{"gene":"SAE1","run_date":"2026-06-10T07:46:29","timeline":{"discoveries":[{"year":1999,"finding":"SAE1 (AOS1) forms a heterodimeric SUMO-activating enzyme complex (E1) with UBA2; UBA2 forms a beta-mercaptoethanol-sensitive (thioester) conjugate with SUMO/sentrin family members in the presence of AOS1, but not with ubiquitin or NEDD8, establishing the heterodimer as the dedicated SUMO E1 activating enzyme.","method":"Molecular cloning, co-expression, biochemical conjugation assay with beta-mercaptoethanol sensitivity test","journal":"FEBS letters","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct biochemical reconstitution of thioester formation, replicated across multiple subsequent studies","pmids":["10217437"],"is_preprint":false},{"year":2001,"finding":"SAE1/SAE2 (E1) and Ubc9 (E2) catalyze the formation of polymeric SUMO-2 and SUMO-3 chains on protein substrates in vitro because SUMO-2 and SUMO-3 contain internal consensus SUMOylation motifs (ψKXE); SUMO-1 lacks this motif and cannot form chains under the same conditions. SUMO-2 chains were also detected in vivo.","method":"In vitro SUMOylation reconstitution assay with purified SAE1/SAE2 and Ubc9; in vivo detection by immunoblot","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with purified components plus in vivo validation; widely replicated foundational finding","pmids":["11451954"],"is_preprint":false},{"year":2012,"finding":"Myc directly binds canonical E-Box sequences near the SAE1 transcription start site and transcriptionally activates SAE1 expression, placing SAE1 as a direct transcriptional target of Myc.","method":"Chromatin immunoprecipitation (ChIP), reporter/transcriptional activation assays","journal":"American journal of cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP demonstrating direct binding plus reporter assay in single lab","pmids":["22679563"],"is_preprint":false},{"year":2019,"finding":"SAE1 promotes AKT SUMOylation (SUMO1 modification) and increases AKT Ser473 phosphorylation in glioma cells; SAE1 knockdown suppresses AKT SUMOylation and phosphorylation, induces G2 cell cycle arrest and apoptosis, and inhibits xenograft tumor growth.","method":"Anti-SUMO1 immunoprecipitation/enrichment, Western blot, siRNA knockdown, flow cytometry, nude mouse xenograft model","journal":"Cell communication and signaling : CCS","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP/enrichment of SUMOylated AKT with functional in vitro and in vivo follow-up in single lab","pmids":["31345225"],"is_preprint":false},{"year":2019,"finding":"SAE1 is required for SUMOylation of XRCC4; reduced SAE1 (via miR-129-3p targeting the SAE1 3'UTR) impairs SUMO modification of XRCC4, disrupts its nuclear localization, and increases DNA damage in gastric cancer cells.","method":"3'UTR reporter assay, Western blot for SUMO-XRCC4, immunofluorescence for XRCC4 localization, DNA damage assay","journal":"International journal of clinical and experimental pathology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional relationship between SAE1 and XRCC4 SUMOylation/localization established by knockdown and direct detection, single lab","pmids":["31933971"],"is_preprint":false},{"year":2020,"finding":"SAE1/UBA2-mediated SUMOylation of pyruvate kinase M2 (PKM2) promotes PKM2 phosphorylation and nuclear translocation while decreasing PK enzymatic activity; this drives glycolysis and the aggressive phenotype of rheumatoid fibroblast-like synoviocytes, with downstream STAT5A signaling mediating these effects.","method":"siRNA knockdown of SAE1/UBA2, co-immunoprecipitation, Western blot, nuclear fractionation, PK activity assay, in vivo arthritis mouse models","journal":"JCI insight","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (co-IP, activity assay, fractionation, in vivo model) in single lab","pmids":["32938830"],"is_preprint":false},{"year":2020,"finding":"SAE1 acts as the E1-activating enzyme for SUMOylation of ZFHX3 at Lys-2806; SAE1 (along with UBC9/E2 and PIAS2/E3) is required for ZFHX3 SUMOylation, which stabilizes ZFHX3 by competing with ubiquitination/proteasomal degradation and promotes ZFHX3-mediated cell proliferation.","method":"Molecular analyses including co-IP, SUMOylation assays, mutagenesis at Lys-2806, proteasome inhibitor treatment, xenograft tumor assay","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal approaches (mutagenesis, co-IP, functional rescue) in single lab study","pmids":["32249212"],"is_preprint":false},{"year":2021,"finding":"SAE1 (Aos1) subunit of the SUMO E1 complex is required for SUMO2/3 (but not SUMO1) modification of RhoGDI1 in vascular smooth muscle cells; Aos1/Uba2 suppression promotes RhoGDI1 ubiquitination and degradation, and inhibits Ang II-induced cell proliferation.","method":"siRNA knockdown of Aos1/Uba2, co-immunoprecipitation for SUMOylation and ubiquitination, EdU cell proliferation assay","journal":"Cardiovascular drugs and therapy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP and functional assays, single lab","pmids":["33891248"],"is_preprint":false},{"year":2023,"finding":"SAE1 promotes hepatocellular carcinoma progression through SUMOylation of mTOR; SAE1 knockdown inhibits proliferation, migration, and invasion of HCC cells in vitro and in vivo, with the effect dependent on mTOR SUMOylation.","method":"siRNA knockdown, xenograft in vivo, co-immunoprecipitation for mTOR SUMOylation, Western blot","journal":"Laboratory investigation; a journal of technical methods and pathology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP evidence for mTOR SUMOylation with functional in vivo corroboration, single lab","pmids":["36748193"],"is_preprint":false},{"year":2025,"finding":"SAE1 directly SUMOylates p27, upregulating total p27 protein and driving liquid-liquid phase separation (LLPS)-mediated nuclear export of p27, thereby relieving p27-induced growth arrest in multiple myeloma cells. A crystal structure of the SAE1 monomer was also determined, and colchicine was identified as binding SAE1.","method":"Proteome microarray to identify SAE1 targets, Western blot for p27 SUMOylation and protein level, LLPS assay, nuclear/cytoplasmic fractionation, crystal structure determination, xenograft (PDX) model, controlled clinical trial","journal":"Acta pharmaceutica Sinica. B","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure of SAE1, in vitro SUMOylation of p27, LLPS assay, multiple in vivo models, and clinical validation in single comprehensive study","pmids":["40486843"],"is_preprint":false},{"year":2025,"finding":"SAE1 SUMOylates N-cadherin, stabilizing it and promoting epithelial-mesenchymal transition (EMT) in non-small cell lung cancer cells, thereby driving lung cancer invasion and metastasis.","method":"Protein expression profiling after SAE1 knockdown, Western blot for N-cadherin SUMOylation and stability, in vitro and in vivo invasion/metastasis assays","journal":"Science China. Life sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct detection of N-cadherin SUMOylation with functional consequence, single lab","pmids":["40643801"],"is_preprint":false},{"year":2025,"finding":"ZNF184 (with abnormally reduced methylation in NSCLC) transcriptionally activates SAE1 expression; elevated SAE1 SUMOylates p53 and suppresses its nuclear retention, inhibiting p53-dependent tumor suppression and promoting immune evasion and cell cycle entry in NSCLC.","method":"Lentiviral shRNA knockdown of SAE1, Western blot for p53 SUMOylation and nuclear export, rescue experiments with p53 silencing and SAE1 overexpression, in vitro and in vivo models","journal":"Respiratory research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis (rescue experiments), direct detection of p53 SUMOylation by SAE1, single lab","pmids":["41024125"],"is_preprint":false},{"year":2025,"finding":"SAE1 interacts with transcription factor YY1 (yin-yang 1), enhances YY1 stability and activity, leading to Wnt3a transcription and Wnt pathway activation, thereby promoting HCC cell migration and invasion.","method":"Co-immunoprecipitation, immunofluorescence, AlphaFold3 structural prediction, in situ and vein tail injection xenograft models, HCC organoids, IHC of HCC tissue samples","journal":"Journal of advanced research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP with functional in vivo and organoid validation, single lab; AlphaFold3 provides structural model but not experimental structure","pmids":["40513659"],"is_preprint":false},{"year":2025,"finding":"Quantitative FRET (qFRET) and SPR measurements revealed the dissociation constant (Kd) and binding kinetics of the SAE1 (Aos1)–UBA2 heterodimer; formation of a thioester bond between SUMO1 and UBA2 increases the FRET signal, indicating that the E1 heterodimer becomes more stable upon SUMO1 charging with ATP.","method":"qFRET assay, surface plasmon resonance (SPR), real-time kinetics measurement","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — direct biophysical measurement of Kd and conformational dynamics by two orthogonal methods; preprint, single lab, not yet peer-reviewed","pmids":["bio_10.1101_2025.07.30.667747"],"is_preprint":true},{"year":2013,"finding":"A mouse Aos1-Uba2 fusion protein (mAU) expressed in baculovirus-insect cells retains SUMO-E1 catalytic activity in multiple in vitro SUMOylation assays, confirming that both subunits together constitute the active SUMO E1 enzyme.","method":"Recombinant protein expression and purification, in vitro SUMOylation assay","journal":"Bioscience, biotechnology, and biochemistry","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — in vitro reconstitution confirming enzymatic activity, single lab, single publication","pmids":["23832333"],"is_preprint":false}],"current_model":"SAE1 (AOS1) is the regulatory subunit of the heterodimeric SUMO E1 activating enzyme (SAE1/UBA2), which catalyzes the first step of the SUMOylation cascade by adenylating SUMO and forming a thioester intermediate on UBA2; the charged E1 then transfers SUMO to the E2 enzyme UBC9. SAE1/UBA2 can conjugate SUMO-1, -2, and -3 to substrates, and uniquely catalyzes polymerization of SUMO-2 and SUMO-3 chains. SAE1 is transcriptionally activated by MYC. Mechanistically, SAE1-driven SUMOylation of specific substrates including AKT, mTOR, PKM2, N-cadherin, p27, p53, XRCC4, RhoGDI1, ZFHX3, and YY1 links SUMOylation to regulation of cell cycle progression, oncogenic signaling, glycolysis, EMT, nuclear export, and protein stability in various cellular contexts."},"narrative":{"mechanistic_narrative":"SAE1 (AOS1) is the regulatory subunit of the heterodimeric SUMO E1 activating enzyme, which initiates the SUMOylation cascade [PMID:10217437]. Together with UBA2 it forms a thioester-linked conjugate selectively with SUMO/sentrin family members but not ubiquitin or NEDD8, establishing the heterodimer as the dedicated SUMO E1 [PMID:10217437]; both subunits together constitute the catalytically active enzyme [PMID:23832333]. With the E2 Ubc9, the SAE1/UBA2 enzyme catalyzes formation of polymeric SUMO-2 and SUMO-3 chains via their internal consensus motifs, whereas SUMO-1 lacks this motif and cannot form chains under the same conditions [PMID:11451954]. Charging of UBA2 with SUMO1 in the presence of ATP stabilizes the heterodimer [PMID:bio_10.1101_2025.07.30.667747]. Through this activating activity, SAE1 supplies the SUMOylation of a broad set of substrates with downstream effects on cell proliferation, oncogenic signaling, glycolysis, EMT, DNA repair, and protein stability: it promotes AKT SUMOylation and Ser473 phosphorylation with cell-cycle and survival consequences [PMID:31345225], mTOR SUMOylation driving hepatocellular carcinoma progression [PMID:36748193], PKM2 SUMOylation that lowers pyruvate kinase activity and promotes nuclear translocation and glycolysis [PMID:32938830], N-cadherin SUMOylation/stabilization driving EMT and metastasis [PMID:40643801], and SUMO-2/3 modification of RhoGDI1 and SUMOylation of ZFHX3 that protect both from ubiquitin-mediated degradation [PMID:32249212, PMID:33891248]. SAE1-mediated SUMOylation also governs nuclear localization, including XRCC4 nuclear retention required for genome integrity [PMID:31933971], LLPS-driven nuclear export of p27 [PMID:40486843], and suppression of p53 nuclear retention [PMID:41024125]. SAE1 is a direct transcriptional target of Myc, which binds E-Box sequences near its transcription start site [PMID:22679563]. A crystal structure of the SAE1 monomer has been determined, and colchicine binds SAE1 [PMID:40486843].","teleology":[{"year":1999,"claim":"Established the molecular identity of the SUMO activating enzyme by showing SAE1 partners with UBA2 to form a SUMO-specific E1, answering which enzyme initiates SUMO conjugation.","evidence":"Molecular cloning, co-expression, and beta-mercaptoethanol-sensitive thioester conjugation assay","pmids":["10217437"],"confidence":"High","gaps":["Did not resolve the catalytic contribution of each subunit","Substrate repertoire and downstream signaling not addressed"]},{"year":2001,"claim":"Defined a unique catalytic capability of the SAE1/UBA2 E1, showing it supports SUMO-2/3 chain polymerization but not SUMO-1 chains, explaining isoform-specific SUMO topology.","evidence":"In vitro reconstitution with purified SAE1/SAE2 and Ubc9 plus in vivo immunoblot","pmids":["11451954"],"confidence":"High","gaps":["Physiological consequences of chain polymerization not addressed","In vivo substrates of poly-SUMO chains not identified"]},{"year":2012,"claim":"Linked SAE1 expression to oncogenic transcriptional control by identifying it as a direct Myc target, placing SUMOylation capacity downstream of Myc.","evidence":"ChIP and reporter/transcriptional activation assays","pmids":["22679563"],"confidence":"Medium","gaps":["Single-lab ChIP/reporter evidence","Functional consequence of Myc-driven SAE1 upregulation not directly tested here"]},{"year":2013,"claim":"Confirmed that both subunits jointly constitute the active enzyme using a recombinant Aos1-Uba2 fusion that retains SUMO E1 activity.","evidence":"Recombinant fusion protein expression and in vitro SUMOylation assay","pmids":["23832333"],"confidence":"Medium","gaps":["Single in vitro study","Did not address subunit-specific catalytic roles"]},{"year":2019,"claim":"Connected SAE1-dependent SUMOylation to oncogenic signaling and cell-cycle control by showing it drives AKT SUMOylation and phosphorylation, with knockdown causing G2 arrest, apoptosis, and reduced tumor growth.","evidence":"Anti-SUMO1 enrichment, siRNA knockdown, flow cytometry, nude mouse xenograft in glioma","pmids":["31345225"],"confidence":"Medium","gaps":["Single-lab co-IP/enrichment evidence","SUMO acceptor site on AKT not mapped","Mechanistic link between AKT SUMOylation and phosphorylation not resolved"]},{"year":2019,"claim":"Linked SAE1 to genome integrity by showing it is required for XRCC4 SUMOylation and nuclear localization, with loss increasing DNA damage.","evidence":"3'UTR reporter, Western blot for SUMO-XRCC4, immunofluorescence, DNA damage assay in gastric cancer cells","pmids":["31933971"],"confidence":"Medium","gaps":["Single-lab study","XRCC4 SUMO site not mapped","Direct effect on NHEJ repair efficiency not quantified"]},{"year":2020,"claim":"Established SAE1-dependent SUMOylation as a regulator of metabolism and substrate stability, modifying PKM2 to shift glycolysis and SUMOylating ZFHX3 at Lys-2806 to block its proteasomal degradation.","evidence":"siRNA knockdown, co-IP, nuclear fractionation, PK activity assay, Lys-2806 mutagenesis, proteasome inhibition, xenograft models","pmids":["32938830","32249212"],"confidence":"Medium","gaps":["Single-lab studies for each substrate","E3 specificity beyond PIAS2 for ZFHX3 not generalized"]},{"year":2021,"claim":"Demonstrated isoform-selective protection of a substrate, showing SAE1 is required for SUMO-2/3 (not SUMO-1) modification of RhoGDI1 that prevents its ubiquitination and degradation.","evidence":"siRNA knockdown of Aos1/Uba2, reciprocal co-IP, EdU proliferation assay in vascular smooth muscle cells","pmids":["33891248"],"confidence":"Medium","gaps":["Single-lab study","RhoGDI1 SUMO acceptor sites not mapped"]},{"year":2023,"claim":"Extended the substrate range to mTOR, showing SAE1-dependent mTOR SUMOylation drives hepatocellular carcinoma progression.","evidence":"siRNA knockdown, co-IP for mTOR SUMOylation, xenograft in vivo","pmids":["36748193"],"confidence":"Medium","gaps":["Single-lab co-IP evidence","mTOR SUMO site and effect on kinase activity not defined"]},{"year":2025,"claim":"Resolved high-resolution structural and mechanistic features of SAE1 while expanding its substrate logic into phase separation, transcriptional control, and tumor suppressor regulation, and biophysically characterized E1 heterodimer assembly dynamics.","evidence":"Crystal structure of SAE1 monomer, proteome microarray, LLPS assays, fractionation for p27/p53; co-IP and AlphaFold3 for YY1; protein profiling for N-cadherin; qFRET and SPR for SAE1-UBA2 binding (one preprint)","pmids":["40486843","40643801","41024125","40513659","bio_10.1101_2025.07.30.667747"],"confidence":"Medium","gaps":["Most substrate findings from single labs","Heterodimer kinetics from an unreviewed preprint","Generality of LLPS mechanism across substrates not established"]},{"year":null,"claim":"How SAE1 substrate selectivity is determined in vivo and how distinct SUMOylation outcomes (degradation protection, localization change, LLPS) are routed for different substrates remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unifying model for substrate-specific E3 pairing","Limited structural data on the charged SAE1/UBA2-substrate interface","Most disease links are correlative oncology studies without germline causation"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016874","term_label":"ligase activity","supporting_discovery_ids":[0,1,14]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,6,9]},{"term_id":"GO:0140657","term_label":"ATP-dependent activity","supporting_discovery_ids":[13]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[4,5,9,11]}],"pathway":[{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0,1]}],"complexes":["SUMO E1 activating enzyme (SAE1/UBA2)"],"partners":["UBA2","UBC9","PIAS2","YY1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9UBE0","full_name":"SUMO-activating enzyme subunit 1","aliases":["Ubiquitin-like 1-activating enzyme E1A"],"length_aa":346,"mass_kda":38.5,"function":"The heterodimer acts as an E1 ligase for SUMO1, SUMO2, SUMO3, and probably SUMO4. It mediates ATP-dependent activation of SUMO proteins followed by formation of a thioester bond between a SUMO protein and a conserved active site cysteine residue on UBA2/SAE2","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/Q9UBE0/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/SAE1","classification":"Common 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SAE1","url":"https://www.omim.org/entry/613294"},{"mim_id":"602362","title":"GTPase-ACTIVATING PROTEIN, RAN, 1; RANGAP1","url":"https://www.omim.org/entry/602362"},{"mim_id":"601661","title":"UBIQUITIN-CONJUGATING ENZYME E2 I; UBE2I","url":"https://www.omim.org/entry/601661"},{"mim_id":"190080","title":"MYC PROTOONCOGENE, bHLH TRANSCRIPTION FACTOR; MYC","url":"https://www.omim.org/entry/190080"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Nucleoplasm","reliability":"Enhanced"},{"location":"Cytosol","reliability":"Enhanced"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/SAE1"},"hgnc":{"alias_symbol":["AOS1","FLJ3091","Sua1"],"prev_symbol":[]},"alphafold":{"accession":"Q9UBE0","domains":[{"cath_id":"3.40.50.720","chopping":"14-170_297-340","consensus_level":"medium","plddt":96.6676,"start":14,"end":340},{"cath_id":"-","chopping":"215-292","consensus_level":"medium","plddt":95.7887,"start":215,"end":292}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UBE0","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UBE0-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UBE0-F1-predicted_aligned_error_v6.png","plddt_mean":91.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SAE1","jax_strain_url":"https://www.jax.org/strain/search?query=SAE1"},"sequence":{"accession":"Q9UBE0","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9UBE0.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9UBE0/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UBE0"}},"corpus_meta":[{"pmid":"11451954","id":"PMC_11451954","title":"Polymeric chains of SUMO-2 and SUMO-3 are conjugated to protein substrates by SAE1/SAE2 and Ubc9.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11451954","citation_count":697,"is_preprint":false},{"pmid":"10217437","id":"PMC_10217437","title":"Molecular cloning and characterization of human AOS1 and UBA2, components of the sentrin-activating enzyme complex.","date":"1999","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/10217437","citation_count":139,"is_preprint":false},{"pmid":"31345225","id":"PMC_31345225","title":"SAE1 promotes human glioma progression through activating AKT SUMOylation-mediated signaling pathways.","date":"2019","source":"Cell communication and signaling : CCS","url":"https://pubmed.ncbi.nlm.nih.gov/31345225","citation_count":54,"is_preprint":false},{"pmid":"32938830","id":"PMC_32938830","title":"Increased SUMO-activating enzyme SAE1/UBA2 promotes glycolysis and pathogenic behavior of rheumatoid fibroblast-like synoviocytes.","date":"2020","source":"JCI insight","url":"https://pubmed.ncbi.nlm.nih.gov/32938830","citation_count":51,"is_preprint":false},{"pmid":"9215889","id":"PMC_9215889","title":"Mutations in Saccharomyces cerevisiae that block meiotic prophase chromosome metabolism and confer cell cycle arrest at pachytene identify two new meiosis-specific genes SAE1 and SAE3.","date":"1997","source":"Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/9215889","citation_count":48,"is_preprint":false},{"pmid":"33477333","id":"PMC_33477333","title":"SUMO-Activating Enzyme Subunit 1 (SAE1) Is a Promising Diagnostic Cancer Metabolism Biomarker of Hepatocellular Carcinoma.","date":"2021","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/33477333","citation_count":36,"is_preprint":false},{"pmid":"32249212","id":"PMC_32249212","title":"SUMOylation of the transcription factor ZFHX3 at Lys-2806 requires SAE1, UBC9, and PIAS2 and enhances its stability and function in cell proliferation.","date":"2020","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/32249212","citation_count":31,"is_preprint":false},{"pmid":"22679563","id":"PMC_22679563","title":"SUMO-activating SAE1 transcription is positively regulated by Myc.","date":"2012","source":"American journal of cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/22679563","citation_count":27,"is_preprint":false},{"pmid":"31933971","id":"PMC_31933971","title":"miR-129-3p inhibits NHEJ pathway by targeting SAE1 and represses gastric cancer progression.","date":"2019","source":"International journal of clinical and experimental pathology","url":"https://pubmed.ncbi.nlm.nih.gov/31933971","citation_count":25,"is_preprint":false},{"pmid":"38351014","id":"PMC_38351014","title":"ROS-mediated up-regulation of SAE1 by Helicobacter pylori promotes human gastric tumor genesis and progression.","date":"2024","source":"Journal of translational 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system.","date":"2013","source":"Bioscience, biotechnology, and biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23832333","citation_count":5,"is_preprint":false},{"pmid":"40486843","id":"PMC_40486843","title":"SAE1 promotes tumor cell malignancy via SUMOylation and liquid-liquid phase separation facilitated nuclear export of p27.","date":"2025","source":"Acta pharmaceutica Sinica. B","url":"https://pubmed.ncbi.nlm.nih.gov/40486843","citation_count":4,"is_preprint":false},{"pmid":"37368909","id":"PMC_37368909","title":"The extensin protein SAE1 plays a role in leaf senescence and is targeted by the ubiquitin ligase SINA4 in tomato.","date":"2023","source":"Journal of experimental botany","url":"https://pubmed.ncbi.nlm.nih.gov/37368909","citation_count":4,"is_preprint":false},{"pmid":"33891248","id":"PMC_33891248","title":"Ang II Promotes SUMO2/3 Modification of RhoGDI1 Through Aos1 and Uba2 Subunits, and then Regulates RhoGDI1 Stability and Cell Proliferation.","date":"2021","source":"Cardiovascular drugs and therapy","url":"https://pubmed.ncbi.nlm.nih.gov/33891248","citation_count":4,"is_preprint":false},{"pmid":"30041050","id":"PMC_30041050","title":"Molecular cloning and characterization of Aos1 and Uba2 from the orange-spotted grouper (Epinephelus coioides).","date":"2018","source":"Fish & shellfish immunology","url":"https://pubmed.ncbi.nlm.nih.gov/30041050","citation_count":4,"is_preprint":false},{"pmid":"25842831","id":"PMC_25842831","title":"[Lentivirus-mediated siRNA targeting sae1 induces cell cycle arrest and apop- tosis in colon cancer cell RKO].","date":"2014","source":"Molekuliarnaia biologiia","url":"https://pubmed.ncbi.nlm.nih.gov/25842831","citation_count":4,"is_preprint":false},{"pmid":"37830399","id":"PMC_37830399","title":"A case of anti-SAE1/2 antibody-positive dermatomyositis with extensive panniculitis: A possible cutaneous manifestation of treatment resistance.","date":"2023","source":"The Journal of dermatology","url":"https://pubmed.ncbi.nlm.nih.gov/37830399","citation_count":4,"is_preprint":false},{"pmid":"39742381","id":"PMC_39742381","title":"Upregulated SAE1 Drives Tumorigenesis and Is Associated with Poor Clinical Outcomes in Breast Cancer.","date":"2024","source":"The breast journal","url":"https://pubmed.ncbi.nlm.nih.gov/39742381","citation_count":2,"is_preprint":false},{"pmid":"40513659","id":"PMC_40513659","title":"SAE1 emerges as a pan-cancer driver and key regulator of HCC metastasis.","date":"2025","source":"Journal of advanced research","url":"https://pubmed.ncbi.nlm.nih.gov/40513659","citation_count":1,"is_preprint":false},{"pmid":"37131050","id":"PMC_37131050","title":"Expression of Mn-sod, PAL1, aos1 and HPL genes in soybean plants overexpressing the NmDef02 defensin.","date":"2023","source":"Transgenic research","url":"https://pubmed.ncbi.nlm.nih.gov/37131050","citation_count":1,"is_preprint":false},{"pmid":"24637489","id":"PMC_24637489","title":"Construction of a mouse Aos1-Uba2 chimeric SUMO-E1 enzyme, mAU, and its expression in baculovirus-insect cells.","date":"2014","source":"Bioengineered","url":"https://pubmed.ncbi.nlm.nih.gov/24637489","citation_count":1,"is_preprint":false},{"pmid":"39575249","id":"PMC_39575249","title":"Clinical features of anti-SAE1 antibody-positive myositis and interstitial lung disease: a multicenter, retrospective study in Taiwan.","date":"2024","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/39575249","citation_count":1,"is_preprint":false},{"pmid":"40643801","id":"PMC_40643801","title":"SUMO-activating enzyme subunit 1 (SAE1) promotes non-small cell lung cancer metastasis by promoting the epithelial-mesenchymal transition through the SUMOylation of N-cadherin.","date":"2025","source":"Science China. 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SUMO-2 chains were also detected in vivo.\",\n      \"method\": \"In vitro SUMOylation reconstitution assay with purified SAE1/SAE2 and Ubc9; in vivo detection by immunoblot\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with purified components plus in vivo validation; widely replicated foundational finding\",\n      \"pmids\": [\"11451954\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Myc directly binds canonical E-Box sequences near the SAE1 transcription start site and transcriptionally activates SAE1 expression, placing SAE1 as a direct transcriptional target of Myc.\",\n      \"method\": \"Chromatin immunoprecipitation (ChIP), reporter/transcriptional activation assays\",\n      \"journal\": \"American journal of cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP demonstrating direct binding plus reporter assay in single lab\",\n      \"pmids\": [\"22679563\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"SAE1 promotes AKT SUMOylation (SUMO1 modification) and increases AKT Ser473 phosphorylation in glioma cells; SAE1 knockdown suppresses AKT SUMOylation and phosphorylation, induces G2 cell cycle arrest and apoptosis, and inhibits xenograft tumor growth.\",\n      \"method\": \"Anti-SUMO1 immunoprecipitation/enrichment, Western blot, siRNA knockdown, flow cytometry, nude mouse xenograft model\",\n      \"journal\": \"Cell communication and signaling : CCS\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP/enrichment of SUMOylated AKT with functional in vitro and in vivo follow-up in single lab\",\n      \"pmids\": [\"31345225\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"SAE1 is required for SUMOylation of XRCC4; reduced SAE1 (via miR-129-3p targeting the SAE1 3'UTR) impairs SUMO modification of XRCC4, disrupts its nuclear localization, and increases DNA damage in gastric cancer cells.\",\n      \"method\": \"3'UTR reporter assay, Western blot for SUMO-XRCC4, immunofluorescence for XRCC4 localization, DNA damage assay\",\n      \"journal\": \"International journal of clinical and experimental pathology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional relationship between SAE1 and XRCC4 SUMOylation/localization established by knockdown and direct detection, single lab\",\n      \"pmids\": [\"31933971\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"SAE1/UBA2-mediated SUMOylation of pyruvate kinase M2 (PKM2) promotes PKM2 phosphorylation and nuclear translocation while decreasing PK enzymatic activity; this drives glycolysis and the aggressive phenotype of rheumatoid fibroblast-like synoviocytes, with downstream STAT5A signaling mediating these effects.\",\n      \"method\": \"siRNA knockdown of SAE1/UBA2, co-immunoprecipitation, Western blot, nuclear fractionation, PK activity assay, in vivo arthritis mouse models\",\n      \"journal\": \"JCI insight\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (co-IP, activity assay, fractionation, in vivo model) in single lab\",\n      \"pmids\": [\"32938830\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"SAE1 acts as the E1-activating enzyme for SUMOylation of ZFHX3 at Lys-2806; SAE1 (along with UBC9/E2 and PIAS2/E3) is required for ZFHX3 SUMOylation, which stabilizes ZFHX3 by competing with ubiquitination/proteasomal degradation and promotes ZFHX3-mediated cell proliferation.\",\n      \"method\": \"Molecular analyses including co-IP, SUMOylation assays, mutagenesis at Lys-2806, proteasome inhibitor treatment, xenograft tumor assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal approaches (mutagenesis, co-IP, functional rescue) in single lab study\",\n      \"pmids\": [\"32249212\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"SAE1 (Aos1) subunit of the SUMO E1 complex is required for SUMO2/3 (but not SUMO1) modification of RhoGDI1 in vascular smooth muscle cells; Aos1/Uba2 suppression promotes RhoGDI1 ubiquitination and degradation, and inhibits Ang II-induced cell proliferation.\",\n      \"method\": \"siRNA knockdown of Aos1/Uba2, co-immunoprecipitation for SUMOylation and ubiquitination, EdU cell proliferation assay\",\n      \"journal\": \"Cardiovascular drugs and therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP and functional assays, single lab\",\n      \"pmids\": [\"33891248\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"SAE1 promotes hepatocellular carcinoma progression through SUMOylation of mTOR; SAE1 knockdown inhibits proliferation, migration, and invasion of HCC cells in vitro and in vivo, with the effect dependent on mTOR SUMOylation.\",\n      \"method\": \"siRNA knockdown, xenograft in vivo, co-immunoprecipitation for mTOR SUMOylation, Western blot\",\n      \"journal\": \"Laboratory investigation; a journal of technical methods and pathology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP evidence for mTOR SUMOylation with functional in vivo corroboration, single lab\",\n      \"pmids\": [\"36748193\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SAE1 directly SUMOylates p27, upregulating total p27 protein and driving liquid-liquid phase separation (LLPS)-mediated nuclear export of p27, thereby relieving p27-induced growth arrest in multiple myeloma cells. A crystal structure of the SAE1 monomer was also determined, and colchicine was identified as binding SAE1.\",\n      \"method\": \"Proteome microarray to identify SAE1 targets, Western blot for p27 SUMOylation and protein level, LLPS assay, nuclear/cytoplasmic fractionation, crystal structure determination, xenograft (PDX) model, controlled clinical trial\",\n      \"journal\": \"Acta pharmaceutica Sinica. B\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure of SAE1, in vitro SUMOylation of p27, LLPS assay, multiple in vivo models, and clinical validation in single comprehensive study\",\n      \"pmids\": [\"40486843\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SAE1 SUMOylates N-cadherin, stabilizing it and promoting epithelial-mesenchymal transition (EMT) in non-small cell lung cancer cells, thereby driving lung cancer invasion and metastasis.\",\n      \"method\": \"Protein expression profiling after SAE1 knockdown, Western blot for N-cadherin SUMOylation and stability, in vitro and in vivo invasion/metastasis assays\",\n      \"journal\": \"Science China. Life sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct detection of N-cadherin SUMOylation with functional consequence, single lab\",\n      \"pmids\": [\"40643801\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ZNF184 (with abnormally reduced methylation in NSCLC) transcriptionally activates SAE1 expression; elevated SAE1 SUMOylates p53 and suppresses its nuclear retention, inhibiting p53-dependent tumor suppression and promoting immune evasion and cell cycle entry in NSCLC.\",\n      \"method\": \"Lentiviral shRNA knockdown of SAE1, Western blot for p53 SUMOylation and nuclear export, rescue experiments with p53 silencing and SAE1 overexpression, in vitro and in vivo models\",\n      \"journal\": \"Respiratory research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis (rescue experiments), direct detection of p53 SUMOylation by SAE1, single lab\",\n      \"pmids\": [\"41024125\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SAE1 interacts with transcription factor YY1 (yin-yang 1), enhances YY1 stability and activity, leading to Wnt3a transcription and Wnt pathway activation, thereby promoting HCC cell migration and invasion.\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence, AlphaFold3 structural prediction, in situ and vein tail injection xenograft models, HCC organoids, IHC of HCC tissue samples\",\n      \"journal\": \"Journal of advanced research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP with functional in vivo and organoid validation, single lab; AlphaFold3 provides structural model but not experimental structure\",\n      \"pmids\": [\"40513659\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Quantitative FRET (qFRET) and SPR measurements revealed the dissociation constant (Kd) and binding kinetics of the SAE1 (Aos1)–UBA2 heterodimer; formation of a thioester bond between SUMO1 and UBA2 increases the FRET signal, indicating that the E1 heterodimer becomes more stable upon SUMO1 charging with ATP.\",\n      \"method\": \"qFRET assay, surface plasmon resonance (SPR), real-time kinetics measurement\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — direct biophysical measurement of Kd and conformational dynamics by two orthogonal methods; preprint, single lab, not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2025.07.30.667747\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"A mouse Aos1-Uba2 fusion protein (mAU) expressed in baculovirus-insect cells retains SUMO-E1 catalytic activity in multiple in vitro SUMOylation assays, confirming that both subunits together constitute the active SUMO E1 enzyme.\",\n      \"method\": \"Recombinant protein expression and purification, in vitro SUMOylation assay\",\n      \"journal\": \"Bioscience, biotechnology, and biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — in vitro reconstitution confirming enzymatic activity, single lab, single publication\",\n      \"pmids\": [\"23832333\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SAE1 (AOS1) is the regulatory subunit of the heterodimeric SUMO E1 activating enzyme (SAE1/UBA2), which catalyzes the first step of the SUMOylation cascade by adenylating SUMO and forming a thioester intermediate on UBA2; the charged E1 then transfers SUMO to the E2 enzyme UBC9. SAE1/UBA2 can conjugate SUMO-1, -2, and -3 to substrates, and uniquely catalyzes polymerization of SUMO-2 and SUMO-3 chains. SAE1 is transcriptionally activated by MYC. Mechanistically, SAE1-driven SUMOylation of specific substrates including AKT, mTOR, PKM2, N-cadherin, p27, p53, XRCC4, RhoGDI1, ZFHX3, and YY1 links SUMOylation to regulation of cell cycle progression, oncogenic signaling, glycolysis, EMT, nuclear export, and protein stability in various cellular contexts.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SAE1 (AOS1) is the regulatory subunit of the heterodimeric SUMO E1 activating enzyme, which initiates the SUMOylation cascade [#0]. Together with UBA2 it forms a thioester-linked conjugate selectively with SUMO/sentrin family members but not ubiquitin or NEDD8, establishing the heterodimer as the dedicated SUMO E1 [#0]; both subunits together constitute the catalytically active enzyme [#14]. With the E2 Ubc9, the SAE1/UBA2 enzyme catalyzes formation of polymeric SUMO-2 and SUMO-3 chains via their internal consensus motifs, whereas SUMO-1 lacks this motif and cannot form chains under the same conditions [#1]. Charging of UBA2 with SUMO1 in the presence of ATP stabilizes the heterodimer [#13]. Through this activating activity, SAE1 supplies the SUMOylation of a broad set of substrates with downstream effects on cell proliferation, oncogenic signaling, glycolysis, EMT, DNA repair, and protein stability: it promotes AKT SUMOylation and Ser473 phosphorylation with cell-cycle and survival consequences [#3], mTOR SUMOylation driving hepatocellular carcinoma progression [#8], PKM2 SUMOylation that lowers pyruvate kinase activity and promotes nuclear translocation and glycolysis [#5], N-cadherin SUMOylation/stabilization driving EMT and metastasis [#10], and SUMO-2/3 modification of RhoGDI1 and SUMOylation of ZFHX3 that protect both from ubiquitin-mediated degradation [#6, #7]. SAE1-mediated SUMOylation also governs nuclear localization, including XRCC4 nuclear retention required for genome integrity [#4], LLPS-driven nuclear export of p27 [#9], and suppression of p53 nuclear retention [#11]. SAE1 is a direct transcriptional target of Myc, which binds E-Box sequences near its transcription start site [#2]. A crystal structure of the SAE1 monomer has been determined, and colchicine binds SAE1 [#9].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Established the molecular identity of the SUMO activating enzyme by showing SAE1 partners with UBA2 to form a SUMO-specific E1, answering which enzyme initiates SUMO conjugation.\",\n      \"evidence\": \"Molecular cloning, co-expression, and beta-mercaptoethanol-sensitive thioester conjugation assay\",\n      \"pmids\": [\"10217437\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve the catalytic contribution of each subunit\", \"Substrate repertoire and downstream signaling not addressed\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Defined a unique catalytic capability of the SAE1/UBA2 E1, showing it supports SUMO-2/3 chain polymerization but not SUMO-1 chains, explaining isoform-specific SUMO topology.\",\n      \"evidence\": \"In vitro reconstitution with purified SAE1/SAE2 and Ubc9 plus in vivo immunoblot\",\n      \"pmids\": [\"11451954\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological consequences of chain polymerization not addressed\", \"In vivo substrates of poly-SUMO chains not identified\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Linked SAE1 expression to oncogenic transcriptional control by identifying it as a direct Myc target, placing SUMOylation capacity downstream of Myc.\",\n      \"evidence\": \"ChIP and reporter/transcriptional activation assays\",\n      \"pmids\": [\"22679563\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab ChIP/reporter evidence\", \"Functional consequence of Myc-driven SAE1 upregulation not directly tested here\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Confirmed that both subunits jointly constitute the active enzyme using a recombinant Aos1-Uba2 fusion that retains SUMO E1 activity.\",\n      \"evidence\": \"Recombinant fusion protein expression and in vitro SUMOylation assay\",\n      \"pmids\": [\"23832333\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single in vitro study\", \"Did not address subunit-specific catalytic roles\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Connected SAE1-dependent SUMOylation to oncogenic signaling and cell-cycle control by showing it drives AKT SUMOylation and phosphorylation, with knockdown causing G2 arrest, apoptosis, and reduced tumor growth.\",\n      \"evidence\": \"Anti-SUMO1 enrichment, siRNA knockdown, flow cytometry, nude mouse xenograft in glioma\",\n      \"pmids\": [\"31345225\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab co-IP/enrichment evidence\", \"SUMO acceptor site on AKT not mapped\", \"Mechanistic link between AKT SUMOylation and phosphorylation not resolved\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Linked SAE1 to genome integrity by showing it is required for XRCC4 SUMOylation and nuclear localization, with loss increasing DNA damage.\",\n      \"evidence\": \"3'UTR reporter, Western blot for SUMO-XRCC4, immunofluorescence, DNA damage assay in gastric cancer cells\",\n      \"pmids\": [\"31933971\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab study\", \"XRCC4 SUMO site not mapped\", \"Direct effect on NHEJ repair efficiency not quantified\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Established SAE1-dependent SUMOylation as a regulator of metabolism and substrate stability, modifying PKM2 to shift glycolysis and SUMOylating ZFHX3 at Lys-2806 to block its proteasomal degradation.\",\n      \"evidence\": \"siRNA knockdown, co-IP, nuclear fractionation, PK activity assay, Lys-2806 mutagenesis, proteasome inhibition, xenograft models\",\n      \"pmids\": [\"32938830\", \"32249212\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab studies for each substrate\", \"E3 specificity beyond PIAS2 for ZFHX3 not generalized\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Demonstrated isoform-selective protection of a substrate, showing SAE1 is required for SUMO-2/3 (not SUMO-1) modification of RhoGDI1 that prevents its ubiquitination and degradation.\",\n      \"evidence\": \"siRNA knockdown of Aos1/Uba2, reciprocal co-IP, EdU proliferation assay in vascular smooth muscle cells\",\n      \"pmids\": [\"33891248\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab study\", \"RhoGDI1 SUMO acceptor sites not mapped\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended the substrate range to mTOR, showing SAE1-dependent mTOR SUMOylation drives hepatocellular carcinoma progression.\",\n      \"evidence\": \"siRNA knockdown, co-IP for mTOR SUMOylation, xenograft in vivo\",\n      \"pmids\": [\"36748193\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab co-IP evidence\", \"mTOR SUMO site and effect on kinase activity not defined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Resolved high-resolution structural and mechanistic features of SAE1 while expanding its substrate logic into phase separation, transcriptional control, and tumor suppressor regulation, and biophysically characterized E1 heterodimer assembly dynamics.\",\n      \"evidence\": \"Crystal structure of SAE1 monomer, proteome microarray, LLPS assays, fractionation for p27/p53; co-IP and AlphaFold3 for YY1; protein profiling for N-cadherin; qFRET and SPR for SAE1-UBA2 binding (one preprint)\",\n      \"pmids\": [\"40486843\", \"40643801\", \"41024125\", \"40513659\", \"bio_10.1101_2025.07.30.667747\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Most substrate findings from single labs\", \"Heterodimer kinetics from an unreviewed preprint\", \"Generality of LLPS mechanism across substrates not established\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How SAE1 substrate selectivity is determined in vivo and how distinct SUMOylation outcomes (degradation protection, localization change, LLPS) are routed for different substrates remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unifying model for substrate-specific E3 pairing\", \"Limited structural data on the charged SAE1/UBA2-substrate interface\", \"Most disease links are correlative oncology studies without germline causation\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016874\", \"supporting_discovery_ids\": [0, 1, 14]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 6, 9]},\n      {\"term_id\": \"GO:0140657\", \"supporting_discovery_ids\": [13]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [4, 5, 9, 11]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"complexes\": [\"SUMO E1 activating enzyme (SAE1/UBA2)\"],\n    \"partners\": [\"UBA2\", \"UBC9\", \"PIAS2\", \"YY1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}