{"gene":"ASCC3","run_date":"2026-06-09T22:02:44","timeline":{"discoveries":[{"year":2011,"finding":"ASCC3, the largest subunit of the Activating Signal Cointegrator Complex (ASCC), encodes a 3'-5' DNA helicase whose unwinding activity generates single-stranded DNA upon which ALKBH3 preferentially functions for dealkylation of N-alkylated nucleotides. ASCC3 and ALKBH3 form a complex (purified by co-immunoprecipitation/mass spectrometry), and loss of ASCC3 leads to increased 3-methylcytosine levels, pH2A.X and 53BP1 foci formation, and reduced cell proliferation.","method":"Complex purification (affinity purification/mass spectrometry), in vitro helicase assay, siRNA knockdown with alkylation damage resistance and proliferation readouts, immunofluorescence for DNA damage markers","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — biochemical complex purification, direct helicase activity assay, and functional loss-of-function experiments with multiple orthogonal readouts in a single study","pmids":["22055184"],"is_preprint":false},{"year":2020,"finding":"ASCC2 and ASCC3 directly interact via a structurally defined interface: the ASCC3 fragment contains a central helical domain and terminal extended arms that clasp the compact ASCC2 unit. This interface is evolutionarily conserved, and somatic cancer mutations at this interface reduce ASCC2-ASCC3 binding affinity. Functional dissection revealed ASCC3 has similar organization and regulation to the spliceosomal RNA helicase Brr2.","method":"X-ray crystallography / structural analysis of interacting regions, quantitative binding affinity measurements, mutagenesis of cancer-associated variants","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure with functional validation by mutagenesis and quantitative binding assays; multiple orthogonal methods in single rigorous study","pmids":["33139697"],"is_preprint":false},{"year":2021,"finding":"ASCC3 promotes removal of MMS-induced 1-methyladenosine (m1A) and 3-methylcytosine (m3C) from mRNA. ASCC3-deficient cells show delayed clearance of these aberrant mRNA methylbases and impaired formation of MMS-induced P-bodies. ASCC3 binds mRNA after alkylation damage (increased mRNA association detected by SILAC-MS), consistent with a role in disassembly of collided ribosomes to allow ALKBH3-mediated demethylation.","method":"Quantitative mass spectrometry of mRNA methylbases, SILAC-MS for mRNA-binding proteome, siRNA knockdown of ASCC3 with mRNA modification and P-body formation readouts","journal":"Journal of translational medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — two orthogonal methods (MS quantification of modifications + SILAC proteomics), single lab","pmids":["34217309"],"is_preprint":false},{"year":2025,"finding":"ASCC3 is recruited to stalled replication forks by its binding partner ASCC2. ASCC2 recruitment to stalled forks requires its ubiquitin-binding activity and polyubiquitylation of PCNA at K164 catalyzed by SHPRH, HLTF, and RFWD3. Upon replication stress, ASCC3's DNA unwinding activity is required for SMARCAL1 recruitment, restrained fork progression, fork degradation in BRCA1/BRCA2-deficient cells, and RPA accumulation on ssDNA to promote ATR activation. ASCC3 remodels gap-containing fork substrates in vitro and antagonizes RAD51-mediated recombination, preventing chromosome breaks/gaps and mis-segregation.","method":"In vitro DNA unwinding assay with fork substrates, iPOND/proximity ligation for fork recruitment, epistasis with SHPRH/HLTF/RFWD3/PCNA mutants, siRNA/CRISPR knockdown with fork progression, ATR activation, and chromosome instability readouts","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro reconstitution with fork substrates, genetic epistasis with multiple E3 ligases, and multiple cellular phenotype readouts across two publications (peer-reviewed + preprint from same group)","pmids":["41785087","40777259"],"is_preprint":false},{"year":2025,"finding":"ASCC3 is an early-acting ribosome-associated quality control (RQC) factor that is recruited to collided ribosomes by FMRP. FMRP recruits ASCC3 to collided ribosomes, and disease-associated ASCC3 variants that perturb ASCC3-FMRP interaction are defective in ribosome association and handling of collided ribosomes. ASCC3 overexpression in Fmr1 KO mice promoted neuronal migration, and CRISPR-mediated ASCC3 activation ameliorated synaptic defects and behavioral deficits in FXS mouse models.","method":"Co-immunoprecipitation (ASCC3-FMRP interaction), ribosome association assays, mutagenesis of disease-associated variants, in vivo AAV-CRISPR activation in Fmr1 KO mice with behavioral and synaptic readouts","journal":"Science translational medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal co-IP, mutagenesis, and in vivo functional rescue across multiple orthogonal methods in a single rigorous study","pmids":["41061044"],"is_preprint":false},{"year":2024,"finding":"ASCC3 (along with 4EHP) suppresses ribosome collisions at UUA sense codons caused by transient eRF1 misrecognition. Depletion of ASCC3 leads to accumulation of ribosomes stalled at UUA codons and triggers stress responses including upregulation of the stress-induced transcription factor ATF3, establishing ASCC3 as a factor that suppresses aberrant ribosome collisions from sense codon misrecognition.","method":"Disome-Seq with ASCC3 depletion, ribosome profiling, stress response gene expression analysis","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — ribosome profiling with clean depletion is Tier 2, but single lab preprint with single primary method","pmids":["bio_10.1101_2024.09.01.610654"],"is_preprint":true},{"year":2023,"finding":"ASCC3 stabilizes STAT3 signaling by recruiting CAND1, which inhibits ubiquitin-mediated degradation of STAT3, thereby impairing the type I interferon response and promoting immunosuppression in NSCLC. This was demonstrated by co-immunoprecipitation and mass spectrometry identifying CAND1 as an ASCC3-interacting protein.","method":"Co-immunoprecipitation, mass spectrometry, immunofluorescence, siRNA knockdown with STAT3 stability, ubiquitination, and interferon response readouts; in vivo mouse tumor models","journal":"Journal for immunotherapy of cancer","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — co-IP/MS plus functional knockdown readouts, single lab, multiple orthogonal methods","pmids":["38148115"],"is_preprint":false},{"year":2026,"finding":"ASCC3 promotes sensitivity to replication stress-inducing chemotherapeutic agents (5-fluorouracil, cisplatin, hydroxyurea) in colorectal cancer cells. ASCC3 loss causes increased chemoresistance despite enhanced DNA damage accumulation. ASCC3 reprograms energy metabolism toward glycolysis and is required for PERK production upon ER stress; impaired PERK production upon ASCC3 loss is associated with reduced CHOP and caspase 3 levels, indicating ASCC3 promotes PERK-mediated cell death in response to chemotherapy.","method":"ASCC3 siRNA knockdown, RNA-seq, extracellular flux assays, stable isotope tracer analysis, Western blotting for PERK/CHOP/caspase 3 upon drug treatment","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — multiple orthogonal functional assays (metabolic, transcriptomic, protein level), single lab","pmids":["41844711"],"is_preprint":false}],"current_model":"ASCC3 is a dual-cassette Ski2-like 3'-5' DNA/RNA helicase and the largest subunit of the ASCC complex that functions in multiple genome maintenance and translation quality control pathways: it unwinds DNA to generate ssDNA for ALKBH3-mediated dealkylation of N-methylated DNA/RNA bases; it is recruited to stalled replication forks via ASCC2 (dependent on PCNA-K164 polyubiquitylation) to promote fork reversal, ATR activation, and antagonism of RAD51-mediated recombination; it acts as an early ribosome-associated quality control factor recruited to collided ribosomes by FMRP to regulate translation fidelity; and it stabilizes STAT3 signaling by recruiting CAND1 to inhibit STAT3 ubiquitination, thereby modulating type I interferon responses."},"narrative":{"mechanistic_narrative":"ASCC3 is a 3'-5' DNA/RNA helicase and the largest subunit of the Activating Signal Cointegrator Complex (ASCC) that operates across DNA repair, replication stress, and translation quality control [PMID:22055184, PMID:41785087, PMID:40777259]. In dealkylation repair, its unwinding activity generates the single-stranded substrate on which the partner demethylase ALKBH3 acts, and loss of ASCC3 elevates 3-methylcytosine, induces pH2A.X/53BP1 foci, and impairs proliferation; this activity also clears m1A and m3C from damaged mRNA, consistent with disassembly of collided ribosomes to permit demethylation [PMID:22055184, PMID:34217309]. Within the complex, ASCC3 binds ASCC2 through a structurally defined interface, and ASCC2's ubiquitin-binding activity recruits ASCC3 to stalled replication forks in a manner dependent on SHPRH/HLTF/RFWD3-mediated polyubiquitylation of PCNA at K164; there ASCC3's helicase activity drives SMARCAL1 recruitment, fork remodeling, RPA accumulation and ATR activation, and antagonizes RAD51-mediated recombination to preserve genome stability [PMID:33139697, PMID:41785087, PMID:40777259]. In translation surveillance ASCC3 acts as an early ribosome-associated quality control factor recruited to collided ribosomes by FMRP, and disease-associated variants that disrupt the ASCC3-FMRP interaction are defective in ribosome handling [PMID:41061044]. Distinct from its genome-maintenance roles, ASCC3 stabilizes STAT3 by recruiting CAND1 to block STAT3 ubiquitination, dampening the type I interferon response [PMID:38148115].","teleology":[{"year":2011,"claim":"Established the founding biochemical function of ASCC3 by showing its helicase generates the ssDNA substrate required for ALKBH3-dependent dealkylation, linking the ASCC complex to active reversal of N-alkylation damage.","evidence":"Affinity purification/MS, in vitro helicase assay, and siRNA knockdown with alkylation-resistance and DNA-damage-foci readouts","pmids":["22055184"],"confidence":"High","gaps":["Did not resolve how ASCC3 helicase activity is coupled to ALKBH3 catalysis structurally","Scope of substrate (DNA vs RNA) not fully delineated"]},{"year":2020,"claim":"Defined the physical basis of the ASCC2-ASCC3 interaction at atomic resolution, showing the interface is conserved and disrupted by cancer mutations, and that ASCC3 is organized like the Brr2 RNA helicase.","evidence":"X-ray crystallography of the interacting regions with quantitative binding affinity and cancer-variant mutagenesis","pmids":["33139697"],"confidence":"High","gaps":["Functional consequence of weakened ASCC2-ASCC3 binding in cells not tested here","Full-length complex architecture not resolved"]},{"year":2021,"claim":"Extended ASCC3's dealkylation role from DNA to mRNA, showing it is needed to clear m1A/m3C methylbases from transcripts and to form MMS-induced P-bodies.","evidence":"MS quantification of mRNA methylbases plus SILAC-MS of the mRNA-bound proteome after alkylation, with knockdown readouts","pmids":["34217309"],"confidence":"Medium","gaps":["Direct ribosome-disassembly activity inferred but not reconstituted here","Single-lab study without orthogonal genetic confirmation"]},{"year":2023,"claim":"Revealed a genome-maintenance-independent role: ASCC3 recruits CAND1 to protect STAT3 from ubiquitin-mediated degradation, dampening type I interferon signaling and promoting tumor immunosuppression.","evidence":"Co-IP/MS identification of CAND1, plus knockdown with STAT3 stability, ubiquitination, interferon, and in vivo tumor readouts in NSCLC","pmids":["38148115"],"confidence":"Medium","gaps":["Whether ASCC3 acts here as a helicase or scaffold is unresolved","Direct vs indirect nature of CAND1 recruitment not structurally defined"]},{"year":2025,"claim":"Placed ASCC3 in the replication stress response, defining a recruitment pathway (PCNA-K164 polyubiquitylation by SHPRH/HLTF/RFWD3 → ASCC2 → ASCC3) and a helicase-dependent role in fork remodeling, ATR activation, and suppression of RAD51 recombination.","evidence":"In vitro fork-substrate unwinding, iPOND/proximity ligation, epistasis with E3-ligase/PCNA mutants, and chromosome-instability phenotyping","pmids":["41785087","40777259"],"confidence":"High","gaps":["How ASCC3 selects fork vs dealkylation substrates is unclear","Mechanism of RAD51 antagonism at the molecular level not defined"]},{"year":2025,"claim":"Identified ASCC3 as an early RQC factor recruited to collided ribosomes by FMRP, with disease-associated variants disrupting this interaction, and demonstrated therapeutic rescue in Fragile X models.","evidence":"Reciprocal co-IP, ribosome-association assays, variant mutagenesis, and in vivo AAV-CRISPR activation in Fmr1 KO mice with synaptic/behavioral readouts","pmids":["41061044"],"confidence":"High","gaps":["Structural basis of the ASCC3-FMRP interaction unresolved","How ASCC3 mechanically resolves collided ribosomes not reconstituted"]},{"year":2024,"claim":"Extended ASCC3's translation surveillance role to suppression of ribosome collisions arising from eRF1 misrecognition at UUA sense codons, coupling its loss to ATF3 stress induction.","evidence":"Disome-Seq and ribosome profiling with ASCC3 depletion plus stress-response gene expression (preprint)","pmids":["bio_10.1101_2024.09.01.610654"],"confidence":"Medium","gaps":["Single-method preprint not independently confirmed","Mechanistic link between ASCC3 and 4EHP at collision sites not established"]},{"year":2026,"claim":"Connected ASCC3 to chemotherapy response, showing it promotes glycolytic metabolic reprogramming and PERK-mediated apoptotic signaling that sensitizes colorectal cells to replication-stress agents.","evidence":"siRNA knockdown with RNA-seq, extracellular flux, isotope tracing, and PERK/CHOP/caspase-3 Western blotting under drug treatment","pmids":["41844711"],"confidence":"Medium","gaps":["Whether metabolic and PERK effects are direct ASCC3 functions or downstream consequences is unclear","Single-lab, single-context study"]},{"year":null,"claim":"How a single helicase is partitioned among its DNA dealkylation, replication-fork remodeling, ribosome quality control, and STAT3-stabilizing roles, and what determines context-specific recruitment, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified model of substrate/partner selection across pathways","Structural basis for FMRP and CAND1 recruitment undefined","Catalytic vs scaffolding requirements not separated for each role"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140657","term_label":"ATP-dependent activity","supporting_discovery_ids":[0,3]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[0,3]},{"term_id":"GO:0140097","term_label":"catalytic activity, acting on DNA","supporting_discovery_ids":[0,3]},{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[2]},{"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":[0,3]},{"term_id":"GO:0005840","term_label":"ribosome","supporting_discovery_ids":[4,2]}],"pathway":[{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[0]},{"term_id":"R-HSA-69306","term_label":"DNA Replication","supporting_discovery_ids":[3]},{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[2,4]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[6]}],"complexes":["ASCC complex"],"partners":["ASCC2","ALKBH3","FMRP","CAND1","SMARCAL1","PCNA"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8N3C0","full_name":"Activating signal cointegrator 1 complex subunit 3","aliases":["ASC-1 complex subunit p200","ASC1p200","Helicase, ATP binding 1","Trip4 complex subunit p200"],"length_aa":2202,"mass_kda":251.5,"function":"ATPase involved both in DNA repair and rescue of stalled ribosomes (PubMed:22055184, PubMed:28757607, PubMed:32099016, PubMed:32579943, PubMed:36302773). 3'-5' DNA helicase involved in repair of alkylated DNA: promotes DNA unwinding to generate single-stranded substrate needed for ALKBH3, enabling ALKBH3 to process alkylated N3-methylcytosine (3mC) within double-stranded regions (PubMed:22055184). Also involved in activation of the ribosome quality control (RQC) pathway, a pathway that degrades nascent peptide chains during problematic translation (PubMed:28757607, PubMed:32099016, PubMed:32579943, PubMed:36302773). Drives the splitting of stalled ribosomes that are ubiquitinated in a ZNF598-dependent manner, as part of the ribosome quality control trigger (RQT) complex (PubMed:28757607, PubMed:32099016, PubMed:32579943, PubMed:36302773). Part of the ASC-1 complex that enhances NF-kappa-B, SRF and AP1 transactivation (PubMed:12077347)","subcellular_location":"Nucleus; Nucleus speckle; Cytoplasm, cytosol","url":"https://www.uniprot.org/uniprotkb/Q8N3C0/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ASCC3","classification":"Not Classified","n_dependent_lines":501,"n_total_lines":1208,"dependency_fraction":0.4147350993377483},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"EIF3G","stoichiometry":4.0},{"gene":"CAPRIN1","stoichiometry":0.2},{"gene":"DDX6","stoichiometry":0.2},{"gene":"EIF3B","stoichiometry":0.2},{"gene":"GSPT1","stoichiometry":0.2},{"gene":"NPM1","stoichiometry":0.2},{"gene":"NPM3","stoichiometry":0.2},{"gene":"PSPC1","stoichiometry":0.2},{"gene":"RACK1","stoichiometry":0.2},{"gene":"RBBP4","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/ASCC3","total_profiled":1310},"omim":[{"mim_id":"620700","title":"INTELLECTUAL DEVELOPMENTAL DISORDER, AUTOSOMAL RECESSIVE 81; MRT81","url":"https://www.omim.org/entry/620700"},{"mim_id":"614217","title":"ACTIVATING SIGNAL COINTEGRATOR 1 COMPLEX, SUBUNIT 3; ASCC3","url":"https://www.omim.org/entry/614217"},{"mim_id":"614216","title":"ACTIVATING SIGNAL COINTEGRATOR 1 COMPLEX, SUBUNIT 2; ASCC2","url":"https://www.omim.org/entry/614216"},{"mim_id":"614215","title":"ACTIVATING SIGNAL COINTEGRATOR 1 COMPLEX, SUBUNIT 1; ASCC1","url":"https://www.omim.org/entry/614215"},{"mim_id":"604501","title":"THYROID HORMONE RECEPTOR INTERACTOR 4; TRIP4","url":"https://www.omim.org/entry/604501"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Cytosol","reliability":"Supported"},{"location":"Golgi apparatus","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/ASCC3"},"hgnc":{"alias_symbol":["RNAH","ASC1p200","dJ121G13.4","dJ467N11.1"],"prev_symbol":["HELIC1"]},"alphafold":{"accession":"Q8N3C0","domains":[{"cath_id":"-","chopping":"50-142","consensus_level":"high","plddt":79.0899,"start":50,"end":142},{"cath_id":"-","chopping":"246-292","consensus_level":"medium","plddt":81.0232,"start":246,"end":292},{"cath_id":"3.40.50.300","chopping":"461-677","consensus_level":"high","plddt":85.1906,"start":461,"end":677},{"cath_id":"3.40.50.300","chopping":"686-873","consensus_level":"high","plddt":82.7526,"start":686,"end":873},{"cath_id":"2.60.40.150","chopping":"1182-1291","consensus_level":"medium","plddt":86.8013,"start":1182,"end":1291},{"cath_id":"3.40.50.300","chopping":"1297-1512","consensus_level":"medium","plddt":87.19,"start":1297,"end":1512},{"cath_id":"3.40.50.300","chopping":"1523-1718","consensus_level":"medium","plddt":84.1331,"start":1523,"end":1718},{"cath_id":"1.10.3380.10","chopping":"1837-1959","consensus_level":"medium","plddt":88.6012,"start":1837,"end":1959},{"cath_id":"2.60.40.150","chopping":"2035-2199","consensus_level":"high","plddt":74.7278,"start":2035,"end":2199},{"cath_id":"1.10.150","chopping":"1960-1980_1993-2033","consensus_level":"medium","plddt":80.9219,"start":1960,"end":2033}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8N3C0","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8N3C0-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8N3C0-F1-predicted_aligned_error_v6.png","plddt_mean":79.75},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ASCC3","jax_strain_url":"https://www.jax.org/strain/search?query=ASCC3"},"sequence":{"accession":"Q8N3C0","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8N3C0.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8N3C0/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8N3C0"}},"corpus_meta":[{"pmid":"22055184","id":"PMC_22055184","title":"DNA unwinding by ASCC3 helicase is coupled to ALKBH3-dependent DNA alkylation repair and cancer cell proliferation.","date":"2011","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/22055184","citation_count":175,"is_preprint":false},{"pmid":"38148115","id":"PMC_38148115","title":"ASCC3 promotes the immunosuppression and progression of non-small cell lung cancer by impairing the type I interferon response via CAND1-mediated ubiquitination inhibition of STAT3.","date":"2023","source":"Journal for immunotherapy of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/38148115","citation_count":25,"is_preprint":false},{"pmid":"33139697","id":"PMC_33139697","title":"The interaction of DNA repair factors ASCC2 and ASCC3 is affected by somatic cancer mutations.","date":"2020","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/33139697","citation_count":21,"is_preprint":false},{"pmid":"34217309","id":"PMC_34217309","title":"ALKBH3 partner ASCC3 mediates P-body formation and selective clearance of MMS-induced 1-methyladenosine and 3-methylcytosine from mRNA.","date":"2021","source":"Journal of translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/34217309","citation_count":20,"is_preprint":false},{"pmid":"3951991","id":"PMC_3951991","title":"Molecular cloning and in vitro transcription of rat 4.5S RNAH genes.","date":"1986","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/3951991","citation_count":13,"is_preprint":false},{"pmid":"35047834","id":"PMC_35047834","title":"Discovery of a neuromuscular syndrome caused by biallelic variants in ASCC3.","date":"2021","source":"HGG advances","url":"https://pubmed.ncbi.nlm.nih.gov/35047834","citation_count":9,"is_preprint":false},{"pmid":"17971306","id":"PMC_17971306","title":"Mouse nucleolin binds to 4.5S RNAh, a small noncoding RNA.","date":"2007","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/17971306","citation_count":3,"is_preprint":false},{"pmid":"26536629","id":"PMC_26536629","title":"Correlations between ASCC3 Gene Polymorphisms and Chronic Hepatitis B in a Chinese Han Population.","date":"2015","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/26536629","citation_count":3,"is_preprint":false},{"pmid":"40881169","id":"PMC_40881169","title":"Integrative multi-omics analysis and machine learning reveal the unique role of ASCC3 in combination with various immune-related genes in rectal adenocarcinoma.","date":"2025","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/40881169","citation_count":2,"is_preprint":false},{"pmid":"41785087","id":"PMC_41785087","title":"Ski2-like helicase ASCC3 unwinds DNA upon fork stalling to control replication stress responses.","date":"2026","source":"Cell 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control","date":"2024-09-01","source":"bioRxiv","url":"https://doi.org/10.1101/2024.09.01.610654","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9967,"output_tokens":2629,"usd":0.034668,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9819,"output_tokens":3345,"usd":0.06636,"stage2_stop_reason":"end_turn"},"total_usd":0.101028,"stage1_batch_id":"msgbatch_0179Z2pxRYBsXi2xADneafRw","stage2_batch_id":"msgbatch_01LaY9ZaVdgjWArcZo9eqQE5","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2011,\n      \"finding\": \"ASCC3, the largest subunit of the Activating Signal Cointegrator Complex (ASCC), encodes a 3'-5' DNA helicase whose unwinding activity generates single-stranded DNA upon which ALKBH3 preferentially functions for dealkylation of N-alkylated nucleotides. ASCC3 and ALKBH3 form a complex (purified by co-immunoprecipitation/mass spectrometry), and loss of ASCC3 leads to increased 3-methylcytosine levels, pH2A.X and 53BP1 foci formation, and reduced cell proliferation.\",\n      \"method\": \"Complex purification (affinity purification/mass spectrometry), in vitro helicase assay, siRNA knockdown with alkylation damage resistance and proliferation readouts, immunofluorescence for DNA damage markers\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — biochemical complex purification, direct helicase activity assay, and functional loss-of-function experiments with multiple orthogonal readouts in a single study\",\n      \"pmids\": [\"22055184\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"ASCC2 and ASCC3 directly interact via a structurally defined interface: the ASCC3 fragment contains a central helical domain and terminal extended arms that clasp the compact ASCC2 unit. This interface is evolutionarily conserved, and somatic cancer mutations at this interface reduce ASCC2-ASCC3 binding affinity. Functional dissection revealed ASCC3 has similar organization and regulation to the spliceosomal RNA helicase Brr2.\",\n      \"method\": \"X-ray crystallography / structural analysis of interacting regions, quantitative binding affinity measurements, mutagenesis of cancer-associated variants\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure with functional validation by mutagenesis and quantitative binding assays; multiple orthogonal methods in single rigorous study\",\n      \"pmids\": [\"33139697\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"ASCC3 promotes removal of MMS-induced 1-methyladenosine (m1A) and 3-methylcytosine (m3C) from mRNA. ASCC3-deficient cells show delayed clearance of these aberrant mRNA methylbases and impaired formation of MMS-induced P-bodies. ASCC3 binds mRNA after alkylation damage (increased mRNA association detected by SILAC-MS), consistent with a role in disassembly of collided ribosomes to allow ALKBH3-mediated demethylation.\",\n      \"method\": \"Quantitative mass spectrometry of mRNA methylbases, SILAC-MS for mRNA-binding proteome, siRNA knockdown of ASCC3 with mRNA modification and P-body formation readouts\",\n      \"journal\": \"Journal of translational medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — two orthogonal methods (MS quantification of modifications + SILAC proteomics), single lab\",\n      \"pmids\": [\"34217309\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ASCC3 is recruited to stalled replication forks by its binding partner ASCC2. ASCC2 recruitment to stalled forks requires its ubiquitin-binding activity and polyubiquitylation of PCNA at K164 catalyzed by SHPRH, HLTF, and RFWD3. Upon replication stress, ASCC3's DNA unwinding activity is required for SMARCAL1 recruitment, restrained fork progression, fork degradation in BRCA1/BRCA2-deficient cells, and RPA accumulation on ssDNA to promote ATR activation. ASCC3 remodels gap-containing fork substrates in vitro and antagonizes RAD51-mediated recombination, preventing chromosome breaks/gaps and mis-segregation.\",\n      \"method\": \"In vitro DNA unwinding assay with fork substrates, iPOND/proximity ligation for fork recruitment, epistasis with SHPRH/HLTF/RFWD3/PCNA mutants, siRNA/CRISPR knockdown with fork progression, ATR activation, and chromosome instability readouts\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro reconstitution with fork substrates, genetic epistasis with multiple E3 ligases, and multiple cellular phenotype readouts across two publications (peer-reviewed + preprint from same group)\",\n      \"pmids\": [\"41785087\", \"40777259\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ASCC3 is an early-acting ribosome-associated quality control (RQC) factor that is recruited to collided ribosomes by FMRP. FMRP recruits ASCC3 to collided ribosomes, and disease-associated ASCC3 variants that perturb ASCC3-FMRP interaction are defective in ribosome association and handling of collided ribosomes. ASCC3 overexpression in Fmr1 KO mice promoted neuronal migration, and CRISPR-mediated ASCC3 activation ameliorated synaptic defects and behavioral deficits in FXS mouse models.\",\n      \"method\": \"Co-immunoprecipitation (ASCC3-FMRP interaction), ribosome association assays, mutagenesis of disease-associated variants, in vivo AAV-CRISPR activation in Fmr1 KO mice with behavioral and synaptic readouts\",\n      \"journal\": \"Science translational medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal co-IP, mutagenesis, and in vivo functional rescue across multiple orthogonal methods in a single rigorous study\",\n      \"pmids\": [\"41061044\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ASCC3 (along with 4EHP) suppresses ribosome collisions at UUA sense codons caused by transient eRF1 misrecognition. Depletion of ASCC3 leads to accumulation of ribosomes stalled at UUA codons and triggers stress responses including upregulation of the stress-induced transcription factor ATF3, establishing ASCC3 as a factor that suppresses aberrant ribosome collisions from sense codon misrecognition.\",\n      \"method\": \"Disome-Seq with ASCC3 depletion, ribosome profiling, stress response gene expression analysis\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — ribosome profiling with clean depletion is Tier 2, but single lab preprint with single primary method\",\n      \"pmids\": [\"bio_10.1101_2024.09.01.610654\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"ASCC3 stabilizes STAT3 signaling by recruiting CAND1, which inhibits ubiquitin-mediated degradation of STAT3, thereby impairing the type I interferon response and promoting immunosuppression in NSCLC. This was demonstrated by co-immunoprecipitation and mass spectrometry identifying CAND1 as an ASCC3-interacting protein.\",\n      \"method\": \"Co-immunoprecipitation, mass spectrometry, immunofluorescence, siRNA knockdown with STAT3 stability, ubiquitination, and interferon response readouts; in vivo mouse tumor models\",\n      \"journal\": \"Journal for immunotherapy of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — co-IP/MS plus functional knockdown readouts, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"38148115\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"ASCC3 promotes sensitivity to replication stress-inducing chemotherapeutic agents (5-fluorouracil, cisplatin, hydroxyurea) in colorectal cancer cells. ASCC3 loss causes increased chemoresistance despite enhanced DNA damage accumulation. ASCC3 reprograms energy metabolism toward glycolysis and is required for PERK production upon ER stress; impaired PERK production upon ASCC3 loss is associated with reduced CHOP and caspase 3 levels, indicating ASCC3 promotes PERK-mediated cell death in response to chemotherapy.\",\n      \"method\": \"ASCC3 siRNA knockdown, RNA-seq, extracellular flux assays, stable isotope tracer analysis, Western blotting for PERK/CHOP/caspase 3 upon drug treatment\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — multiple orthogonal functional assays (metabolic, transcriptomic, protein level), single lab\",\n      \"pmids\": [\"41844711\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ASCC3 is a dual-cassette Ski2-like 3'-5' DNA/RNA helicase and the largest subunit of the ASCC complex that functions in multiple genome maintenance and translation quality control pathways: it unwinds DNA to generate ssDNA for ALKBH3-mediated dealkylation of N-methylated DNA/RNA bases; it is recruited to stalled replication forks via ASCC2 (dependent on PCNA-K164 polyubiquitylation) to promote fork reversal, ATR activation, and antagonism of RAD51-mediated recombination; it acts as an early ribosome-associated quality control factor recruited to collided ribosomes by FMRP to regulate translation fidelity; and it stabilizes STAT3 signaling by recruiting CAND1 to inhibit STAT3 ubiquitination, thereby modulating type I interferon responses.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"ASCC3 is a 3'-5' DNA/RNA helicase and the largest subunit of the Activating Signal Cointegrator Complex (ASCC) that operates across DNA repair, replication stress, and translation quality control [#0, #3]. In dealkylation repair, its unwinding activity generates the single-stranded substrate on which the partner demethylase ALKBH3 acts, and loss of ASCC3 elevates 3-methylcytosine, induces pH2A.X/53BP1 foci, and impairs proliferation; this activity also clears m1A and m3C from damaged mRNA, consistent with disassembly of collided ribosomes to permit demethylation [#0, #2]. Within the complex, ASCC3 binds ASCC2 through a structurally defined interface, and ASCC2's ubiquitin-binding activity recruits ASCC3 to stalled replication forks in a manner dependent on SHPRH/HLTF/RFWD3-mediated polyubiquitylation of PCNA at K164; there ASCC3's helicase activity drives SMARCAL1 recruitment, fork remodeling, RPA accumulation and ATR activation, and antagonizes RAD51-mediated recombination to preserve genome stability [#1, #3]. In translation surveillance ASCC3 acts as an early ribosome-associated quality control factor recruited to collided ribosomes by FMRP, and disease-associated variants that disrupt the ASCC3-FMRP interaction are defective in ribosome handling [#4]. Distinct from its genome-maintenance roles, ASCC3 stabilizes STAT3 by recruiting CAND1 to block STAT3 ubiquitination, dampening the type I interferon response [#6].\",\n  \"teleology\": [\n    {\n      \"year\": 2011,\n      \"claim\": \"Established the founding biochemical function of ASCC3 by showing its helicase generates the ssDNA substrate required for ALKBH3-dependent dealkylation, linking the ASCC complex to active reversal of N-alkylation damage.\",\n      \"evidence\": \"Affinity purification/MS, in vitro helicase assay, and siRNA knockdown with alkylation-resistance and DNA-damage-foci readouts\",\n      \"pmids\": [\"22055184\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve how ASCC3 helicase activity is coupled to ALKBH3 catalysis structurally\", \"Scope of substrate (DNA vs RNA) not fully delineated\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Defined the physical basis of the ASCC2-ASCC3 interaction at atomic resolution, showing the interface is conserved and disrupted by cancer mutations, and that ASCC3 is organized like the Brr2 RNA helicase.\",\n      \"evidence\": \"X-ray crystallography of the interacting regions with quantitative binding affinity and cancer-variant mutagenesis\",\n      \"pmids\": [\"33139697\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of weakened ASCC2-ASCC3 binding in cells not tested here\", \"Full-length complex architecture not resolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Extended ASCC3's dealkylation role from DNA to mRNA, showing it is needed to clear m1A/m3C methylbases from transcripts and to form MMS-induced P-bodies.\",\n      \"evidence\": \"MS quantification of mRNA methylbases plus SILAC-MS of the mRNA-bound proteome after alkylation, with knockdown readouts\",\n      \"pmids\": [\"34217309\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct ribosome-disassembly activity inferred but not reconstituted here\", \"Single-lab study without orthogonal genetic confirmation\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Revealed a genome-maintenance-independent role: ASCC3 recruits CAND1 to protect STAT3 from ubiquitin-mediated degradation, dampening type I interferon signaling and promoting tumor immunosuppression.\",\n      \"evidence\": \"Co-IP/MS identification of CAND1, plus knockdown with STAT3 stability, ubiquitination, interferon, and in vivo tumor readouts in NSCLC\",\n      \"pmids\": [\"38148115\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether ASCC3 acts here as a helicase or scaffold is unresolved\", \"Direct vs indirect nature of CAND1 recruitment not structurally defined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Placed ASCC3 in the replication stress response, defining a recruitment pathway (PCNA-K164 polyubiquitylation by SHPRH/HLTF/RFWD3 → ASCC2 → ASCC3) and a helicase-dependent role in fork remodeling, ATR activation, and suppression of RAD51 recombination.\",\n      \"evidence\": \"In vitro fork-substrate unwinding, iPOND/proximity ligation, epistasis with E3-ligase/PCNA mutants, and chromosome-instability phenotyping\",\n      \"pmids\": [\"41785087\", \"40777259\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How ASCC3 selects fork vs dealkylation substrates is unclear\", \"Mechanism of RAD51 antagonism at the molecular level not defined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified ASCC3 as an early RQC factor recruited to collided ribosomes by FMRP, with disease-associated variants disrupting this interaction, and demonstrated therapeutic rescue in Fragile X models.\",\n      \"evidence\": \"Reciprocal co-IP, ribosome-association assays, variant mutagenesis, and in vivo AAV-CRISPR activation in Fmr1 KO mice with synaptic/behavioral readouts\",\n      \"pmids\": [\"41061044\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of the ASCC3-FMRP interaction unresolved\", \"How ASCC3 mechanically resolves collided ribosomes not reconstituted\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Extended ASCC3's translation surveillance role to suppression of ribosome collisions arising from eRF1 misrecognition at UUA sense codons, coupling its loss to ATF3 stress induction.\",\n      \"evidence\": \"Disome-Seq and ribosome profiling with ASCC3 depletion plus stress-response gene expression (preprint)\",\n      \"pmids\": [\"bio_10.1101_2024.09.01.610654\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-method preprint not independently confirmed\", \"Mechanistic link between ASCC3 and 4EHP at collision sites not established\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Connected ASCC3 to chemotherapy response, showing it promotes glycolytic metabolic reprogramming and PERK-mediated apoptotic signaling that sensitizes colorectal cells to replication-stress agents.\",\n      \"evidence\": \"siRNA knockdown with RNA-seq, extracellular flux, isotope tracing, and PERK/CHOP/caspase-3 Western blotting under drug treatment\",\n      \"pmids\": [\"41844711\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether metabolic and PERK effects are direct ASCC3 functions or downstream consequences is unclear\", \"Single-lab, single-context study\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How a single helicase is partitioned among its DNA dealkylation, replication-fork remodeling, ribosome quality control, and STAT3-stabilizing roles, and what determines context-specific recruitment, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model of substrate/partner selection across pathways\", \"Structural basis for FMRP and CAND1 recruitment undefined\", \"Catalytic vs scaffolding requirements not separated for each role\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140657\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0140097\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [4, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0005840\", \"supporting_discovery_ids\": [4, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-69306\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [2, 4]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"complexes\": [\"ASCC complex\"],\n    \"partners\": [\"ASCC2\", \"ALKBH3\", \"FMRP\", \"CAND1\", \"SMARCAL1\", \"PCNA\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}