embryonic development (By similarity). Acts as an enhancer of the transcriptional responses of the SMAD2/SMAD3 effectors, which are activated downstream of BMP (PubMed:14657019, PubMed:16601693). Acts by mediating ubiquitination and degradation of SMAD inhibitors such as SMAD7, inducing their proteasomal degradation and thereby enhancing the transcriptional activity of TGF-beta and BMP (PubMed:14657019, PubMed:16601693). In addition to enhance transcription of SMAD2/SMAD3 effectors, also regulates their turnover by mediating their ubiquitination and subsequent degradation, coupling their activation with degradation, thereby ensuring that only effectors 'in use' are degraded (By similarity). Activates SMAD3/SMAD4-dependent transcription by triggering signal-induced degradation of SNON isoform of SKIL (PubMed:17591695). Associates with UBE2D2 as an E2 enzyme (PubMed:22411132). Specifically binds polysumoylated chains via SUMO interaction motifs (SIMs) and mediates ubiquitination of sumoylated substrates (PubMed:23751493). Catalyzes 'Lys-63'-linked ubiquitination of sumoylated XPC in response to UV irradiation, promoting nucleotide excision repair (PubMed:23751493). Mediates ubiquitination and degradation of sumoylated PML (By similarity). The regulation of the BMP-SMAD signaling is however independent of sumoylation and is not dependent of SUMO interaction motifs (SIMs) (By similarity)","subcellular_location":"Nucleus; Cytoplasm; Nucleus, PML body","url":"https://www.uniprot.org/uniprotkb/Q6ZNA4/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/RNF111","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":[{"gene":"CSNK2B","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/RNF111","total_profiled":1310},"omim":[{"mim_id":"621303","title":"ARKADIA/RNF111 N-TERMINAL-LIKE PKA SIGNALING REGULATOR 2N; ARK2N","url":"https://www.omim.org/entry/621303"},{"mim_id":"605840","title":"RING FINGER PROTEIN 111; RNF111","url":"https://www.omim.org/entry/605840"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/RNF111"},"hgnc":{"alias_symbol":["ARK","Arkadia","FLJ38008","DKFZP761D081"],"prev_symbol":[]},"alphafold":{"accession":"Q6ZNA4","domains":[{"cath_id":"3.30.40.10","chopping":"894-914_940-994","consensus_level":"medium","plddt":89.3509,"start":894,"end":994}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6ZNA4","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q6ZNA4-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q6ZNA4-F1-predicted_aligned_error_v6.png","plddt_mean":46.34},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RNF111","jax_strain_url":"https://www.jax.org/strain/search?query=RNF111"},"sequence":{"accession":"Q6ZNA4","fasta_url":"https://rest.uniprot.org/uniprotkb/Q6ZNA4.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q6ZNA4/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6ZNA4"}},"corpus_meta":[{"pmid":"14657019","id":"PMC_14657019","title":"Arkadia 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genetic interaction with Nodal revealed by chimera analysis showing Arkadia functions in extraembryonic tissues to induce the node and is required for HNF3beta expression in the anterior primitive streak.\",\n      \"method\": \"Gene-trap mutagenesis, chimeric embryo analysis, genetic epistasis with Nodal\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis and chimeric embryo analysis replicated across two independent back-to-back Nature papers (PMID:11298452, PMID:11298453)\",\n      \"pmids\": [\"11298452\", \"11298453\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Arkadia specifically potentiates the mesendoderm-inducing activity of a subset of TGF-beta/Nodal family members in Xenopus; it functions as a nuclear protein that enhances Nodal signaling when co-expressed and can act in cells adjacent to those producing the Nodal signal.\",\n      \"method\": \"Xenopus overexpression, morpholino knockdown, genetic interaction with extracellular Nodal blockade\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — functional epistasis with Nodal, replicated alongside companion mouse paper, multiple assays\",\n      \"pmids\": [\"11298453\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Arkadia physically interacts with inhibitory Smad7, induces its poly-ubiquitination and proteasome-dependent degradation via its RING domain, thereby amplifying both TGF-beta and BMP signaling; unlike Smurf1, Arkadia does not associate with TGF-beta receptors.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, siRNA knockdown, Western blot for Smad7 accumulation\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — Co-IP plus ubiquitination assay plus RNAi phenotype, independently replicated in multiple subsequent studies\",\n      \"pmids\": [\"14657019\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Axin acts as a scaffold protein that forms a multimeric complex with Smad7 and Arkadia, facilitating Arkadia-mediated Smad7 ubiquitination and degradation to activate TGF-beta signaling; Axin also induces nuclear export of Smad7.\",\n      \"method\": \"Co-immunoprecipitation, siRNA knockdown, pulse-chase experiment, nuclear export assay\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP, pulse-chase, and siRNA rescue, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"16601693\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Arkadia is absolutely required for TGF-beta-induced Smad3/Smad4-dependent transcription; it activates this transcription by inducing signal-dependent degradation of transcriptional repressor SnoN. Arkadia interacts with SnoN and ubiquitinates it constitutively, but efficient degradation requires a complex of Arkadia, SnoN, and phosphorylated Smad2 or Smad3.\",\n      \"method\": \"siRNA library screen, dominant-negative mutant overexpression, luciferase reporter assay, Co-IP, ubiquitination assay, rescue experiment in SEG-1 cancer cells\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (reporter, Co-IP, ubiquitination, rescue), replicated by companion paper same year\",\n      \"pmids\": [\"17591695\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Arkadia induces ubiquitin-dependent degradation of SnoN and c-Ski (in addition to Smad7) via its C-terminal RING domain; Arkadia interacts with SnoN and c-Ski both in their free forms and when bound to Smad proteins.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, Western blot for protein levels, RING domain mutant analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — Co-IP plus ubiquitination assay with RING mutant control, replicated by companion paper same year\",\n      \"pmids\": [\"17510063\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Arkadia interacts with and ubiquitinates phospho-Smad2/3 (P-Smad2/3), inducing their degradation; this is mediated by the same domains required for enhancing their transcriptional activity. Loss of Arkadia causes nuclear accumulation of hypoactive P-Smad2/3. Arkadia thus couples degradation of P-Smad2/3 with activation of target gene transcription, providing a signaling termination mechanism.\",\n      \"method\": \"Knockout embryonic stem cells, chimeric embryo analysis, Co-IP, ubiquitination assay, gene expression analysis, rescue by reintroduction of Arkadia\",\n      \"journal\": \"PLoS biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo genetic knockout, Co-IP, ubiquitination, transcriptional readout, multiple orthogonal approaches\",\n      \"pmids\": [\"17341133\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Arkadia RING-H2 domain was recombinantly expressed and shown by NMR to be a stably folded protein with a RING-H2 type architecture, suitable for structural studies of its E3 ubiquitin ligase activity.\",\n      \"method\": \"Recombinant protein expression, NMR spectroscopy\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — NMR structure determination of isolated domain, single lab, preliminary characterization only\",\n      \"pmids\": [\"19032943\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Arkadia regulates myoblast differentiation by inducing degradation of Ski and Ski-bound phospho-Smad2/3 complexes; it binds Smad2/3 via Ski to induce ubiquitination of the Smad2/3 complex, affecting myoblast differentiation through both Smad-dependent and Smad-independent pathways.\",\n      \"method\": \"siRNA knockdown, overexpression, Co-IP, ubiquitination assay, C2C12 differentiation assay\",\n      \"journal\": \"Bone\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP, ubiquitination, and differentiation phenotype in single lab with multiple methods\",\n      \"pmids\": [\"18950738\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Arkadia interacts with the mu2 subunit of the clathrin-adaptor AP2 complex through its N-terminal YALL motif binding to the YXXΦ-binding domain of mu2; Arkadia ubiquitylates mu2 at Lys130 and modifies EGFR endocytosis induced by EGF. Arkadia localizes to both nucleus and cytosol.\",\n      \"method\": \"Yeast-two-hybrid screening, Co-IP, ubiquitination assay, endocytosis assay, subcellular fractionation\",\n      \"journal\": \"Journal of biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast-two-hybrid, Co-IP, ubiquitination assay, and functional endocytosis readout in single lab\",\n      \"pmids\": [\"20965945\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"The Arkadia RING-H2 domain requires two Zn(II) ions coordinated through a Cys3-His2-Cys3 motif; mutation of Cys955 to Arg (C955R) dramatically reduces zinc-binding affinity and disrupts global structural integrity of the RING domain.\",\n      \"method\": \"Site-directed mutagenesis, recombinant protein expression, atomic absorption spectroscopy, NMR\",\n      \"journal\": \"Bioinorganic chemistry and applications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — mutagenesis plus atomic absorption and NMR, single lab, single study\",\n      \"pmids\": [\"20689703\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"NMR solution structure of Arkadia's RING-H2 domain revealed a ββbα fold with cross-brace Zn(II) ligation; chemical shift perturbation showed that the RING-H2 domain interacts with the E2 enzyme UbcH5b.\",\n      \"method\": \"NMR spectroscopy, chemical shift perturbation mapping\",\n      \"journal\": \"Proteins\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — NMR structure determination with E2 interaction mapping, single lab but Tier 1 method\",\n      \"pmids\": [\"22411132\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"FHL2 binds Arkadia and increases its half-life by inhibiting K27-linked polyubiquitination of Arkadia, thereby stabilizing Arkadia and enhancing TGF-beta signaling. Arkadia undergoes K63- and K27-linked polyubiquitination, partly via autocatalysis; K27-linked ubiquitination promotes its proteolytic turnover.\",\n      \"method\": \"Co-IP, ubiquitination assay with linkage-specific mutants, cycloheximide chase, siRNA knockdown, luciferase reporter assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP, ubiquitination linkage analysis, and half-life measurements in single lab with multiple orthogonal methods\",\n      \"pmids\": [\"23212909\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"RB1CC1/FIP200 is a substrate-selective cofactor of Arkadia that enhances Arkadia E3 ligase activity specifically toward c-Ski but not SnoN, through direct physical interaction with c-Ski as a scaffold.\",\n      \"method\": \"Co-IP, ubiquitination assay, siRNA knockdown, overexpression, luciferase reporter assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP, ubiquitination, reporter, and KD phenotype, single lab with multiple methods\",\n      \"pmids\": [\"21795712\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"RNF111/Arkadia is a SUMO-targeted ubiquitin ligase (STUbL) that uses three adjacent SUMO-interacting motifs (SIMs) for specific recognition of poly-SUMO2/3 chains. It uses Ubc13-Mms2 as cognate E2 to promote non-proteolytic K63-linked ubiquitylation of SUMOylated target proteins. RNF111 promotes K63-linked ubiquitylation of SUMOylated XPC and facilitates nucleotide excision repair by regulating XPC recruitment to UV-damaged DNA.\",\n      \"method\": \"SUMO-interaction assay, ubiquitination assay with linkage-specific antibodies, Co-IP, NER recruitment assay, UV damage response, siRNA knockdown\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — in vitro ubiquitination assay with chain linkage determination, SIM-deletion mutants, XPC functional recruitment assay; multiple orthogonal methods in single rigorous study\",\n      \"pmids\": [\"23751493\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Arkadia contains three successive SUMO-interacting motifs (SIMs) that mediate interaction with poly-SUMO2; the third SIM (VVDL) is most relevant. Arkadia functions as a STUbL by ubiquitinating SUMO chains. Arkadia's SIMs are required for its interaction with polysumoylated PML and for arsenic-induced degradation of polysumoylated PML. Arkadia homodimerizes but does not heterodimerize with RNF4.\",\n      \"method\": \"Co-IP, ubiquitination assay, siRNA knockdown, immunofluorescence for PML bodies, dimerization assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (Co-IP, ubiquitination, knockdown, localization), confirmed STUbL activity on PML substrate\",\n      \"pmids\": [\"23530056\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"RNF111 promotes DNA damage-induced NEDD8 (neddylation) accumulation at DNA damage sites; this requires the E2 enzyme UBE2M. RNF111 catalyzes polyneddylation of histone H4 at N-terminal lysine residues in response to DNA damage. NEDD8 chains are recognized by the MIU domain of RNF168, and RNF111-dependent neddylation promotes RNF168 foci formation and downstream recruitment of 53BP1 and BRCA1.\",\n      \"method\": \"siRNA/shRNA knockdown, ubiquitin-like modification assay, mass spectrometry, Co-IP, immunofluorescence for damage foci\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo neddylation assay, MS identification of H4 neddylation sites, genetic knockdown with functional foci readout, multiple orthogonal methods\",\n      \"pmids\": [\"23394999\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Arkadia/RNF111 colocalizes with CBX4/Pc2 in Polycomb bodies; both the SUMO-interacting motifs (SIMs) and a unique M domain (absent in paralogs ARKL1/ARKL2 and RNF4) redundantly promote this colocalization and activation of a TGF-beta transcriptional reporter. Transcriptome profiling showed Arkadia can both promote and inhibit gene expression depending on epigenetic context.\",\n      \"method\": \"Immunofluorescence colocalization, domain-deletion mutant analysis, TGF-beta reporter assay, RNA-seq transcriptome profiling\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct colocalization, mutant analysis, and transcriptome profiling; single lab\",\n      \"pmids\": [\"24912682\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Arkadia ubiquitylates and induces proteasome-dependent degradation of Smad6 (a BMP-specific inhibitory Smad), as shown by activity of wild-type but not C937A RING-dead mutant Arkadia; elevated Smad6 protein was detected in Arkadia KO MEFs. Arkadia knockdown reduces BMP-induced osteoblast differentiation markers.\",\n      \"method\": \"Ubiquitination assay with RING mutant, Western blot in KO MEFs, siRNA knockdown, BMP differentiation reporter assay\",\n      \"journal\": \"Journal of biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ubiquitination assay with RING mutant control plus KO cell validation, single lab\",\n      \"pmids\": [\"25762727\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Arkadia physically interacts with ESRP2 (epithelial splicing regulatory protein 2), induces its polyubiquitination, and modulates its splicing function; Arkadia and ESRP2 cooperate to suppress ccRCC tumor growth.\",\n      \"method\": \"Co-IP, ubiquitination assay, tumor growth assay in vivo, RNA-seq splicing analysis\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP, ubiquitination, and in vivo tumor suppression, single lab\",\n      \"pmids\": [\"26522722\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"NMR analysis of Arkadia RING-H2 W972 mutants showed that W972R (but not W972A) disrupts interaction with E2 enzyme UbcH5b, with structural changes in the C-terminal alpha-helix and increased distance between Zn(II) ions; W972R abolishes TGF-beta signaling enhancement while W972A retains full activity.\",\n      \"method\": \"NMR spectroscopy, E2 interaction assay, TGF-beta luciferase reporter assay, site-directed mutagenesis\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — NMR structure plus mutagenesis plus functional reporter assay; single lab but multiple orthogonal Tier 1–2 methods\",\n      \"pmids\": [\"28647409\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Arkadia/RNF111 ubiquitinates Nrf2 via K48-linked chains, paradoxically stabilizing Nrf2 (rather than degrading it) and promoting Nrf2-dependent gene transcription. This sumoylation-dependent stabilization occurs in PML-nuclear body-enriched fractions.\",\n      \"method\": \"Co-immunoprecipitation, K48-linkage-specific ubiquitin antibody, cycloheximide chase, ARE-luciferase reporter assay\",\n      \"journal\": \"Cellular physiology and biochemistry\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single Co-IP method, unusual mechanistic claim (K48 stabilization) not independently replicated\",\n      \"pmids\": [\"29597191\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"RNF111 (Rnf111) is the Nedd8 E3 ligase for cGAS; it interacts with and polyneddylates cGAS at Lys231 and Lys421 (identified by mass spectrometry), which promotes cGAS dimerization and enhances its DNA-binding ability, leading to proper cGAS-STING pathway activation and antiviral innate immunity.\",\n      \"method\": \"Co-IP, mass spectrometry identification of neddylation sites, neddylation assay, cGAS dimerization assay, DNA-binding assay, Rnf111 knockout mice susceptibility to HSV-1\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — Co-IP, MS site identification, functional neddylation assay, dimerization assay, in vivo KO phenotype; multiple orthogonal methods\",\n      \"pmids\": [\"33720974\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Arkadia-mediated degradation of SKI and SnoN is required for iTreg (but not Th17) cell differentiation; genetic ablation of SKI and SnoN rescues Arkadia-deficient iTreg differentiation both in vitro and in vivo, establishing SKI/SnoN as the functionally relevant Arkadia substrates in this context.\",\n      \"method\": \"Conditional knockout of Arkadia in CD4+ T cells, double-knockout of SKI and SnoN, in vitro differentiation assay, in vivo intestinal lamina propria analysis\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional KO with specific cellular phenotype plus genetic rescue by substrate ablation; in vitro and in vivo validation\",\n      \"pmids\": [\"34473197\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Quantitative ubiquitylome proteomics in CRISPR-engineered U2OS cells (expressing RING-truncated RNF111) demonstrated that SKI and SKIL/SnoN are the only substrates ubiquitylated and degraded by RNF111 upon TGF-beta signaling; lysine 343 in the SAND domain of SKIL is identified as the RNF111 ubiquitylation target site.\",\n      \"method\": \"CRISPR engineering, label-free quantitative proteomics, diGly immunoprecipitation, ubiquitin pan-nanobody immunoprecipitation, mass spectrometry\",\n      \"journal\": \"Molecular & cellular proteomics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — systematic quantitative ubiquitylome by two orthogonal enrichment methods in CRISPR-engineered cells, single lab but highly rigorous\",\n      \"pmids\": [\"34740826\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Non-RING elements of Arkadia (including conserved NRGA and TIER motifs) are required for E2 (UbcH5B) interaction and for efficient auto-ubiquitination; Arkadia isoform-1 does not interact with free ubiquitin, unlike isoform-2 and its homolog Ark2C.\",\n      \"method\": \"NMR interaction studies, UBCH5B C85S oxyester hydrolysis assay, auto-ubiquitination assay, mutant analysis\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — NMR plus in vitro ubiquitination assay with mutants, single lab\",\n      \"pmids\": [\"36142504\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"UBXN7 directly interacts with the RING domain of RNF111 through its UAS thioredoxin-like domain, inhibiting RNF111 auto-ubiquitination by preventing E2 conjugating enzyme binding; UBXN7 overexpression stabilizes RNF111, while UBXN7 depletion reduces RNF111 protein levels. This modulates TGF-beta-induced SKIL/SnoN degradation.\",\n      \"method\": \"Co-IP, direct binding assay, ubiquitination assay, siRNA knockdown, overexpression, interactome mass spectrometry\",\n      \"journal\": \"BMC biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct binding, Co-IP, ubiquitination assay with functional substrate degradation readout; single lab, multiple methods\",\n      \"pmids\": [\"37024974\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Arkadia RING domain interacts with E2 enzymes UbcH5B, UbcH13, and UbcH7 through a similar interaction surface; cooperation with different E2s results in distinct ubiquitin chain linkages (monoubiquitylation, K63, K48, or K11), determining substrate fate.\",\n      \"method\": \"NMR chemical shift perturbation, ubiquitination assay with linkage-specific E2 enzymes\",\n      \"journal\": \"Cancers\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — NMR interaction mapping plus in vitro ubiquitination chain-type assays; single lab\",\n      \"pmids\": [\"36831384\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Arkadia and the related E3 Ark2C promote substrate ubiquitylation with multiple E2 enzymes (including Ubc13 and Ube2K) that require a priming ubiquitin before subsequent chain assembly; substrates that bind Arkadia more tightly are more extensively modified, and prior substrate ubiquitylation enhances subsequent ubiquitylation.\",\n      \"method\": \"Crystal/structural analysis of RING-E2 complexes, binding assays, in vitro substrate ubiquitylation assays, activity assays with E2 panel\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — structural characterization of RING-E2 complexes plus in vitro reconstituted substrate ubiquitylation assays with mechanistic detail; single lab but multiple rigorous Tier 1 methods\",\n      \"pmids\": [\"40451499\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Arkadia interacts with Merlin (NF2) and the SKI family co-repressor SKOR2 in human Schwann cells (validated by Co-IP/MS in hiPSC-derived SCs); this Merlin-Arkadia-SKOR2 complex is required for proper Schwann cell proliferation control.\",\n      \"method\": \"Co-immunoprecipitation followed by mass spectrometry, hiPSC-derived Schwann cell model, NF2 mutant vs wild-type comparison\",\n      \"journal\": \"Stem cell research & therapy\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP/MS experiment in single lab, interaction validated but mechanism not fully characterized\",\n      \"pmids\": [\"40188079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Rnf111 deficiency in zebrafish reduces phosphorylation of Smad2/3 in hematopoietic stem and progenitor cells (HSPC), impairing definitive hematopoiesis; restoration of TGF-beta/Smad2 signaling with IDE2 rescues HSPC development. Gcsfr/NO signaling is identified as a downstream target pathway of Smad2/3 in Rnf111-mediated HSPC development.\",\n      \"method\": \"CRISPR/Cas9 Rnf111 knockout zebrafish, phospho-Smad2/3 Western blot, pharmacological rescue with IDE2, genetic epistasis with Gcsfr/NO pathway\",\n      \"journal\": \"Haematologica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CRISPR KO with defined cellular phenotype plus pharmacological rescue and pathway epistasis; single lab in zebrafish model\",\n      \"pmids\": [\"39363867\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Arkadia (E3 ubiquitin ligase for SKI) overexpression reduces SKI protein levels in human Treg cells, enhancing Treg cell stability and immunosuppressive function under TGF-beta inhibition and inflammatory conditions.\",\n      \"method\": \"Lentiviral overexpression of ARKADIA in human Treg subsets, flow cytometry, Western blotting, transcriptomics, co-culture suppression assay\",\n      \"journal\": \"Frontiers in immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — gain-of-function with defined molecular (SKI degradation) and functional (Treg stability) readout; single lab\",\n      \"pmids\": [\"40995370\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RNF111/Arkadia is a nuclear RING-H2 E3 ubiquitin ligase and SUMO-targeted ubiquitin ligase (STUbL) that amplifies TGF-β/Nodal/BMP signaling by targeting the transcriptional repressors SnoN/SKIL, c-SKI, and inhibitory Smads (Smad6, Smad7) for polyubiquitination and proteasomal degradation via its RING domain; it also promotes non-proteolytic K63-linked ubiquitylation of SUMOylated substrates (including XPC in NER), polyneddylation of cGAS to enhance antiviral immunity, and histone H4 neddylation in the DNA damage response, with its ubiquitin chain-type specificity tuned by the choice of E2 partner enzyme (UbcH5B for K48, Ubc13 for K63) and its activity regulated by scaffold proteins (Axin, RB1CC1), stabilizing partners (FHL2, UBXN7), and autocatalytic ubiquitination.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RNF111/Arkadia is a nuclear RING-H2 E3 ubiquitin ligase that amplifies TGF-β/Nodal/BMP signaling and was first defined genetically as an essential inducer of the embryonic node acting in extraembryonic tissue downstream of Nodal [#0, #1]. Its core function is to drive signal-dependent polyubiquitination and proteasomal degradation of negative regulators of the pathway: the inhibitory Smads (Smad7 in TGF-β/BMP signaling, the BMP-specific Smad6) and the transcriptional repressors SnoN/SKIL and c-SKI, thereby permitting Smad3/Smad4-dependent transcription [#2, #4, #5, #18]. Substrate engagement frequently occurs in complex with phosphorylated Smad2/3, and RNF111 also ubiquitinates phospho-Smad2/3 itself, coupling transcriptional activation to signal termination [#4, #6]; systematic ubiquitylome profiling confirms SKI and SKIL/SnoN as its principal degradative substrates upon TGF-β stimulation, with SKIL targeted at Lys343 [#24]. The RING-H2 domain coordinates two Zn(II) ions in a cross-brace ββα fold and engages E2 enzymes via a defined surface, and the identity of the cooperating E2 dictates ubiquitin chain linkage and hence substrate fate—UbcH5B for proteolytic chains, Ubc13–Mms2 for non-proteolytic K63 chains [#11, #20, #27]. Beyond TGF-β, RNF111 acts as a SUMO-targeted ubiquitin ligase: three tandem SUMO-interacting motifs recognize poly-SUMO2/3 chains, enabling K63-linked ubiquitylation of SUMOylated substrates including XPC during nucleotide excision repair and degradation of polysumoylated PML [#14, #15]. It additionally functions as a NEDD8 ligase, catalyzing DNA-damage-induced histone H4 polyneddylation that promotes RNF168, 53BP1 and BRCA1 recruitment, and polyneddylating cGAS at Lys231/Lys421 to enhance cGAS dimerization and antiviral cGAS-STING signaling [#16, #22]. RNF111 activity is tuned by scaffold and stabilizing partners—Axin and RB1CC1/FIP200 promote substrate selection, while FHL2 and UBXN7 stabilize RNF111 by limiting its auto-ubiquitination [#3, #13, #12, #26]. Physiologically these activities control iTreg/Treg differentiation through SKI/SnoN degradation and definitive hematopoiesis via Smad2/3 [#23, #31, #30].\"\n,\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Established Arkadia/RNF111 as a genetically required positive regulator of Nodal/TGF-β signaling in vivo, defining its biological role before any biochemical mechanism was known.\",\n      \"evidence\": \"Gene-trap mutagenesis and chimeric embryo analysis with Nodal epistasis in mouse, and overexpression/morpholino assays in Xenopus\",\n      \"pmids\": [\"11298452\", \"11298453\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular mechanism of signal potentiation not yet defined\", \"Did not identify substrates or enzymatic activity\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Defined the molecular mechanism of pathway amplification: Arkadia is a RING E3 ligase that degrades inhibitory Smad7, distinguishing it from receptor-associated Smurf1.\",\n      \"evidence\": \"Co-IP, ubiquitination assay, and siRNA knockdown with Smad7 accumulation readout\",\n      \"pmids\": [\"14657019\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"E2 partner not identified\", \"Chain linkage type not resolved\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Expanded the substrate repertoire to the transcriptional repressors SnoN and c-SKI and to phospho-Smad2/3, showing degradation of repressors activates transcription while phospho-Smad turnover terminates the signal.\",\n      \"evidence\": \"siRNA screen, Co-IP, ubiquitination assays, reporter assays in cancer cells, and knockout ES cell/chimera analysis\",\n      \"pmids\": [\"17591695\", \"17510063\", \"17341133\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How efficient SnoN degradation requires phospho-Smad complex mechanistically unclear\", \"Quantitative substrate hierarchy not established\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Determined the structural basis of catalysis: the RING-H2 domain folds independently and binds the E2 UbcH5b, linking structure to E3 activity.\",\n      \"evidence\": \"Recombinant expression, NMR spectroscopy, and chemical shift perturbation E2 mapping\",\n      \"pmids\": [\"19032943\", \"22411132\", \"20689703\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full-length structure with substrate not solved\", \"Chain-type determinants not yet mapped\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Revealed that Arkadia activity is itself regulated by partners and autoubiquitination, identifying Axin, RB1CC1/FIP200 and FHL2 as substrate-selective or stabilizing cofactors.\",\n      \"evidence\": \"Co-IP, linkage-specific ubiquitination assays, pulse-chase/cycloheximide, and reporter assays\",\n      \"pmids\": [\"16601693\", \"21795712\", \"23212909\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab characterization for each cofactor\", \"Quantitative contribution to physiological substrate selection unclear\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Reclassified RNF111 as a SUMO-targeted ubiquitin ligase and a NEDD8 ligase, dramatically broadening its function beyond TGF-β to DNA repair, PML turnover, and damage-response neddylation.\",\n      \"evidence\": \"SIM-deletion mutants, linkage-specific ubiquitination with Ubc13-Mms2, NER recruitment assays, MS identification of H4 neddylation, and damage foci readouts\",\n      \"pmids\": [\"23751493\", \"23530056\", \"23394999\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How RNF111 switches between ubiquitin and NEDD8 ligase modes unclear\", \"Full SUMOylated substrate range not defined\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Defined precise RING residues controlling E2 engagement, separating structural integrity from functional signaling output.\",\n      \"evidence\": \"NMR of W972 mutants, E2 interaction assays, and TGF-β reporter assays\",\n      \"pmids\": [\"28647409\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Effect of these residues on STUbL/neddylation activities not tested\", \"No co-structure with E2 bound\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Pinned down the physiologically relevant degradative substrates (SKI/SKIL) by systematic proteomics and genetic rescue, and demonstrated context-specific roles in iTreg differentiation, antiviral immunity, and hematopoiesis.\",\n      \"evidence\": \"Quantitative diGly ubiquitylome in CRISPR cells, conditional KO with SKI/SnoN double-KO rescue, cGAS neddylation with KO mice, and zebrafish Rnf111 KO with rescue\",\n      \"pmids\": [\"34740826\", \"34473197\", \"33720974\", \"39363867\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Tissue-specific substrate selection mechanism not fully resolved\", \"Relationship between cGAS neddylation and TGF-β functions unexplored\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Established that E2 choice and non-RING elements dictate ubiquitin chain architecture and substrate fate, and identified UBXN7 as a regulator of RNF111 stability.\",\n      \"evidence\": \"NMR with E2 panel, linkage-specific ubiquitination assays, and Co-IP/binding with UBXN7\",\n      \"pmids\": [\"36831384\", \"37024974\", \"36142504\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In-cell relevance of each chain type to specific substrates not fully mapped\", \"Single-lab structural assignments\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Provided structural and mechanistic detail of priming-dependent processive chain assembly across multiple E2s, refining the model of how substrate affinity governs modification extent.\",\n      \"evidence\": \"Structural analysis of RING-E2 complexes and reconstituted in vitro ubiquitylation assays with an E2 panel\",\n      \"pmids\": [\"40451499\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo validation of priming requirement lacking\", \"How priming integrates with SUMO/NEDD8 targeting unclear\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unresolved how RNF111 selects among its ubiquitin-, SUMO-, and NEDD8-directed activities in a given cellular context and how partner proteins coordinate this switch.\",\n      \"evidence\": \"No single study in the corpus integrates the STUbL, neddylation, and Smad-degradation modes mechanistically\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No unified model of modifier-type and substrate selection\", \"Schwann cell Merlin-SKOR2 complex and Nrf2 stabilization rest on single low-confidence reports\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016874\", \"supporting_discovery_ids\": [2, 5, 14, 16, 22]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [2, 4, 5, 6, 18, 24]},\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [16, 22]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [4, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 1, 9]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [9]},\n      {\"term_id\": \"GO:0005654\", \"supporting_discovery_ids\": [15, 17]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2, 4, 5, 6]},\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [14, 16]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [22, 23, 31]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0, 1, 30]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [2, 5, 24]}\n    ],\n    \"complexes\": [\"Merlin(NF2)-Arkadia-SKOR2 complex\"],\n    \"partners\": [\"SKIL/SnoN\", \"SKI\", \"SMAD7\", \"SMAD6\", \"AXIN1\", \"FHL2\", \"UBXN7\", \"RB1CC1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}