{"gene":"CKAP2","run_date":"2026-06-09T22:57:18","timeline":{"discoveries":[{"year":2022,"finding":"In vitro reconstitution assays showed that CKAP2 potently promotes microtubule nucleation, lowering the critical tubulin concentration ~100-fold, increases the apparent rate constant of microtubule growth ~50-fold, increases microtubule growth rates, and strongly suppresses catastrophes, identifying CKAP2 as the most potent microtubule growth factor known.","method":"In vitro reconstitution assay (microtubule polymerization)","journal":"eLife","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct in vitro reconstitution with quantitative measurements, single rigorous study with multiple orthogonal readouts","pmids":["35029146"],"is_preprint":false},{"year":2024,"finding":"CRISPR-Cas9 knock-out and live-cell microtubule plus-end tracking showed that CKAP2 is required for normal microtubule growth rates in cells during mitosis; CKAP2 KO cells display reduced microtubule growth rates, increased chromosome segregation errors, and aneuploidy, all rescued by ectopic CKAP2 expression. Endogenously labeled CKAP2 localizes to the spindle during mitosis and shifts to chromatin upon mitotic exit before degradation.","method":"CRISPR-Cas9 KO, live-cell microtubule plus-end tracking imaging, ectopic re-expression rescue","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — CRISPR KO with rescue, live-cell imaging, multiple orthogonal methods in one study","pmids":["38381793"],"is_preprint":false},{"year":2025,"finding":"Endogenous CKAP2 immunoprecipitation from mitotic cells followed by mass spectrometry identified Aurora kinase A and its activator TPX2 (but not Aurora B) as specific CKAP2 interactors. Aurora A directly phosphorylates CKAP2 in vitro and in cells, and this phosphorylation decreases CKAP2's microtubule affinity in cells and in vitro, revealing a regulatory pathway controlling spindle growth.","method":"Endogenous co-immunoprecipitation, mass spectrometry, in vitro kinase assay, microtubule affinity assay in cells","journal":"bioRxiv","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — reciprocal IP/MS plus in vitro kinase assay plus cellular microtubule affinity measurement in one study; preprint not yet peer-reviewed lowers ceiling slightly","pmids":["bio_10.1101_2025.09.09.675182"],"is_preprint":true},{"year":2025,"finding":"A 284-amino acid intrinsically disordered domain of CKAP2 is sufficient to catalyze both microtubule polymerization and depolymerization in vitro. CKAP2 promotes tubulin incorporation without high-affinity tubulin binding, suggesting a transition-state-based catalytic mechanism distinct from known microtubule polymerases.","method":"In vitro reconstitution with isolated CKAP2 domain, microtubule polymerization/depolymerization assays","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — in vitro reconstitution with isolated domain, single lab, preprint not yet peer-reviewed","pmids":["bio_10.1101_2025.09.02.673730"],"is_preprint":true},{"year":2007,"finding":"CKAP2 is a physiological substrate of the APC/C–Cdh1 ubiquitin ligase. Ubiquitination and degradation of CKAP2 in vitro require a KEN-box motif and are mediated by Cdh1. CKAP2 protein levels are high in mitosis and drop during mitotic exit; Cdh1 overexpression reduces CKAP2 in a KEN-box-dependent manner and Cdh1 knockdown extends CKAP2 half-life. Ectopic expression of wild-type or non-degradable CKAP2 causes mitotic arrest with monopolar spindles and bundled microtubules.","method":"In vitro ubiquitination assay, KEN-box mutagenesis, Cdh1 overexpression/knockdown, cell cycle fractionation, immunofluorescence","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — in vitro ubiquitination reconstitution plus mutagenesis plus cellular validation; replicated in a companion paper (PMID 17339342)","pmids":["17376772"],"is_preprint":false},{"year":2007,"finding":"APC/C–Cdh1-mediated degradation of CKAP2 during mitotic exit is required for completion of cytokinesis and maintenance of spindle bipolarity. The KEN-box near the N-terminus is necessary for CKAP2 destruction. Overexpression of CKAP2 induces microtubule bundling, centrosome separation defects, and monopolar spindle formation; non-degradable CKAP2 significantly increases spindle defects and cytokinesis failure.","method":"KEN-box mutagenesis, non-degradable mutant expression, siRNA knockdown, immunofluorescence, live-cell imaging","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — mutagenesis plus cellular gain/loss-of-function with specific mitotic phenotypes; replicates and extends PMID 17376772","pmids":["17339342"],"is_preprint":false},{"year":2004,"finding":"Mouse CKAP2 protein co-localizes with microtubules throughout the cell cycle and overexpression stabilizes microtubules against nocodazole-induced depolymerization, establishing CKAP2 as a microtubule-associated protein with microtubule-stabilizing properties.","method":"Immunocytochemistry, nocodazole resistance assay, co-localization with tubulin","journal":"Cancer science","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — cellular co-localization and drug resistance assay, single lab, two methods","pmids":["15504249"],"is_preprint":false},{"year":2005,"finding":"Overexpressed CKAP2 co-localizes with and stabilizes microtubules. In p53-null cells, CKAP2 overexpression induces tetraploidy with aberrant centrosome numbers; in p53-competent cells it activates p53-mediated cell cycle arrest and apoptosis, suggesting CKAP2 activates the G1 tetraploidy checkpoint. DNA damage induces CKAP2 expression in a p53-dependent manner and p53 activates the Ckap2 promoter.","method":"DNA microarray, promoter reporter assay, overexpression in p53-null vs. p53-competent cells, immunofluorescence, flow cytometry","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — promoter assay, genetic cell line comparison (p53-null vs. competent), multiple readouts in one study","pmids":["16061649"],"is_preprint":false},{"year":2009,"finding":"siRNA-mediated depletion of CKAP2 in mammalian cells causes chromatin bridge formation, abnormal nuclear morphology (with abnormal nuclear lamina organization), defects in chromosome segregation revealed by time-lapse microscopy, reduced spindle checkpoint activity, reduced cell viability, and increased chromosomal instability.","method":"siRNA knockdown, time-lapse video microscopy, immunofluorescence of nuclear lamina, chromosomal instability assay","journal":"Cell cycle (Georgetown, Tex.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA KD with live imaging and multiple cellular readouts, single lab","pmids":["19158495"],"is_preprint":false},{"year":2013,"finding":"RNAi depletion of CKAP2 results in multipolar mitoses and spindle pole defects; CKAP2-depleted cells show dispersal of newly polymerized microtubules into a cage-like structure around chromatin immediately after mitotic release, indicating defective focusing of microtubule minus ends to spindle poles. CKAP2 suppression also increases merotelic kinetochore attachments, anaphase lagging, and polyploidy.","method":"RNAi knockdown, microtubule regrowth assay after cold treatment, immunofluorescence, FISH for aneuploidy","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi with microtubule regrowth assay and multiple orthogonal phenotypic readouts, single lab","pmids":["23737987"],"is_preprint":false},{"year":2008,"finding":"CKAP2 is transiently phosphorylated at Thr-596 (mouse T596, equivalent human site) specifically during early mitotic phases (prophase through metaphase); phosphorylation at T596 abolishes recognition by a monoclonal antibody (D-12-3) and was identified by epitope mapping. Immunofluorescence showed the phosphorylated form disappears at anaphase, indicating dephosphorylation during late mitosis.","method":"Epitope mapping with monoclonal antibodies, immunofluorescence on mitotic cells, phospho-peptide competition","journal":"Experimental & molecular medicine","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — epitope mapping plus immunofluorescence cell cycle staging, single lab, two methods","pmids":["18779650"],"is_preprint":false},{"year":2010,"finding":"Aurora B kinase directly phosphorylates CKAP2 (TMAP) at Ser627 in vitro and in vivo. The motif (625)RRSRRL(630) surrounding Ser627 is required for efficient phosphorylation; substitutions within this motif both diminish kinase-substrate recognition and alter CKAP2 subcellular localization during late mitosis (mutants remain associated with microtubules/centrosomes instead of relocating to the chromosome region).","method":"In vitro kinase assay with Aurora B, site-directed mutagenesis of phosphorylation motif, immunofluorescence for subcellular localization","journal":"Cell cycle (Georgetown, Tex.)","confidence":"Medium","confidence_rationale":"Tier 1–2 / Moderate — in vitro kinase assay plus mutagenesis plus localization imaging, single lab","pmids":["20458174"],"is_preprint":false},{"year":2017,"finding":"CDK1-cyclin B1 phosphorylates mouse CKAP2 at T603 and possibly S608 during mitosis. Ectopic expression of T603A and S608A mutants fails to rescue centrosomal abnormalities (amplified centrosomes and aberrant chromosome segregation) in CKAP2-depleted primary hepatocytes, demonstrating that these phosphorylation events are required for centrosome integrity and bipolar spindle formation.","method":"In vitro CDK1/cyclin B1 kinase assay, phosphorylation site mutagenesis, rescue experiment in CKAP2-depleted hepatocytes, immunofluorescence","journal":"Experimental & molecular medicine","confidence":"Medium","confidence_rationale":"Tier 1–2 / Moderate — in vitro kinase assay with mutagenesis rescue, single lab, multiple methods","pmids":["28706298"],"is_preprint":false},{"year":2012,"finding":"The human CKAP2 promoter contains a GC box (−41 to −32 bp) bound by transcription factor Sp1 (confirmed by supershift and ChIP assays) and a CHR element (−110 to −104 bp) that together drive cell-cycle-dependent CKAP2 transcription. Cyclin A/CDK2 promotes Sp1 binding to the GC box; depletion of Cyclin A reduces Sp1 occupancy, which is restored by adding back the Cyclin A/CDK2 complex, establishing Cyclin A-mediated Sp1 phosphorylation as the mechanism for G2/M-peak CKAP2 expression.","method":"Promoter reporter assay, EMSA supershift, ChIP assay, Cyclin A depletion with add-back experiment, mutagenesis of regulatory elements","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP, supershift, and Cyclin A add-back, multiple methods in single lab","pmids":["22465120"],"is_preprint":false},{"year":2016,"finding":"CKAP2-depleted primary hepatocytes display over-duplicated centrosomes, disjoined chromosomes from the metaphase plate, and proceed to apoptosis or multipolar cell division; CKAP2 is required for spindle bipolarity in diploid somatic cells. In vivo, CKAP2 depletion in mouse liver markedly reduces hepatic regeneration efficiency.","method":"siRNA knockdown in primary hepatocytes, immunofluorescence, in vivo partial hepatectomy model","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with defined centrosome/spindle phenotype in primary cells plus in vivo model, single lab","pmids":["27055594"],"is_preprint":false},{"year":2006,"finding":"CKAP2 expression is cell-cycle-dependent in human foreskin fibroblasts, absent in G0/G1-arrested cells and peaking at G2/M. Knockdown of CKAP2 reduces pRB phosphorylation and increases p27 expression, reducing proliferation; constitutive CKAP2 expression increases pRB phosphorylation and enhances proliferation, placing CKAP2 upstream of the Rb/p27 pathway in cell cycle progression.","method":"siRNA knockdown, constitutive overexpression, Western blot for pRB/p27, proliferation assays","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — bidirectional (KD and OE) with molecular readouts pRB and p27, single lab","pmids":["16876122"],"is_preprint":false},{"year":2007,"finding":"CKAP2 localizes to centrosomal microtubules in late G2 (only after centrosome separation), then to spindle poles and spindle microtubules from prophase through anaphase, and disappears from microtubules during cytokinesis, as determined by live and fixed-cell immunofluorescence.","method":"Immunofluorescence across cell cycle stages, centrosome co-localization","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — detailed spatiotemporal localization by immunofluorescence, replicated across two papers (PMID 17376772, 17339342)","pmids":["17376772","17339342"],"is_preprint":false},{"year":2017,"finding":"In cervical carcinoma cells, CKAP2 knockdown reduces phosphorylation of ERK2 (p-ERK2) and inhibits cell proliferation, migration, and invasion; FAK inhibitor (PF-562271) and ERK2 inhibitor (VX-11e) block CKAP2 overexpression-induced proliferation and motility, placing CKAP2 upstream of the FAK–ERK2 signaling axis.","method":"siRNA knockdown, pharmacological inhibitors, Western blot for p-ERK2, proliferation/migration/invasion assays, in vivo xenograft","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — bidirectional manipulation (KD and inhibitor) with defined signaling readout, single lab","pmids":["28522860"],"is_preprint":false},{"year":2023,"finding":"ZC3H13 mediates N6-methyladenosine (m6A) modification of CKAP2 mRNA to stabilize its expression in cervical cancer cells; ZC3H13 inhibition decreases CKAP2 levels, and CKAP2 overexpression partially rescues the malignant phenotype suppressed by ZC3H13 knockdown, establishing a ZC3H13–m6A–CKAP2 regulatory axis.","method":"m6A modification level measurement, ZC3H13 overexpression/knockdown, CKAP2 rescue experiment, qRT-PCR, Western blot, proliferation/invasion/migration assays","journal":"Critical reviews in immunology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — epistasis rescue assay with m6A measurement, single lab, mechanistic detail limited in abstract","pmids":["37943149"],"is_preprint":false},{"year":2024,"finding":"CKAP2 interacts with TFDP1 (confirmed by immunoprecipitation and dual-luciferase reporter assay), and TFDP1 positively regulates CKAP2 transcription; CKAP2 overexpression reverses the inhibitory effects of TFDP1 knockdown on colorectal cancer cell proliferation, migration, and invasion, placing CKAP2 downstream of TFDP1.","method":"Co-immunoprecipitation, dual-luciferase reporter assay, siRNA/overexpression rescue experiment","journal":"Journal of microbiology and biotechnology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP and reporter assay with rescue, single lab","pmids":["39403723"],"is_preprint":false}],"current_model":"CKAP2 is a mitotic spindle-associated microtubule-associated protein that potently promotes microtubule nucleation and growth (lowering the critical tubulin concentration ~100-fold and increasing growth rate ~50-fold) via an intrinsically disordered domain, localizes to spindle microtubules and poles from prophase through anaphase, and is required for proper chromosome segregation; its levels are tightly regulated by APC/C–Cdh1-mediated proteasomal degradation (via a KEN-box) during mitotic exit, its transcription is driven by Cyclin A/CDK2-mediated Sp1 phosphorylation at a promoter GC box, and its activity/localization during mitosis is modulated by phosphorylation—notably by Aurora kinase A (which decreases microtubule affinity), CDK1/cyclin B1 (at T603/S608, required for centrosome integrity), and transiently at T596 during early mitosis—placing CKAP2 as a central, multiply regulated effector of spindle assembly whose overexpression causes monopolar spindles and aneuploidy."},"narrative":{"mechanistic_narrative":"CKAP2 is a mitotic spindle-associated microtubule-associated protein that acts as a potent catalyst of microtubule nucleation and growth, functioning as a central effector of bipolar spindle assembly and faithful chromosome segregation [PMID:35029146, PMID:38381793]. In reconstituted systems CKAP2 lowers the critical tubulin concentration ~100-fold, increases the apparent growth-rate constant ~50-fold, and suppresses catastrophes, with a 284-residue intrinsically disordered domain sufficient to catalyze both microtubule polymerization and depolymerization without high-affinity tubulin binding [PMID:35029146, PMID:bio_10.1101_2025.09.02.673730]. CKAP2 co-localizes with microtubules across the cell cycle, concentrating on centrosomes after their separation in late G2 and on spindle poles and spindle microtubules from prophase through anaphase before relocating to chromatin and being cleared at mitotic exit [PMID:15504249, PMID:17376772, PMID:17339342, PMID:38381793]. Loss of CKAP2 reduces cellular microtubule growth rates and produces spindle pole and centrosome defects, merotelic attachments, chromatin bridges, chromosome segregation errors, and aneuploidy [PMID:38381793, PMID:23737987, PMID:19158495, PMID:27055594]. CKAP2 abundance is gated through the cell cycle by transcriptional and degradative controls: Cyclin A/CDK2-driven Sp1 phosphorylation at a promoter GC box drives a G2/M expression peak [PMID:22465120], while APC/C–Cdh1 ubiquitinates CKAP2 via an N-terminal KEN-box to enforce its destruction during mitotic exit, a step required for spindle bipolarity and cytokinesis completion [PMID:17376772, PMID:17339342]. Mitotic kinases further tune CKAP2: Aurora kinase A, recruited with TPX2, directly phosphorylates CKAP2 to lower its microtubule affinity [PMID:bio_10.1101_2025.09.09.675182], and CDK1/cyclin B1 phosphorylation at T603/S608 is required for centrosome integrity and bipolar spindle formation [PMID:28706298]. Overexpression or expression of non-degradable CKAP2 causes microtubule bundling, monopolar spindles, and aneuploidy [PMID:17376772, PMID:17339342], and CKAP2 also engages a p53-dependent G1 tetraploidy checkpoint and the Rb/p27 proliferative axis [PMID:16061649, PMID:16876122].","teleology":[{"year":2004,"claim":"Established CKAP2 as a bona fide microtubule-associated protein, answering whether it physically engages and influences microtubules.","evidence":"Immunocytochemical co-localization with tubulin and nocodazole-resistance assay in mouse cells","pmids":["15504249"],"confidence":"Medium","gaps":["Did not distinguish direct stabilization from indirect effects","No biochemical reconstitution","Localization dynamics across mitosis not resolved"]},{"year":2006,"claim":"Linked CKAP2 to cell cycle progression by placing it upstream of the Rb/p27 pathway, framing it as more than a passive cytoskeletal component.","evidence":"siRNA knockdown and constitutive overexpression with pRB/p27 Western blots and proliferation assays in fibroblasts","pmids":["16876122"],"confidence":"Medium","gaps":["Mechanism connecting CKAP2 to Rb phosphorylation unresolved","Correlative rather than direct molecular link"]},{"year":2007,"claim":"Defined how CKAP2 levels are restricted to mitosis, identifying it as an APC/C–Cdh1 substrate degraded via a KEN-box, and showed why this destruction matters for spindle bipolarity and cytokinesis.","evidence":"In vitro ubiquitination, KEN-box mutagenesis, Cdh1 manipulation, and non-degradable mutant phenotyping, plus cell-cycle localization imaging","pmids":["17376772","17339342"],"confidence":"High","gaps":["Phosphorylation inputs controlling degradation timing not addressed","Did not establish the catalytic basis of microtubule effects"]},{"year":2007,"claim":"Connected CKAP2 to genome-integrity surveillance, showing its overexpression triggers tetraploidy in p53-null cells but a p53-mediated checkpoint in p53-competent cells.","evidence":"Overexpression in p53-null vs competent cells, promoter reporter, microarray, flow cytometry","pmids":["16061649"],"confidence":"Medium","gaps":["Direct biochemical link between CKAP2 and p53 activation unclear","Whether checkpoint engagement is centrosome-driven not resolved"]},{"year":2008,"claim":"Revealed dynamic mitotic phosphoregulation of CKAP2 by identifying transient T596 phosphorylation in early mitosis that reverses at anaphase.","evidence":"Epitope mapping with monoclonal antibodies and immunofluorescence cell-cycle staging","pmids":["18779650"],"confidence":"Medium","gaps":["Responsible kinase not identified","Functional consequence of T596 phosphorylation not tested"]},{"year":2009,"claim":"Demonstrated that CKAP2 is required for accurate chromosome segregation and spindle checkpoint function, defining a loss-of-function genomic instability phenotype.","evidence":"siRNA depletion with time-lapse microscopy, nuclear lamina imaging, and chromosomal instability assays","pmids":["19158495"],"confidence":"Medium","gaps":["Molecular cause of checkpoint weakening not defined","Single-lab knockdown without rescue"]},{"year":2010,"claim":"Identified Aurora B as a direct CKAP2 kinase phosphorylating Ser627 within an RRSRRL motif that controls CKAP2 relocalization during late mitosis.","evidence":"In vitro Aurora B kinase assay, phosphomotif mutagenesis, and subcellular localization imaging","pmids":["20458174"],"confidence":"Medium","gaps":["In vivo requirement of Ser627 for segregation fidelity not established","Relationship to other mitotic phosphosites unclear"]},{"year":2012,"claim":"Explained the G2/M transcriptional peak of CKAP2 through Cyclin A/CDK2-driven Sp1 phosphorylation at a promoter GC box, plus a CHR element.","evidence":"Promoter reporter, EMSA supershift, ChIP, and Cyclin A depletion/add-back","pmids":["22465120"],"confidence":"Medium","gaps":["Direct phosphorylation of Sp1 inferred rather than mapped","CHR-binding repressor not identified"]},{"year":2013,"claim":"Showed CKAP2 is needed to focus microtubule minus ends to spindle poles, with depletion causing cage-like microtubule dispersal, merotely, and polyploidy.","evidence":"RNAi with cold-induced microtubule regrowth assay, immunofluorescence, and FISH","pmids":["23737987"],"confidence":"Medium","gaps":["Pole-focusing partners not identified","Mechanistic link to minus-end clustering machinery unknown"]},{"year":2016,"claim":"Established CKAP2 as required for spindle bipolarity in diploid somatic cells and for tissue regeneration in vivo, extending its role beyond cancer cell lines.","evidence":"siRNA knockdown in primary hepatocytes with centrosome/spindle imaging and an in vivo partial hepatectomy model","pmids":["27055594"],"confidence":"Medium","gaps":["Molecular basis of centrosome over-duplication not defined","In vivo phenotype not linked to a specific phosphosite"]},{"year":2017,"claim":"Defined a required CDK1/cyclin B1 phosphorylation of CKAP2 at T603/S608 for centrosome integrity, distinguishing it from Aurora B regulation.","evidence":"In vitro CDK1/cyclin B1 kinase assay with phosphosite mutant rescue in CKAP2-depleted hepatocytes","pmids":["28706298"],"confidence":"Medium","gaps":["How these phosphosites alter microtubule activity not resolved","Interplay with Aurora and APC/C regulation untested"]},{"year":2017,"claim":"Implicated CKAP2 in oncogenic FAK–ERK2 signaling driving proliferation and motility in cervical carcinoma.","evidence":"Knockdown, pharmacological FAK/ERK2 inhibition, p-ERK2 Western blot, motility assays, and xenograft","pmids":["28522860"],"confidence":"Medium","gaps":["Direct molecular link between CKAP2 and FAK activation unclear","May reflect proliferation phenotype rather than dedicated signaling role"]},{"year":2022,"claim":"Quantitatively redefined CKAP2 as the most potent known microtubule growth factor through direct in vitro reconstitution.","evidence":"In vitro microtubule polymerization assays with quantitative kinetic measurements","pmids":["35029146"],"confidence":"High","gaps":["Domain responsible not yet mapped at this stage","Cellular requirement not yet tested in this study"]},{"year":2023,"claim":"Added a post-transcriptional control layer via a ZC3H13–m6A–CKAP2 axis stabilizing CKAP2 mRNA in cervical cancer.","evidence":"m6A measurement, ZC3H13 manipulation, and CKAP2 rescue in cancer cells","pmids":["37943149"],"confidence":"Low","gaps":["Mechanistic detail limited; single lab","Direct m6A site on CKAP2 mRNA not mapped","Reader/effector linking m6A to stability not defined"]},{"year":2024,"claim":"Established the cellular requirement for CKAP2 in mitotic microtubule growth with rescue, confirming the in vitro activity operates in cells and tracking endogenous localization.","evidence":"CRISPR-Cas9 KO with live-cell plus-end tracking, endogenous tagging, and ectopic re-expression rescue","pmids":["38381793"],"confidence":"High","gaps":["Did not resolve the molecular catalytic mechanism","Phospho-dependence of cellular activity not dissected here"]},{"year":2024,"claim":"Placed CKAP2 downstream of TFDP1 transcriptional control in colorectal cancer proliferation.","evidence":"Co-IP, dual-luciferase reporter, and rescue experiments","pmids":["39403723"],"confidence":"Low","gaps":["Single Co-IP without reciprocal validation","Direct vs indirect transcriptional regulation unclear"]},{"year":2025,"claim":"Localized the catalytic activity to a 284-residue intrinsically disordered domain and proposed a transition-state-based mechanism distinct from canonical polymerases.","evidence":"In vitro reconstitution with isolated CKAP2 domain measuring polymerization/depolymerization (preprint)","pmids":["bio_10.1101_2025.09.02.673730"],"confidence":"Medium","gaps":["Preprint, single lab, not peer reviewed","Structural basis of transition-state catalysis not defined","Domain behavior in cells not validated"]},{"year":2025,"claim":"Identified Aurora kinase A/TPX2 as specific CKAP2 interactors and showed Aurora A phosphorylation lowers CKAP2 microtubule affinity, defining a spindle-growth regulatory pathway.","evidence":"Endogenous Co-IP/MS, in vitro kinase assay, and cellular microtubule affinity measurement (preprint)","pmids":["bio_10.1101_2025.09.09.675182"],"confidence":"High","gaps":["Preprint, not yet peer reviewed","Phosphosite(s) targeted by Aurora A not pinpointed in this entry","Integration with CDK1 and Aurora B inputs unresolved"]},{"year":null,"claim":"The structural and transition-state basis by which the CKAP2 intrinsically disordered domain catalyzes microtubule growth without high-affinity tubulin binding, and how the multiple kinase inputs (Aurora A, Aurora B, CDK1) are integrated to time spindle assembly, remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of the catalytic IDR","No unified scheme integrating phospho-inputs with degradation timing","Direct binding/regulatory partners at spindle poles undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[0,1,6,16]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,3]}],"localization":[{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[16,12,14]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[6,16,1]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[1,8]}],"pathway":[{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[1,4,5,9,16]}],"complexes":[],"partners":["AURKA","TPX2","AURKB","CDK1","TFDP1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8WWK9","full_name":"Cytoskeleton-associated protein 2","aliases":["CTCL tumor antigen se20-10","Tumor- and microtubule-associated protein"],"length_aa":683,"mass_kda":77.0,"function":"Possesses microtubule stabilizing properties. Involved in regulating aneuploidy, cell cycling, and cell death in a p53/TP53-dependent manner (By similarity)","subcellular_location":"Cytoplasm, cytoskeleton; Cytoplasm, cytoskeleton, spindle; Cytoplasm, cytoskeleton, spindle pole","url":"https://www.uniprot.org/uniprotkb/Q8WWK9/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CKAP2","classification":"Not Classified","n_dependent_lines":102,"n_total_lines":1208,"dependency_fraction":0.08443708609271523},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000136108","cell_line_id":"CID001503","localizations":[{"compartment":"centrosome","grade":3},{"compartment":"cytoskeleton","grade":3}],"interactors":[{"gene":"MED18","stoichiometry":10.0},{"gene":"KIF22","stoichiometry":10.0},{"gene":"SSBP1","stoichiometry":10.0},{"gene":"HERC2","stoichiometry":4.0},{"gene":"ACTG1","stoichiometry":0.2},{"gene":"KIF2A","stoichiometry":0.2},{"gene":"SSSCA1","stoichiometry":0.2},{"gene":"HSPA5","stoichiometry":0.2},{"gene":"MYCBP2","stoichiometry":0.2},{"gene":"PEO1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID001503","total_profiled":1310},"omim":[{"mim_id":"616174","title":"CYTOSKELETON-ASSOCIATED PROTEIN 2-LIKE; CKAP2L","url":"https://www.omim.org/entry/616174"},{"mim_id":"611569","title":"CYTOSKELETON-ASSOCIATED PROTEIN 2; CKAP2","url":"https://www.omim.org/entry/611569"},{"mim_id":"263450","title":"POLYDACTYLY, POSTAXIAL, TYPE A5; PAPA5","url":"https://www.omim.org/entry/263450"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Microtubules","reliability":"Supported"},{"location":"Mitotic spindle","reliability":"Supported"},{"location":"Primary cilium","reliability":"Supported"},{"location":"Centrosome","reliability":"Additional"},{"location":"Basal body","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"bone marrow","ntpm":63.9}],"url":"https://www.proteinatlas.org/search/CKAP2"},"hgnc":{"alias_symbol":["LB1","FLJ10749","se20-10","TMAP"],"prev_symbol":[]},"alphafold":{"accession":"Q8WWK9","domains":[{"cath_id":"-","chopping":"589-674","consensus_level":"high","plddt":82.0262,"start":589,"end":674},{"cath_id":"1.25.40","chopping":"415-513","consensus_level":"high","plddt":88.6363,"start":415,"end":513}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8WWK9","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8WWK9-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8WWK9-F1-predicted_aligned_error_v6.png","plddt_mean":58.78},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CKAP2","jax_strain_url":"https://www.jax.org/strain/search?query=CKAP2"},"sequence":{"accession":"Q8WWK9","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8WWK9.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8WWK9/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8WWK9"}},"corpus_meta":[{"pmid":"25189355","id":"PMC_25189355","title":"RSK promotes prostate cancer progression in bone through ING3, CKAP2, and PTK6-mediated cell survival.","date":"2014","source":"Molecular cancer research : MCR","url":"https://pubmed.ncbi.nlm.nih.gov/25189355","citation_count":46,"is_preprint":false},{"pmid":"16061649","id":"PMC_16061649","title":"Ckap2 regulates aneuploidy, cell cycling, and cell death in a p53-dependent manner.","date":"2005","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/16061649","citation_count":43,"is_preprint":false},{"pmid":"17376772","id":"PMC_17376772","title":"CKAP2 is a spindle-associated protein degraded by APC/C-Cdh1 during mitotic exit.","date":"2007","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17376772","citation_count":41,"is_preprint":false},{"pmid":"17339342","id":"PMC_17339342","title":"Functional importance of the anaphase-promoting complex-Cdh1-mediated degradation of TMAP/CKAP2 in regulation of spindle function and cytokinesis.","date":"2007","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/17339342","citation_count":34,"is_preprint":false},{"pmid":"15504249","id":"PMC_15504249","title":"Identification of a mouse cytoskeleton-associated protein, CKAP2, with microtubule-stabilizing properties.","date":"2004","source":"Cancer science","url":"https://pubmed.ncbi.nlm.nih.gov/15504249","citation_count":34,"is_preprint":false},{"pmid":"1982895","id":"PMC_1982895","title":"A human glioma cell line retaining expression of GFAP and gangliosides, recognized by A2B5 and LB1 antibodies, after prolonged passage.","date":"1990","source":"Neuropathology and applied neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/1982895","citation_count":30,"is_preprint":false},{"pmid":"19158495","id":"PMC_19158495","title":"TMAP/CKAP2 is essential for proper chromosome segregation.","date":"2009","source":"Cell cycle (Georgetown, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/19158495","citation_count":28,"is_preprint":false},{"pmid":"34596006","id":"PMC_34596006","title":"LncRNA DARS-AS1 aggravates the growth and metastasis of hepatocellular carcinoma via regulating the miR-3200-5p-Cytoskeleton associated protein 2 (CKAP2) axis.","date":"2021","source":"Bioengineered","url":"https://pubmed.ncbi.nlm.nih.gov/34596006","citation_count":28,"is_preprint":false},{"pmid":"28522860","id":"PMC_28522860","title":"Involvement of FAK-ERK2 signaling pathway in CKAP2-induced proliferation and motility in cervical carcinoma cell lines.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/28522860","citation_count":27,"is_preprint":false},{"pmid":"16876122","id":"PMC_16876122","title":"A cytoskeleton-associated protein, TMAP/CKAP2, is involved in the proliferation of human foreskin fibroblasts.","date":"2006","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/16876122","citation_count":24,"is_preprint":false},{"pmid":"35429924","id":"PMC_35429924","title":"A chalcone-syringaldehyde hybrid inhibits triple-negative breast cancer cell proliferation and migration by inhibiting CKAP2-mediated FAK and STAT3 phosphorylation.","date":"2022","source":"Phytomedicine : international journal of phytotherapy and phytopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/35429924","citation_count":24,"is_preprint":false},{"pmid":"25655308","id":"PMC_25655308","title":"LB-1 Exerts Antitumor Activity in Pancreatic Cancer by Inhibiting HIF-1α and Stat3 Signaling.","date":"2015","source":"Journal of cellular physiology","url":"https://pubmed.ncbi.nlm.nih.gov/25655308","citation_count":23,"is_preprint":false},{"pmid":"28848598","id":"PMC_28848598","title":"Development of a High-Efficient Mutation Resource with Phenotypic Variation in Hexaploid Winter Wheat and Identification of Novel Alleles in the TaAGP.L-B1 Gene.","date":"2017","source":"Frontiers in plant science","url":"https://pubmed.ncbi.nlm.nih.gov/28848598","citation_count":23,"is_preprint":false},{"pmid":"18779650","id":"PMC_18779650","title":"Transient phosphorylation of tumor associated microtubule associated protein (TMAP)/cytoskeleton associated protein 2 (CKAP2) at Thr-596 during early phases of mitosis.","date":"2008","source":"Experimental & molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/18779650","citation_count":22,"is_preprint":false},{"pmid":"34796123","id":"PMC_34796123","title":"Lactobacillus rhamnosus LB1 Alleviates Enterotoxigenic Escherichia coli-Induced Adverse Effects in Piglets by Improving Host Immune Response and Anti-Oxidation Stress and Restoring Intestinal Integrity.","date":"2021","source":"Frontiers in cellular and infection microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/34796123","citation_count":22,"is_preprint":false},{"pmid":"28933561","id":"PMC_28933561","title":"CKAP2 Promotes Ovarian Cancer Proliferation and Tumorigenesis Through the FAK-ERK Pathway.","date":"2017","source":"DNA and cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/28933561","citation_count":20,"is_preprint":false},{"pmid":"35853854","id":"PMC_35853854","title":"Long non-coding RNA DLEU1 promotes malignancy of breast cancer by acting as an indispensable coactivator for HIF-1α-induced transcription of CKAP2.","date":"2022","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/35853854","citation_count":19,"is_preprint":false},{"pmid":"17343908","id":"PMC_17343908","title":"Interaction of an Fe derivative of TMAP (Fe(TMAP)OAc) with DNA in comparison with free-base TMAP.","date":"2007","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/17343908","citation_count":17,"is_preprint":false},{"pmid":"35029146","id":"PMC_35029146","title":"The mitotic spindle protein CKAP2 potently increases formation and stability of microtubules.","date":"2022","source":"eLife","url":"https://pubmed.ncbi.nlm.nih.gov/35029146","citation_count":16,"is_preprint":false},{"pmid":"23737987","id":"PMC_23737987","title":"CKAP2 ensures chromosomal stability by maintaining the integrity of microtubule nucleation sites.","date":"2013","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23737987","citation_count":16,"is_preprint":false},{"pmid":"16708278","id":"PMC_16708278","title":"Tumor microvascular architecture phenotype (T-MAP) as a new concept for studies of angiogenesis and oncology.","date":"2006","source":"Journal of neuro-oncology","url":"https://pubmed.ncbi.nlm.nih.gov/16708278","citation_count":16,"is_preprint":false},{"pmid":"37943149","id":"PMC_37943149","title":"ZC3H13 Enhances the Malignancy of Cervical Cancer by Regulating m6A Modification of CKAP2.","date":"2023","source":"Critical reviews in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/37943149","citation_count":14,"is_preprint":false},{"pmid":"35954424","id":"PMC_35954424","title":"Knockdown of CKAP2 Inhibits Proliferation, Migration, and Aggregate Formation in Aggressive Breast Cancer.","date":"2022","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/35954424","citation_count":11,"is_preprint":false},{"pmid":"38542789","id":"PMC_38542789","title":"Effect of Probiotic Lacticaseibacillus rhamnosus LB1.5 on Anxiety-like Behavior, Neuroprotection and Neuroinflammation Markers of Male Mice Fed a High-Fat Diet.","date":"2024","source":"Nutrients","url":"https://pubmed.ncbi.nlm.nih.gov/38542789","citation_count":11,"is_preprint":false},{"pmid":"28706298","id":"PMC_28706298","title":"CKAP2 phosphorylation by CDK1/cyclinB1 is crucial for maintaining centrosome integrity.","date":"2017","source":"Experimental & molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/28706298","citation_count":10,"is_preprint":false},{"pmid":"20458174","id":"PMC_20458174","title":"Specific primary sequence requirements for Aurora B kinase-mediated phosphorylation and subcellular localization of TMAP during mitosis.","date":"2010","source":"Cell cycle (Georgetown, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/20458174","citation_count":10,"is_preprint":false},{"pmid":"22465120","id":"PMC_22465120","title":"Cyclin A regulates a cell-cycle-dependent expression of CKAP2 through phosphorylation of Sp1.","date":"2012","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/22465120","citation_count":8,"is_preprint":false},{"pmid":"22020800","id":"PMC_22020800","title":"Condensed chromatin staining of CKAP2 as surrogate marker for mitotic figures.","date":"2011","source":"Journal of cancer research and clinical oncology","url":"https://pubmed.ncbi.nlm.nih.gov/22020800","citation_count":8,"is_preprint":false},{"pmid":"31275710","id":"PMC_31275710","title":"Production, purification and characterization of a milk clotting enzyme from Bacillus methanolicus LB-1.","date":"2019","source":"Food science and biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/31275710","citation_count":8,"is_preprint":false},{"pmid":"6163729","id":"PMC_6163729","title":"Effect of seminal plasma on Chlamydia trachomatis strain LB-1 in cell culture.","date":"1981","source":"Infection and immunity","url":"https://pubmed.ncbi.nlm.nih.gov/6163729","citation_count":8,"is_preprint":false},{"pmid":"37424820","id":"PMC_37424820","title":"CKAP2 promotes cervical cancer progression by modulating the tumor microenvironment via NF-κB signaling.","date":"2023","source":"American journal of cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/37424820","citation_count":7,"is_preprint":false},{"pmid":"38381793","id":"PMC_38381793","title":"The spindle protein CKAP2 regulates microtubule dynamics and ensures faithful chromosome segregation.","date":"2024","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/38381793","citation_count":6,"is_preprint":false},{"pmid":"34216644","id":"PMC_34216644","title":"Cytoskeleton-associated protein 2 (CKAP2) is regulated by vascular endothelial growth factor and p53 in retinal capillary endothelial cells under high-glucose conditions.","date":"2021","source":"Molecular and cellular endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/34216644","citation_count":6,"is_preprint":false},{"pmid":"24280143","id":"PMC_24280143","title":"RHOA, SEMA3B, and CKAP2 expression in leukaemia of different types: the results of a pilot experiment.","date":"2013","source":"Folia biologica","url":"https://pubmed.ncbi.nlm.nih.gov/24280143","citation_count":5,"is_preprint":false},{"pmid":"25273340","id":"PMC_25273340","title":"Comparative study of the interaction of meso-tetrakis (N-para-trimethyl-anilium) porphyrin (TMAP) in its free base and Fe derivative form with oligo(dA.dT)15 and oligo(dG.dC)15.","date":"2014","source":"Journal of biomolecular structure & dynamics","url":"https://pubmed.ncbi.nlm.nih.gov/25273340","citation_count":5,"is_preprint":false},{"pmid":"31071262","id":"PMC_31071262","title":"Exploring the Folding Mechanism of Small Proteins GB1 and LB1.","date":"2019","source":"Journal of chemical theory and computation","url":"https://pubmed.ncbi.nlm.nih.gov/31071262","citation_count":4,"is_preprint":false},{"pmid":"27055594","id":"PMC_27055594","title":"CKAP2 is necessary to ensure the faithful spindle bipolarity in a dividing diploid hepatocyte.","date":"2016","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/27055594","citation_count":4,"is_preprint":false},{"pmid":"12923770","id":"PMC_12923770","title":"Tissue Molecular Anatomy Project (TMAP): an expression database for comparative cancer proteomics.","date":"2003","source":"Proteomics","url":"https://pubmed.ncbi.nlm.nih.gov/12923770","citation_count":4,"is_preprint":false},{"pmid":"9501410","id":"PMC_9501410","title":"Alpha 2,3-specific desialylation of human red cells: effect on the autoantigens of the Pr, Sa and Sia-l1, -b1, -lb1 series.","date":"1998","source":"Vox sanguinis","url":"https://pubmed.ncbi.nlm.nih.gov/9501410","citation_count":4,"is_preprint":false},{"pmid":"40636121","id":"PMC_40636121","title":"Identification and validation of CKAP2 as a novel biomarker in the development and progression of rheumatoid arthritis.","date":"2025","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/40636121","citation_count":2,"is_preprint":false},{"pmid":"39403723","id":"PMC_39403723","title":"CKAP2 Regulated by TFDP1 Promotes Metastasis and Proliferation of Colorectal Cancer through Affecting the Tumor Microenvironment.","date":"2024","source":"Journal of microbiology and biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/39403723","citation_count":2,"is_preprint":false},{"pmid":"11234418","id":"PMC_11234418","title":"[Evolutionarily-conserved gene CKAP2,located in region 13q14.3 of the human genome, is frequently rearranged in various tumors].","date":"2001","source":"Genetika","url":"https://pubmed.ncbi.nlm.nih.gov/11234418","citation_count":2,"is_preprint":false},{"pmid":"39203494","id":"PMC_39203494","title":"Analysis of the Probiotic Potential of Lactiplantibacillus plantarum LB1_P46 Isolated from the Mexican Fermented Pulque Beverage: A Functional and Genomic Analysis.","date":"2024","source":"Microorganisms","url":"https://pubmed.ncbi.nlm.nih.gov/39203494","citation_count":2,"is_preprint":false},{"pmid":"36564253","id":"PMC_36564253","title":"Biosynthesis of lactosucrose by a new source of β-fructofuranosidase from Bacillus methanolicus LB-1.","date":"2022","source":"Journal of bioscience and bioengineering","url":"https://pubmed.ncbi.nlm.nih.gov/36564253","citation_count":2,"is_preprint":false},{"pmid":"40004022","id":"PMC_40004022","title":"Identification of CKAP2 as a Potential Target for Prevention of Gastric Cancer Progression: A Multi-Omics Study.","date":"2025","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/40004022","citation_count":1,"is_preprint":false},{"pmid":"12500535","id":"PMC_12500535","title":"[The structure of the human oncogenesis-associated CKAP2 (LB1) gene].","date":"2002","source":"Molekuliarnaia biologiia","url":"https://pubmed.ncbi.nlm.nih.gov/12500535","citation_count":1,"is_preprint":false},{"pmid":"40581697","id":"PMC_40581697","title":"Effects of Lacticaseibacillus rhamnosus LB1.5 as potential probiotic supplement on the liver and adipose tissue of adult male mice to a high-fat diet.","date":"2025","source":"Molecular and cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/40581697","citation_count":1,"is_preprint":false},{"pmid":"39296286","id":"PMC_39296286","title":"Antifungal metabolites of biocontrol stain LB-1 and their inhibition mechanism against Botrytis cinerea.","date":"2024","source":"Frontiers in microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/39296286","citation_count":1,"is_preprint":false},{"pmid":"29622612","id":"PMC_29622612","title":"Complete Genome Sequence of Lactobacillus plantarum subsp. plantarum Strain LB1-2, Isolated from the Hindgut of European Honeybees, Apis mellifera L., from the Philippines.","date":"2018","source":"Genome announcements","url":"https://pubmed.ncbi.nlm.nih.gov/29622612","citation_count":1,"is_preprint":false},{"pmid":"41476086","id":"PMC_41476086","title":"CKAP2, miR-941, miR-548 and LINC02577 as biomarkers for early diagnosis in colorectal cancer.","date":"2025","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/41476086","citation_count":0,"is_preprint":false},{"pmid":"42245497","id":"PMC_42245497","title":"Antifungal activity of the culture filtrate of Chaetomium subaffine LB-1 against Bipolaris maydis and its underlying interaction mechanism.","date":"2026","source":"Frontiers in microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/42245497","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.10.22.683830","title":"Lamin B1 physically regulates neuronal migration by modulating nuclear deformability in the developing cortex","date":"2025-10-22","source":"bioRxiv","url":"https://doi.org/10.1101/2025.10.22.683830","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.09.09.675182","title":"An Aurora Kinase A/TPX2 complex phosphorylates CKAP2 to control mitotic spindle growth","date":"2025-09-15","source":"bioRxiv","url":"https://doi.org/10.1101/2025.09.09.675182","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.09.02.673730","title":"Enzymatic Function of an Intrinsically Disordered Protein","date":"2025-09-03","source":"bioRxiv","url":"https://doi.org/10.1101/2025.09.02.673730","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.02.16.636527","title":"Lamin B1 and LAP2β resist cytoskeletal force to maintain lamin A/C meshwork organization and preserve nuclear integrity","date":"2025-02-16","source":"bioRxiv","url":"https://doi.org/10.1101/2025.02.16.636527","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":28058,"output_tokens":5390,"usd":0.082512,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":13695,"output_tokens":5179,"usd":0.098975,"stage2_stop_reason":"end_turn"},"total_usd":0.181487,"stage1_batch_id":"msgbatch_01ACAxJQabDsht39JXeWG22d","stage2_batch_id":"msgbatch_01QEU22A9U5sbPTgsMzTmvSf","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2022,\n      \"finding\": \"In vitro reconstitution assays showed that CKAP2 potently promotes microtubule nucleation, lowering the critical tubulin concentration ~100-fold, increases the apparent rate constant of microtubule growth ~50-fold, increases microtubule growth rates, and strongly suppresses catastrophes, identifying CKAP2 as the most potent microtubule growth factor known.\",\n      \"method\": \"In vitro reconstitution assay (microtubule polymerization)\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct in vitro reconstitution with quantitative measurements, single rigorous study with multiple orthogonal readouts\",\n      \"pmids\": [\"35029146\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"CRISPR-Cas9 knock-out and live-cell microtubule plus-end tracking showed that CKAP2 is required for normal microtubule growth rates in cells during mitosis; CKAP2 KO cells display reduced microtubule growth rates, increased chromosome segregation errors, and aneuploidy, all rescued by ectopic CKAP2 expression. Endogenously labeled CKAP2 localizes to the spindle during mitosis and shifts to chromatin upon mitotic exit before degradation.\",\n      \"method\": \"CRISPR-Cas9 KO, live-cell microtubule plus-end tracking imaging, ectopic re-expression rescue\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — CRISPR KO with rescue, live-cell imaging, multiple orthogonal methods in one study\",\n      \"pmids\": [\"38381793\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Endogenous CKAP2 immunoprecipitation from mitotic cells followed by mass spectrometry identified Aurora kinase A and its activator TPX2 (but not Aurora B) as specific CKAP2 interactors. Aurora A directly phosphorylates CKAP2 in vitro and in cells, and this phosphorylation decreases CKAP2's microtubule affinity in cells and in vitro, revealing a regulatory pathway controlling spindle growth.\",\n      \"method\": \"Endogenous co-immunoprecipitation, mass spectrometry, in vitro kinase assay, microtubule affinity assay in cells\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — reciprocal IP/MS plus in vitro kinase assay plus cellular microtubule affinity measurement in one study; preprint not yet peer-reviewed lowers ceiling slightly\",\n      \"pmids\": [\"bio_10.1101_2025.09.09.675182\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"A 284-amino acid intrinsically disordered domain of CKAP2 is sufficient to catalyze both microtubule polymerization and depolymerization in vitro. CKAP2 promotes tubulin incorporation without high-affinity tubulin binding, suggesting a transition-state-based catalytic mechanism distinct from known microtubule polymerases.\",\n      \"method\": \"In vitro reconstitution with isolated CKAP2 domain, microtubule polymerization/depolymerization assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — in vitro reconstitution with isolated domain, single lab, preprint not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2025.09.02.673730\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"CKAP2 is a physiological substrate of the APC/C–Cdh1 ubiquitin ligase. Ubiquitination and degradation of CKAP2 in vitro require a KEN-box motif and are mediated by Cdh1. CKAP2 protein levels are high in mitosis and drop during mitotic exit; Cdh1 overexpression reduces CKAP2 in a KEN-box-dependent manner and Cdh1 knockdown extends CKAP2 half-life. Ectopic expression of wild-type or non-degradable CKAP2 causes mitotic arrest with monopolar spindles and bundled microtubules.\",\n      \"method\": \"In vitro ubiquitination assay, KEN-box mutagenesis, Cdh1 overexpression/knockdown, cell cycle fractionation, immunofluorescence\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — in vitro ubiquitination reconstitution plus mutagenesis plus cellular validation; replicated in a companion paper (PMID 17339342)\",\n      \"pmids\": [\"17376772\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"APC/C–Cdh1-mediated degradation of CKAP2 during mitotic exit is required for completion of cytokinesis and maintenance of spindle bipolarity. The KEN-box near the N-terminus is necessary for CKAP2 destruction. Overexpression of CKAP2 induces microtubule bundling, centrosome separation defects, and monopolar spindle formation; non-degradable CKAP2 significantly increases spindle defects and cytokinesis failure.\",\n      \"method\": \"KEN-box mutagenesis, non-degradable mutant expression, siRNA knockdown, immunofluorescence, live-cell imaging\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — mutagenesis plus cellular gain/loss-of-function with specific mitotic phenotypes; replicates and extends PMID 17376772\",\n      \"pmids\": [\"17339342\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Mouse CKAP2 protein co-localizes with microtubules throughout the cell cycle and overexpression stabilizes microtubules against nocodazole-induced depolymerization, establishing CKAP2 as a microtubule-associated protein with microtubule-stabilizing properties.\",\n      \"method\": \"Immunocytochemistry, nocodazole resistance assay, co-localization with tubulin\",\n      \"journal\": \"Cancer science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — cellular co-localization and drug resistance assay, single lab, two methods\",\n      \"pmids\": [\"15504249\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Overexpressed CKAP2 co-localizes with and stabilizes microtubules. In p53-null cells, CKAP2 overexpression induces tetraploidy with aberrant centrosome numbers; in p53-competent cells it activates p53-mediated cell cycle arrest and apoptosis, suggesting CKAP2 activates the G1 tetraploidy checkpoint. DNA damage induces CKAP2 expression in a p53-dependent manner and p53 activates the Ckap2 promoter.\",\n      \"method\": \"DNA microarray, promoter reporter assay, overexpression in p53-null vs. p53-competent cells, immunofluorescence, flow cytometry\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — promoter assay, genetic cell line comparison (p53-null vs. competent), multiple readouts in one study\",\n      \"pmids\": [\"16061649\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"siRNA-mediated depletion of CKAP2 in mammalian cells causes chromatin bridge formation, abnormal nuclear morphology (with abnormal nuclear lamina organization), defects in chromosome segregation revealed by time-lapse microscopy, reduced spindle checkpoint activity, reduced cell viability, and increased chromosomal instability.\",\n      \"method\": \"siRNA knockdown, time-lapse video microscopy, immunofluorescence of nuclear lamina, chromosomal instability assay\",\n      \"journal\": \"Cell cycle (Georgetown, Tex.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA KD with live imaging and multiple cellular readouts, single lab\",\n      \"pmids\": [\"19158495\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"RNAi depletion of CKAP2 results in multipolar mitoses and spindle pole defects; CKAP2-depleted cells show dispersal of newly polymerized microtubules into a cage-like structure around chromatin immediately after mitotic release, indicating defective focusing of microtubule minus ends to spindle poles. CKAP2 suppression also increases merotelic kinetochore attachments, anaphase lagging, and polyploidy.\",\n      \"method\": \"RNAi knockdown, microtubule regrowth assay after cold treatment, immunofluorescence, FISH for aneuploidy\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi with microtubule regrowth assay and multiple orthogonal phenotypic readouts, single lab\",\n      \"pmids\": [\"23737987\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"CKAP2 is transiently phosphorylated at Thr-596 (mouse T596, equivalent human site) specifically during early mitotic phases (prophase through metaphase); phosphorylation at T596 abolishes recognition by a monoclonal antibody (D-12-3) and was identified by epitope mapping. Immunofluorescence showed the phosphorylated form disappears at anaphase, indicating dephosphorylation during late mitosis.\",\n      \"method\": \"Epitope mapping with monoclonal antibodies, immunofluorescence on mitotic cells, phospho-peptide competition\",\n      \"journal\": \"Experimental & molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — epitope mapping plus immunofluorescence cell cycle staging, single lab, two methods\",\n      \"pmids\": [\"18779650\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Aurora B kinase directly phosphorylates CKAP2 (TMAP) at Ser627 in vitro and in vivo. The motif (625)RRSRRL(630) surrounding Ser627 is required for efficient phosphorylation; substitutions within this motif both diminish kinase-substrate recognition and alter CKAP2 subcellular localization during late mitosis (mutants remain associated with microtubules/centrosomes instead of relocating to the chromosome region).\",\n      \"method\": \"In vitro kinase assay with Aurora B, site-directed mutagenesis of phosphorylation motif, immunofluorescence for subcellular localization\",\n      \"journal\": \"Cell cycle (Georgetown, Tex.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro kinase assay plus mutagenesis plus localization imaging, single lab\",\n      \"pmids\": [\"20458174\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CDK1-cyclin B1 phosphorylates mouse CKAP2 at T603 and possibly S608 during mitosis. Ectopic expression of T603A and S608A mutants fails to rescue centrosomal abnormalities (amplified centrosomes and aberrant chromosome segregation) in CKAP2-depleted primary hepatocytes, demonstrating that these phosphorylation events are required for centrosome integrity and bipolar spindle formation.\",\n      \"method\": \"In vitro CDK1/cyclin B1 kinase assay, phosphorylation site mutagenesis, rescue experiment in CKAP2-depleted hepatocytes, immunofluorescence\",\n      \"journal\": \"Experimental & molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro kinase assay with mutagenesis rescue, single lab, multiple methods\",\n      \"pmids\": [\"28706298\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"The human CKAP2 promoter contains a GC box (−41 to −32 bp) bound by transcription factor Sp1 (confirmed by supershift and ChIP assays) and a CHR element (−110 to −104 bp) that together drive cell-cycle-dependent CKAP2 transcription. Cyclin A/CDK2 promotes Sp1 binding to the GC box; depletion of Cyclin A reduces Sp1 occupancy, which is restored by adding back the Cyclin A/CDK2 complex, establishing Cyclin A-mediated Sp1 phosphorylation as the mechanism for G2/M-peak CKAP2 expression.\",\n      \"method\": \"Promoter reporter assay, EMSA supershift, ChIP assay, Cyclin A depletion with add-back experiment, mutagenesis of regulatory elements\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP, supershift, and Cyclin A add-back, multiple methods in single lab\",\n      \"pmids\": [\"22465120\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"CKAP2-depleted primary hepatocytes display over-duplicated centrosomes, disjoined chromosomes from the metaphase plate, and proceed to apoptosis or multipolar cell division; CKAP2 is required for spindle bipolarity in diploid somatic cells. In vivo, CKAP2 depletion in mouse liver markedly reduces hepatic regeneration efficiency.\",\n      \"method\": \"siRNA knockdown in primary hepatocytes, immunofluorescence, in vivo partial hepatectomy model\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with defined centrosome/spindle phenotype in primary cells plus in vivo model, single lab\",\n      \"pmids\": [\"27055594\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"CKAP2 expression is cell-cycle-dependent in human foreskin fibroblasts, absent in G0/G1-arrested cells and peaking at G2/M. Knockdown of CKAP2 reduces pRB phosphorylation and increases p27 expression, reducing proliferation; constitutive CKAP2 expression increases pRB phosphorylation and enhances proliferation, placing CKAP2 upstream of the Rb/p27 pathway in cell cycle progression.\",\n      \"method\": \"siRNA knockdown, constitutive overexpression, Western blot for pRB/p27, proliferation assays\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — bidirectional (KD and OE) with molecular readouts pRB and p27, single lab\",\n      \"pmids\": [\"16876122\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"CKAP2 localizes to centrosomal microtubules in late G2 (only after centrosome separation), then to spindle poles and spindle microtubules from prophase through anaphase, and disappears from microtubules during cytokinesis, as determined by live and fixed-cell immunofluorescence.\",\n      \"method\": \"Immunofluorescence across cell cycle stages, centrosome co-localization\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — detailed spatiotemporal localization by immunofluorescence, replicated across two papers (PMID 17376772, 17339342)\",\n      \"pmids\": [\"17376772\", \"17339342\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"In cervical carcinoma cells, CKAP2 knockdown reduces phosphorylation of ERK2 (p-ERK2) and inhibits cell proliferation, migration, and invasion; FAK inhibitor (PF-562271) and ERK2 inhibitor (VX-11e) block CKAP2 overexpression-induced proliferation and motility, placing CKAP2 upstream of the FAK–ERK2 signaling axis.\",\n      \"method\": \"siRNA knockdown, pharmacological inhibitors, Western blot for p-ERK2, proliferation/migration/invasion assays, in vivo xenograft\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — bidirectional manipulation (KD and inhibitor) with defined signaling readout, single lab\",\n      \"pmids\": [\"28522860\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"ZC3H13 mediates N6-methyladenosine (m6A) modification of CKAP2 mRNA to stabilize its expression in cervical cancer cells; ZC3H13 inhibition decreases CKAP2 levels, and CKAP2 overexpression partially rescues the malignant phenotype suppressed by ZC3H13 knockdown, establishing a ZC3H13–m6A–CKAP2 regulatory axis.\",\n      \"method\": \"m6A modification level measurement, ZC3H13 overexpression/knockdown, CKAP2 rescue experiment, qRT-PCR, Western blot, proliferation/invasion/migration assays\",\n      \"journal\": \"Critical reviews in immunology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — epistasis rescue assay with m6A measurement, single lab, mechanistic detail limited in abstract\",\n      \"pmids\": [\"37943149\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"CKAP2 interacts with TFDP1 (confirmed by immunoprecipitation and dual-luciferase reporter assay), and TFDP1 positively regulates CKAP2 transcription; CKAP2 overexpression reverses the inhibitory effects of TFDP1 knockdown on colorectal cancer cell proliferation, migration, and invasion, placing CKAP2 downstream of TFDP1.\",\n      \"method\": \"Co-immunoprecipitation, dual-luciferase reporter assay, siRNA/overexpression rescue experiment\",\n      \"journal\": \"Journal of microbiology and biotechnology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP and reporter assay with rescue, single lab\",\n      \"pmids\": [\"39403723\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CKAP2 is a mitotic spindle-associated microtubule-associated protein that potently promotes microtubule nucleation and growth (lowering the critical tubulin concentration ~100-fold and increasing growth rate ~50-fold) via an intrinsically disordered domain, localizes to spindle microtubules and poles from prophase through anaphase, and is required for proper chromosome segregation; its levels are tightly regulated by APC/C–Cdh1-mediated proteasomal degradation (via a KEN-box) during mitotic exit, its transcription is driven by Cyclin A/CDK2-mediated Sp1 phosphorylation at a promoter GC box, and its activity/localization during mitosis is modulated by phosphorylation—notably by Aurora kinase A (which decreases microtubule affinity), CDK1/cyclin B1 (at T603/S608, required for centrosome integrity), and transiently at T596 during early mitosis—placing CKAP2 as a central, multiply regulated effector of spindle assembly whose overexpression causes monopolar spindles and aneuploidy.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CKAP2 is a mitotic spindle-associated microtubule-associated protein that acts as a potent catalyst of microtubule nucleation and growth, functioning as a central effector of bipolar spindle assembly and faithful chromosome segregation [#0, #1]. In reconstituted systems CKAP2 lowers the critical tubulin concentration ~100-fold, increases the apparent growth-rate constant ~50-fold, and suppresses catastrophes, with a 284-residue intrinsically disordered domain sufficient to catalyze both microtubule polymerization and depolymerization without high-affinity tubulin binding [#0, #3]. CKAP2 co-localizes with microtubules across the cell cycle, concentrating on centrosomes after their separation in late G2 and on spindle poles and spindle microtubules from prophase through anaphase before relocating to chromatin and being cleared at mitotic exit [#6, #16, #1]. Loss of CKAP2 reduces cellular microtubule growth rates and produces spindle pole and centrosome defects, merotelic attachments, chromatin bridges, chromosome segregation errors, and aneuploidy [#1, #9, #8, #14]. CKAP2 abundance is gated through the cell cycle by transcriptional and degradative controls: Cyclin A/CDK2-driven Sp1 phosphorylation at a promoter GC box drives a G2/M expression peak [#13], while APC/C\\u2013Cdh1 ubiquitinates CKAP2 via an N-terminal KEN-box to enforce its destruction during mitotic exit, a step required for spindle bipolarity and cytokinesis completion [#4, #5]. Mitotic kinases further tune CKAP2: Aurora kinase A, recruited with TPX2, directly phosphorylates CKAP2 to lower its microtubule affinity [#2], and CDK1/cyclin B1 phosphorylation at T603/S608 is required for centrosome integrity and bipolar spindle formation [#12]. Overexpression or expression of non-degradable CKAP2 causes microtubule bundling, monopolar spindles, and aneuploidy [#4, #5], and CKAP2 also engages a p53-dependent G1 tetraploidy checkpoint and the Rb/p27 proliferative axis [#7, #15].\",\n  \"teleology\": [\n    {\n      \"year\": 2004,\n      \"claim\": \"Established CKAP2 as a bona fide microtubule-associated protein, answering whether it physically engages and influences microtubules.\",\n      \"evidence\": \"Immunocytochemical co-localization with tubulin and nocodazole-resistance assay in mouse cells\",\n      \"pmids\": [\"15504249\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not distinguish direct stabilization from indirect effects\", \"No biochemical reconstitution\", \"Localization dynamics across mitosis not resolved\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Linked CKAP2 to cell cycle progression by placing it upstream of the Rb/p27 pathway, framing it as more than a passive cytoskeletal component.\",\n      \"evidence\": \"siRNA knockdown and constitutive overexpression with pRB/p27 Western blots and proliferation assays in fibroblasts\",\n      \"pmids\": [\"16876122\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting CKAP2 to Rb phosphorylation unresolved\", \"Correlative rather than direct molecular link\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Defined how CKAP2 levels are restricted to mitosis, identifying it as an APC/C\\u2013Cdh1 substrate degraded via a KEN-box, and showed why this destruction matters for spindle bipolarity and cytokinesis.\",\n      \"evidence\": \"In vitro ubiquitination, KEN-box mutagenesis, Cdh1 manipulation, and non-degradable mutant phenotyping, plus cell-cycle localization imaging\",\n      \"pmids\": [\"17376772\", \"17339342\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Phosphorylation inputs controlling degradation timing not addressed\", \"Did not establish the catalytic basis of microtubule effects\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Connected CKAP2 to genome-integrity surveillance, showing its overexpression triggers tetraploidy in p53-null cells but a p53-mediated checkpoint in p53-competent cells.\",\n      \"evidence\": \"Overexpression in p53-null vs competent cells, promoter reporter, microarray, flow cytometry\",\n      \"pmids\": [\"16061649\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct biochemical link between CKAP2 and p53 activation unclear\", \"Whether checkpoint engagement is centrosome-driven not resolved\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Revealed dynamic mitotic phosphoregulation of CKAP2 by identifying transient T596 phosphorylation in early mitosis that reverses at anaphase.\",\n      \"evidence\": \"Epitope mapping with monoclonal antibodies and immunofluorescence cell-cycle staging\",\n      \"pmids\": [\"18779650\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Responsible kinase not identified\", \"Functional consequence of T596 phosphorylation not tested\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Demonstrated that CKAP2 is required for accurate chromosome segregation and spindle checkpoint function, defining a loss-of-function genomic instability phenotype.\",\n      \"evidence\": \"siRNA depletion with time-lapse microscopy, nuclear lamina imaging, and chromosomal instability assays\",\n      \"pmids\": [\"19158495\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular cause of checkpoint weakening not defined\", \"Single-lab knockdown without rescue\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Identified Aurora B as a direct CKAP2 kinase phosphorylating Ser627 within an RRSRRL motif that controls CKAP2 relocalization during late mitosis.\",\n      \"evidence\": \"In vitro Aurora B kinase assay, phosphomotif mutagenesis, and subcellular localization imaging\",\n      \"pmids\": [\"20458174\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo requirement of Ser627 for segregation fidelity not established\", \"Relationship to other mitotic phosphosites unclear\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Explained the G2/M transcriptional peak of CKAP2 through Cyclin A/CDK2-driven Sp1 phosphorylation at a promoter GC box, plus a CHR element.\",\n      \"evidence\": \"Promoter reporter, EMSA supershift, ChIP, and Cyclin A depletion/add-back\",\n      \"pmids\": [\"22465120\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct phosphorylation of Sp1 inferred rather than mapped\", \"CHR-binding repressor not identified\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Showed CKAP2 is needed to focus microtubule minus ends to spindle poles, with depletion causing cage-like microtubule dispersal, merotely, and polyploidy.\",\n      \"evidence\": \"RNAi with cold-induced microtubule regrowth assay, immunofluorescence, and FISH\",\n      \"pmids\": [\"23737987\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Pole-focusing partners not identified\", \"Mechanistic link to minus-end clustering machinery unknown\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Established CKAP2 as required for spindle bipolarity in diploid somatic cells and for tissue regeneration in vivo, extending its role beyond cancer cell lines.\",\n      \"evidence\": \"siRNA knockdown in primary hepatocytes with centrosome/spindle imaging and an in vivo partial hepatectomy model\",\n      \"pmids\": [\"27055594\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular basis of centrosome over-duplication not defined\", \"In vivo phenotype not linked to a specific phosphosite\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Defined a required CDK1/cyclin B1 phosphorylation of CKAP2 at T603/S608 for centrosome integrity, distinguishing it from Aurora B regulation.\",\n      \"evidence\": \"In vitro CDK1/cyclin B1 kinase assay with phosphosite mutant rescue in CKAP2-depleted hepatocytes\",\n      \"pmids\": [\"28706298\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How these phosphosites alter microtubule activity not resolved\", \"Interplay with Aurora and APC/C regulation untested\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Implicated CKAP2 in oncogenic FAK\\u2013ERK2 signaling driving proliferation and motility in cervical carcinoma.\",\n      \"evidence\": \"Knockdown, pharmacological FAK/ERK2 inhibition, p-ERK2 Western blot, motility assays, and xenograft\",\n      \"pmids\": [\"28522860\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular link between CKAP2 and FAK activation unclear\", \"May reflect proliferation phenotype rather than dedicated signaling role\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Quantitatively redefined CKAP2 as the most potent known microtubule growth factor through direct in vitro reconstitution.\",\n      \"evidence\": \"In vitro microtubule polymerization assays with quantitative kinetic measurements\",\n      \"pmids\": [\"35029146\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Domain responsible not yet mapped at this stage\", \"Cellular requirement not yet tested in this study\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Added a post-transcriptional control layer via a ZC3H13\\u2013m6A\\u2013CKAP2 axis stabilizing CKAP2 mRNA in cervical cancer.\",\n      \"evidence\": \"m6A measurement, ZC3H13 manipulation, and CKAP2 rescue in cancer cells\",\n      \"pmids\": [\"37943149\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Mechanistic detail limited; single lab\", \"Direct m6A site on CKAP2 mRNA not mapped\", \"Reader/effector linking m6A to stability not defined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Established the cellular requirement for CKAP2 in mitotic microtubule growth with rescue, confirming the in vitro activity operates in cells and tracking endogenous localization.\",\n      \"evidence\": \"CRISPR-Cas9 KO with live-cell plus-end tracking, endogenous tagging, and ectopic re-expression rescue\",\n      \"pmids\": [\"38381793\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve the molecular catalytic mechanism\", \"Phospho-dependence of cellular activity not dissected here\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Placed CKAP2 downstream of TFDP1 transcriptional control in colorectal cancer proliferation.\",\n      \"evidence\": \"Co-IP, dual-luciferase reporter, and rescue experiments\",\n      \"pmids\": [\"39403723\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single Co-IP without reciprocal validation\", \"Direct vs indirect transcriptional regulation unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Localized the catalytic activity to a 284-residue intrinsically disordered domain and proposed a transition-state-based mechanism distinct from canonical polymerases.\",\n      \"evidence\": \"In vitro reconstitution with isolated CKAP2 domain measuring polymerization/depolymerization (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.09.02.673730\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, single lab, not peer reviewed\", \"Structural basis of transition-state catalysis not defined\", \"Domain behavior in cells not validated\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified Aurora kinase A/TPX2 as specific CKAP2 interactors and showed Aurora A phosphorylation lowers CKAP2 microtubule affinity, defining a spindle-growth regulatory pathway.\",\n      \"evidence\": \"Endogenous Co-IP/MS, in vitro kinase assay, and cellular microtubule affinity measurement (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.09.09.675182\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Preprint, not yet peer reviewed\", \"Phosphosite(s) targeted by Aurora A not pinpointed in this entry\", \"Integration with CDK1 and Aurora B inputs unresolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural and transition-state basis by which the CKAP2 intrinsically disordered domain catalyzes microtubule growth without high-affinity tubulin binding, and how the multiple kinase inputs (Aurora A, Aurora B, CDK1) are integrated to time spindle assembly, remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of the catalytic IDR\", \"No unified scheme integrating phospho-inputs with degradation timing\", \"Direct binding/regulatory partners at spindle poles undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [0, 1, 6, 16]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [16, 12, 14]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [6, 16, 1]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [1, 8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [1, 4, 5, 9, 16]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"AURKA\", \"TPX2\", \"AURKB\", \"CDK1\", \"TFDP1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}