{"gene":"CKS2","run_date":"2026-04-28T17:28:52","timeline":{"discoveries":[{"year":2008,"finding":"Cks2 associates with cyclin-dependent kinases and is recruited to chromatin, including promoter regions and open reading frames of CCNB1, CCNA2, and CDK1 genes, with cell cycle periodicity correlating with their transcription; CKS1/CKS2 double knockdown causes G2 arrest rescued by cyclin B1 restoration, indicating a direct transcriptional role in cell cycle gene expression","method":"RNAi silencing in MEFs and HeLa cells, chromatin immunoprecipitation, rescue experiments with cyclin B1 re-expression, double knockout mouse (embryonic lethal at morula stage)","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (RNAi, ChIP, genetic KO, rescue), strong mechanistic follow-through","pmids":["18625720"],"is_preprint":false},{"year":2011,"finding":"Cks2 binds CDK2 and this interaction confers partial resistance to inhibitory tyrosine phosphorylation mediated by the intra-S-phase checkpoint, allowing continued DNA replication under replicative stress","method":"Overexpression of Cks1/Cks2 in human mammary epithelial and breast cancer cells, intra-S-phase checkpoint assays, CDK2 binding studies","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 — direct CDK2-binding mechanism with functional checkpoint assay, multiple cell types tested","pmids":["21697511"],"is_preprint":false},{"year":2012,"finding":"CKS2 counteracts CKS1 to stabilize p27 (CDKN1B); in Cks2−/− mice, unopposed CKS1 activity leads to p27 loss, unrestricted cyclin A/CDK2 activity, shortened cell cycle, increased replication fork velocity, and DNA damage; CKS2 loss also impairs cortical progenitor differentiation into neurons, phenocopying p27 loss","method":"Cks2 knockout mouse model, genetic epistasis with Cks1, p27 protein quantification, replication fork velocity assays, cortical neurogenesis analysis","journal":"Developmental cell","confidence":"High","confidence_rationale":"Tier 2 — clean KO with multiple defined cellular phenotypes and genetic epistasis placing CKS2 upstream of CKS1/p27/cyclinA-CDK2 axis","pmids":["22898779"],"is_preprint":false},{"year":2017,"finding":"CKS1 and CKS2 proteins interact with both the MllN and MllC subunits of Mll1 (Mixed-lineage leukaemia 1), and together define Mll1 protein levels throughout the cell cycle, in concert with SCFSkp2 and APCCdc20 ubiquitin ligase complexes","method":"Co-immunoprecipitation, small molecule inhibitors of protein degradation (MLN4924 and C1), proliferation assays in MLLr cell lines","journal":"Biochimica et biophysica acta. Molecular cell research","confidence":"Medium","confidence_rationale":"Tier 3 — Co-IP interaction validated with functional inhibitor experiments, single lab","pmids":["28939057"],"is_preprint":false},{"year":2019,"finding":"CKS2 forms a complex with mitochondrial single-stranded DNA binding protein SSBP1 and CDK1 in the mitochondrion, with complex abundance regulated by cell cycle progression consistent with mitochondrial DNA replication activity; cytoplasmic/mitochondrial CKS2 localization adds independent prognostic impact beyond nuclear CKS2","method":"In situ proximity ligation assay in tumor samples and cervical cancer cell lines (HeLa, SiHa), flow cytometry cell cycle analysis, hypoxia modulation of complex abundance, immunohistochemistry","journal":"Neoplasia (New York, N.Y.)","confidence":"Medium","confidence_rationale":"Tier 3 — proximity ligation assay (not full Co-IP reconstitution) with cell cycle functional correlation; single lab","pmids":["30856376"],"is_preprint":false},{"year":2008,"finding":"CKS2 overexpression downregulates tumor suppressor p53 and p21(Cip1) in gastric cancer cells, increasing cell growth; conversely, CKS2 siRNA increases p53/p21 and decreases growth; GFP-CKS2 fusion localizes to nucleus","method":"GFP-CKS2 overexpression, CKS2-siRNA, western blot for p53/p21, cell proliferation assays, subcellular localization by fluorescence microscopy","journal":"Journal of cancer research and clinical oncology","confidence":"Medium","confidence_rationale":"Tier 3 — single lab with OE/KD and downstream protein readout; no direct binding assay","pmids":["19034516"],"is_preprint":false},{"year":2008,"finding":"CKS2 knockdown in malignant prostate tumor cells induces programmed cell death (apoptosis), distinct from CKS1 knockdown which primarily inhibits proliferation, indicating non-redundant anti-apoptotic function for CKS2","method":"RNAi-mediated knockdown of CKS1 and CKS2 separately in prostate cancer cell lines, anchorage-independent growth assays, migration assays, cell viability","journal":"International journal of cancer","confidence":"Medium","confidence_rationale":"Tier 3 — KD with specific phenotypic readout distinguishing CKS2 from CKS1; single lab","pmids":["18498131"],"is_preprint":false},{"year":2013,"finding":"miR-26a directly targets the 3'-UTR of CKS2 mRNA to repress its expression; CKS2 in turn indirectly regulates cyclin B1, cyclin A, CDK1, Bcl-xL, and AKT levels; CKS2 knockdown or miR-26a overexpression causes G2 phase arrest in thyroid papillary carcinoma cells","method":"Luciferase reporter assay, western blot, anti-miR/mimic transfection, siRNA, cell cycle assays, xenograft in SCID mice","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 3 — direct 3'-UTR targeting validated by luciferase assay; downstream pathway inferred without direct binding","pmids":["23861775"],"is_preprint":false},{"year":2016,"finding":"miR-7 directly binds the 3'-UTR of CKS2 and negatively regulates CKS2 protein expression; CKS2 downstream targets cyclin B1 and CDK1 are regulated via the miR-7/CKS2 axis; CKS2 knockdown suppresses proliferation, migration, invasion, and causes G0/G1 arrest in thyroid papillary cancer cells","method":"Dual-luciferase reporter assay, western blot, CKS2-siRNA knockdown, cell cycle and apoptosis assays by flow cytometry","journal":"International journal of oncology","confidence":"Medium","confidence_rationale":"Tier 3 — direct 3'-UTR targeting by luciferase assay; downstream cyclin B1/CDK1 regulation by western blot","pmids":["27633373"],"is_preprint":false},{"year":2020,"finding":"CKS2 interacts with DUTPase (DUT) as shown by co-localization and co-immunoprecipitation; CKS2 knockdown does not alter DUTPase total expression but reduces its nuclear distribution, linking CKS2 to regulation of DUTPase subcellular localization and G2/M cell cycle progression","method":"Co-immunoprecipitation, immunofluorescence co-localization, CKS2 siRNA knockdown, flow cytometry cell cycle assay","journal":"Journal of oral pathology & medicine","confidence":"Medium","confidence_rationale":"Tier 3 — Co-IP and IF co-localization with functional nuclear localization consequence; single lab","pmids":["33107644"],"is_preprint":false},{"year":2022,"finding":"The E3 ubiquitin ligase Parkin (PARK2) overexpression decreases CKS2 protein levels in ccRCC cells; mutation of the catalytic domain of PARK2 abolishes the decrease in migration, linking Parkin's ubiquitin ligase activity to CKS2 protein abundance and migratory phenotype","method":"PARK2 overexpression, catalytic domain mutagenesis, mass spectrometry proteomics, CKS2 silencing, migration/invasion assays","journal":"International journal of oncology","confidence":"Medium","confidence_rationale":"Tier 2 — mutagenesis of writer (Parkin catalytic domain) abolishes effect on CKS2 levels; supported by MS proteomics","pmids":["35059737"],"is_preprint":false},{"year":2022,"finding":"E2F1 transcription factor binds the CKS2 promoter to enhance CKS2 expression; CKS2 in turn regulates the PI3K-AKT/PTEN pathway to drive retinoblastoma cell proliferation and DNA replication; CKS2 depletion reduces proliferation, delays DNA replication, and slows xenograft growth","method":"E2F1 ChIP-seq data integration, RNA-seq, CKS2 siRNA KD, rescue overexpression, xenograft in nude mice, western blot for PTEN/PI3K-AKT markers","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP-seq evidence for E2F1 at CKS2 promoter with functional KD and rescue; single lab","pmids":["36096885"],"is_preprint":false},{"year":2022,"finding":"CKS2 overexpression induces nucleocytoplasmic translocation of SMAD2/3 and activates TGFβ/SMAD signaling; inhibition of TGFβ/SMAD (by LY2157299 or SMAD4 siRNA) reverses the tumor-promoting and EMT effects caused by CKS2 overexpression in glioma cells","method":"CKS2 siRNA/overexpression plasmid, western blot and immunofluorescence for EMT/SMAD markers, TGFβ inhibitor LY2157299, SMAD4 siRNA rescue","journal":"Cancer medicine","confidence":"Medium","confidence_rationale":"Tier 3 — genetic rescue with pathway inhibitor places CKS2 upstream of TGFβ/SMAD; single lab","pmids":["36284444"],"is_preprint":false},{"year":2015,"finding":"Cks1 and Cks2 promote proliferation and prevent apoptosis of HepG2 hepatocellular carcinoma cells; knockdown of either reduces phospho-Akt and phospho-GSK-3β levels, implicating the PI3K/Akt signaling pathway downstream of CKS proteins","method":"siRNA knockdown and cDNA overexpression, CCK-8/cell counting proliferation assay, Annexin V/PI apoptosis assay, western blot for p-Akt and p-GSK-3β","journal":"Oncology reports","confidence":"Low","confidence_rationale":"Tier 3 — single lab, single method per readout, pathway placement indirect","pmids":["26531156"],"is_preprint":false},{"year":2017,"finding":"CKS2 knockdown in HCC cells induces PTEN upregulation, suggesting CKS2 suppresses PTEN and may activate the p53 pathway to regulate proliferation","method":"siRNA knockdown in HepG2/C3A and Bel7402 cells, colony formation assay, western blot for PTEN","journal":"Pathology, research and practice","confidence":"Low","confidence_rationale":"Tier 3 — single lab, western blot only for pathway readout","pmids":["29487004"],"is_preprint":false},{"year":2023,"finding":"CKS2 directly interacts with thioredoxin (TXN) as shown by co-immunoprecipitation; TXN functions as an upstream regulatory factor governing CKS2 protein stability in multiple myeloma cells; CKS2 depletion modulates proliferation and apoptosis via the PTEN/AKT/mTOR signaling axis","method":"Co-immunoprecipitation, confocal immunofluorescence, AlphaFold2 structural modeling, CKS2 KD/OE in MM.1S and RPMI-8226 cells, western blot, xenograft model","journal":"Journal of Cancer","confidence":"Low","confidence_rationale":"Tier 3 — Co-IP for TXN interaction is single method; PTEN/AKT/mTOR placement inferred from KD without direct mechanistic rescue","pmids":["40092696"],"is_preprint":false},{"year":2023,"finding":"ELK1 transcription factor directly regulates transcription of the CKS2 gene in pancreatic cancer cells; CKS2 knockdown increases Bax, caspase-3, p53, p21, GADD45α and decreases Bcl-2, cyclin B1, CDK1, cyclin A, and Cdc25C levels","method":"ELK1/CKS2 expression correlation analysis, CKS2 KD/OE functional assays, western blot for downstream targets, xenograft model","journal":"Molecular carcinogenesis","confidence":"Low","confidence_rationale":"Tier 3 — transcription factor regulation inferred without ChIP; downstream targets from western blot only","pmids":["37642304"],"is_preprint":false},{"year":2025,"finding":"DNMT1-mediated hypermethylation of the SOX21 gene promoter silences SOX21, which normally represses CKS2 transcription by binding its promoter; loss of SOX21 therefore leads to elevated CKS2 expression and promotes gastric cancer progression; ChIP and dual-luciferase reporter confirmed SOX21 binding to the CKS2 promoter","method":"ChIP assay, dual-luciferase reporter assay, SOX21 and DNMT1 KD/OE, qMSP for SOX21 methylation, xenograft, rescue experiments","journal":"BMC cancer","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP and luciferase reporter directly validate SOX21 binding to CKS2 promoter with rescue epistasis","pmids":["40676553"],"is_preprint":false},{"year":2025,"finding":"CKS2 promotes bladder cancer cell proliferation and migration via dual mechanisms: downregulating PTEN protein levels (relieving PIP3 degradation and activating PI3K/AKT) and promoting phosphorylation and degradation of p27Kip1 (Thr187), both converging on PI3K/AKT pathway activation; PI3K inhibitor LY294002 reverses CKS2-induced phenotypes","method":"CKS2 OE/KD, western blot for PTEN and p-p27Kip1(Thr187), PI3K inhibitor rescue (LY294002), proliferation/migration/invasion assays","journal":"Cell cycle (Georgetown, Tex.)","confidence":"Medium","confidence_rationale":"Tier 3 — two distinct mechanistic arms (PTEN and p27 phosphorylation) validated by pharmacological rescue; single lab","pmids":["41200902"],"is_preprint":false},{"year":2025,"finding":"CKS2 knockdown decreases phosphorylation of CDK1 (Thr161) and Cyclin B1 (Ser126) in neuroblastoma cells; importin-β inhibitor (importazole) causes CKS2 to accumulate in the cytoplasm rather than the nucleus, inhibiting proliferation; combined CKS2 KD and importazole produces additive anti-tumor effect, indicating nuclear localization is required for CKS2 pro-proliferative function","method":"CKS2 siRNA KD, importazole (importin-β inhibitor) treatment, subcellular fractionation/immunofluorescence for CKS2 localization, western blot for CDK1(Thr161) and CyclinB1(Ser126), in vivo xenograft","journal":"Neurochemical research","confidence":"Medium","confidence_rationale":"Tier 2 — nuclear localization directly tied to proliferative function via importin-β inhibition; CDK1/CyclinB1 phosphorylation readout","pmids":["40696188"],"is_preprint":false},{"year":2025,"finding":"CKS2 activates PI3K/AKT signaling in uterine sarcoma cells, reducing MICA expression on the tumor cell surface and thereby inhibiting NKT cell cytotoxic activity, contributing to immune escape; PI3K inhibitors reversed this effect","method":"CKS2 KD stable lines, colony/TUNEL/invasion assays, PI3K inhibitor rescue, multiplex immunofluorescence for NKT cells and MICA in tumor tissue","journal":"Translational cancer research","confidence":"Low","confidence_rationale":"Tier 3 — PI3K/MICA/NKT axis inferred from KD plus inhibitor; single lab without direct binding or reconstitution","pmids":["40950663"],"is_preprint":false},{"year":2024,"finding":"CKS2 promotes ferroptosis resistance in colon cancer by inducing autophagy-mediated glutathione (GSH) metabolic reprogramming; CKS2 knockdown reduces GSH levels and enhances erastin-induced ferroptosis, and also downregulates GPX4 expression; CKS2 overexpression has opposite effects","method":"CKS2 KD/OE, BODIPY and DCFH-DA staining for lipid peroxidation/ROS, GSH assay, transmission electron microscopy for autophagy, western blot for GPX4, in vivo xenograft with ferroptosis inducers","journal":"Molecular medicine (Cambridge, Mass.)","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal methods (lipid peroxidation, GSH assay, TEM for autophagy, GPX4 western blot, in vivo) in single lab","pmids":["39548421"],"is_preprint":false},{"year":2026,"finding":"METTL3-mediated m6A modification stabilizes CKS2 mRNA in an IGF2BP1-dependent manner; IGF2BP1 directly binds m6A-modified CKS2 transcripts; METTL3 overexpression rescues the suppressive effects of CKS2 silencing on osteosarcoma cells","method":"RIP, MeRIP (m6A-RIP), mRNA stability assays, western blot, co-expression analysis, METTL3 OE rescue of CKS2 KD, in vivo xenograft","journal":"International reviews of immunology","confidence":"Medium","confidence_rationale":"Tier 2 — RIP and MeRIP directly validate m6A reader IGF2BP1 binding CKS2 transcripts; mRNA stability confirmed; rescue epistasis","pmids":["41822976"],"is_preprint":false},{"year":2025,"finding":"In MRTF-null fibroblasts and epithelial cells, CKS2 protein levels are decreased alongside CDK1, while CDK inhibitor p27 is elevated; re-expression of MRTF-A fully reverses these changes, placing CKS2 expression downstream of the MRTF-SRF cytoskeletal transcriptional program","method":"MRTF-A/B genetic knockout in primary and immortalised cells, MRTF-A re-expression rescue, western blot for CKS2/CDK1/p27 protein levels, ROCK/myosin ATPase inhibitor phenocopy experiments","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 — clean genetic KO with full rescue by MRTF-A re-expression, multiple cell types; preprint not yet peer-reviewed","pmids":[],"is_preprint":true}],"current_model":"CKS2 is an evolutionarily conserved CDK-binding subunit that associates directly with CDK2 to confer partial resistance to inhibitory checkpoint phosphorylation, counteracts CKS1-driven p27 degradation to restrain cyclin A/CDK2 activity and safeguard replication fidelity, is recruited to chromatin to promote transcription of CCNB1, CCNA2, and CDK1, interacts with mitochondrial SSBP1 and CDK1 to support mitochondrial DNA replication and OXPHOS, interacts with DUTPase to regulate its nuclear localization, interacts with MLL1 subunits to modulate MLL1 protein levels through the cell cycle, is stabilized by METTL3/IGF2BP1-mediated m6A mRNA modification, is transcriptionally activated by E2F1 and ELK1 and repressed by SOX21 (itself silenced by DNMT1), and requires nuclear import via importin-β for its pro-proliferative function; collectively, CKS2 promotes cell cycle progression and survival through downstream regulation of the PI3K/AKT/PTEN axis, TGFβ/SMAD signaling, p27 phospho-degradation, and ferroptosis resistance via autophagy-driven glutathione metabolism."},"narrative":{"teleology":[{"year":2008,"claim":"Establishing that CKS2 has a direct chromatin-level transcriptional role—not merely a CDK-activating role—resolved how CKS proteins control G2/M gene expression (CCNB1, CCNA2, CDK1) and why combined CKS1/CKS2 loss causes G2 arrest.","evidence":"ChIP showing cell-cycle-periodic CKS2 recruitment to promoters/ORFs of mitotic genes in MEFs and HeLa, RNAi double-KD with cyclin B1 rescue, double-KO embryonic lethality","pmids":["18625720"],"confidence":"High","gaps":["Whether CKS2 acts as a transcriptional co-activator, a chromatin remodeler recruiter, or through CDK-dependent histone phosphorylation is unresolved","Relative contribution of CKS1 vs CKS2 to transcription at individual loci unclear"]},{"year":2008,"claim":"Demonstrating non-redundant functions of CKS2 vs CKS1 in cancer cells—CKS2 knockdown induces apoptosis whereas CKS1 knockdown inhibits proliferation—revealed a specific anti-apoptotic role for CKS2.","evidence":"Separate RNAi KD of CKS1 and CKS2 in prostate cancer cell lines with proliferation and apoptosis readouts","pmids":["18498131"],"confidence":"Medium","gaps":["Direct molecular target mediating the anti-apoptotic effect not identified","Not confirmed in non-cancer cells"]},{"year":2011,"claim":"Showing that CKS2 binding to CDK2 confers partial resistance to inhibitory tyrosine phosphorylation established a mechanism by which CKS2 enables continued DNA replication under checkpoint-activating replicative stress.","evidence":"CKS2 overexpression in mammary epithelial and breast cancer cells with intra-S-phase checkpoint assays and CDK2 binding studies","pmids":["21697511"],"confidence":"High","gaps":["Structural basis of how CKS2 binding shields CDK2 from Wee1/Myt1 phosphorylation unknown","Whether this mechanism operates independently of CKS2's chromatin role is untested"]},{"year":2012,"claim":"Genetic epistasis in Cks2-knockout mice demonstrated that CKS2 restrains CKS1-driven p27 degradation; without CKS2, unopposed CKS1 causes p27 loss, accelerated replication, and DNA damage, revealing CKS2 as a genome-integrity guardian rather than a simple CDK activator.","evidence":"Cks2 KO mouse, genetic epistasis with Cks1, p27 quantification, replication fork velocity assays, cortical neurogenesis analysis","pmids":["22898779"],"confidence":"High","gaps":["Biochemical mechanism by which CKS2 antagonizes CKS1-driven SCFSkp2-mediated p27 ubiquitination is not resolved","Whether CKS2 directly competes with CKS1 for SCFSkp2 binding or operates indirectly is unknown"]},{"year":2017,"claim":"Identification of CKS2 interaction with MLL1 subunits linked CKS proteins to cell-cycle-dependent regulation of MLL1 protein levels, connecting CDK-associated factors to epigenetic gene regulation.","evidence":"Co-immunoprecipitation of CKS1/CKS2 with MllN and MllC, functional inhibitor experiments in MLLr cell lines","pmids":["28939057"],"confidence":"Medium","gaps":["Whether CKS2 directly recruits SCFSkp2 or APCCdc20 to MLL1 for degradation not shown","Functional consequences of CKS2–MLL1 interaction on target gene transcription not defined"]},{"year":2019,"claim":"Detection of a CKS2–CDK1–SSBP1 complex in mitochondria extended CKS2 function beyond the nucleus, suggesting a role in cell-cycle-coupled mitochondrial DNA replication.","evidence":"Proximity ligation assay in tumor tissue and cervical cancer cell lines, flow cytometry cell cycle correlation, hypoxia modulation","pmids":["30856376"],"confidence":"Medium","gaps":["Interaction validated only by PLA, not by reciprocal co-IP or in vitro reconstitution","Direct functional impact on mtDNA replication not measured"]},{"year":2020,"claim":"CKS2 was shown to interact with DUTPase and regulate its nuclear localization, linking CKS2 to nucleotide metabolism and genome maintenance beyond its CDK-binding role.","evidence":"Co-IP and immunofluorescence co-localization; CKS2 KD reduces DUTPase nuclear fraction with G2/M arrest","pmids":["33107644"],"confidence":"Medium","gaps":["Whether CKS2 acts as a nuclear import chaperone for DUTPase or regulates retention indirectly is unknown","Functional consequence of altered DUTPase localization on dUTP misincorporation not tested"]},{"year":2022,"claim":"Convergent studies established that CKS2 expression is transcriptionally driven by E2F1 (ChIP-seq validated) and that CKS2 activates PI3K/AKT signaling through PTEN suppression, placing CKS2 within the Rb–E2F–PI3K axis and the TGFβ/SMAD pathway.","evidence":"E2F1 ChIP-seq at CKS2 promoter with functional KD/rescue and xenograft (retinoblastoma); CKS2 OE inducing SMAD2/3 nuclear translocation reversed by TGFβ inhibitor (glioma)","pmids":["36096885","36284444"],"confidence":"Medium","gaps":["Whether CKS2 directly interacts with PTEN or regulates it transcriptionally/post-translationally not determined","Connection between CKS2-TGFβ axis and CKS2-PI3K axis unclear"]},{"year":2022,"claim":"Parkin (PARK2) ubiquitin ligase activity was shown to reduce CKS2 protein levels, identifying CKS2 as a potential Parkin substrate and connecting CKS2 turnover to the ubiquitin-proteasome system.","evidence":"PARK2 overexpression reduces CKS2; catalytic domain mutation abolishes the effect; mass spectrometry proteomics in ccRCC cells","pmids":["35059737"],"confidence":"Medium","gaps":["Direct ubiquitination of CKS2 by Parkin not demonstrated","Ubiquitination site on CKS2 not mapped"]},{"year":2024,"claim":"CKS2 was found to confer ferroptosis resistance in colon cancer through autophagy-driven glutathione metabolic reprogramming and GPX4 maintenance, revealing a non-canonical cell death regulatory function.","evidence":"CKS2 KD/OE with BODIPY/DCFH-DA lipid peroxidation staining, GSH assay, TEM for autophagy, GPX4 western blot, xenograft with ferroptosis inducers","pmids":["39548421"],"confidence":"Medium","gaps":["Direct molecular link between CKS2 and autophagy induction machinery not identified","Whether ferroptosis regulation depends on CKS2's CDK-binding or transcriptional role is unknown"]},{"year":2025,"claim":"Multiple studies collectively established the upstream regulatory architecture of CKS2: SOX21 directly represses CKS2 transcription (itself silenced by DNMT1 methylation), METTL3/IGF2BP1 m6A modification stabilizes CKS2 mRNA, and nuclear import via importin-β is required for CKS2 function.","evidence":"ChIP/luciferase for SOX21 at CKS2 promoter with DNMT1 epistasis; RIP/MeRIP for IGF2BP1 binding m6A-CKS2 with stability assays; importazole-induced cytoplasmic CKS2 retention with proliferation/xenograft readout","pmids":["40676553","41822976","40696188"],"confidence":"Medium","gaps":["How importin-β recognizes CKS2 (NLS not mapped) is unknown","Relative contribution of transcriptional vs post-transcriptional regulation of CKS2 in normal tissues not assessed"]},{"year":2025,"claim":"CKS2 was shown to promote PTEN downregulation and p27 Thr187 phosphorylation as convergent mechanisms activating PI3K/AKT in bladder cancer, mechanistically unifying earlier observations about PTEN and p27 into a single pathway model.","evidence":"CKS2 OE/KD with western blot for PTEN and p-p27(Thr187), PI3K inhibitor LY294002 rescue in bladder cancer cells","pmids":["41200902"],"confidence":"Medium","gaps":["Whether CKS2 directly mediates p27 Thr187 phosphorylation through CDK2 activation or an independent mechanism not dissected","PTEN downregulation mechanism (transcriptional vs proteasomal) not resolved"]},{"year":null,"claim":"The structural basis of how CKS2 binds chromatin and CDK substrates distinctly from CKS1, the direct biochemical mechanism by which it antagonizes CKS1-driven SCFSkp2 activity, and whether its mitochondrial, ferroptosis-regulatory, and transcriptional roles are mechanistically separable remain unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No crystal structure of CKS2 in complex with chromatin or transcription factors","No reconstituted biochemical assay distinguishing CKS2 from CKS1 at the level of SCFSkp2 substrate recognition","Mitochondrial vs nuclear vs cytoplasmic functions of CKS2 have not been dissected with separation-of-function mutants"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[1,2,18]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,5,19]},{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[0]},{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[4]}],"pathway":[{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[0,1,2,7,8,18,19]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[11,12,13,18]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[0,11,17]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[6,21]}],"complexes":[],"partners":["CDK2","CDK1","SSBP1","DUT","MLL1","TXN","IGF2BP1"],"other_free_text":[]},"mechanistic_narrative":"CKS2 is a cyclin-dependent kinase (CDK)-binding regulatory subunit that promotes cell cycle progression by coordinating CDK activity, checkpoint control, and transcription of mitotic genes. CKS2 is recruited to chromatin with cell-cycle periodicity to drive transcription of CCNB1, CCNA2, and CDK1 [PMID:18625720], and its binding to CDK2 confers partial resistance to inhibitory checkpoint phosphorylation during S phase [PMID:21697511]; simultaneously, CKS2 opposes CKS1-mediated p27 degradation, restraining cyclin A/CDK2 activity to safeguard replication fidelity and cortical neurogenesis [PMID:22898779]. Nuclear import via importin-β is required for its pro-proliferative function [PMID:40696188], and CKS2 expression is controlled transcriptionally by E2F1 and SOX21 [PMID:36096885, PMID:40676553] and post-transcriptionally by METTL3/IGF2BP1-mediated m6A mRNA stabilization [PMID:41822976]. Downstream, CKS2 activates the PI3K/AKT pathway partly through PTEN downregulation and p27 phospho-degradation [PMID:41200902], promotes ferroptosis resistance via autophagy-driven glutathione metabolism [PMID:39548421], and interacts with DUTPase to regulate its nuclear localization [PMID:33107644]."},"prefetch_data":{"uniprot":{"accession":"P33552","full_name":"Cyclin-dependent kinases regulatory subunit 2","aliases":[],"length_aa":79,"mass_kda":9.9,"function":"Binds to the catalytic subunit of the cyclin dependent kinases and is essential for their biological function","subcellular_location":"","url":"https://www.uniprot.org/uniprotkb/P33552/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CKS2","classification":"Not Classified","n_dependent_lines":97,"n_total_lines":1208,"dependency_fraction":0.0802980132450331},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"PKMYT1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/CKS2","total_profiled":1310},"omim":[{"mim_id":"116940","title":"CYCLIN-DEPENDENT KINASE 1; CDK1","url":"https://www.omim.org/entry/116940"},{"mim_id":"116901","title":"CDC2-ASSOCIATED PROTEIN CKS2; CKS2","url":"https://www.omim.org/entry/116901"},{"mim_id":"116900","title":"CDC28 PROTEIN KINASE 1B; CKS1B","url":"https://www.omim.org/entry/116900"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Mitochondria","reliability":"Approved"},{"location":"Cytosol","reliability":"Approved"},{"location":"Nucleoplasm","reliability":"Additional"},{"location":"Vesicles","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"bone marrow","ntpm":167.0},{"tissue":"testis","ntpm":175.8}],"url":"https://www.proteinatlas.org/search/CKS2"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"P33552","domains":[{"cath_id":"3.30.170.10","chopping":"20-63","consensus_level":"medium","plddt":95.6577,"start":20,"end":63}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P33552","model_url":"https://alphafold.ebi.ac.uk/files/AF-P33552-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P33552-F1-predicted_aligned_error_v6.png","plddt_mean":92.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CKS2","jax_strain_url":"https://www.jax.org/strain/search?query=CKS2"},"sequence":{"accession":"P33552","fasta_url":"https://rest.uniprot.org/uniprotkb/P33552.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P33552/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P33552"}},"corpus_meta":[{"pmid":"18625720","id":"PMC_18625720","title":"Cyclin-dependent kinase-associated proteins Cks1 and Cks2 are essential during early embryogenesis and for cell cycle progression in somatic cells.","date":"2008","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/18625720","citation_count":105,"is_preprint":false},{"pmid":"18498131","id":"PMC_18498131","title":"Aberrant expression of Cks1 and Cks2 contributes to prostate tumorigenesis by promoting proliferation and inhibiting programmed cell death.","date":"2008","source":"International journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/18498131","citation_count":82,"is_preprint":false},{"pmid":"21697511","id":"PMC_21697511","title":"Cyclin-dependent kinase subunit (Cks) 1 or Cks2 overexpression overrides the DNA damage response barrier triggered by activated oncoproteins.","date":"2011","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/21697511","citation_count":66,"is_preprint":false},{"pmid":"21672358","id":"PMC_21672358","title":"Cyclin-dependent kinase-associated protein Cks2 is associated with bladder cancer progression.","date":"2011","source":"The Journal of international medical research","url":"https://pubmed.ncbi.nlm.nih.gov/21672358","citation_count":55,"is_preprint":false},{"pmid":"27633373","id":"PMC_27633373","title":"MicroRNA-7 inhibits proliferation, migration and invasion of thyroid papillary cancer cells via targeting CKS2.","date":"2016","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/27633373","citation_count":54,"is_preprint":false},{"pmid":"23861775","id":"PMC_23861775","title":"miR-26a and its target CKS2 modulate cell growth and tumorigenesis of papillary thyroid carcinoma.","date":"2013","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23861775","citation_count":40,"is_preprint":false},{"pmid":"26137251","id":"PMC_26137251","title":"CKS2 in human cancers: Clinical roles and current perspectives (Review).","date":"2015","source":"Molecular and clinical oncology","url":"https://pubmed.ncbi.nlm.nih.gov/26137251","citation_count":37,"is_preprint":false},{"pmid":"19034516","id":"PMC_19034516","title":"Upregulation of the cycline kinase subunit CKS2 increases cell proliferation rate in gastric cancer.","date":"2008","source":"Journal of cancer research and clinical oncology","url":"https://pubmed.ncbi.nlm.nih.gov/19034516","citation_count":34,"is_preprint":false},{"pmid":"22898779","id":"PMC_22898779","title":"The CDK subunit CKS2 counteracts CKS1 to control cyclin A/CDK2 activity in maintaining replicative fidelity and neurodevelopment.","date":"2012","source":"Developmental cell","url":"https://pubmed.ncbi.nlm.nih.gov/22898779","citation_count":34,"is_preprint":false},{"pmid":"30856376","id":"PMC_30856376","title":"Mitochondrial Function of CKS2 Oncoprotein Links Oxidative Phosphorylation with Cell Division in Chemoradioresistant Cervical Cancer.","date":"2019","source":"Neoplasia (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/30856376","citation_count":24,"is_preprint":false},{"pmid":"32426838","id":"PMC_32426838","title":"LINC00657/miR-26a-5p/CKS2 ceRNA network promotes the growth of esophageal cancer cells via the MDM2/p53/Bcl2/Bax pathway.","date":"2020","source":"Bioscience reports","url":"https://pubmed.ncbi.nlm.nih.gov/32426838","citation_count":24,"is_preprint":false},{"pmid":"30129142","id":"PMC_30129142","title":"EGFL7 promotes hepatocellular carcinoma cell proliferation and inhibits cell apoptosis through increasing CKS2 expression by activating Wnt/β-catenin signaling.","date":"2018","source":"Journal of cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/30129142","citation_count":22,"is_preprint":false},{"pmid":"26531156","id":"PMC_26531156","title":"Depletion of Cks1 and Cks2 expression compromises cell proliferation and enhance chemotherapy-induced apoptosis in HepG2 cells.","date":"2015","source":"Oncology reports","url":"https://pubmed.ncbi.nlm.nih.gov/26531156","citation_count":20,"is_preprint":false},{"pmid":"35663965","id":"PMC_35663965","title":"High Expression of CKS2 Predicts Adverse Outcomes: A Potential Therapeutic Target for Glioma.","date":"2022","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/35663965","citation_count":19,"is_preprint":false},{"pmid":"36096885","id":"PMC_36096885","title":"E2F1/CKS2/PTEN signaling axis regulates malignant phenotypes in pediatric retinoblastoma.","date":"2022","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/36096885","citation_count":17,"is_preprint":false},{"pmid":"8697818","id":"PMC_8697818","title":"Chromosomal mapping of the human genes CKS1 to 8q21 and CKS2 to 9q22.","date":"1996","source":"Cytogenetics and cell genetics","url":"https://pubmed.ncbi.nlm.nih.gov/8697818","citation_count":16,"is_preprint":false},{"pmid":"29487004","id":"PMC_29487004","title":"High-expressed CKS2 is associated with hepatocellular carcinoma cell proliferation through down-regulating PTEN.","date":"2017","source":"Pathology, research and practice","url":"https://pubmed.ncbi.nlm.nih.gov/29487004","citation_count":16,"is_preprint":false},{"pmid":"36284444","id":"PMC_36284444","title":"Cyclin-dependent kinase subunit2 (CKS2) promotes malignant phenotypes and epithelial-mesenchymal transition-like process in glioma by activating TGFβ/SMAD signaling.","date":"2022","source":"Cancer medicine","url":"https://pubmed.ncbi.nlm.nih.gov/36284444","citation_count":15,"is_preprint":false},{"pmid":"29143362","id":"PMC_29143362","title":"MicroRNA-26a inhibits proliferation and tumorigenesis via targeting CKS2 in laryngeal squamous cell carcinoma.","date":"2018","source":"Clinical and experimental pharmacology & physiology","url":"https://pubmed.ncbi.nlm.nih.gov/29143362","citation_count":15,"is_preprint":false},{"pmid":"34333494","id":"PMC_34333494","title":"CKS2 Promotes the Growth in Non-Small-Cell Lung Cancer by Downregulating Cyclin-Dependent Kinase Inhibitor.","date":"2021","source":"Pathobiology : journal of immunopathology, molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/34333494","citation_count":13,"is_preprint":false},{"pmid":"33107644","id":"PMC_33107644","title":"CKS2 modulates cell-cycle progression of tongue squamous cell carcinoma cells partly via modulating the cellular distribution of DUTPase.","date":"2020","source":"Journal of oral pathology & medicine : official publication of the International Association of Oral Pathologists and the American Academy of Oral Pathology","url":"https://pubmed.ncbi.nlm.nih.gov/33107644","citation_count":13,"is_preprint":false},{"pmid":"28939057","id":"PMC_28939057","title":"The Cks1/Cks2 axis fine-tunes Mll1 expression and is crucial for MLL-rearranged leukaemia cell viability.","date":"2017","source":"Biochimica et biophysica acta. Molecular cell research","url":"https://pubmed.ncbi.nlm.nih.gov/28939057","citation_count":13,"is_preprint":false},{"pmid":"20920335","id":"PMC_20920335","title":"Expression and biological-clinical significance of hTR, hTERT and CKS2 in washing fluids of patients with bladder cancer.","date":"2010","source":"BMC urology","url":"https://pubmed.ncbi.nlm.nih.gov/20920335","citation_count":10,"is_preprint":false},{"pmid":"36874381","id":"PMC_36874381","title":"The CKS1/CKS2 Proteostasis Axis Is Crucial to Maintain Hematopoietic Stem Cell Function.","date":"2023","source":"HemaSphere","url":"https://pubmed.ncbi.nlm.nih.gov/36874381","citation_count":9,"is_preprint":false},{"pmid":"37841370","id":"PMC_37841370","title":"Expression of CKS2 in Hepatocellular Carcinoma: Correlation with Survival Outcomes and Immune Microenvironment.","date":"2023","source":"Journal of hepatocellular carcinoma","url":"https://pubmed.ncbi.nlm.nih.gov/37841370","citation_count":7,"is_preprint":false},{"pmid":"37642304","id":"PMC_37642304","title":"Aberrant expression of CKS2 induced by ELK1 contributes to malignant progression of pancreatic cancer.","date":"2023","source":"Molecular carcinogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/37642304","citation_count":6,"is_preprint":false},{"pmid":"35059737","id":"PMC_35059737","title":"Overexpression of Parkin in clear cell renal cell carcinoma decreases tumor aggressiveness by regulating CKS2 levels.","date":"2022","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/35059737","citation_count":6,"is_preprint":false},{"pmid":"39548421","id":"PMC_39548421","title":"CKS2 induces autophagy-mediated glutathione metabolic reprogramming to facilitate ferroptosis resistance in colon cancer.","date":"2024","source":"Molecular medicine (Cambridge, Mass.)","url":"https://pubmed.ncbi.nlm.nih.gov/39548421","citation_count":6,"is_preprint":false},{"pmid":"37744456","id":"PMC_37744456","title":"Knockdown of DLK4 inhibits non-small cell lung cancer tumor growth by downregulating CKS2.","date":"2023","source":"Open life sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37744456","citation_count":4,"is_preprint":false},{"pmid":"39188686","id":"PMC_39188686","title":"Biological functions and therapeutic potential of CKS2 in human cancer.","date":"2024","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/39188686","citation_count":3,"is_preprint":false},{"pmid":"35789606","id":"PMC_35789606","title":"CKS2 and S100A12: Two Novel Diagnostic Biomarkers for Rheumatoid Arthritis.","date":"2022","source":"Disease markers","url":"https://pubmed.ncbi.nlm.nih.gov/35789606","citation_count":3,"is_preprint":false},{"pmid":"41166795","id":"PMC_41166795","title":"Synergistic dual oncogenic role of CKS2 and ACAT2: Enhanced regulatory coherence and biomarker potential in adrenocortical carcinoma.","date":"2025","source":"Cancer genetics","url":"https://pubmed.ncbi.nlm.nih.gov/41166795","citation_count":2,"is_preprint":false},{"pmid":"17268179","id":"PMC_17268179","title":"Rat gene mapping in the post-genome sequencing era: the continued utility of cell hybrids to localize rat genes (Cks2, Ephb4, Fabp5, Il13ra1, Rpl10, Ssr4).","date":"2007","source":"Cytogenetic and genome research","url":"https://pubmed.ncbi.nlm.nih.gov/17268179","citation_count":1,"is_preprint":false},{"pmid":"40092696","id":"PMC_40092696","title":"CKS2 Silencing Affects Proliferation and Apoptosis in Multiple Myeloma through the PTEN/ AKT/mTOR Pathway.","date":"2025","source":"Journal of Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/40092696","citation_count":0,"is_preprint":false},{"pmid":"39560180","id":"PMC_39560180","title":"Unveiling CKS2: A Key Player in Aggressive B-Cell Lymphoma Progression and a Target for Synergistic Therapy.","date":"2024","source":"Cancer medicine","url":"https://pubmed.ncbi.nlm.nih.gov/39560180","citation_count":0,"is_preprint":false},{"pmid":"41200902","id":"PMC_41200902","title":"CKS2 promotes the malignant phenotypes of bladder cancer cells via PI3K/AKT signaling pathway activation.","date":"2025","source":"Cell cycle (Georgetown, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/41200902","citation_count":0,"is_preprint":false},{"pmid":"40676553","id":"PMC_40676553","title":"DNMT1 blocks SOX21-repressed CKS2 transcription to promote gastric cancer progression.","date":"2025","source":"BMC cancer","url":"https://pubmed.ncbi.nlm.nih.gov/40676553","citation_count":0,"is_preprint":false},{"pmid":"40696188","id":"PMC_40696188","title":"Nuclear Transport Receptor Importin-β Inhibition Enhances Cell Cycle Arrest Induced by CKS2 Knockdown to Suppress Neuroblastoma Progression.","date":"2025","source":"Neurochemical research","url":"https://pubmed.ncbi.nlm.nih.gov/40696188","citation_count":0,"is_preprint":false},{"pmid":"40950663","id":"PMC_40950663","title":"Facilitation of natural killer T-cell cytotoxic activity in uterine sarcoma via the CKS2-PI3K-AKT-MICA axis.","date":"2025","source":"Translational cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/40950663","citation_count":0,"is_preprint":false},{"pmid":"41763168","id":"PMC_41763168","title":"A multi-omics R-loop-linked risk program highlights CKS2-positive proliferative tumor cells as drivers of glioma growth.","date":"2026","source":"International immunopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/41763168","citation_count":0,"is_preprint":false},{"pmid":"40908951","id":"PMC_40908951","title":"CKS2 Mediates Hepatocellular Carcinoma Recurrence After Hepatic Ischemia-Reperfusion Injury Related to M2 Macrophages.","date":"2025","source":"Journal of inflammation research","url":"https://pubmed.ncbi.nlm.nih.gov/40908951","citation_count":0,"is_preprint":false},{"pmid":"41061391","id":"PMC_41061391","title":"CKS2 is overexpressed in high-grade and recurrent meningiomas and functions as an oncogene via the CKS2/miR-26a/miR-101 axis.","date":"2025","source":"Computers in biology and medicine","url":"https://pubmed.ncbi.nlm.nih.gov/41061391","citation_count":0,"is_preprint":false},{"pmid":"41950730","id":"PMC_41950730","title":"Characterization of cyclotide Vdif A from Viola diffusa inhibits non-small cell lung cancer cells via regulation of CKS2.","date":"2026","source":"Phytomedicine : international journal of phytotherapy and phytopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/41950730","citation_count":0,"is_preprint":false},{"pmid":"41822976","id":"PMC_41822976","title":"CKS2, regulated by METTL3, contributes to osteosarcoma progression in an IGF2BP1-dependent manner.","date":"2026","source":"International reviews of immunology","url":"https://pubmed.ncbi.nlm.nih.gov/41822976","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.06.06.657372","title":"MRTF-dependent cytoskeletal dynamics drive efficient cell cycle progression","date":"2025-06-07","source":"bioRxiv","url":"https://doi.org/10.1101/2025.06.06.657372","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":25048,"output_tokens":6173,"usd":0.083869},"stage2":{"model":"claude-opus-4-6","input_tokens":9783,"output_tokens":3565,"usd":0.20706},"total_usd":0.290929,"stage1_batch_id":"msgbatch_011kfMfE81o6CTcyhVUqumuW","stage2_batch_id":"msgbatch_01DTputS6WNkH745x1nVSoBo","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2008,\n      \"finding\": \"Cks2 associates with cyclin-dependent kinases and is recruited to chromatin, including promoter regions and open reading frames of CCNB1, CCNA2, and CDK1 genes, with cell cycle periodicity correlating with their transcription; CKS1/CKS2 double knockdown causes G2 arrest rescued by cyclin B1 restoration, indicating a direct transcriptional role in cell cycle gene expression\",\n      \"method\": \"RNAi silencing in MEFs and HeLa cells, chromatin immunoprecipitation, rescue experiments with cyclin B1 re-expression, double knockout mouse (embryonic lethal at morula stage)\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (RNAi, ChIP, genetic KO, rescue), strong mechanistic follow-through\",\n      \"pmids\": [\"18625720\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Cks2 binds CDK2 and this interaction confers partial resistance to inhibitory tyrosine phosphorylation mediated by the intra-S-phase checkpoint, allowing continued DNA replication under replicative stress\",\n      \"method\": \"Overexpression of Cks1/Cks2 in human mammary epithelial and breast cancer cells, intra-S-phase checkpoint assays, CDK2 binding studies\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct CDK2-binding mechanism with functional checkpoint assay, multiple cell types tested\",\n      \"pmids\": [\"21697511\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"CKS2 counteracts CKS1 to stabilize p27 (CDKN1B); in Cks2−/− mice, unopposed CKS1 activity leads to p27 loss, unrestricted cyclin A/CDK2 activity, shortened cell cycle, increased replication fork velocity, and DNA damage; CKS2 loss also impairs cortical progenitor differentiation into neurons, phenocopying p27 loss\",\n      \"method\": \"Cks2 knockout mouse model, genetic epistasis with Cks1, p27 protein quantification, replication fork velocity assays, cortical neurogenesis analysis\",\n      \"journal\": \"Developmental cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with multiple defined cellular phenotypes and genetic epistasis placing CKS2 upstream of CKS1/p27/cyclinA-CDK2 axis\",\n      \"pmids\": [\"22898779\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CKS1 and CKS2 proteins interact with both the MllN and MllC subunits of Mll1 (Mixed-lineage leukaemia 1), and together define Mll1 protein levels throughout the cell cycle, in concert with SCFSkp2 and APCCdc20 ubiquitin ligase complexes\",\n      \"method\": \"Co-immunoprecipitation, small molecule inhibitors of protein degradation (MLN4924 and C1), proliferation assays in MLLr cell lines\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — Co-IP interaction validated with functional inhibitor experiments, single lab\",\n      \"pmids\": [\"28939057\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"CKS2 forms a complex with mitochondrial single-stranded DNA binding protein SSBP1 and CDK1 in the mitochondrion, with complex abundance regulated by cell cycle progression consistent with mitochondrial DNA replication activity; cytoplasmic/mitochondrial CKS2 localization adds independent prognostic impact beyond nuclear CKS2\",\n      \"method\": \"In situ proximity ligation assay in tumor samples and cervical cancer cell lines (HeLa, SiHa), flow cytometry cell cycle analysis, hypoxia modulation of complex abundance, immunohistochemistry\",\n      \"journal\": \"Neoplasia (New York, N.Y.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — proximity ligation assay (not full Co-IP reconstitution) with cell cycle functional correlation; single lab\",\n      \"pmids\": [\"30856376\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"CKS2 overexpression downregulates tumor suppressor p53 and p21(Cip1) in gastric cancer cells, increasing cell growth; conversely, CKS2 siRNA increases p53/p21 and decreases growth; GFP-CKS2 fusion localizes to nucleus\",\n      \"method\": \"GFP-CKS2 overexpression, CKS2-siRNA, western blot for p53/p21, cell proliferation assays, subcellular localization by fluorescence microscopy\",\n      \"journal\": \"Journal of cancer research and clinical oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single lab with OE/KD and downstream protein readout; no direct binding assay\",\n      \"pmids\": [\"19034516\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"CKS2 knockdown in malignant prostate tumor cells induces programmed cell death (apoptosis), distinct from CKS1 knockdown which primarily inhibits proliferation, indicating non-redundant anti-apoptotic function for CKS2\",\n      \"method\": \"RNAi-mediated knockdown of CKS1 and CKS2 separately in prostate cancer cell lines, anchorage-independent growth assays, migration assays, cell viability\",\n      \"journal\": \"International journal of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — KD with specific phenotypic readout distinguishing CKS2 from CKS1; single lab\",\n      \"pmids\": [\"18498131\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"miR-26a directly targets the 3'-UTR of CKS2 mRNA to repress its expression; CKS2 in turn indirectly regulates cyclin B1, cyclin A, CDK1, Bcl-xL, and AKT levels; CKS2 knockdown or miR-26a overexpression causes G2 phase arrest in thyroid papillary carcinoma cells\",\n      \"method\": \"Luciferase reporter assay, western blot, anti-miR/mimic transfection, siRNA, cell cycle assays, xenograft in SCID mice\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — direct 3'-UTR targeting validated by luciferase assay; downstream pathway inferred without direct binding\",\n      \"pmids\": [\"23861775\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"miR-7 directly binds the 3'-UTR of CKS2 and negatively regulates CKS2 protein expression; CKS2 downstream targets cyclin B1 and CDK1 are regulated via the miR-7/CKS2 axis; CKS2 knockdown suppresses proliferation, migration, invasion, and causes G0/G1 arrest in thyroid papillary cancer cells\",\n      \"method\": \"Dual-luciferase reporter assay, western blot, CKS2-siRNA knockdown, cell cycle and apoptosis assays by flow cytometry\",\n      \"journal\": \"International journal of oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — direct 3'-UTR targeting by luciferase assay; downstream cyclin B1/CDK1 regulation by western blot\",\n      \"pmids\": [\"27633373\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CKS2 interacts with DUTPase (DUT) as shown by co-localization and co-immunoprecipitation; CKS2 knockdown does not alter DUTPase total expression but reduces its nuclear distribution, linking CKS2 to regulation of DUTPase subcellular localization and G2/M cell cycle progression\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence co-localization, CKS2 siRNA knockdown, flow cytometry cell cycle assay\",\n      \"journal\": \"Journal of oral pathology & medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — Co-IP and IF co-localization with functional nuclear localization consequence; single lab\",\n      \"pmids\": [\"33107644\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"The E3 ubiquitin ligase Parkin (PARK2) overexpression decreases CKS2 protein levels in ccRCC cells; mutation of the catalytic domain of PARK2 abolishes the decrease in migration, linking Parkin's ubiquitin ligase activity to CKS2 protein abundance and migratory phenotype\",\n      \"method\": \"PARK2 overexpression, catalytic domain mutagenesis, mass spectrometry proteomics, CKS2 silencing, migration/invasion assays\",\n      \"journal\": \"International journal of oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis of writer (Parkin catalytic domain) abolishes effect on CKS2 levels; supported by MS proteomics\",\n      \"pmids\": [\"35059737\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"E2F1 transcription factor binds the CKS2 promoter to enhance CKS2 expression; CKS2 in turn regulates the PI3K-AKT/PTEN pathway to drive retinoblastoma cell proliferation and DNA replication; CKS2 depletion reduces proliferation, delays DNA replication, and slows xenograft growth\",\n      \"method\": \"E2F1 ChIP-seq data integration, RNA-seq, CKS2 siRNA KD, rescue overexpression, xenograft in nude mice, western blot for PTEN/PI3K-AKT markers\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP-seq evidence for E2F1 at CKS2 promoter with functional KD and rescue; single lab\",\n      \"pmids\": [\"36096885\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"CKS2 overexpression induces nucleocytoplasmic translocation of SMAD2/3 and activates TGFβ/SMAD signaling; inhibition of TGFβ/SMAD (by LY2157299 or SMAD4 siRNA) reverses the tumor-promoting and EMT effects caused by CKS2 overexpression in glioma cells\",\n      \"method\": \"CKS2 siRNA/overexpression plasmid, western blot and immunofluorescence for EMT/SMAD markers, TGFβ inhibitor LY2157299, SMAD4 siRNA rescue\",\n      \"journal\": \"Cancer medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — genetic rescue with pathway inhibitor places CKS2 upstream of TGFβ/SMAD; single lab\",\n      \"pmids\": [\"36284444\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Cks1 and Cks2 promote proliferation and prevent apoptosis of HepG2 hepatocellular carcinoma cells; knockdown of either reduces phospho-Akt and phospho-GSK-3β levels, implicating the PI3K/Akt signaling pathway downstream of CKS proteins\",\n      \"method\": \"siRNA knockdown and cDNA overexpression, CCK-8/cell counting proliferation assay, Annexin V/PI apoptosis assay, western blot for p-Akt and p-GSK-3β\",\n      \"journal\": \"Oncology reports\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single lab, single method per readout, pathway placement indirect\",\n      \"pmids\": [\"26531156\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CKS2 knockdown in HCC cells induces PTEN upregulation, suggesting CKS2 suppresses PTEN and may activate the p53 pathway to regulate proliferation\",\n      \"method\": \"siRNA knockdown in HepG2/C3A and Bel7402 cells, colony formation assay, western blot for PTEN\",\n      \"journal\": \"Pathology, research and practice\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single lab, western blot only for pathway readout\",\n      \"pmids\": [\"29487004\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CKS2 directly interacts with thioredoxin (TXN) as shown by co-immunoprecipitation; TXN functions as an upstream regulatory factor governing CKS2 protein stability in multiple myeloma cells; CKS2 depletion modulates proliferation and apoptosis via the PTEN/AKT/mTOR signaling axis\",\n      \"method\": \"Co-immunoprecipitation, confocal immunofluorescence, AlphaFold2 structural modeling, CKS2 KD/OE in MM.1S and RPMI-8226 cells, western blot, xenograft model\",\n      \"journal\": \"Journal of Cancer\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — Co-IP for TXN interaction is single method; PTEN/AKT/mTOR placement inferred from KD without direct mechanistic rescue\",\n      \"pmids\": [\"40092696\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"ELK1 transcription factor directly regulates transcription of the CKS2 gene in pancreatic cancer cells; CKS2 knockdown increases Bax, caspase-3, p53, p21, GADD45α and decreases Bcl-2, cyclin B1, CDK1, cyclin A, and Cdc25C levels\",\n      \"method\": \"ELK1/CKS2 expression correlation analysis, CKS2 KD/OE functional assays, western blot for downstream targets, xenograft model\",\n      \"journal\": \"Molecular carcinogenesis\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — transcription factor regulation inferred without ChIP; downstream targets from western blot only\",\n      \"pmids\": [\"37642304\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"DNMT1-mediated hypermethylation of the SOX21 gene promoter silences SOX21, which normally represses CKS2 transcription by binding its promoter; loss of SOX21 therefore leads to elevated CKS2 expression and promotes gastric cancer progression; ChIP and dual-luciferase reporter confirmed SOX21 binding to the CKS2 promoter\",\n      \"method\": \"ChIP assay, dual-luciferase reporter assay, SOX21 and DNMT1 KD/OE, qMSP for SOX21 methylation, xenograft, rescue experiments\",\n      \"journal\": \"BMC cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP and luciferase reporter directly validate SOX21 binding to CKS2 promoter with rescue epistasis\",\n      \"pmids\": [\"40676553\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CKS2 promotes bladder cancer cell proliferation and migration via dual mechanisms: downregulating PTEN protein levels (relieving PIP3 degradation and activating PI3K/AKT) and promoting phosphorylation and degradation of p27Kip1 (Thr187), both converging on PI3K/AKT pathway activation; PI3K inhibitor LY294002 reverses CKS2-induced phenotypes\",\n      \"method\": \"CKS2 OE/KD, western blot for PTEN and p-p27Kip1(Thr187), PI3K inhibitor rescue (LY294002), proliferation/migration/invasion assays\",\n      \"journal\": \"Cell cycle (Georgetown, Tex.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — two distinct mechanistic arms (PTEN and p27 phosphorylation) validated by pharmacological rescue; single lab\",\n      \"pmids\": [\"41200902\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CKS2 knockdown decreases phosphorylation of CDK1 (Thr161) and Cyclin B1 (Ser126) in neuroblastoma cells; importin-β inhibitor (importazole) causes CKS2 to accumulate in the cytoplasm rather than the nucleus, inhibiting proliferation; combined CKS2 KD and importazole produces additive anti-tumor effect, indicating nuclear localization is required for CKS2 pro-proliferative function\",\n      \"method\": \"CKS2 siRNA KD, importazole (importin-β inhibitor) treatment, subcellular fractionation/immunofluorescence for CKS2 localization, western blot for CDK1(Thr161) and CyclinB1(Ser126), in vivo xenograft\",\n      \"journal\": \"Neurochemical research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — nuclear localization directly tied to proliferative function via importin-β inhibition; CDK1/CyclinB1 phosphorylation readout\",\n      \"pmids\": [\"40696188\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CKS2 activates PI3K/AKT signaling in uterine sarcoma cells, reducing MICA expression on the tumor cell surface and thereby inhibiting NKT cell cytotoxic activity, contributing to immune escape; PI3K inhibitors reversed this effect\",\n      \"method\": \"CKS2 KD stable lines, colony/TUNEL/invasion assays, PI3K inhibitor rescue, multiplex immunofluorescence for NKT cells and MICA in tumor tissue\",\n      \"journal\": \"Translational cancer research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — PI3K/MICA/NKT axis inferred from KD plus inhibitor; single lab without direct binding or reconstitution\",\n      \"pmids\": [\"40950663\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"CKS2 promotes ferroptosis resistance in colon cancer by inducing autophagy-mediated glutathione (GSH) metabolic reprogramming; CKS2 knockdown reduces GSH levels and enhances erastin-induced ferroptosis, and also downregulates GPX4 expression; CKS2 overexpression has opposite effects\",\n      \"method\": \"CKS2 KD/OE, BODIPY and DCFH-DA staining for lipid peroxidation/ROS, GSH assay, transmission electron microscopy for autophagy, western blot for GPX4, in vivo xenograft with ferroptosis inducers\",\n      \"journal\": \"Molecular medicine (Cambridge, Mass.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (lipid peroxidation, GSH assay, TEM for autophagy, GPX4 western blot, in vivo) in single lab\",\n      \"pmids\": [\"39548421\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"METTL3-mediated m6A modification stabilizes CKS2 mRNA in an IGF2BP1-dependent manner; IGF2BP1 directly binds m6A-modified CKS2 transcripts; METTL3 overexpression rescues the suppressive effects of CKS2 silencing on osteosarcoma cells\",\n      \"method\": \"RIP, MeRIP (m6A-RIP), mRNA stability assays, western blot, co-expression analysis, METTL3 OE rescue of CKS2 KD, in vivo xenograft\",\n      \"journal\": \"International reviews of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — RIP and MeRIP directly validate m6A reader IGF2BP1 binding CKS2 transcripts; mRNA stability confirmed; rescue epistasis\",\n      \"pmids\": [\"41822976\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In MRTF-null fibroblasts and epithelial cells, CKS2 protein levels are decreased alongside CDK1, while CDK inhibitor p27 is elevated; re-expression of MRTF-A fully reverses these changes, placing CKS2 expression downstream of the MRTF-SRF cytoskeletal transcriptional program\",\n      \"method\": \"MRTF-A/B genetic knockout in primary and immortalised cells, MRTF-A re-expression rescue, western blot for CKS2/CDK1/p27 protein levels, ROCK/myosin ATPase inhibitor phenocopy experiments\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean genetic KO with full rescue by MRTF-A re-expression, multiple cell types; preprint not yet peer-reviewed\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"CKS2 is an evolutionarily conserved CDK-binding subunit that associates directly with CDK2 to confer partial resistance to inhibitory checkpoint phosphorylation, counteracts CKS1-driven p27 degradation to restrain cyclin A/CDK2 activity and safeguard replication fidelity, is recruited to chromatin to promote transcription of CCNB1, CCNA2, and CDK1, interacts with mitochondrial SSBP1 and CDK1 to support mitochondrial DNA replication and OXPHOS, interacts with DUTPase to regulate its nuclear localization, interacts with MLL1 subunits to modulate MLL1 protein levels through the cell cycle, is stabilized by METTL3/IGF2BP1-mediated m6A mRNA modification, is transcriptionally activated by E2F1 and ELK1 and repressed by SOX21 (itself silenced by DNMT1), and requires nuclear import via importin-β for its pro-proliferative function; collectively, CKS2 promotes cell cycle progression and survival through downstream regulation of the PI3K/AKT/PTEN axis, TGFβ/SMAD signaling, p27 phospho-degradation, and ferroptosis resistance via autophagy-driven glutathione metabolism.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"CKS2 is a cyclin-dependent kinase (CDK)-binding regulatory subunit that promotes cell cycle progression by coordinating CDK activity, checkpoint control, and transcription of mitotic genes. CKS2 is recruited to chromatin with cell-cycle periodicity to drive transcription of CCNB1, CCNA2, and CDK1 [PMID:18625720], and its binding to CDK2 confers partial resistance to inhibitory checkpoint phosphorylation during S phase [PMID:21697511]; simultaneously, CKS2 opposes CKS1-mediated p27 degradation, restraining cyclin A/CDK2 activity to safeguard replication fidelity and cortical neurogenesis [PMID:22898779]. Nuclear import via importin-β is required for its pro-proliferative function [PMID:40696188], and CKS2 expression is controlled transcriptionally by E2F1 and SOX21 [PMID:36096885, PMID:40676553] and post-transcriptionally by METTL3/IGF2BP1-mediated m6A mRNA stabilization [PMID:41822976]. Downstream, CKS2 activates the PI3K/AKT pathway partly through PTEN downregulation and p27 phospho-degradation [PMID:41200902], promotes ferroptosis resistance via autophagy-driven glutathione metabolism [PMID:39548421], and interacts with DUTPase to regulate its nuclear localization [PMID:33107644].\",\n  \"teleology\": [\n    {\n      \"year\": 2008,\n      \"claim\": \"Establishing that CKS2 has a direct chromatin-level transcriptional role—not merely a CDK-activating role—resolved how CKS proteins control G2/M gene expression (CCNB1, CCNA2, CDK1) and why combined CKS1/CKS2 loss causes G2 arrest.\",\n      \"evidence\": \"ChIP showing cell-cycle-periodic CKS2 recruitment to promoters/ORFs of mitotic genes in MEFs and HeLa, RNAi double-KD with cyclin B1 rescue, double-KO embryonic lethality\",\n      \"pmids\": [\"18625720\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether CKS2 acts as a transcriptional co-activator, a chromatin remodeler recruiter, or through CDK-dependent histone phosphorylation is unresolved\", \"Relative contribution of CKS1 vs CKS2 to transcription at individual loci unclear\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Demonstrating non-redundant functions of CKS2 vs CKS1 in cancer cells—CKS2 knockdown induces apoptosis whereas CKS1 knockdown inhibits proliferation—revealed a specific anti-apoptotic role for CKS2.\",\n      \"evidence\": \"Separate RNAi KD of CKS1 and CKS2 in prostate cancer cell lines with proliferation and apoptosis readouts\",\n      \"pmids\": [\"18498131\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular target mediating the anti-apoptotic effect not identified\", \"Not confirmed in non-cancer cells\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Showing that CKS2 binding to CDK2 confers partial resistance to inhibitory tyrosine phosphorylation established a mechanism by which CKS2 enables continued DNA replication under checkpoint-activating replicative stress.\",\n      \"evidence\": \"CKS2 overexpression in mammary epithelial and breast cancer cells with intra-S-phase checkpoint assays and CDK2 binding studies\",\n      \"pmids\": [\"21697511\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of how CKS2 binding shields CDK2 from Wee1/Myt1 phosphorylation unknown\", \"Whether this mechanism operates independently of CKS2's chromatin role is untested\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Genetic epistasis in Cks2-knockout mice demonstrated that CKS2 restrains CKS1-driven p27 degradation; without CKS2, unopposed CKS1 causes p27 loss, accelerated replication, and DNA damage, revealing CKS2 as a genome-integrity guardian rather than a simple CDK activator.\",\n      \"evidence\": \"Cks2 KO mouse, genetic epistasis with Cks1, p27 quantification, replication fork velocity assays, cortical neurogenesis analysis\",\n      \"pmids\": [\"22898779\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Biochemical mechanism by which CKS2 antagonizes CKS1-driven SCFSkp2-mediated p27 ubiquitination is not resolved\", \"Whether CKS2 directly competes with CKS1 for SCFSkp2 binding or operates indirectly is unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Identification of CKS2 interaction with MLL1 subunits linked CKS proteins to cell-cycle-dependent regulation of MLL1 protein levels, connecting CDK-associated factors to epigenetic gene regulation.\",\n      \"evidence\": \"Co-immunoprecipitation of CKS1/CKS2 with MllN and MllC, functional inhibitor experiments in MLLr cell lines\",\n      \"pmids\": [\"28939057\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether CKS2 directly recruits SCFSkp2 or APCCdc20 to MLL1 for degradation not shown\", \"Functional consequences of CKS2–MLL1 interaction on target gene transcription not defined\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Detection of a CKS2–CDK1–SSBP1 complex in mitochondria extended CKS2 function beyond the nucleus, suggesting a role in cell-cycle-coupled mitochondrial DNA replication.\",\n      \"evidence\": \"Proximity ligation assay in tumor tissue and cervical cancer cell lines, flow cytometry cell cycle correlation, hypoxia modulation\",\n      \"pmids\": [\"30856376\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Interaction validated only by PLA, not by reciprocal co-IP or in vitro reconstitution\", \"Direct functional impact on mtDNA replication not measured\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"CKS2 was shown to interact with DUTPase and regulate its nuclear localization, linking CKS2 to nucleotide metabolism and genome maintenance beyond its CDK-binding role.\",\n      \"evidence\": \"Co-IP and immunofluorescence co-localization; CKS2 KD reduces DUTPase nuclear fraction with G2/M arrest\",\n      \"pmids\": [\"33107644\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether CKS2 acts as a nuclear import chaperone for DUTPase or regulates retention indirectly is unknown\", \"Functional consequence of altered DUTPase localization on dUTP misincorporation not tested\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Convergent studies established that CKS2 expression is transcriptionally driven by E2F1 (ChIP-seq validated) and that CKS2 activates PI3K/AKT signaling through PTEN suppression, placing CKS2 within the Rb–E2F–PI3K axis and the TGFβ/SMAD pathway.\",\n      \"evidence\": \"E2F1 ChIP-seq at CKS2 promoter with functional KD/rescue and xenograft (retinoblastoma); CKS2 OE inducing SMAD2/3 nuclear translocation reversed by TGFβ inhibitor (glioma)\",\n      \"pmids\": [\"36096885\", \"36284444\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether CKS2 directly interacts with PTEN or regulates it transcriptionally/post-translationally not determined\", \"Connection between CKS2-TGFβ axis and CKS2-PI3K axis unclear\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Parkin (PARK2) ubiquitin ligase activity was shown to reduce CKS2 protein levels, identifying CKS2 as a potential Parkin substrate and connecting CKS2 turnover to the ubiquitin-proteasome system.\",\n      \"evidence\": \"PARK2 overexpression reduces CKS2; catalytic domain mutation abolishes the effect; mass spectrometry proteomics in ccRCC cells\",\n      \"pmids\": [\"35059737\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct ubiquitination of CKS2 by Parkin not demonstrated\", \"Ubiquitination site on CKS2 not mapped\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"CKS2 was found to confer ferroptosis resistance in colon cancer through autophagy-driven glutathione metabolic reprogramming and GPX4 maintenance, revealing a non-canonical cell death regulatory function.\",\n      \"evidence\": \"CKS2 KD/OE with BODIPY/DCFH-DA lipid peroxidation staining, GSH assay, TEM for autophagy, GPX4 western blot, xenograft with ferroptosis inducers\",\n      \"pmids\": [\"39548421\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular link between CKS2 and autophagy induction machinery not identified\", \"Whether ferroptosis regulation depends on CKS2's CDK-binding or transcriptional role is unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Multiple studies collectively established the upstream regulatory architecture of CKS2: SOX21 directly represses CKS2 transcription (itself silenced by DNMT1 methylation), METTL3/IGF2BP1 m6A modification stabilizes CKS2 mRNA, and nuclear import via importin-β is required for CKS2 function.\",\n      \"evidence\": \"ChIP/luciferase for SOX21 at CKS2 promoter with DNMT1 epistasis; RIP/MeRIP for IGF2BP1 binding m6A-CKS2 with stability assays; importazole-induced cytoplasmic CKS2 retention with proliferation/xenograft readout\",\n      \"pmids\": [\"40676553\", \"41822976\", \"40696188\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How importin-β recognizes CKS2 (NLS not mapped) is unknown\", \"Relative contribution of transcriptional vs post-transcriptional regulation of CKS2 in normal tissues not assessed\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"CKS2 was shown to promote PTEN downregulation and p27 Thr187 phosphorylation as convergent mechanisms activating PI3K/AKT in bladder cancer, mechanistically unifying earlier observations about PTEN and p27 into a single pathway model.\",\n      \"evidence\": \"CKS2 OE/KD with western blot for PTEN and p-p27(Thr187), PI3K inhibitor LY294002 rescue in bladder cancer cells\",\n      \"pmids\": [\"41200902\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether CKS2 directly mediates p27 Thr187 phosphorylation through CDK2 activation or an independent mechanism not dissected\", \"PTEN downregulation mechanism (transcriptional vs proteasomal) not resolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis of how CKS2 binds chromatin and CDK substrates distinctly from CKS1, the direct biochemical mechanism by which it antagonizes CKS1-driven SCFSkp2 activity, and whether its mitochondrial, ferroptosis-regulatory, and transcriptional roles are mechanistically separable remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No crystal structure of CKS2 in complex with chromatin or transcription factors\", \"No reconstituted biochemical assay distinguishing CKS2 from CKS1 at the level of SCFSkp2 substrate recognition\", \"Mitochondrial vs nuclear vs cytoplasmic functions of CKS2 have not been dissected with separation-of-function mutants\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [1, 2, 18]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 5, 19]},\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [0, 1, 2, 7, 8, 18, 19]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [11, 12, 13, 18]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [0, 11, 17]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [6, 21]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"CDK2\", \"CDK1\", \"SSBP1\", \"DUT\", \"MLL1\", \"TXN\", \"IGF2BP1\"],\n    \"other_free_text\": []\n  }\n}\n```"}