{"gene":"CEP295","run_date":"2026-06-09T22:57:18","timeline":{"discoveries":[{"year":2014,"finding":"CEP295 (KIAA1731) is a newborn centriole-enriched protein specifically required for centriole-to-centrosome conversion (CCC) but dispensable for cartwheel removal. In its absence, centrioles form and lose their cartwheel in mitosis but fail to recruit pericentriolar material (PCM), resulting in progressive loss of centriolar components. Centrioles associating with either the cartwheel or PCM alone remain stable, but cartwheel-less centrioles without PCM disintegrate, demonstrating that CEP295-mediated CCC maintains centriole stability for duplication.","method":"RNAi knockdown in human cells, cell cycle staging, immunofluorescence, electron microscopy","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean knockdown with specific phenotypic readouts, replicated by multiple subsequent independent labs","pmids":["25131205"],"is_preprint":false},{"year":2015,"finding":"Centriole-to-centrosome conversion requires sequential loading of Cep135, Ana1 (CEP295), and Asterless (Cep152) onto daughter centrioles during mitotic progression in both Drosophila and human cells. Ana1/CEP295 forms a molecular strut within this network spanning the inner to outermost centriole, and its essential role can be substituted by an engineered fragment providing an alternative linkage between Asterless/Cep152 and Cep135. This framework is essential for loading Cep152, the partner of the master regulator of centriole duplication, Plk4.","method":"Epistasis/genetic rescue experiments, co-immunoprecipitation, super-resolution microscopy, engineered molecular bridge constructs in Drosophila and human cells","journal":"Nature cell biology","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods (Co-IP, epistasis, engineered rescue), independently replicated in two organisms","pmids":["26595382"],"is_preprint":false},{"year":2016,"finding":"CEP295 directly interacts with microtubules and is required for building the distal half of centrioles during S and G2. CEP295 is recruited to the proximal end of procentrioles in early S phase and localizes at the centriolar microtubule wall surrounding the SAS6 cartwheel hub. Depletion of CEP295 inhibits recruitment of POC5 and POC1B to distal half centrioles, resulting in shorter centrioles, and blocks post-translational modifications of centriolar microtubules (acetylation and glutamylation). Excess CEP295 induces overly long centrioles; the N-terminal domain exerts a dominant-negative effect on centriole elongation.","method":"siRNA depletion, super-resolution and immunogold electron microscopy, in vitro microtubule-binding assay, overexpression of domains, immunofluorescence","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — direct microtubule binding assay, dominant-negative domain mapping, super-resolution/immunogold EM, multiple orthogonal methods in one study","pmids":["27185865"],"is_preprint":false},{"year":2016,"finding":"Cep295 is recruited to the proximal centriole wall in early stages of procentriole assembly and acts as a scaffold for proper daughter centriole assembly. Cep295 directly binds to and recruits Cep192 onto the daughter centriole wall, which endows the new mother centriole with PCM assembly capacity, microtubule-organizing centre activity, and the ability to support centriole formation.","method":"Depletion by siRNA/RNAi, direct binding assay (pull-down/Co-IP), immunofluorescence, functional assays for MTOC activity","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — direct binding demonstrated for Cep295–Cep192 interaction, functional rescue experiments, multiple readouts","pmids":["27562453"],"is_preprint":false},{"year":2016,"finding":"Drosophila Ana1 (CEP295 ortholog) is irreversibly incorporated into centrioles during assembly and is required for assembling functional centrosomes and cilia. Ana1 plays a more important role in maintaining Asl (Cep152) at centrioles than in initially recruiting it. Ana1 promotes centriole elongation in a dose-dependent manner; a GFP-Ana1 fusion lacking the N-terminal 639 amino acids can support centrosome assembly and cilium function but cannot promote centriole over-elongation, indicating these are separable functions.","method":"Drosophila ana1 mutant analysis, GFP-Ana1 truncation rescue experiments, fluorescence microscopy, FRAP (irreversible incorporation)","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo mutant analysis with domain-separated rescue constructs, replicated in independent Drosophila lab","pmids":["27206860"],"is_preprint":false},{"year":2017,"finding":"CEP295 acts as an upstream effector of POC1B and POC5 loading onto distal-half centrioles. RTTN, which directly interacts with STIL, acts upstream of CEP295 in centriole assembly; CEP295 is downstream of STIL-mediated assembly and upstream of POC1B/POC5 recruitment.","method":"CRISPR/Cas9 knockout, super-resolution microscopy, co-immunoprecipitation (RTTN-STIL interaction), epistasis analysis","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — epistasis established by KO combined with immunofluorescence, CEP295 pathway position inferred from orthogonal KO experiments in same study","pmids":["28811500"],"is_preprint":false},{"year":2018,"finding":"PPP1R35 acts upstream of CEP295 to induce centriole-to-centrosome conversion. In PPP1R35-null cells, centriole assembly initiates normally but CEP295 is not recruited to nascent centrioles, and centrioles disintegrate after mitosis upon cartwheel removal, placing PPP1R35 upstream of CEP295 in the CCC pathway.","method":"CRISPR/Cas9 knockout, immunofluorescence, epistasis analysis by marker recruitment","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KO with defined pathway placement of CEP295 downstream of PPP1R35, single lab","pmids":["30230954"],"is_preprint":false},{"year":2020,"finding":"CEP44, which binds A-microtubules in the centriole lumen and interacts with POC1B, is required for centriole-to-centrosome conversion even when CEP295 is bound to centrioles. This places a centriole structural pathway (CEP44–POC1B–TUBE1–TUBD1) alongside CEP295 as required for CCC, and shows that CEP295 binding alone is insufficient for conversion if the centriole wall is disrupted.","method":"siRNA depletion, immunofluorescence, epistasis analysis, centriole structural analysis","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — systematic epistasis with multiple pathway components, single lab","pmids":["32060285"],"is_preprint":false},{"year":2021,"finding":"Ana1 (Drosophila CEP295 ortholog) helps recruit Polo kinase to mother centrioles. When Ana1-dependent Polo recruitment is specifically impaired, mother centrioles can duplicate, disengage from daughters, and form functional cilia, but they fail to efficiently assemble mitotic PCM or elongate during G2. This demonstrates that Ana1 specifically promotes mitotic centrosome assembly and G2 centriole elongation via Polo recruitment, independently of centriole duplication or cilia assembly.","method":"Drosophila genetics, domain-specific Ana1 mutants disrupting Polo binding, immunofluorescence, functional assays for PCM assembly, centriole duplication, cilia formation","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal functional readouts with separation-of-function mutants establishing specific pathway role for Ana1–Polo interaction","pmids":["34156068"],"is_preprint":false},{"year":2022,"finding":"In Drosophila syncytial blastoderm embryos, centrosomal Polo levels rise and fall during PCM assembly, peaking then declining while PCM scaffold levels continue to rise. Mathematical modeling and experiments indicate that a centriolar pulse of Polo activity, generated by the interaction between Polo and its centriole receptor Ana1 (CEP295 in humans), explains these scaffold assembly dynamics. This supports a model where centrioles generate a local pulse of Polo activity prior to mitotic entry to initiate centrosome maturation.","method":"Live imaging of Drosophila embryos, quantitative fluorescence microscopy, mathematical modeling, genetic perturbation","journal":"The EMBO journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — live imaging with quantitative analysis and mathematical modeling, single lab; model partially inferred","pmids":["35505659"],"is_preprint":false},{"year":2023,"finding":"Depletion of CEP295 in human cells decreases centriole and centrosome numbers and triggers p53-dependent G1 cell cycle arrest. Loss of CEP295 also causes extensive primary ciliary defects in patient-derived fibroblasts and RPE1 cells. Wild-type CEP295, but not a disease-associated missense mutant, can rescue centrosome/centriole developmental defects and cilia defects in patient cells.","method":"Whole-exome sequencing of patients, patient-derived fibroblast analysis, siRNA depletion in U2OS and RPE1 cells, mRNA complementation assay, immunofluorescence, cell cycle analysis","journal":"EBioMedicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — patient cells plus isogenic rescue experiments, multiple orthogonal readouts, distinct mechanistic findings (CCC, ciliogenesis, p53-G1 arrest)","pmids":["38154379"],"is_preprint":false},{"year":2024,"finding":"Ana1/CEP295 is essential for maintaining centrosome integrity in Drosophila. Polo kinase requires Ana1 to promote centriole stability. Ana1 expression prevents centriole loss upon PCM downregulation. However, centrioles maintained solely by ANA1 overexpression are inactive as MTOCs, unlike those maintained by Polo kinase tethering, indicating that CEP295/Ana1 maintains centriole structure but not MTOC activity independently.","method":"Drosophila genetics (overexpression, tethering experiments), immunofluorescence, oogenesis model of centriole loss","journal":"EMBO reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic overexpression and tethering in Drosophila with functional MTOC readout, single lab","pmids":["38200359"],"is_preprint":false},{"year":2010,"finding":"Exogenously expressed KIAA1731 (CEP295) localizes to the centrosome in human cells. RNAi-mediated depletion of KIAA1731 affects centriole formation/stability, suggesting a role in maintaining centriole structure.","method":"Exogenous expression with immunofluorescence, RNAi depletion with phenotypic scoring","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — initial characterization by overexpression localization and RNAi, single lab, limited mechanistic follow-up","pmids":["20844083"],"is_preprint":false},{"year":2026,"finding":"In Drosophila male germline cells, Ana1 (CEP295) is required for the conversion of microtubule doublets to triplets (C-tubule assembly) during spermatogenesis. The Ana1 N-terminal region localizes adjacent to microtubule doublets and promotes modest elongation, while the C-terminal region extends outward and is sufficient for C-tubule assembly. Ana1 recruits centrobin to centrioles via its C-terminal region, and targeted recruitment of centrobin to centrioles restores C-tubule formation in Ana1-deficient cells. Triplet microtubule integrity is critical for male fertility.","method":"Drosophila genetics (Ana1 deletion mutants), domain-mapping with truncation constructs, electron microscopy, centrobin tethering rescue experiments, fertility assays","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — domain separation, direct rescue by centrobin tethering, electron microscopy structural validation, multiple orthogonal approaches in single study","pmids":["42159626"],"is_preprint":false},{"year":2024,"finding":"Mutant alleles encoding overlapping N- and C-terminal parts of Ana1 (CEP295) can complement intragенically to rescue centriole radial expansion and Asl (Cep152) recruitment, thereby restoring centriole duplication and mechanosensory cilia formation, but not elongation of triplet-microtubule-containing centrioles in primary spermatocytes. Full-length continuous Ana1 sequence is required for centriole elongation. A defined internal region, when deleted from otherwise intact Ana1, prevents primary spermatocyte centriole elongation but still allows Asl recruitment, showing that radial expansion and elongation have distinct structural requirements within CEP295.","method":"Drosophila intragenic complementation genetics, domain deletion analysis, electron microscopy, immunofluorescence, fertility assays","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic complementation with domain separation in Drosophila, preprint not peer-reviewed","pmids":["bio_10.1101_2024.10.28.620588"],"is_preprint":true}],"current_model":"CEP295 (Ana1 in Drosophila) is a conserved centriole wall protein recruited to the proximal end of procentrioles in early S phase that functions as a molecular scaffold for centriole-to-centrosome conversion: it directly binds microtubules, recruits CEP192 to endow new mother centrioles with PCM-organizing capacity, bridges Cep135 and Cep152/Asterless to enable Plk4/Polo recruitment and centriole duplication, promotes Polo kinase activity at centrioles to drive mitotic centrosome maturation and G2 centriole elongation, mediates loading of distal-half proteins POC5 and POC1B, and—in the male germline—drives the conversion of microtubule doublets to triplets by recruiting centrobin via its C-terminal region; loss of CEP295 in human cells causes failure of centrosome conversion, progressive centriole disintegration, ciliogenesis defects, and p53-dependent G1 arrest, while in humans bi-allelic loss-of-function variants cause a Seckel-like syndrome with primary microcephaly."},"narrative":{"mechanistic_narrative":"CEP295 (Drosophila Ana1) is a conserved centriole wall protein that serves as the central scaffold for centriole-to-centrosome conversion (CCC), the process that endows newly formed centrioles with the capacity to organize pericentriolar material and to duplicate [PMID:25131205, PMID:26595382]. Recruited to the proximal end of procentrioles in early S phase, CEP295 is irreversibly incorporated into the centriolar microtubule wall surrounding the SAS6 cartwheel hub, where it directly binds microtubules [PMID:27185865, PMID:27206860]. There it acts as a molecular strut spanning the inner to outermost centriole, sequentially bridging Cep135 and Cep152/Asterless—the receptor for the master duplication kinase Plk4—to license centriole duplication [PMID:26595382]. CEP295 directly binds and recruits CEP192 onto the daughter centriole wall, conferring PCM-assembly and microtubule-organizing-center activity on the new mother centriole [PMID:27562453]. Beyond conversion, CEP295 governs construction of the distal centriole half by loading POC5 and POC1B and enabling tubulin acetylation and glutamylation, with its N-terminal domain controlling centriole elongation [PMID:27185865, PMID:28811500]. CEP295 also recruits Polo/Plk kinase to mother centrioles to drive mitotic centrosome maturation and G2 centriole elongation, functions separable from its role in duplication and ciliogenesis [PMID:34156068, PMID:35505659]. In the male germline it directs conversion of microtubule doublets to triplets by recruiting centrobin through its C-terminal region [PMID:42159626]. CEP295 is positioned downstream of RTTN/STIL and PPP1R35 in the assembly pathway and acts in parallel with a CEP44–POC1B structural pathway, such that CEP295 binding alone is insufficient for conversion when the centriole wall is disrupted [PMID:28811500, PMID:30230954, PMID:32060285]. Loss of CEP295 in human cells causes failure of CCC, progressive centriole disintegration, ciliogenesis defects, and p53-dependent G1 arrest; bi-allelic CEP295 variants underlie a primary microcephaly syndrome, and wild-type but not a disease-associated mutant rescues the centriole and cilia defects of patient cells [PMID:25131205, PMID:38154379].","teleology":[{"year":2010,"claim":"Established CEP295 (KIAA1731) as a centrosomal protein whose depletion perturbs centriole formation/stability, providing the first link between this uncharacterized gene and the centriole.","evidence":"Exogenous expression localization and RNAi phenotypic scoring in human cells","pmids":["20844083"],"confidence":"Medium","gaps":["No molecular mechanism or interaction partners identified","Localization shown only by overexpression","Single lab, limited follow-up"]},{"year":2014,"claim":"Defined the specific cellular role of CEP295 as the factor required for centriole-to-centrosome conversion, resolving why centrioles lacking it disintegrate—they fail to recruit PCM after cartwheel removal.","evidence":"RNAi knockdown with cell-cycle staging, immunofluorescence and electron microscopy in human cells","pmids":["25131205"],"confidence":"High","gaps":["Direct binding partners mediating PCM recruitment not yet identified","Molecular nature of the conversion event undefined"]},{"year":2015,"claim":"Placed CEP295/Ana1 within an ordered Cep135–Ana1–Asterless/Cep152 loading hierarchy, showing it acts as a structural bridge essential for recruiting the Plk4 partner Cep152 and thus for duplication.","evidence":"Epistasis/rescue, Co-IP, super-resolution microscopy and engineered bridge constructs in Drosophila and human cells","pmids":["26595382"],"confidence":"High","gaps":["Atomic/structural basis of the bridge not resolved","Whether interactions with Cep135 and Cep152 are direct or indirect not fully defined"]},{"year":2016,"claim":"Showed CEP295 directly binds microtubules and builds the distal centriole half, identifying POC5/POC1B loading and tubulin modification as downstream events and mapping elongation control to the N-terminal domain.","evidence":"siRNA depletion, super-resolution/immunogold EM, in vitro microtubule-binding assay, domain overexpression in human cells","pmids":["27185865"],"confidence":"High","gaps":["Mechanism by which microtubule binding controls elongation not defined","How POC5/POC1B recruitment is achieved at molecular level unknown"]},{"year":2016,"claim":"Identified the molecular basis of conversion: CEP295 directly binds and recruits CEP192, the factor that confers PCM-assembly and MTOC capacity on the new mother centriole.","evidence":"siRNA/RNAi depletion, direct binding/pull-down assays, MTOC functional readouts in human/Drosophila cells","pmids":["27562453"],"confidence":"High","gaps":["Structural details of the CEP295–CEP192 interface not resolved","Coordination between CEP192 recruitment and Cep152 loading unclear"]},{"year":2016,"claim":"Demonstrated in vivo that Ana1 is irreversibly incorporated and that centrosome/cilium function is separable from its dose-dependent role in centriole over-elongation, mapping the latter to the N-terminal 639 residues.","evidence":"Drosophila ana1 mutant analysis, truncation rescue, FRAP, fluorescence microscopy","pmids":["27206860"],"confidence":"High","gaps":["Molecular distinction between maintaining vs initially recruiting Asl not defined","Mechanism of irreversible incorporation unknown"]},{"year":2017,"claim":"Positioned CEP295 in the assembly hierarchy as downstream of RTTN/STIL-mediated assembly and upstream of POC1B/POC5 loading, clarifying the order of distal-half construction.","evidence":"CRISPR/Cas9 knockout, super-resolution microscopy, Co-IP and epistasis in human cells","pmids":["28811500"],"confidence":"Medium","gaps":["CEP295 pathway position partly inferred from orthogonal KOs","Direct vs indirect connection to RTTN/STIL not established"]},{"year":2018,"claim":"Identified PPP1R35 as a factor upstream of CEP295 recruitment, showing that nascent centrioles initiate normally but require PPP1R35 to load CEP295 and undergo conversion.","evidence":"CRISPR/Cas9 knockout, immunofluorescence, epistasis by marker recruitment","pmids":["30230954"],"confidence":"Medium","gaps":["Whether PPP1R35 recruits CEP295 directly is unknown","Single lab"]},{"year":2020,"claim":"Showed that CEP295 binding is necessary but not sufficient for conversion: a parallel CEP44–POC1B–TUBD1/TUBE1 wall-integrity pathway is also required, refining the conversion model.","evidence":"siRNA depletion, epistasis and centriole structural analysis in human cells","pmids":["32060285"],"confidence":"Medium","gaps":["How wall integrity gates CEP295 function mechanistically unclear","Single lab"]},{"year":2021,"claim":"Established that Ana1 recruits Polo kinase to mother centrioles to specifically drive mitotic PCM assembly and G2 elongation, separable from its roles in duplication and cilia.","evidence":"Drosophila genetics with Polo-binding-deficient Ana1 mutants and multiple functional readouts","pmids":["34156068"],"confidence":"High","gaps":["Whether human CEP295 recruits Plk in the same manner not directly shown","Structural basis of Ana1–Polo interaction undefined"]},{"year":2022,"claim":"Provided a quantitative model in which Ana1 acts as the centriole receptor generating a local pulse of Polo activity that times centrosome maturation prior to mitosis.","evidence":"Live imaging of Drosophila embryos, quantitative microscopy, mathematical modeling and genetic perturbation","pmids":["35505659"],"confidence":"Medium","gaps":["Model partly inferred from fitting","Direct measurement of Polo activity dynamics not achieved","Single lab"]},{"year":2023,"claim":"Connected CEP295 loss to human disease, showing depletion causes reduced centriole/centrosome numbers, p53-dependent G1 arrest and ciliary defects, with isogenic rescue distinguishing pathogenic from wild-type alleles.","evidence":"Patient exome sequencing, patient-derived fibroblasts, siRNA in U2OS/RPE1, mRNA complementation, cell-cycle analysis","pmids":["38154379"],"confidence":"High","gaps":["Tissue specificity of microcephaly phenotype not mechanistically explained","Link between centriole loss and p53 activation undefined"]},{"year":2024,"claim":"Demonstrated Ana1 is required to maintain centriole structural integrity (in a Polo-dependent manner) but that centrioles maintained by Ana1 alone are MTOC-inactive, separating structural maintenance from MTOC activity.","evidence":"Drosophila overexpression and tethering genetics with MTOC functional readout in an oogenesis centriole-loss model","pmids":["38200359"],"confidence":"Medium","gaps":["Molecular basis of structural maintenance vs MTOC activity not defined","Single lab"]},{"year":2024,"claim":"Intragenic complementation genetics dissected CEP295 into separable functional modules, showing radial expansion/Asl recruitment can be rescued by overlapping fragments while centriole elongation requires continuous full-length sequence including a defined internal region.","evidence":"Drosophila intragenic complementation, domain deletion, EM, fertility assays (preprint)","pmids":["bio_10.1101_2024.10.28.620588"],"confidence":"Medium","gaps":["Preprint, not peer-reviewed","Molecular identity of the elongation-required internal region not characterized"]},{"year":2026,"claim":"Identified a germline-specific role in which Ana1 drives microtubule doublet-to-triplet conversion by recruiting centrobin through its C-terminal region, with centrobin tethering sufficient to restore C-tubule formation.","evidence":"Drosophila deletion mutants, domain truncations, EM, centrobin tethering rescue and fertility assays","pmids":["42159626"],"confidence":"High","gaps":["Whether human CEP295 recruits centrobin similarly not shown","Mechanism of C-tubule template formation downstream of centrobin undefined"]},{"year":null,"claim":"The structural basis of how CEP295 simultaneously bridges multiple partners (Cep135, Cep152, CEP192, Polo, centrobin) along the centriole wall, and how its distinct domains coordinate conversion, elongation and tissue-specific functions, remains unresolved.","evidence":"No atomic-resolution structural model of CEP295 or its complexes reported in the timeline","pmids":[],"confidence":"Medium","gaps":["No high-resolution structure of CEP295 or its interfaces","Mechanism linking centriole loss to p53/G1 arrest unknown","Human relevance of germline centrobin/triplet functions untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[2]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[0,1,2]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[1,3,8]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[8,9]}],"localization":[{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[3,12]},{"term_id":"GO:0005929","term_label":"cilium","supporting_discovery_ids":[4,10]}],"pathway":[{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[0,1,10]},{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[2,3,4]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[10,13]}],"complexes":["centriole","centrosome"],"partners":["CEP192","CEP152","CEP135","POC5","POC1B","POLO","CNTROB","RTTN"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9C0D2","full_name":"Centrosomal protein of 295 kDa","aliases":[],"length_aa":2601,"mass_kda":295.2,"function":"Centriole-enriched microtubule-binding protein involved in centriole biogenesis (PubMed:20844083, PubMed:25131205, PubMed:27185865, PubMed:38154379). Essential for the generation of the distal portion of new-born centrioles in a CPAP- and CEP120-mediated elongation dependent manner during the cell cycle S/G2 phase after formation of the initiating cartwheel structure (PubMed:27185865). Required for the recruitment of centriolar proteins, such as POC1B, POC5 and CEP135, into the distal portion of centrioles (PubMed:27185865). Also required for centriole-to-centrosome conversion during mitotic progression, but is dispensable for cartwheel removal or centriole disengagement (PubMed:25131205). Binds to and stabilizes centriolar microtubule (PubMed:27185865). May be involved in ciliogenesis (PubMed:38154379)","subcellular_location":"Cytoplasm, cytoskeleton, microtubule organizing center, centrosome, centriole; Cytoplasm, cytoskeleton, microtubule organizing center, centrosome; Cytoplasm, cytoskeleton, spindle; Cytoplasm, cytoskeleton","url":"https://www.uniprot.org/uniprotkb/Q9C0D2/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CEP295","classification":"Not Classified","n_dependent_lines":93,"n_total_lines":1208,"dependency_fraction":0.07698675496688742},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"HSPA4","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/CEP295","total_profiled":1310},"omim":[{"mim_id":"621444","title":"TBC1 DOMAIN FAMILY, MEMBER 31; TBC1D31","url":"https://www.omim.org/entry/621444"},{"mim_id":"620767","title":"SECKEL SYNDROME 11; SCKL11","url":"https://www.omim.org/entry/620767"},{"mim_id":"620217","title":"CENTROSOMAL PROTEIN, 44-KD; CEP44","url":"https://www.omim.org/entry/620217"},{"mim_id":"618937","title":"PROTEIN PHOSPHATASE 1, REGULATORY SUBUNIT 35; PPP1R35","url":"https://www.omim.org/entry/618937"},{"mim_id":"617728","title":"CENTROSOMAL PROTEIN, 295-KD; CEP295","url":"https://www.omim.org/entry/617728"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/CEP295"},"hgnc":{"alias_symbol":[],"prev_symbol":["KIAA1731"]},"alphafold":{"accession":"Q9C0D2","domains":[],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9C0D2","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9C0D2-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9C0D2-F1-predicted_aligned_error_v6.png","plddt_mean":43.88},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CEP295","jax_strain_url":"https://www.jax.org/strain/search?query=CEP295"},"sequence":{"accession":"Q9C0D2","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9C0D2.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9C0D2/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9C0D2"}},"corpus_meta":[{"pmid":"26595382","id":"PMC_26595382","title":"Conserved molecular interactions in centriole-to-centrosome conversion.","date":"2015","source":"Nature cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/26595382","citation_count":110,"is_preprint":false},{"pmid":"25131205","id":"PMC_25131205","title":"Stabilization of cartwheel-less centrioles for duplication requires CEP295-mediated centriole-to-centrosome conversion.","date":"2014","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/25131205","citation_count":91,"is_preprint":false},{"pmid":"20844083","id":"PMC_20844083","title":"Centriolar association of ALMS1 and likely centrosomal functions of the ALMS motif-containing proteins C10orf90 and KIAA1731.","date":"2010","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/20844083","citation_count":89,"is_preprint":false},{"pmid":"30421101","id":"PMC_30421101","title":"ALMS1 and Alström syndrome: a recessive form of metabolic, neurosensory and cardiac deficits.","date":"2018","source":"Journal of molecular medicine (Berlin, Germany)","url":"https://pubmed.ncbi.nlm.nih.gov/30421101","citation_count":84,"is_preprint":false},{"pmid":"27185865","id":"PMC_27185865","title":"CEP295 interacts with microtubules and is required for centriole elongation.","date":"2016","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/27185865","citation_count":63,"is_preprint":false},{"pmid":"26376864","id":"PMC_26376864","title":"Gene-based meta-analysis of genome-wide association studies implicates new loci involved in obesity.","date":"2015","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/26376864","citation_count":55,"is_preprint":false},{"pmid":"27562453","id":"PMC_27562453","title":"Cep295 is a conserved scaffold protein required for generation of a bona fide mother centriole.","date":"2016","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/27562453","citation_count":54,"is_preprint":false},{"pmid":"32060285","id":"PMC_32060285","title":"CEP44 ensures the formation of bona fide centriole wall, a requirement for the centriole-to-centrosome conversion.","date":"2020","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/32060285","citation_count":40,"is_preprint":false},{"pmid":"28811500","id":"PMC_28811500","title":"Human microcephaly protein RTTN interacts with STIL and is required to build full-length centrioles.","date":"2017","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/28811500","citation_count":39,"is_preprint":false},{"pmid":"27206860","id":"PMC_27206860","title":"Drosophila Ana1 is required for centrosome assembly and centriole elongation.","date":"2016","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/27206860","citation_count":34,"is_preprint":false},{"pmid":"35505659","id":"PMC_35505659","title":"Centrioles generate a local pulse of Polo/PLK1 activity to initiate mitotic centrosome assembly.","date":"2022","source":"The EMBO 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science","url":"https://pubmed.ncbi.nlm.nih.gov/34156068","citation_count":12,"is_preprint":false},{"pmid":"36355624","id":"PMC_36355624","title":"IQUB deficiency causes male infertility by affecting the activity of p-ERK1/2/RSPH3.","date":"2023","source":"Human reproduction (Oxford, England)","url":"https://pubmed.ncbi.nlm.nih.gov/36355624","citation_count":8,"is_preprint":false},{"pmid":"38200359","id":"PMC_38200359","title":"Ana1/CEP295 is an essential player in the centrosome maintenance program regulated by Polo kinase and the PCM.","date":"2024","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/38200359","citation_count":7,"is_preprint":false},{"pmid":"38154379","id":"PMC_38154379","title":"Bi-allelic variants in CEP295 cause Seckel-like syndrome presenting with primary microcephaly, developmental delay, intellectual disability, short stature, craniofacial and digital abnormalities.","date":"2023","source":"EBioMedicine","url":"https://pubmed.ncbi.nlm.nih.gov/38154379","citation_count":6,"is_preprint":false},{"pmid":"36982708","id":"PMC_36982708","title":"Heritable Risk and Protective Genetic Components of Glaucoma Medication Non-Adherence.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/36982708","citation_count":6,"is_preprint":false},{"pmid":"34233584","id":"PMC_34233584","title":"Triple deletion of TP53, PCNT, and CEP215 promotes centriole amplification in the M phase.","date":"2021","source":"Cell cycle (Georgetown, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/34233584","citation_count":5,"is_preprint":false},{"pmid":"34418690","id":"PMC_34418690","title":"Coding variants in the PCNT and CEP295 genes contribute to breast cancer risk in Chinese women.","date":"2021","source":"Pathology, research and practice","url":"https://pubmed.ncbi.nlm.nih.gov/34418690","citation_count":3,"is_preprint":false},{"pmid":"42159626","id":"PMC_42159626","title":"Ana1/CEP295 regulates centriolar doublet-to-triplet conversion during spermatogenesis.","date":"2026","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/42159626","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.10.28.620588","title":"Interactions of N- and C-terminal parts of Ana1 permitting centriole duplication but not elongation","date":"2024-10-31","source":"bioRxiv","url":"https://doi.org/10.1101/2024.10.28.620588","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13099,"output_tokens":4257,"usd":0.051576,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":12218,"output_tokens":5103,"usd":0.094332,"stage2_stop_reason":"end_turn"},"total_usd":0.145908,"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\": 2014,\n      \"finding\": \"CEP295 (KIAA1731) is a newborn centriole-enriched protein specifically required for centriole-to-centrosome conversion (CCC) but dispensable for cartwheel removal. In its absence, centrioles form and lose their cartwheel in mitosis but fail to recruit pericentriolar material (PCM), resulting in progressive loss of centriolar components. Centrioles associating with either the cartwheel or PCM alone remain stable, but cartwheel-less centrioles without PCM disintegrate, demonstrating that CEP295-mediated CCC maintains centriole stability for duplication.\",\n      \"method\": \"RNAi knockdown in human cells, cell cycle staging, immunofluorescence, electron microscopy\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean knockdown with specific phenotypic readouts, replicated by multiple subsequent independent labs\",\n      \"pmids\": [\"25131205\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Centriole-to-centrosome conversion requires sequential loading of Cep135, Ana1 (CEP295), and Asterless (Cep152) onto daughter centrioles during mitotic progression in both Drosophila and human cells. Ana1/CEP295 forms a molecular strut within this network spanning the inner to outermost centriole, and its essential role can be substituted by an engineered fragment providing an alternative linkage between Asterless/Cep152 and Cep135. This framework is essential for loading Cep152, the partner of the master regulator of centriole duplication, Plk4.\",\n      \"method\": \"Epistasis/genetic rescue experiments, co-immunoprecipitation, super-resolution microscopy, engineered molecular bridge constructs in Drosophila and human cells\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods (Co-IP, epistasis, engineered rescue), independently replicated in two organisms\",\n      \"pmids\": [\"26595382\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"CEP295 directly interacts with microtubules and is required for building the distal half of centrioles during S and G2. CEP295 is recruited to the proximal end of procentrioles in early S phase and localizes at the centriolar microtubule wall surrounding the SAS6 cartwheel hub. Depletion of CEP295 inhibits recruitment of POC5 and POC1B to distal half centrioles, resulting in shorter centrioles, and blocks post-translational modifications of centriolar microtubules (acetylation and glutamylation). Excess CEP295 induces overly long centrioles; the N-terminal domain exerts a dominant-negative effect on centriole elongation.\",\n      \"method\": \"siRNA depletion, super-resolution and immunogold electron microscopy, in vitro microtubule-binding assay, overexpression of domains, immunofluorescence\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — direct microtubule binding assay, dominant-negative domain mapping, super-resolution/immunogold EM, multiple orthogonal methods in one study\",\n      \"pmids\": [\"27185865\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Cep295 is recruited to the proximal centriole wall in early stages of procentriole assembly and acts as a scaffold for proper daughter centriole assembly. Cep295 directly binds to and recruits Cep192 onto the daughter centriole wall, which endows the new mother centriole with PCM assembly capacity, microtubule-organizing centre activity, and the ability to support centriole formation.\",\n      \"method\": \"Depletion by siRNA/RNAi, direct binding assay (pull-down/Co-IP), immunofluorescence, functional assays for MTOC activity\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — direct binding demonstrated for Cep295–Cep192 interaction, functional rescue experiments, multiple readouts\",\n      \"pmids\": [\"27562453\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Drosophila Ana1 (CEP295 ortholog) is irreversibly incorporated into centrioles during assembly and is required for assembling functional centrosomes and cilia. Ana1 plays a more important role in maintaining Asl (Cep152) at centrioles than in initially recruiting it. Ana1 promotes centriole elongation in a dose-dependent manner; a GFP-Ana1 fusion lacking the N-terminal 639 amino acids can support centrosome assembly and cilium function but cannot promote centriole over-elongation, indicating these are separable functions.\",\n      \"method\": \"Drosophila ana1 mutant analysis, GFP-Ana1 truncation rescue experiments, fluorescence microscopy, FRAP (irreversible incorporation)\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo mutant analysis with domain-separated rescue constructs, replicated in independent Drosophila lab\",\n      \"pmids\": [\"27206860\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CEP295 acts as an upstream effector of POC1B and POC5 loading onto distal-half centrioles. RTTN, which directly interacts with STIL, acts upstream of CEP295 in centriole assembly; CEP295 is downstream of STIL-mediated assembly and upstream of POC1B/POC5 recruitment.\",\n      \"method\": \"CRISPR/Cas9 knockout, super-resolution microscopy, co-immunoprecipitation (RTTN-STIL interaction), epistasis analysis\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis established by KO combined with immunofluorescence, CEP295 pathway position inferred from orthogonal KO experiments in same study\",\n      \"pmids\": [\"28811500\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"PPP1R35 acts upstream of CEP295 to induce centriole-to-centrosome conversion. In PPP1R35-null cells, centriole assembly initiates normally but CEP295 is not recruited to nascent centrioles, and centrioles disintegrate after mitosis upon cartwheel removal, placing PPP1R35 upstream of CEP295 in the CCC pathway.\",\n      \"method\": \"CRISPR/Cas9 knockout, immunofluorescence, epistasis analysis by marker recruitment\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined pathway placement of CEP295 downstream of PPP1R35, single lab\",\n      \"pmids\": [\"30230954\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CEP44, which binds A-microtubules in the centriole lumen and interacts with POC1B, is required for centriole-to-centrosome conversion even when CEP295 is bound to centrioles. This places a centriole structural pathway (CEP44–POC1B–TUBE1–TUBD1) alongside CEP295 as required for CCC, and shows that CEP295 binding alone is insufficient for conversion if the centriole wall is disrupted.\",\n      \"method\": \"siRNA depletion, immunofluorescence, epistasis analysis, centriole structural analysis\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — systematic epistasis with multiple pathway components, single lab\",\n      \"pmids\": [\"32060285\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Ana1 (Drosophila CEP295 ortholog) helps recruit Polo kinase to mother centrioles. When Ana1-dependent Polo recruitment is specifically impaired, mother centrioles can duplicate, disengage from daughters, and form functional cilia, but they fail to efficiently assemble mitotic PCM or elongate during G2. This demonstrates that Ana1 specifically promotes mitotic centrosome assembly and G2 centriole elongation via Polo recruitment, independently of centriole duplication or cilia assembly.\",\n      \"method\": \"Drosophila genetics, domain-specific Ana1 mutants disrupting Polo binding, immunofluorescence, functional assays for PCM assembly, centriole duplication, cilia formation\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal functional readouts with separation-of-function mutants establishing specific pathway role for Ana1–Polo interaction\",\n      \"pmids\": [\"34156068\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"In Drosophila syncytial blastoderm embryos, centrosomal Polo levels rise and fall during PCM assembly, peaking then declining while PCM scaffold levels continue to rise. Mathematical modeling and experiments indicate that a centriolar pulse of Polo activity, generated by the interaction between Polo and its centriole receptor Ana1 (CEP295 in humans), explains these scaffold assembly dynamics. This supports a model where centrioles generate a local pulse of Polo activity prior to mitotic entry to initiate centrosome maturation.\",\n      \"method\": \"Live imaging of Drosophila embryos, quantitative fluorescence microscopy, mathematical modeling, genetic perturbation\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live imaging with quantitative analysis and mathematical modeling, single lab; model partially inferred\",\n      \"pmids\": [\"35505659\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Depletion of CEP295 in human cells decreases centriole and centrosome numbers and triggers p53-dependent G1 cell cycle arrest. Loss of CEP295 also causes extensive primary ciliary defects in patient-derived fibroblasts and RPE1 cells. Wild-type CEP295, but not a disease-associated missense mutant, can rescue centrosome/centriole developmental defects and cilia defects in patient cells.\",\n      \"method\": \"Whole-exome sequencing of patients, patient-derived fibroblast analysis, siRNA depletion in U2OS and RPE1 cells, mRNA complementation assay, immunofluorescence, cell cycle analysis\",\n      \"journal\": \"EBioMedicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — patient cells plus isogenic rescue experiments, multiple orthogonal readouts, distinct mechanistic findings (CCC, ciliogenesis, p53-G1 arrest)\",\n      \"pmids\": [\"38154379\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Ana1/CEP295 is essential for maintaining centrosome integrity in Drosophila. Polo kinase requires Ana1 to promote centriole stability. Ana1 expression prevents centriole loss upon PCM downregulation. However, centrioles maintained solely by ANA1 overexpression are inactive as MTOCs, unlike those maintained by Polo kinase tethering, indicating that CEP295/Ana1 maintains centriole structure but not MTOC activity independently.\",\n      \"method\": \"Drosophila genetics (overexpression, tethering experiments), immunofluorescence, oogenesis model of centriole loss\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic overexpression and tethering in Drosophila with functional MTOC readout, single lab\",\n      \"pmids\": [\"38200359\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Exogenously expressed KIAA1731 (CEP295) localizes to the centrosome in human cells. RNAi-mediated depletion of KIAA1731 affects centriole formation/stability, suggesting a role in maintaining centriole structure.\",\n      \"method\": \"Exogenous expression with immunofluorescence, RNAi depletion with phenotypic scoring\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — initial characterization by overexpression localization and RNAi, single lab, limited mechanistic follow-up\",\n      \"pmids\": [\"20844083\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"In Drosophila male germline cells, Ana1 (CEP295) is required for the conversion of microtubule doublets to triplets (C-tubule assembly) during spermatogenesis. The Ana1 N-terminal region localizes adjacent to microtubule doublets and promotes modest elongation, while the C-terminal region extends outward and is sufficient for C-tubule assembly. Ana1 recruits centrobin to centrioles via its C-terminal region, and targeted recruitment of centrobin to centrioles restores C-tubule formation in Ana1-deficient cells. Triplet microtubule integrity is critical for male fertility.\",\n      \"method\": \"Drosophila genetics (Ana1 deletion mutants), domain-mapping with truncation constructs, electron microscopy, centrobin tethering rescue experiments, fertility assays\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — domain separation, direct rescue by centrobin tethering, electron microscopy structural validation, multiple orthogonal approaches in single study\",\n      \"pmids\": [\"42159626\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Mutant alleles encoding overlapping N- and C-terminal parts of Ana1 (CEP295) can complement intragенically to rescue centriole radial expansion and Asl (Cep152) recruitment, thereby restoring centriole duplication and mechanosensory cilia formation, but not elongation of triplet-microtubule-containing centrioles in primary spermatocytes. Full-length continuous Ana1 sequence is required for centriole elongation. A defined internal region, when deleted from otherwise intact Ana1, prevents primary spermatocyte centriole elongation but still allows Asl recruitment, showing that radial expansion and elongation have distinct structural requirements within CEP295.\",\n      \"method\": \"Drosophila intragenic complementation genetics, domain deletion analysis, electron microscopy, immunofluorescence, fertility assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic complementation with domain separation in Drosophila, preprint not peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2024.10.28.620588\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"CEP295 (Ana1 in Drosophila) is a conserved centriole wall protein recruited to the proximal end of procentrioles in early S phase that functions as a molecular scaffold for centriole-to-centrosome conversion: it directly binds microtubules, recruits CEP192 to endow new mother centrioles with PCM-organizing capacity, bridges Cep135 and Cep152/Asterless to enable Plk4/Polo recruitment and centriole duplication, promotes Polo kinase activity at centrioles to drive mitotic centrosome maturation and G2 centriole elongation, mediates loading of distal-half proteins POC5 and POC1B, and—in the male germline—drives the conversion of microtubule doublets to triplets by recruiting centrobin via its C-terminal region; loss of CEP295 in human cells causes failure of centrosome conversion, progressive centriole disintegration, ciliogenesis defects, and p53-dependent G1 arrest, while in humans bi-allelic loss-of-function variants cause a Seckel-like syndrome with primary microcephaly.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CEP295 (Drosophila Ana1) is a conserved centriole wall protein that serves as the central scaffold for centriole-to-centrosome conversion (CCC), the process that endows newly formed centrioles with the capacity to organize pericentriolar material and to duplicate [#0, #1]. Recruited to the proximal end of procentrioles in early S phase, CEP295 is irreversibly incorporated into the centriolar microtubule wall surrounding the SAS6 cartwheel hub, where it directly binds microtubules [#2, #4]. There it acts as a molecular strut spanning the inner to outermost centriole, sequentially bridging Cep135 and Cep152/Asterless—the receptor for the master duplication kinase Plk4—to license centriole duplication [#1]. CEP295 directly binds and recruits CEP192 onto the daughter centriole wall, conferring PCM-assembly and microtubule-organizing-center activity on the new mother centriole [#3]. Beyond conversion, CEP295 governs construction of the distal centriole half by loading POC5 and POC1B and enabling tubulin acetylation and glutamylation, with its N-terminal domain controlling centriole elongation [#2, #5]. CEP295 also recruits Polo/Plk kinase to mother centrioles to drive mitotic centrosome maturation and G2 centriole elongation, functions separable from its role in duplication and ciliogenesis [#8, #9]. In the male germline it directs conversion of microtubule doublets to triplets by recruiting centrobin through its C-terminal region [#13]. CEP295 is positioned downstream of RTTN/STIL and PPP1R35 in the assembly pathway and acts in parallel with a CEP44–POC1B structural pathway, such that CEP295 binding alone is insufficient for conversion when the centriole wall is disrupted [#5, #6, #7]. Loss of CEP295 in human cells causes failure of CCC, progressive centriole disintegration, ciliogenesis defects, and p53-dependent G1 arrest; bi-allelic CEP295 variants underlie a primary microcephaly syndrome, and wild-type but not a disease-associated mutant rescues the centriole and cilia defects of patient cells [#0, #10].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Established CEP295 (KIAA1731) as a centrosomal protein whose depletion perturbs centriole formation/stability, providing the first link between this uncharacterized gene and the centriole.\",\n      \"evidence\": \"Exogenous expression localization and RNAi phenotypic scoring in human cells\",\n      \"pmids\": [\"20844083\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"No molecular mechanism or interaction partners identified\", \"Localization shown only by overexpression\", \"Single lab, limited follow-up\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Defined the specific cellular role of CEP295 as the factor required for centriole-to-centrosome conversion, resolving why centrioles lacking it disintegrate—they fail to recruit PCM after cartwheel removal.\",\n      \"evidence\": \"RNAi knockdown with cell-cycle staging, immunofluorescence and electron microscopy in human cells\",\n      \"pmids\": [\"25131205\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Direct binding partners mediating PCM recruitment not yet identified\", \"Molecular nature of the conversion event undefined\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Placed CEP295/Ana1 within an ordered Cep135–Ana1–Asterless/Cep152 loading hierarchy, showing it acts as a structural bridge essential for recruiting the Plk4 partner Cep152 and thus for duplication.\",\n      \"evidence\": \"Epistasis/rescue, Co-IP, super-resolution microscopy and engineered bridge constructs in Drosophila and human cells\",\n      \"pmids\": [\"26595382\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Atomic/structural basis of the bridge not resolved\", \"Whether interactions with Cep135 and Cep152 are direct or indirect not fully defined\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Showed CEP295 directly binds microtubules and builds the distal centriole half, identifying POC5/POC1B loading and tubulin modification as downstream events and mapping elongation control to the N-terminal domain.\",\n      \"evidence\": \"siRNA depletion, super-resolution/immunogold EM, in vitro microtubule-binding assay, domain overexpression in human cells\",\n      \"pmids\": [\"27185865\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Mechanism by which microtubule binding controls elongation not defined\", \"How POC5/POC1B recruitment is achieved at molecular level unknown\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Identified the molecular basis of conversion: CEP295 directly binds and recruits CEP192, the factor that confers PCM-assembly and MTOC capacity on the new mother centriole.\",\n      \"evidence\": \"siRNA/RNAi depletion, direct binding/pull-down assays, MTOC functional readouts in human/Drosophila cells\",\n      \"pmids\": [\"27562453\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Structural details of the CEP295–CEP192 interface not resolved\", \"Coordination between CEP192 recruitment and Cep152 loading unclear\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Demonstrated in vivo that Ana1 is irreversibly incorporated and that centrosome/cilium function is separable from its dose-dependent role in centriole over-elongation, mapping the latter to the N-terminal 639 residues.\",\n      \"evidence\": \"Drosophila ana1 mutant analysis, truncation rescue, FRAP, fluorescence microscopy\",\n      \"pmids\": [\"27206860\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Molecular distinction between maintaining vs initially recruiting Asl not defined\", \"Mechanism of irreversible incorporation unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Positioned CEP295 in the assembly hierarchy as downstream of RTTN/STIL-mediated assembly and upstream of POC1B/POC5 loading, clarifying the order of distal-half construction.\",\n      \"evidence\": \"CRISPR/Cas9 knockout, super-resolution microscopy, Co-IP and epistasis in human cells\",\n      \"pmids\": [\"28811500\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"CEP295 pathway position partly inferred from orthogonal KOs\", \"Direct vs indirect connection to RTTN/STIL not established\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Identified PPP1R35 as a factor upstream of CEP295 recruitment, showing that nascent centrioles initiate normally but require PPP1R35 to load CEP295 and undergo conversion.\",\n      \"evidence\": \"CRISPR/Cas9 knockout, immunofluorescence, epistasis by marker recruitment\",\n      \"pmids\": [\"30230954\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Whether PPP1R35 recruits CEP295 directly is unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Showed that CEP295 binding is necessary but not sufficient for conversion: a parallel CEP44–POC1B–TUBD1/TUBE1 wall-integrity pathway is also required, refining the conversion model.\",\n      \"evidence\": \"siRNA depletion, epistasis and centriole structural analysis in human cells\",\n      \"pmids\": [\"32060285\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"How wall integrity gates CEP295 function mechanistically unclear\", \"Single lab\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Established that Ana1 recruits Polo kinase to mother centrioles to specifically drive mitotic PCM assembly and G2 elongation, separable from its roles in duplication and cilia.\",\n      \"evidence\": \"Drosophila genetics with Polo-binding-deficient Ana1 mutants and multiple functional readouts\",\n      \"pmids\": [\"34156068\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Whether human CEP295 recruits Plk in the same manner not directly shown\", \"Structural basis of Ana1–Polo interaction undefined\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Provided a quantitative model in which Ana1 acts as the centriole receptor generating a local pulse of Polo activity that times centrosome maturation prior to mitosis.\",\n      \"evidence\": \"Live imaging of Drosophila embryos, quantitative microscopy, mathematical modeling and genetic perturbation\",\n      \"pmids\": [\"35505659\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Model partly inferred from fitting\", \"Direct measurement of Polo activity dynamics not achieved\", \"Single lab\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Connected CEP295 loss to human disease, showing depletion causes reduced centriole/centrosome numbers, p53-dependent G1 arrest and ciliary defects, with isogenic rescue distinguishing pathogenic from wild-type alleles.\",\n      \"evidence\": \"Patient exome sequencing, patient-derived fibroblasts, siRNA in U2OS/RPE1, mRNA complementation, cell-cycle analysis\",\n      \"pmids\": [\"38154379\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Tissue specificity of microcephaly phenotype not mechanistically explained\", \"Link between centriole loss and p53 activation undefined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Demonstrated Ana1 is required to maintain centriole structural integrity (in a Polo-dependent manner) but that centrioles maintained by Ana1 alone are MTOC-inactive, separating structural maintenance from MTOC activity.\",\n      \"evidence\": \"Drosophila overexpression and tethering genetics with MTOC functional readout in an oogenesis centriole-loss model\",\n      \"pmids\": [\"38200359\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Molecular basis of structural maintenance vs MTOC activity not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Intragenic complementation genetics dissected CEP295 into separable functional modules, showing radial expansion/Asl recruitment can be rescued by overlapping fragments while centriole elongation requires continuous full-length sequence including a defined internal region.\",\n      \"evidence\": \"Drosophila intragenic complementation, domain deletion, EM, fertility assays (preprint)\",\n      \"pmids\": [\"bio_10.1101_2024.10.28.620588\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Preprint, not peer-reviewed\", \"Molecular identity of the elongation-required internal region not characterized\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Identified a germline-specific role in which Ana1 drives microtubule doublet-to-triplet conversion by recruiting centrobin through its C-terminal region, with centrobin tethering sufficient to restore C-tubule formation.\",\n      \"evidence\": \"Drosophila deletion mutants, domain truncations, EM, centrobin tethering rescue and fertility assays\",\n      \"pmids\": [\"42159626\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Whether human CEP295 recruits centrobin similarly not shown\", \"Mechanism of C-tubule template formation downstream of centrobin undefined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis of how CEP295 simultaneously bridges multiple partners (Cep135, Cep152, CEP192, Polo, centrobin) along the centriole wall, and how its distinct domains coordinate conversion, elongation and tissue-specific functions, remains unresolved.\",\n      \"evidence\": \"No atomic-resolution structural model of CEP295 or its complexes reported in the timeline\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"No high-resolution structure of CEP295 or its interfaces\", \"Mechanism linking centriole loss to p53/G1 arrest unknown\", \"Human relevance of germline centrobin/triplet functions untested\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [1, 3, 8]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [8, 9]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005814\", \"supporting_discovery_ids\": [0, 2, 3, 12]},\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [3, 12]},\n      {\"term_id\": \"GO:0005929\", \"supporting_discovery_ids\": [4, 10]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [0, 1, 10]},\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [2, 3, 4]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [10, 13]}\n    ],\n    \"complexes\": [\n      \"centriole\",\n      \"centrosome\"\n    ],\n    \"partners\": [\n      \"CEP192\",\n      \"CEP152\",\n      \"CEP135\",\n      \"POC5\",\n      \"POC1B\",\n      \"POLO\",\n      \"CNTROB\",\n      \"RTTN\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":9,"faith_pct":88.88888888888889}}