{"gene":"SPC24","run_date":"2026-06-10T07:46:39","timeline":{"discoveries":[{"year":2002,"finding":"Yeast Spc24 physically interacts with Mps2 (verified by co-immunoprecipitation in vivo and in vitro interaction of recombinant proteins), and also interacts with Spc25 and Ndc80 (verified by TAP-tag purification). Spc24 is required for chromosome segregation but not spindle pole body duplication.","method":"Co-immunoprecipitation, in vitro recombinant protein interaction, TAP-tag purification, two-hybrid, thermosensitive mutant phenotypic analysis","journal":"Molecular microbiology","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — reciprocal Co-IP plus in vitro recombinant protein interaction plus TAP purification, multiple orthogonal methods in one study","pmids":["11952896"],"is_preprint":false},{"year":2007,"finding":"Yeast Spc24 (Ndc80 kinetochore complex component) is required for spindle integrity during DNA replication stress; loss of Spc24 function causes premature spindle expansion and segregation of incompletely replicated DNA upon hydroxyurea treatment. Spc24 is required for kinetochore localization of the MT-associated protein Stu2 (XMAP215 orthologue); mislocalization of Stu2 leads to premature spindle expansion in spc24 mutants.","method":"Genetic epistasis (spc24-9 thermosensitive mutant + hydroxyurea), overexpression rescue, live-cell imaging, fluorescence localization of Stu1 and Stu2","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (genetics, localization, epistasis rescue), single lab","pmids":["17507656"],"is_preprint":false},{"year":2016,"finding":"Mouse Spc24 localizes to kinetochores during oocyte meiosis. Depletion of Spc24 by siRNA causes defective kinetochore-microtubule attachments, chromosome misalignment, accelerated first meiosis, abrogation of kinetochore recruitment of the spindle assembly checkpoint protein Mad2, and high incidence of aneuploidy.","method":"siRNA knockdown in mouse oocytes, immunofluorescence localization, spindle assembly checkpoint analysis (Mad2 kinetochore recruitment)","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization experiment plus functional siRNA knockdown with defined molecular phenotype (Mad2 loss from kinetochore), single lab","pmids":["27713128"],"is_preprint":false},{"year":2017,"finding":"SPC24 knockdown in osteosarcoma cells decreases EGFR, Ras, and phospho-ERK levels and increases E-cadherin levels, placing SPC24 upstream of the EGFR/Ras/ERK signaling pathway and EMT in osteosarcoma. This was recapitulated in vivo in xenograft models.","method":"siRNA/shRNA knockdown, western blotting, xenograft in vivo model","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — KD with defined molecular readouts (EGFR, phospho-ERK, E-cadherin) in vitro and in vivo, single lab","pmids":["29285250"],"is_preprint":false},{"year":2018,"finding":"SPC24 knockdown in breast cancer cells attenuates cell growth, increases apoptosis, and alters cell cycle progression; molecular analysis indicates SPC24 regulates the PI3K/AKT signaling pathway.","method":"shRNA knockdown, western blotting for PI3K/AKT pathway components, in vivo xenograft","journal":"Gene","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, KD with pathway western blot but no direct biochemical linkage between SPC24 and PI3K/AKT","pmids":["30180968"],"is_preprint":false},{"year":2021,"finding":"miR-7-5p directly targets SPC24 mRNA; luciferase reporter and RNA pull-down assays confirmed the interaction. miR-7-5p suppresses HCC cell proliferation, migration, and promotes apoptosis, and this effect is relieved by overexpression of SPC24.","method":"Luciferase reporter assay, RNA pull-down, CCK-8/BrdU/transwell assays, rescue overexpression","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — two orthogonal binding assays (luciferase + RNA pull-down) plus functional rescue, single lab","pmids":["34020142"],"is_preprint":false},{"year":2022,"finding":"The lncRNA LINC02154 enhances SPC24 promoter activity (at the -500 bp to -1000 bp region) as shown by dual-luciferase reporter assay, leading to upregulation of SPC24 and activation of PI3K/AKT signaling and downstream cell cycle and EMT-associated gene expression in HCC cells.","method":"Dual-luciferase reporter assay, RNA sequencing, western blotting, nuclear-cytoplasmic fractionation, FISH","journal":"Cellular oncology (Dordrecht, Netherlands)","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — direct promoter activity assay plus transcriptomic/WB validation, single lab; mechanistic link to PI3K/AKT is indirect","pmids":["35543858"],"is_preprint":false},{"year":2025,"finding":"LOH12CR2 lncRNA interacts with and stabilizes the m6A methyltransferase METTL14, which in turn enhances m6A modification of SPC24 mRNA, leading to its degradation. This post-transcriptional mechanism downregulates SPC24 in colorectal cancer cells and suppresses tumor growth.","method":"Transcriptome sequencing, RNA immunoprecipitation/interaction assay, m6A modification assay, functional in vitro and in vivo (xenograft) experiments","journal":"Cellular signalling","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — mechanistic pathway (LOH12CR2-METTL14-m6A-SPC24 mRNA) supported by multiple methods, single lab","pmids":["40848939"],"is_preprint":false},{"year":2025,"finding":"Transcription factor E2F7 transcriptionally activates SPC24 expression in breast cancer, as validated by dual-luciferase reporter assay and chromatin immunoprecipitation (ChIP). SPC24 promotes cancer cell stemness through aerobic glycolysis reprogramming (upregulating LDHA, HK2, GLUT1).","method":"Dual-luciferase reporter assay, ChIP, western blotting (glycolysis markers), ECAR/OCR measurement, sphere formation assay","journal":"Journal of bioenergetics and biomembranes","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — two orthogonal methods for transcriptional regulation (luciferase + ChIP) plus functional metabolic readouts, single lab","pmids":["40663204"],"is_preprint":false},{"year":2025,"finding":"Non-catalytic SRC (when its kinase activity is inhibited) promotes transcription of SPC24 by binding to the SPC24 promoter sequence, contributing to resistance to SRC kinase inhibitors in solid tumors.","method":"Promoter binding assay, ChIP (inferred from promoter sequence binding), functional resistance assays in cancer cell lines","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 / Weak — preprint, single lab, limited methodological detail in abstract for the SPC24-specific promoter binding claim","pmids":["bio_10.1101_2025.02.15.638389"],"is_preprint":true}],"current_model":"SPC24 is a conserved component of the Ndc80 kinetochore complex that physically interacts with Spc25, Ndc80, and Mps2, localizes to kinetochores, is required for proper kinetochore-microtubule attachment, spindle assembly checkpoint signaling (Mad2 recruitment), and faithful chromosome segregation during both mitosis and meiosis; in cancer contexts, SPC24 expression is regulated at the transcriptional level by E2F7 and at the post-transcriptional level by miR-7-5p and METTL14-mediated m6A mRNA modification, while SPC24 activity promotes tumor progression through activation of PI3K/AKT and EGFR/Ras/ERK signaling pathways and metabolic reprogramming toward aerobic glycolysis."},"narrative":{"mechanistic_narrative":"SPC24 is a conserved subunit of the Ndc80 kinetochore complex that couples chromosomes to spindle microtubules and supports faithful chromosome segregation [PMID:11952896, PMID:27713128]. In yeast it physically associates with Spc25 and Ndc80 within this complex and additionally interacts with Mps2, and its loss disrupts chromosome segregation without affecting spindle pole body duplication [PMID:11952896]; it is also required for spindle integrity under replication stress, in part by recruiting the microtubule-associated protein Stu2 to kinetochores so that loss of SPC24 causes premature spindle expansion and segregation of incompletely replicated DNA [PMID:17507656]. During mouse oocyte meiosis SPC24 localizes to kinetochores and is needed for proper kinetochore-microtubule attachment, chromosome alignment, and kinetochore recruitment of the spindle assembly checkpoint protein Mad2, with its depletion producing aneuploidy [PMID:27713128]. In cancer, SPC24 is positioned upstream of mitogenic signaling, promoting EGFR/Ras/ERK activity and EMT and PI3K/AKT-driven proliferation [PMID:29285250, PMID:35543858], and its expression is set by multiple regulatory inputs: transcriptional activation by E2F7, which links SPC24 to aerobic glycolysis reprogramming and stemness [PMID:40663204], promoter activation by the lncRNA LINC02154 [PMID:35543858], and post-transcriptional control by miR-7-5p targeting and METTL14-mediated m6A modification of its mRNA [PMID:34020142, PMID:40848939].","teleology":[{"year":2002,"claim":"Established SPC24 as a physical member of the Ndc80 kinetochore complex required for chromosome segregation, distinguishing its role from spindle pole body duplication.","evidence":"Co-IP, in vitro recombinant interaction, TAP-tag purification and thermosensitive mutant analysis in yeast","pmids":["11952896"],"confidence":"High","gaps":["No structural model of how SPC24 bridges Spc25/Ndc80 to microtubules","Functional significance of the Mps2 interaction unresolved"]},{"year":2007,"claim":"Showed SPC24 maintains spindle integrity under replication stress by recruiting the microtubule-associated protein Stu2 to kinetochores, linking the complex to controlled spindle expansion.","evidence":"Genetic epistasis with hydroxyurea, overexpression rescue, and fluorescence localization in yeast","pmids":["17507656"],"confidence":"High","gaps":["Direct SPC24-Stu2 binding not demonstrated","Conservation of the Stu2 recruitment role in metazoans untested"]},{"year":2016,"claim":"Extended SPC24 function to meiosis, demonstrating it is required for kinetochore-microtubule attachment and Mad2-dependent checkpoint signaling to prevent aneuploidy.","evidence":"siRNA knockdown, immunofluorescence localization and Mad2 recruitment analysis in mouse oocytes","pmids":["27713128"],"confidence":"Medium","gaps":["Mechanism of Mad2 recruitment by SPC24 not defined","Single-lab knockdown without rescue"]},{"year":2018,"claim":"Implicated SPC24 in cancer cell growth and survival via PI3K/AKT signaling.","evidence":"shRNA knockdown with pathway western blotting and xenografts in breast cancer cells","pmids":["30180968"],"confidence":"Low","gaps":["No direct biochemical link between SPC24 and PI3K/AKT components","Effect may be secondary to mitotic defects"]},{"year":2017,"claim":"Positioned SPC24 upstream of EGFR/Ras/ERK signaling and EMT in solid tumors.","evidence":"siRNA/shRNA knockdown with western blotting and xenografts in osteosarcoma","pmids":["29285250"],"confidence":"Medium","gaps":["Mechanism by which a kinetochore subunit modulates EGFR/ERK signaling unclear","Single lab, single tumor type"]},{"year":2022,"claim":"Identified transcriptional and non-coding RNA inputs controlling SPC24 abundance, with LINC02154 enhancing its promoter activity and driving PI3K/AKT and EMT programs.","evidence":"Dual-luciferase promoter assay, RNA-seq, fractionation and FISH in HCC cells","pmids":["35543858"],"confidence":"Medium","gaps":["Link to PI3K/AKT is indirect","Direct downstream effectors of SPC24 not identified"]},{"year":2021,"claim":"Defined miR-7-5p as a direct post-transcriptional repressor of SPC24 mRNA controlling HCC proliferation and apoptosis.","evidence":"Luciferase reporter, RNA pull-down and functional rescue overexpression in HCC cells","pmids":["34020142"],"confidence":"Medium","gaps":["Physiological context of miR-7-5p regulation unclear","Single lab"]},{"year":2025,"claim":"Revealed m6A-based control of SPC24 mRNA stability through a LOH12CR2-METTL14 axis that degrades SPC24 transcript to suppress tumor growth.","evidence":"RNA immunoprecipitation, m6A modification assays and xenografts in colorectal cancer","pmids":["40848939"],"confidence":"Medium","gaps":["m6A reader mediating decay not identified","Single lab"]},{"year":2025,"claim":"Linked E2F7-driven transcription of SPC24 to metabolic reprogramming toward aerobic glycolysis and cancer cell stemness.","evidence":"Dual-luciferase reporter, ChIP, glycolysis marker WB and ECAR/OCR measurements in breast cancer","pmids":["40663204"],"confidence":"Medium","gaps":["Mechanistic link between SPC24 and glycolytic gene expression undefined","Single lab"]},{"year":2025,"claim":"Proposed non-catalytic SRC promotes SPC24 transcription to drive resistance to SRC kinase inhibitors.","evidence":"Promoter binding/ChIP and resistance assays in cancer cell lines (preprint)","pmids":["bio_10.1101_2025.02.15.638389"],"confidence":"Low","gaps":["Preprint, limited methodological detail","Direct SRC-promoter binding not independently confirmed"]},{"year":null,"claim":"How SPC24's core kinetochore function mechanistically connects to the diverse oncogenic signaling and metabolic phenotypes attributed to it remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No direct biochemical bridge between SPC24 and EGFR/ERK, PI3K/AKT, or glycolytic machinery","Human kinetochore localization not directly demonstrated in the corpus","Whether oncogenic effects are downstream of mitotic fidelity or separable functions is untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[0,1]}],"localization":[{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[0,1,2]}],"pathway":[{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[0,1,2]}],"complexes":["Ndc80 complex"],"partners":["SPC25","NDC80","MPS2","STU2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8NBT2","full_name":"Kinetochore protein Spc24","aliases":[],"length_aa":197,"mass_kda":22.4,"function":"Acts as a component of the essential kinetochore-associated NDC80 complex, which is required for chromosome segregation and spindle checkpoint activity (PubMed:14738735). Required for kinetochore integrity and the organization of stable microtubule binding sites in the outer plate of the kinetochore (PubMed:14738735). The NDC80 complex synergistically enhances the affinity of the SKA1 complex for microtubules and may allow the NDC80 complex to track depolymerizing microtubules (PubMed:23085020)","subcellular_location":"Nucleus; Chromosome, centromere, kinetochore","url":"https://www.uniprot.org/uniprotkb/Q8NBT2/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/SPC24","classification":"Common Essential","n_dependent_lines":1207,"n_total_lines":1208,"dependency_fraction":0.9991721854304636},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"MIS12","stoichiometry":4.0},{"gene":"HSPA4","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/SPC24","total_profiled":1310},"omim":[{"mim_id":"609395","title":"SPC25, NDC80 KINETOCHORE COMPLEX COMPONENT; SPC25","url":"https://www.omim.org/entry/609395"},{"mim_id":"609394","title":"SPC24, NDC80 KINETOCHORE COMPLEX COMPONENT; SPC24","url":"https://www.omim.org/entry/609394"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"},{"location":"Nucleoli","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"bone marrow","ntpm":24.3},{"tissue":"lymphoid tissue","ntpm":13.7}],"url":"https://www.proteinatlas.org/search/SPC24"},"hgnc":{"alias_symbol":["FLJ90806"],"prev_symbol":["SPBC24"]},"alphafold":{"accession":"Q8NBT2","domains":[{"cath_id":"-","chopping":"152-197","consensus_level":"medium","plddt":89.6552,"start":152,"end":197},{"cath_id":"1.20.5","chopping":"85-148","consensus_level":"medium","plddt":95.2722,"start":85,"end":148}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NBT2","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NBT2-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NBT2-F1-predicted_aligned_error_v6.png","plddt_mean":91.38},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SPC24","jax_strain_url":"https://www.jax.org/strain/search?query=SPC24"},"sequence":{"accession":"Q8NBT2","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8NBT2.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8NBT2/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NBT2"}},"corpus_meta":[{"pmid":"35543858","id":"PMC_35543858","title":"LINC02154 promotes the proliferation and metastasis of hepatocellular carcinoma by enhancing SPC24 promoter activity and activating the PI3K-AKT signaling pathway.","date":"2022","source":"Cellular oncology (Dordrecht, Netherlands)","url":"https://pubmed.ncbi.nlm.nih.gov/35543858","citation_count":25,"is_preprint":false},{"pmid":"11952896","id":"PMC_11952896","title":"Spc24 interacts with Mps2 and is required for chromosome segregation, but is not implicated in spindle pole body duplication.","date":"2002","source":"Molecular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/11952896","citation_count":24,"is_preprint":false},{"pmid":"17507656","id":"PMC_17507656","title":"Spc24 and Stu2 promote spindle integrity when DNA replication is stalled.","date":"2007","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/17507656","citation_count":23,"is_preprint":false},{"pmid":"34020142","id":"PMC_34020142","title":"hsa-miR-7-5p suppresses proliferation, migration and promotes apoptosis in hepatocellular carcinoma cell lines by inhibiting SPC24 expression.","date":"2021","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/34020142","citation_count":23,"is_preprint":false},{"pmid":"30180968","id":"PMC_30180968","title":"SPC24 Regulates breast cancer progression by PI3K/AKT signaling.","date":"2018","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/30180968","citation_count":21,"is_preprint":false},{"pmid":"28423533","id":"PMC_28423533","title":"SPC24 is critical for anaplastic thyroid cancer progression.","date":"2017","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/28423533","citation_count":18,"is_preprint":false},{"pmid":"29285250","id":"PMC_29285250","title":"SPC24 promotes osteosarcoma progression by increasing EGFR/MAPK signaling.","date":"2017","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/29285250","citation_count":12,"is_preprint":false},{"pmid":"27713128","id":"PMC_27713128","title":"Spc24 is required for meiotic kinetochore-microtubule attachment and production of euploid eggs.","date":"2016","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/27713128","citation_count":9,"is_preprint":false},{"pmid":"34306192","id":"PMC_34306192","title":"Increased SPC24 in prostatic diseases and diagnostic value of SPC24 and its interacting partners in prostate cancer.","date":"2021","source":"Experimental and therapeutic medicine","url":"https://pubmed.ncbi.nlm.nih.gov/34306192","citation_count":5,"is_preprint":false},{"pmid":"40848939","id":"PMC_40848939","title":"LOH12CR2 activated by sodium butyrate suppresses tumorigenesis in colorectal cancer via METTL14-mediated N6-methyladenosine modification of SPC24 mRNA.","date":"2025","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/40848939","citation_count":1,"is_preprint":false},{"pmid":"40663204","id":"PMC_40663204","title":"E2F7 transcriptionally upregulates SPC24 to mediate aerobic Glycolysis and facilitate stemness of breast cancer.","date":"2025","source":"Journal of bioenergetics and biomembranes","url":"https://pubmed.ncbi.nlm.nih.gov/40663204","citation_count":1,"is_preprint":false},{"pmid":"42109651","id":"PMC_42109651","title":"SPC24 boosts tumor progression and correlates with immune infiltrates in pancreatic adenocarcinoma.","date":"2026","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/42109651","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.02.15.638389","title":"Targeting Non-catalytic Sites of SRC Sensitizes the Efficacy of SRC Kinase Inhibitors in Solid Tumors","date":"2025-02-18","source":"bioRxiv","url":"https://doi.org/10.1101/2025.02.15.638389","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":8161,"output_tokens":2540,"usd":0.031291,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9681,"output_tokens":2946,"usd":0.061027,"stage2_stop_reason":"end_turn"},"total_usd":0.092318,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2002,\n      \"finding\": \"Yeast Spc24 physically interacts with Mps2 (verified by co-immunoprecipitation in vivo and in vitro interaction of recombinant proteins), and also interacts with Spc25 and Ndc80 (verified by TAP-tag purification). Spc24 is required for chromosome segregation but not spindle pole body duplication.\",\n      \"method\": \"Co-immunoprecipitation, in vitro recombinant protein interaction, TAP-tag purification, two-hybrid, thermosensitive mutant phenotypic analysis\",\n      \"journal\": \"Molecular microbiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — reciprocal Co-IP plus in vitro recombinant protein interaction plus TAP purification, multiple orthogonal methods in one study\",\n      \"pmids\": [\"11952896\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Yeast Spc24 (Ndc80 kinetochore complex component) is required for spindle integrity during DNA replication stress; loss of Spc24 function causes premature spindle expansion and segregation of incompletely replicated DNA upon hydroxyurea treatment. Spc24 is required for kinetochore localization of the MT-associated protein Stu2 (XMAP215 orthologue); mislocalization of Stu2 leads to premature spindle expansion in spc24 mutants.\",\n      \"method\": \"Genetic epistasis (spc24-9 thermosensitive mutant + hydroxyurea), overexpression rescue, live-cell imaging, fluorescence localization of Stu1 and Stu2\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (genetics, localization, epistasis rescue), single lab\",\n      \"pmids\": [\"17507656\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Mouse Spc24 localizes to kinetochores during oocyte meiosis. Depletion of Spc24 by siRNA causes defective kinetochore-microtubule attachments, chromosome misalignment, accelerated first meiosis, abrogation of kinetochore recruitment of the spindle assembly checkpoint protein Mad2, and high incidence of aneuploidy.\",\n      \"method\": \"siRNA knockdown in mouse oocytes, immunofluorescence localization, spindle assembly checkpoint analysis (Mad2 kinetochore recruitment)\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization experiment plus functional siRNA knockdown with defined molecular phenotype (Mad2 loss from kinetochore), single lab\",\n      \"pmids\": [\"27713128\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"SPC24 knockdown in osteosarcoma cells decreases EGFR, Ras, and phospho-ERK levels and increases E-cadherin levels, placing SPC24 upstream of the EGFR/Ras/ERK signaling pathway and EMT in osteosarcoma. This was recapitulated in vivo in xenograft models.\",\n      \"method\": \"siRNA/shRNA knockdown, western blotting, xenograft in vivo model\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — KD with defined molecular readouts (EGFR, phospho-ERK, E-cadherin) in vitro and in vivo, single lab\",\n      \"pmids\": [\"29285250\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"SPC24 knockdown in breast cancer cells attenuates cell growth, increases apoptosis, and alters cell cycle progression; molecular analysis indicates SPC24 regulates the PI3K/AKT signaling pathway.\",\n      \"method\": \"shRNA knockdown, western blotting for PI3K/AKT pathway components, in vivo xenograft\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, KD with pathway western blot but no direct biochemical linkage between SPC24 and PI3K/AKT\",\n      \"pmids\": [\"30180968\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"miR-7-5p directly targets SPC24 mRNA; luciferase reporter and RNA pull-down assays confirmed the interaction. miR-7-5p suppresses HCC cell proliferation, migration, and promotes apoptosis, and this effect is relieved by overexpression of SPC24.\",\n      \"method\": \"Luciferase reporter assay, RNA pull-down, CCK-8/BrdU/transwell assays, rescue overexpression\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — two orthogonal binding assays (luciferase + RNA pull-down) plus functional rescue, single lab\",\n      \"pmids\": [\"34020142\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"The lncRNA LINC02154 enhances SPC24 promoter activity (at the -500 bp to -1000 bp region) as shown by dual-luciferase reporter assay, leading to upregulation of SPC24 and activation of PI3K/AKT signaling and downstream cell cycle and EMT-associated gene expression in HCC cells.\",\n      \"method\": \"Dual-luciferase reporter assay, RNA sequencing, western blotting, nuclear-cytoplasmic fractionation, FISH\",\n      \"journal\": \"Cellular oncology (Dordrecht, Netherlands)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — direct promoter activity assay plus transcriptomic/WB validation, single lab; mechanistic link to PI3K/AKT is indirect\",\n      \"pmids\": [\"35543858\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"LOH12CR2 lncRNA interacts with and stabilizes the m6A methyltransferase METTL14, which in turn enhances m6A modification of SPC24 mRNA, leading to its degradation. This post-transcriptional mechanism downregulates SPC24 in colorectal cancer cells and suppresses tumor growth.\",\n      \"method\": \"Transcriptome sequencing, RNA immunoprecipitation/interaction assay, m6A modification assay, functional in vitro and in vivo (xenograft) experiments\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — mechanistic pathway (LOH12CR2-METTL14-m6A-SPC24 mRNA) supported by multiple methods, single lab\",\n      \"pmids\": [\"40848939\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Transcription factor E2F7 transcriptionally activates SPC24 expression in breast cancer, as validated by dual-luciferase reporter assay and chromatin immunoprecipitation (ChIP). SPC24 promotes cancer cell stemness through aerobic glycolysis reprogramming (upregulating LDHA, HK2, GLUT1).\",\n      \"method\": \"Dual-luciferase reporter assay, ChIP, western blotting (glycolysis markers), ECAR/OCR measurement, sphere formation assay\",\n      \"journal\": \"Journal of bioenergetics and biomembranes\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — two orthogonal methods for transcriptional regulation (luciferase + ChIP) plus functional metabolic readouts, single lab\",\n      \"pmids\": [\"40663204\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Non-catalytic SRC (when its kinase activity is inhibited) promotes transcription of SPC24 by binding to the SPC24 promoter sequence, contributing to resistance to SRC kinase inhibitors in solid tumors.\",\n      \"method\": \"Promoter binding assay, ChIP (inferred from promoter sequence binding), functional resistance assays in cancer cell lines\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — preprint, single lab, limited methodological detail in abstract for the SPC24-specific promoter binding claim\",\n      \"pmids\": [\"bio_10.1101_2025.02.15.638389\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"SPC24 is a conserved component of the Ndc80 kinetochore complex that physically interacts with Spc25, Ndc80, and Mps2, localizes to kinetochores, is required for proper kinetochore-microtubule attachment, spindle assembly checkpoint signaling (Mad2 recruitment), and faithful chromosome segregation during both mitosis and meiosis; in cancer contexts, SPC24 expression is regulated at the transcriptional level by E2F7 and at the post-transcriptional level by miR-7-5p and METTL14-mediated m6A mRNA modification, while SPC24 activity promotes tumor progression through activation of PI3K/AKT and EGFR/Ras/ERK signaling pathways and metabolic reprogramming toward aerobic glycolysis.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SPC24 is a conserved subunit of the Ndc80 kinetochore complex that couples chromosomes to spindle microtubules and supports faithful chromosome segregation [#0, #2]. In yeast it physically associates with Spc25 and Ndc80 within this complex and additionally interacts with Mps2, and its loss disrupts chromosome segregation without affecting spindle pole body duplication [#0]; it is also required for spindle integrity under replication stress, in part by recruiting the microtubule-associated protein Stu2 to kinetochores so that loss of SPC24 causes premature spindle expansion and segregation of incompletely replicated DNA [#1]. During mouse oocyte meiosis SPC24 localizes to kinetochores and is needed for proper kinetochore-microtubule attachment, chromosome alignment, and kinetochore recruitment of the spindle assembly checkpoint protein Mad2, with its depletion producing aneuploidy [#2]. In cancer, SPC24 is positioned upstream of mitogenic signaling, promoting EGFR/Ras/ERK activity and EMT and PI3K/AKT-driven proliferation [#3, #6], and its expression is set by multiple regulatory inputs: transcriptional activation by E2F7, which links SPC24 to aerobic glycolysis reprogramming and stemness [#8], promoter activation by the lncRNA LINC02154 [#6], and post-transcriptional control by miR-7-5p targeting and METTL14-mediated m6A modification of its mRNA [#5, #7].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Established SPC24 as a physical member of the Ndc80 kinetochore complex required for chromosome segregation, distinguishing its role from spindle pole body duplication.\",\n      \"evidence\": \"Co-IP, in vitro recombinant interaction, TAP-tag purification and thermosensitive mutant analysis in yeast\",\n      \"pmids\": [\"11952896\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structural model of how SPC24 bridges Spc25/Ndc80 to microtubules\", \"Functional significance of the Mps2 interaction unresolved\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Showed SPC24 maintains spindle integrity under replication stress by recruiting the microtubule-associated protein Stu2 to kinetochores, linking the complex to controlled spindle expansion.\",\n      \"evidence\": \"Genetic epistasis with hydroxyurea, overexpression rescue, and fluorescence localization in yeast\",\n      \"pmids\": [\"17507656\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct SPC24-Stu2 binding not demonstrated\", \"Conservation of the Stu2 recruitment role in metazoans untested\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Extended SPC24 function to meiosis, demonstrating it is required for kinetochore-microtubule attachment and Mad2-dependent checkpoint signaling to prevent aneuploidy.\",\n      \"evidence\": \"siRNA knockdown, immunofluorescence localization and Mad2 recruitment analysis in mouse oocytes\",\n      \"pmids\": [\"27713128\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of Mad2 recruitment by SPC24 not defined\", \"Single-lab knockdown without rescue\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Implicated SPC24 in cancer cell growth and survival via PI3K/AKT signaling.\",\n      \"evidence\": \"shRNA knockdown with pathway western blotting and xenografts in breast cancer cells\",\n      \"pmids\": [\"30180968\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct biochemical link between SPC24 and PI3K/AKT components\", \"Effect may be secondary to mitotic defects\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Positioned SPC24 upstream of EGFR/Ras/ERK signaling and EMT in solid tumors.\",\n      \"evidence\": \"siRNA/shRNA knockdown with western blotting and xenografts in osteosarcoma\",\n      \"pmids\": [\"29285250\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which a kinetochore subunit modulates EGFR/ERK signaling unclear\", \"Single lab, single tumor type\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identified transcriptional and non-coding RNA inputs controlling SPC24 abundance, with LINC02154 enhancing its promoter activity and driving PI3K/AKT and EMT programs.\",\n      \"evidence\": \"Dual-luciferase promoter assay, RNA-seq, fractionation and FISH in HCC cells\",\n      \"pmids\": [\"35543858\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Link to PI3K/AKT is indirect\", \"Direct downstream effectors of SPC24 not identified\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Defined miR-7-5p as a direct post-transcriptional repressor of SPC24 mRNA controlling HCC proliferation and apoptosis.\",\n      \"evidence\": \"Luciferase reporter, RNA pull-down and functional rescue overexpression in HCC cells\",\n      \"pmids\": [\"34020142\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological context of miR-7-5p regulation unclear\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Revealed m6A-based control of SPC24 mRNA stability through a LOH12CR2-METTL14 axis that degrades SPC24 transcript to suppress tumor growth.\",\n      \"evidence\": \"RNA immunoprecipitation, m6A modification assays and xenografts in colorectal cancer\",\n      \"pmids\": [\"40848939\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"m6A reader mediating decay not identified\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Linked E2F7-driven transcription of SPC24 to metabolic reprogramming toward aerobic glycolysis and cancer cell stemness.\",\n      \"evidence\": \"Dual-luciferase reporter, ChIP, glycolysis marker WB and ECAR/OCR measurements in breast cancer\",\n      \"pmids\": [\"40663204\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanistic link between SPC24 and glycolytic gene expression undefined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Proposed non-catalytic SRC promotes SPC24 transcription to drive resistance to SRC kinase inhibitors.\",\n      \"evidence\": \"Promoter binding/ChIP and resistance assays in cancer cell lines (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.02.15.638389\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Preprint, limited methodological detail\", \"Direct SRC-promoter binding not independently confirmed\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How SPC24's core kinetochore function mechanistically connects to the diverse oncogenic signaling and metabolic phenotypes attributed to it remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct biochemical bridge between SPC24 and EGFR/ERK, PI3K/AKT, or glycolytic machinery\", \"Human kinetochore localization not directly demonstrated in the corpus\", \"Whether oncogenic effects are downstream of mitotic fidelity or separable functions is untested\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"complexes\": [\"Ndc80 complex\"],\n    \"partners\": [\"SPC25\", \"NDC80\", \"MPS2\", \"STU2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":4,"faith_pct":100.0}}