{"gene":"DSN1","run_date":"2026-06-09T23:54:42","timeline":{"discoveries":[{"year":2013,"finding":"The Mub1/Ubr2 ubiquitin ligase complex associates with kinetochore particles through CENP-C (Mif2) and regulates the levels of yeast Dsn1 via ubiquitylation; deletion of Mub1/Ubr2 restores levels of a mutant Dsn1, indicating a quality control mechanism that targets aberrant Dsn1 for proteasomal degradation.","method":"Kinetochore particle purification, Co-IP/mass spectrometry, genetic deletion analysis, ubiquitylation assays","journal":"PLoS genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal biochemical purification, genetic epistasis (deletion rescue of mutant), and ubiquitylation assay; multiple orthogonal methods in a single rigorous study","pmids":["23408894"],"is_preprint":false},{"year":2024,"finding":"Mammalian germ cells express a germline-specific alternative splice isoform of DSN1 that lacks a key regulatory region required for Aurora kinase phosphorylation, resulting in constitutive centromere/kinetochore localization independent of Aurora B phosphorylation. Expression of this isoform in somatic cells causes constitutive kinetochore localization, chromosome segregation errors, and growth defects. Precise elimination of this germline isoform in mice disrupts oocyte maturation, early embryonic divisions, and reduces fertility.","method":"Alternative splicing identification, live-cell imaging, mouse genetic knockout of germline isoform, cell-based overexpression assays, Aurora kinase phosphorylation analysis","journal":"Current biology : CB","confidence":"High","confidence_rationale":"Tier 2 / Strong — mouse knockout model with specific fertility/oocyte phenotype, somatic cell expression with defined segregation phenotype, mechanistic link to Aurora kinase phosphorylation; multiple orthogonal methods","pmids":["39178843"],"is_preprint":false},{"year":2024,"finding":"A germline-specific DSN1 splice isoform (preprint version of the same study) bypasses Aurora kinase phosphorylation requirement for centromere localization; somatic expression causes constitutive kinetochore localization and chromosome segregation errors; germline isoform knockout in mice impairs oocyte maturation and early embryo divisions.","method":"Mouse genetic models, cell-based expression assays, live-cell imaging","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — same findings as peer-reviewed paper but preprint; included only to note temporal precedence; confidence limited to preprint status","pmids":["38659852"],"is_preprint":true},{"year":2025,"finding":"Cryo-EM structures of the budding yeast KMN complex reveal that the N-terminal auto-inhibitory segment of Dsn1 (Dsn1-AI) folds into two α-helices that engage the Mis12c head domain, occluding binding sites for inner kinetochore subunits CENP-C (Mif2) and CENP-U (Ame1), reducing their affinity for Mis12c. Aurora B (Ipl1) phosphorylation of Dsn1-AI releases this auto-inhibition, strengthening inner-outer kinetochore connections. C-terminal α-helical motifs of Dsn1, Mis12/Mtw1, and Nnf1 bind Knl1c and Ndc80c to mediate KMN assembly.","method":"Cryo-EM structure determination, biochemical binding assays, genetic experiments","journal":"bioRxiv","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structure with biochemical and genetic validation; multiple orthogonal methods in a single rigorous study; preprint but with comprehensive structural and functional data","pmids":["bio_10.1101_2025.06.03.657598"],"is_preprint":true},{"year":2024,"finding":"In chicken DT40 cells lacking CENP-C–Mis12C interaction, CENP-T interacts with Mis12C through two distinct binding surfaces; this interaction is cooperatively regulated by dual phosphorylation of Dsn1 (a Mis12C component) and CENP-T, ensuring robust CENP-T–Mis12C interaction and proper mitotic progression.","method":"AlphaFold2-guided mutagenesis, cell viability assays in DT40 cells lacking CENP-C–Mis12C interaction, biochemical binding experiments","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic cell system with defined interaction surfaces and phosphorylation sites, AlphaFold2-guided but experimentally validated; preprint, single lab","pmids":["bio_10.1101_2024.06.20.599825"],"is_preprint":true},{"year":2024,"finding":"DSN1 directly interacts with Centromere Protein T (CENPT) in hepatocellular carcinoma cells, and elevated DSN1 expression leads to overproduction of cell cycle-related proteins through this interaction, contributing to chromosomal instability.","method":"siRNA/shRNA knockdown, overexpression vectors, co-immunoprecipitation implied by 'direct interaction', xenograft model","journal":"Molecular carcinogenesis","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, interaction inferred from cancer cell lines with limited mechanistic detail in abstract; no structural or reconstitution data described","pmids":["39560395"],"is_preprint":false},{"year":2022,"finding":"SRSF9 binds to DSN1 mRNA in an m6A-dependent manner (two m6A modification sites identified in the SRSF9-binding region) and stabilizes DSN1 mRNA; METTL3 knockdown impairs SRSF9-mediated stabilization of DSN1 mRNA, establishing METTL3 as the m6A writer enabling SRSF9 (reader) to stabilize DSN1 transcript.","method":"Methylated RNA affinity assays, gene-specific m6A qRT-PCR, RNA stability assays, METTL3 knockdown, dual-luciferase reporter assays","journal":"Journal of translational medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (RNA affinity, m6A qRT-PCR, stability assays, writer knockdown) in single lab; establishes mechanistic post-transcriptional regulation of DSN1 mRNA","pmids":["35509101"],"is_preprint":false},{"year":2021,"finding":"ESRRA acts as a transcription factor that directly binds the DSN1 promoter and activates DSN1 transcription; ESRRA silencing causes G2/M arrest via the CDC25C–CDK1–Cyclin B1 pathway, which is downstream of DSN1.","method":"RNA-seq, dual-luciferase assay, ChIP assay, Western blotting, flow cytometry, ESRRA knockdown","journal":"International journal of biological sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and dual-luciferase confirm direct promoter binding; pathway placement via ESRRA→DSN1→CDC25C-CDK1-CyclinB1; single lab","pmids":["34131395"],"is_preprint":false},{"year":2026,"finding":"DSN1 competes with c-MYC for binding to FZR1 (an E3 ubiquitin ligase), thereby attenuating FZR1-mediated ubiquitination of c-MYC and preventing its proteasomal degradation; DSN1 knockdown accelerates c-MYC protein degradation through the ubiquitin-proteasome pathway without affecting c-MYC mRNA levels.","method":"Cycloheximide chase assay, proteasome inhibition assay, co-immunoprecipitation to identify FZR1-DSN1-c-MYC interaction, rescue experiments with c-MYC overexpression, in vivo metastasis assays","journal":"Experimental cell research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — competitive binding mechanism supported by Co-IP, cycloheximide chase, proteasome inhibition, and rescue experiments; single lab, multiple orthogonal methods","pmids":["41713835"],"is_preprint":false}],"current_model":"DSN1 is a core subunit of the MIS12 kinetochore complex that bridges centromeres to spindle microtubules; its N-terminal auto-inhibitory segment occludes CENP-C and CENP-U binding sites until Aurora B phosphorylation releases this inhibition to license inner-outer kinetochore assembly, a somatic regulation bypassed by a germline-specific splice isoform required for mammalian fertility; at the protein level, Mub1/Ubr2 ubiquitin ligase provides quality control by ubiquitylating aberrant Dsn1, while in cancer cells DSN1 also stabilizes c-MYC by competing with FZR1-mediated ubiquitination; transcriptionally, ESRRA drives DSN1 expression, and post-transcriptionally SRSF9 stabilizes DSN1 mRNA in an METTL3-dependent m6A-reading mechanism."},"narrative":{"mechanistic_narrative":"DSN1 is a core subunit of the MIS12 (Mis12c) kinetochore complex that bridges the inner centromere to the outer microtubule-binding machinery during mitosis [PMID:bio_10.1101_2025.06.03.657598]. Structurally, its N-terminal auto-inhibitory segment folds into two α-helices that engage the Mis12c head and occlude the binding sites for inner kinetochore subunits CENP-C (Mif2) and CENP-U (Ame1); Aurora B (Ipl1) phosphorylation of this segment relieves the auto-inhibition to strengthen inner-outer kinetochore connections, while C-terminal α-helical motifs of Dsn1 together with Mis12 and Nnf1 bind Knl1c and Ndc80c to assemble the KMN network [PMID:bio_10.1101_2025.06.03.657598]. DSN1 phosphorylation also cooperates with CENP-T phosphorylation to support a CENP-T–Mis12c interaction that ensures proper mitotic progression [PMID:bio_10.1101_2024.06.20.599825]. A germline-specific alternative splice isoform lacks the regulatory region required for Aurora kinase phosphorylation, producing constitutive centromere localization; ectopic somatic expression of this isoform causes chromosome segregation errors, and its elimination in mice disrupts oocyte maturation, early embryonic divisions, and fertility [PMID:39178843]. DSN1 abundance is controlled at multiple levels: the Mub1/Ubr2 ubiquitin ligase ubiquitylates aberrant Dsn1 for proteasomal degradation as a quality-control mechanism [PMID:23408894], ESRRA directly activates DSN1 transcription upstream of a CDC25C–CDK1–Cyclin B1 axis [PMID:34131395], and METTL3-dependent m6A marks on DSN1 mRNA are read by SRSF9 to stabilize the transcript [PMID:35509101]. In cancer cells DSN1 additionally stabilizes c-MYC by competing with FZR1 for binding, thereby attenuating FZR1-mediated c-MYC ubiquitination [PMID:41713835].","teleology":[{"year":2013,"claim":"Established that Dsn1 protein levels are actively policed at the kinetochore, identifying a ubiquitin-dependent quality control route for aberrant subunit.","evidence":"Kinetochore particle purification, Co-IP/mass spectrometry, and ubiquitylation assays with genetic deletion rescue in yeast","pmids":["23408894"],"confidence":"High","gaps":["Does not define which structural features of Dsn1 mark it as aberrant","Mammalian conservation of Mub1/Ubr2-mediated control not addressed"]},{"year":2021,"claim":"Identified ESRRA as a direct transcriptional activator of DSN1, placing DSN1 upstream of the CDC25C–CDK1–Cyclin B1 G2/M control axis.","evidence":"ChIP, dual-luciferase promoter assay, RNA-seq and flow cytometry with ESRRA knockdown","pmids":["34131395"],"confidence":"Medium","gaps":["Single lab","Mechanistic link between DSN1 and CDC25C-CDK1-CyclinB1 not biochemically resolved"]},{"year":2022,"claim":"Defined post-transcriptional control of DSN1 by an m6A-reader mechanism, explaining how DSN1 transcript stability is set.","evidence":"m6A affinity and qRT-PCR, RNA stability assays, dual-luciferase reporters with METTL3 knockdown","pmids":["35509101"],"confidence":"Medium","gaps":["Single lab","Physiological/disease context of SRSF9-DSN1 regulation not established"]},{"year":2024,"claim":"Showed that a germline-specific DSN1 splice isoform bypasses Aurora-dependent regulation, linking DSN1 phospho-regulation to mammalian fertility and chromosome segregation fidelity.","evidence":"Alternative splice identification, live-cell imaging, somatic overexpression phenotyping, and mouse knockout of the germline isoform","pmids":["39178843","38659852"],"confidence":"High","gaps":["Why germline cells require phosphorylation-independent localization is unresolved","Structural basis of isoform behavior not directly determined"]},{"year":2024,"claim":"Established an alternative CENP-T–Mis12c attachment route co-regulated by Dsn1 and CENP-T phosphorylation, complementing the CENP-C-dependent pathway.","evidence":"AlphaFold2-guided mutagenesis and viability/binding assays in DT40 cells lacking CENP-C–Mis12c interaction","pmids":["bio_10.1101_2024.06.20.599825"],"confidence":"Medium","gaps":["Preprint, single lab","Relative contribution of CENP-T versus CENP-C pathways in normal cells not quantified"]},{"year":2024,"claim":"Reported a direct DSN1–CENPT interaction driving cell-cycle protein overproduction and chromosomal instability in hepatocellular carcinoma, suggesting an oncogenic dimension to DSN1 function.","evidence":"siRNA/shRNA knockdown, overexpression, co-immunoprecipitation, and xenograft model in HCC cells","pmids":["39560395"],"confidence":"Low","gaps":["Interaction inferred with limited mechanistic detail; no structural or reconstitution data","Single lab"]},{"year":2025,"claim":"Provided the structural mechanism of DSN1 auto-inhibition, showing how its N-terminal segment occludes CENP-C/CENP-U binding until Aurora B phosphorylation licenses kinetochore assembly.","evidence":"Cryo-EM of the budding yeast KMN complex with biochemical binding and genetic validation","pmids":["bio_10.1101_2025.06.03.657598"],"confidence":"High","gaps":["Preprint","Human KMN structural confirmation not provided","Dynamics of phosphorylation-triggered release not directly visualized"]},{"year":2026,"claim":"Defined a non-kinetochore moonlighting role in which DSN1 stabilizes c-MYC by competing with FZR1, linking DSN1 to oncogenic protein homeostasis.","evidence":"Cycloheximide chase, proteasome inhibition, Co-IP, c-MYC rescue, and in vivo metastasis assays","pmids":["41713835"],"confidence":"Medium","gaps":["Single lab","Whether this function depends on or is separable from kinetochore DSN1 is unknown","Structural basis of DSN1-FZR1 competition undefined"]},{"year":null,"claim":"How DSN1's canonical kinetochore role mechanistically connects to its proposed oncogenic functions (CENPT-driven instability, c-MYC stabilization) remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No reconstitution distinguishing kinetochore versus cytoplasmic DSN1 pools","Human structural data for auto-inhibition lacking","Causality of DSN1 in human tumorigenesis not established by genetic models"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[3]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[3,4]}],"localization":[{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[1,3]}],"pathway":[{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[1,3,7]}],"complexes":["MIS12 complex (Mis12c)","KMN network","kinetochore"],"partners":["CENP-C","CENP-U","CENPT","MIS12","NNF1","FZR1","SRSF9","ESRRA"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9H410","full_name":"Kinetochore-associated protein DSN1 homolog","aliases":[],"length_aa":356,"mass_kda":40.1,"function":"Part of the MIS12 complex which is required for normal chromosome alignment and segregation and kinetochore formation during mitosis","subcellular_location":"Nucleus; Chromosome, centromere, kinetochore","url":"https://www.uniprot.org/uniprotkb/Q9H410/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/DSN1","classification":"Common Essential","n_dependent_lines":1106,"n_total_lines":1208,"dependency_fraction":0.9155629139072847},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"MIS12","stoichiometry":10.0},{"gene":"CBX1","stoichiometry":0.2},{"gene":"DNAJC7","stoichiometry":0.2},{"gene":"HSPA4","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/DSN1","total_profiled":1310},"omim":[{"mim_id":"609175","title":"DSN1, MIS12 KINETOCHORE COMPLEX COMPONENT; DSN1","url":"https://www.omim.org/entry/609175"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"},{"location":"Nucleoli fibrillar center","reliability":"Additional"},{"location":"Nuclear bodies","reliability":"Additional"},{"location":"Kinetochore","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/DSN1"},"hgnc":{"alias_symbol":["dJ469A13.2","MIS13","KNL3","hKNL-3"],"prev_symbol":["C20orf172"]},"alphafold":{"accession":"Q9H410","domains":[{"cath_id":"-","chopping":"118-194","consensus_level":"high","plddt":88.5304,"start":118,"end":194}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H410","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H410-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H410-F1-predicted_aligned_error_v6.png","plddt_mean":67.75},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=DSN1","jax_strain_url":"https://www.jax.org/strain/search?query=DSN1"},"sequence":{"accession":"Q9H410","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9H410.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9H410/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H410"}},"corpus_meta":[{"pmid":"27329586","id":"PMC_27329586","title":"Over-expression of AURKA, SKA3 and DSN1 contributes to colorectal adenoma to carcinoma progression.","date":"2016","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/27329586","citation_count":68,"is_preprint":false},{"pmid":"34131395","id":"PMC_34131395","title":"ESRRA promotes gastric cancer development by regulating the CDC25C/CDK1/CyclinB1 pathway via DSN1.","date":"2021","source":"International journal of biological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/34131395","citation_count":43,"is_preprint":false},{"pmid":"35509101","id":"PMC_35509101","title":"SRSF9 promotes colorectal cancer progression via stabilizing DSN1 mRNA in an m6A-related manner.","date":"2022","source":"Journal of translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/35509101","citation_count":37,"is_preprint":false},{"pmid":"23408894","id":"PMC_23408894","title":"The Mub1/Ubr2 ubiquitin ligase complex regulates the conserved Dsn1 kinetochore protein.","date":"2013","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/23408894","citation_count":26,"is_preprint":false},{"pmid":"33153400","id":"PMC_33153400","title":"Identification of CDCA8, DSN1 and BIRC5 in Regulating Cell Cycle and Apoptosis in Osteosarcoma Using Bioinformatics and Cell Biology.","date":"2020","source":"Technology in cancer research & treatment","url":"https://pubmed.ncbi.nlm.nih.gov/33153400","citation_count":17,"is_preprint":false},{"pmid":"19270503","id":"PMC_19270503","title":"Searching for Drosophila Dsn1 kinetochore protein.","date":"2009","source":"Cell cycle (Georgetown, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/19270503","citation_count":14,"is_preprint":false},{"pmid":"39178843","id":"PMC_39178843","title":"A conserved germline-specific Dsn1 alternative splice isoform supports oocyte and embryo development.","date":"2024","source":"Current biology : CB","url":"https://pubmed.ncbi.nlm.nih.gov/39178843","citation_count":10,"is_preprint":false},{"pmid":"38659852","id":"PMC_38659852","title":"A conserved germline-specific Dsn1 alternative splice isoform supports oocyte and embryo development.","date":"2024","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/38659852","citation_count":1,"is_preprint":false},{"pmid":"39560395","id":"PMC_39560395","title":"DSN1 Interaction With Centromere-Associated Proteins Promotes Chromosomal Instability in Hepatocellular Carcinoma.","date":"2024","source":"Molecular carcinogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/39560395","citation_count":1,"is_preprint":false},{"pmid":"41640445","id":"PMC_41640445","title":"DSN1 drives breast cancer progression via cell cycle regulation: diagnostic and therapeutic implications.","date":"2026","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/41640445","citation_count":0,"is_preprint":false},{"pmid":"41713835","id":"PMC_41713835","title":"DSN1 promotes colorectal cancer metastasis by Inhibiting FZR1-Mediated ubiquitination of c-MYC.","date":"2026","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/41713835","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.06.03.657598","title":"Assembly and phospho-regulatory mechanisms of the budding yeast outer kinetochore KMN complex","date":"2025-06-04","source":"bioRxiv","url":"https://doi.org/10.1101/2025.06.03.657598","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.11.27.24318050","title":"Bioinformatics and machine learning-based identification of cell cycle-related genes and molecular subtypes in endometrial cancer","date":"2024-11-28","source":"bioRxiv","url":"https://doi.org/10.1101/2024.11.27.24318050","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.06.20.599825","title":"Molecular details and phospho-regulation of the CENP-T-Mis12 complex interaction during mitosis in DT40 cells","date":"2024-06-20","source":"bioRxiv","url":"https://doi.org/10.1101/2024.06.20.599825","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9136,"output_tokens":2614,"usd":0.033309,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9822,"output_tokens":2996,"usd":0.062005,"stage2_stop_reason":"end_turn"},"total_usd":0.095314,"stage1_batch_id":"msgbatch_01AsR7g8dGTEiEw9U83bJeWn","stage2_batch_id":"msgbatch_01YV5ZyxtFNUZEjxRcpd9jzb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2013,\n      \"finding\": \"The Mub1/Ubr2 ubiquitin ligase complex associates with kinetochore particles through CENP-C (Mif2) and regulates the levels of yeast Dsn1 via ubiquitylation; deletion of Mub1/Ubr2 restores levels of a mutant Dsn1, indicating a quality control mechanism that targets aberrant Dsn1 for proteasomal degradation.\",\n      \"method\": \"Kinetochore particle purification, Co-IP/mass spectrometry, genetic deletion analysis, ubiquitylation assays\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal biochemical purification, genetic epistasis (deletion rescue of mutant), and ubiquitylation assay; multiple orthogonal methods in a single rigorous study\",\n      \"pmids\": [\"23408894\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Mammalian germ cells express a germline-specific alternative splice isoform of DSN1 that lacks a key regulatory region required for Aurora kinase phosphorylation, resulting in constitutive centromere/kinetochore localization independent of Aurora B phosphorylation. Expression of this isoform in somatic cells causes constitutive kinetochore localization, chromosome segregation errors, and growth defects. Precise elimination of this germline isoform in mice disrupts oocyte maturation, early embryonic divisions, and reduces fertility.\",\n      \"method\": \"Alternative splicing identification, live-cell imaging, mouse genetic knockout of germline isoform, cell-based overexpression assays, Aurora kinase phosphorylation analysis\",\n      \"journal\": \"Current biology : CB\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — mouse knockout model with specific fertility/oocyte phenotype, somatic cell expression with defined segregation phenotype, mechanistic link to Aurora kinase phosphorylation; multiple orthogonal methods\",\n      \"pmids\": [\"39178843\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"A germline-specific DSN1 splice isoform (preprint version of the same study) bypasses Aurora kinase phosphorylation requirement for centromere localization; somatic expression causes constitutive kinetochore localization and chromosome segregation errors; germline isoform knockout in mice impairs oocyte maturation and early embryo divisions.\",\n      \"method\": \"Mouse genetic models, cell-based expression assays, live-cell imaging\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — same findings as peer-reviewed paper but preprint; included only to note temporal precedence; confidence limited to preprint status\",\n      \"pmids\": [\"38659852\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Cryo-EM structures of the budding yeast KMN complex reveal that the N-terminal auto-inhibitory segment of Dsn1 (Dsn1-AI) folds into two α-helices that engage the Mis12c head domain, occluding binding sites for inner kinetochore subunits CENP-C (Mif2) and CENP-U (Ame1), reducing their affinity for Mis12c. Aurora B (Ipl1) phosphorylation of Dsn1-AI releases this auto-inhibition, strengthening inner-outer kinetochore connections. C-terminal α-helical motifs of Dsn1, Mis12/Mtw1, and Nnf1 bind Knl1c and Ndc80c to mediate KMN assembly.\",\n      \"method\": \"Cryo-EM structure determination, biochemical binding assays, genetic experiments\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structure with biochemical and genetic validation; multiple orthogonal methods in a single rigorous study; preprint but with comprehensive structural and functional data\",\n      \"pmids\": [\"bio_10.1101_2025.06.03.657598\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"In chicken DT40 cells lacking CENP-C–Mis12C interaction, CENP-T interacts with Mis12C through two distinct binding surfaces; this interaction is cooperatively regulated by dual phosphorylation of Dsn1 (a Mis12C component) and CENP-T, ensuring robust CENP-T–Mis12C interaction and proper mitotic progression.\",\n      \"method\": \"AlphaFold2-guided mutagenesis, cell viability assays in DT40 cells lacking CENP-C–Mis12C interaction, biochemical binding experiments\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic cell system with defined interaction surfaces and phosphorylation sites, AlphaFold2-guided but experimentally validated; preprint, single lab\",\n      \"pmids\": [\"bio_10.1101_2024.06.20.599825\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"DSN1 directly interacts with Centromere Protein T (CENPT) in hepatocellular carcinoma cells, and elevated DSN1 expression leads to overproduction of cell cycle-related proteins through this interaction, contributing to chromosomal instability.\",\n      \"method\": \"siRNA/shRNA knockdown, overexpression vectors, co-immunoprecipitation implied by 'direct interaction', xenograft model\",\n      \"journal\": \"Molecular carcinogenesis\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, interaction inferred from cancer cell lines with limited mechanistic detail in abstract; no structural or reconstitution data described\",\n      \"pmids\": [\"39560395\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"SRSF9 binds to DSN1 mRNA in an m6A-dependent manner (two m6A modification sites identified in the SRSF9-binding region) and stabilizes DSN1 mRNA; METTL3 knockdown impairs SRSF9-mediated stabilization of DSN1 mRNA, establishing METTL3 as the m6A writer enabling SRSF9 (reader) to stabilize DSN1 transcript.\",\n      \"method\": \"Methylated RNA affinity assays, gene-specific m6A qRT-PCR, RNA stability assays, METTL3 knockdown, dual-luciferase reporter assays\",\n      \"journal\": \"Journal of translational medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (RNA affinity, m6A qRT-PCR, stability assays, writer knockdown) in single lab; establishes mechanistic post-transcriptional regulation of DSN1 mRNA\",\n      \"pmids\": [\"35509101\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"ESRRA acts as a transcription factor that directly binds the DSN1 promoter and activates DSN1 transcription; ESRRA silencing causes G2/M arrest via the CDC25C–CDK1–Cyclin B1 pathway, which is downstream of DSN1.\",\n      \"method\": \"RNA-seq, dual-luciferase assay, ChIP assay, Western blotting, flow cytometry, ESRRA knockdown\",\n      \"journal\": \"International journal of biological sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and dual-luciferase confirm direct promoter binding; pathway placement via ESRRA→DSN1→CDC25C-CDK1-CyclinB1; single lab\",\n      \"pmids\": [\"34131395\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"DSN1 competes with c-MYC for binding to FZR1 (an E3 ubiquitin ligase), thereby attenuating FZR1-mediated ubiquitination of c-MYC and preventing its proteasomal degradation; DSN1 knockdown accelerates c-MYC protein degradation through the ubiquitin-proteasome pathway without affecting c-MYC mRNA levels.\",\n      \"method\": \"Cycloheximide chase assay, proteasome inhibition assay, co-immunoprecipitation to identify FZR1-DSN1-c-MYC interaction, rescue experiments with c-MYC overexpression, in vivo metastasis assays\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — competitive binding mechanism supported by Co-IP, cycloheximide chase, proteasome inhibition, and rescue experiments; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"41713835\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"DSN1 is a core subunit of the MIS12 kinetochore complex that bridges centromeres to spindle microtubules; its N-terminal auto-inhibitory segment occludes CENP-C and CENP-U binding sites until Aurora B phosphorylation releases this inhibition to license inner-outer kinetochore assembly, a somatic regulation bypassed by a germline-specific splice isoform required for mammalian fertility; at the protein level, Mub1/Ubr2 ubiquitin ligase provides quality control by ubiquitylating aberrant Dsn1, while in cancer cells DSN1 also stabilizes c-MYC by competing with FZR1-mediated ubiquitination; transcriptionally, ESRRA drives DSN1 expression, and post-transcriptionally SRSF9 stabilizes DSN1 mRNA in an METTL3-dependent m6A-reading mechanism.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"DSN1 is a core subunit of the MIS12 (Mis12c) kinetochore complex that bridges the inner centromere to the outer microtubule-binding machinery during mitosis [#3]. Structurally, its N-terminal auto-inhibitory segment folds into two α-helices that engage the Mis12c head and occlude the binding sites for inner kinetochore subunits CENP-C (Mif2) and CENP-U (Ame1); Aurora B (Ipl1) phosphorylation of this segment relieves the auto-inhibition to strengthen inner-outer kinetochore connections, while C-terminal α-helical motifs of Dsn1 together with Mis12 and Nnf1 bind Knl1c and Ndc80c to assemble the KMN network [#3]. DSN1 phosphorylation also cooperates with CENP-T phosphorylation to support a CENP-T–Mis12c interaction that ensures proper mitotic progression [#4]. A germline-specific alternative splice isoform lacks the regulatory region required for Aurora kinase phosphorylation, producing constitutive centromere localization; ectopic somatic expression of this isoform causes chromosome segregation errors, and its elimination in mice disrupts oocyte maturation, early embryonic divisions, and fertility [#1]. DSN1 abundance is controlled at multiple levels: the Mub1/Ubr2 ubiquitin ligase ubiquitylates aberrant Dsn1 for proteasomal degradation as a quality-control mechanism [#0], ESRRA directly activates DSN1 transcription upstream of a CDC25C–CDK1–Cyclin B1 axis [#7], and METTL3-dependent m6A marks on DSN1 mRNA are read by SRSF9 to stabilize the transcript [#6]. In cancer cells DSN1 additionally stabilizes c-MYC by competing with FZR1 for binding, thereby attenuating FZR1-mediated c-MYC ubiquitination [#8].\",\n  \"teleology\": [\n    {\n      \"year\": 2013,\n      \"claim\": \"Established that Dsn1 protein levels are actively policed at the kinetochore, identifying a ubiquitin-dependent quality control route for aberrant subunit.\",\n      \"evidence\": \"Kinetochore particle purification, Co-IP/mass spectrometry, and ubiquitylation assays with genetic deletion rescue in yeast\",\n      \"pmids\": [\"23408894\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not define which structural features of Dsn1 mark it as aberrant\", \"Mammalian conservation of Mub1/Ubr2-mediated control not addressed\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identified ESRRA as a direct transcriptional activator of DSN1, placing DSN1 upstream of the CDC25C–CDK1–Cyclin B1 G2/M control axis.\",\n      \"evidence\": \"ChIP, dual-luciferase promoter assay, RNA-seq and flow cytometry with ESRRA knockdown\",\n      \"pmids\": [\"34131395\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Mechanistic link between DSN1 and CDC25C-CDK1-CyclinB1 not biochemically resolved\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Defined post-transcriptional control of DSN1 by an m6A-reader mechanism, explaining how DSN1 transcript stability is set.\",\n      \"evidence\": \"m6A affinity and qRT-PCR, RNA stability assays, dual-luciferase reporters with METTL3 knockdown\",\n      \"pmids\": [\"35509101\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Physiological/disease context of SRSF9-DSN1 regulation not established\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Showed that a germline-specific DSN1 splice isoform bypasses Aurora-dependent regulation, linking DSN1 phospho-regulation to mammalian fertility and chromosome segregation fidelity.\",\n      \"evidence\": \"Alternative splice identification, live-cell imaging, somatic overexpression phenotyping, and mouse knockout of the germline isoform\",\n      \"pmids\": [\"39178843\", \"38659852\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Why germline cells require phosphorylation-independent localization is unresolved\", \"Structural basis of isoform behavior not directly determined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Established an alternative CENP-T–Mis12c attachment route co-regulated by Dsn1 and CENP-T phosphorylation, complementing the CENP-C-dependent pathway.\",\n      \"evidence\": \"AlphaFold2-guided mutagenesis and viability/binding assays in DT40 cells lacking CENP-C–Mis12c interaction\",\n      \"pmids\": [\"bio_10.1101_2024.06.20.599825\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, single lab\", \"Relative contribution of CENP-T versus CENP-C pathways in normal cells not quantified\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Reported a direct DSN1–CENPT interaction driving cell-cycle protein overproduction and chromosomal instability in hepatocellular carcinoma, suggesting an oncogenic dimension to DSN1 function.\",\n      \"evidence\": \"siRNA/shRNA knockdown, overexpression, co-immunoprecipitation, and xenograft model in HCC cells\",\n      \"pmids\": [\"39560395\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Interaction inferred with limited mechanistic detail; no structural or reconstitution data\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Provided the structural mechanism of DSN1 auto-inhibition, showing how its N-terminal segment occludes CENP-C/CENP-U binding until Aurora B phosphorylation licenses kinetochore assembly.\",\n      \"evidence\": \"Cryo-EM of the budding yeast KMN complex with biochemical binding and genetic validation\",\n      \"pmids\": [\"bio_10.1101_2025.06.03.657598\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Preprint\", \"Human KMN structural confirmation not provided\", \"Dynamics of phosphorylation-triggered release not directly visualized\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Defined a non-kinetochore moonlighting role in which DSN1 stabilizes c-MYC by competing with FZR1, linking DSN1 to oncogenic protein homeostasis.\",\n      \"evidence\": \"Cycloheximide chase, proteasome inhibition, Co-IP, c-MYC rescue, and in vivo metastasis assays\",\n      \"pmids\": [\"41713835\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Whether this function depends on or is separable from kinetochore DSN1 is unknown\", \"Structural basis of DSN1-FZR1 competition undefined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How DSN1's canonical kinetochore role mechanistically connects to its proposed oncogenic functions (CENPT-driven instability, c-MYC stabilization) remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No reconstitution distinguishing kinetochore versus cytoplasmic DSN1 pools\", \"Human structural data for auto-inhibition lacking\", \"Causality of DSN1 in human tumorigenesis not established by genetic models\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [3, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [1, 3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [1, 3, 7]}\n    ],\n    \"complexes\": [\"MIS12 complex (Mis12c)\", \"KMN network\", \"kinetochore\"],\n    \"partners\": [\"CENP-C\", \"CENP-U\", \"CENPT\", \"MIS12\", \"NNF1\", \"FZR1\", \"SRSF9\", \"ESRRA\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":3,"faith_total":3,"faith_pct":100.0}}