Affinage

CEP295

Centrosomal protein of 295 kDa · UniProt Q9C0D2

Length
2601 aa
Mass
295.2 kDa
Annotated
2026-04-28
20 papers in source corpus 15 papers cited in narrative 15 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

CEP295 (Ana1 in Drosophila) is a conserved centriole wall scaffold protein that serves as the central mediator of centriole-to-centrosome conversion, centriole structural maintenance, and centriole elongation. Recruited to the proximal procentriole in early S phase downstream of PPP1R35, RTTN, and CPAP, CEP295 directly binds centriolar microtubules and bridges the inner centriole component Cep135 to the outer component Cep152/Asterless, thereby enabling Plk4-driven centriole duplication and loading of distal centriole proteins POC5 and POC1B required for centriole elongation and post-translational modification of centriolar microtubules (PMID:25131205, PMID:26595382, PMID:27185865, PMID:28811500). CEP295 directly recruits CEP192 to daughter centrioles to initiate pericentriolar material assembly and microtubule-organizing center activity, and recruits Polo/PLK1 to mother centrioles to generate a local kinase pulse that drives mitotic centrosome maturation (PMID:27562453, PMID:34156068, PMID:35505659). Loss of CEP295 causes progressive centriole disintegration after cartwheel removal, reduced centrosome numbers with p53-dependent G1 arrest, and primary ciliary defects, and biallelic mutations in CEP295 are associated with a ciliopathy rescued by wild-type CEP295 complementation (PMID:25131205, PMID:38154379).

Mechanistic history

Synthesis pass · year-by-year structured walk · 12 steps
  1. 2010 Medium

    Identification of KIAA1731/CEP295 as a centrosomal protein required for centriole integrity established it as a component warranting mechanistic investigation.

    Evidence Exogenous expression with immunofluorescence and RNAi knockdown in human cells

    PMID:20844083

    Open questions at the time
    • No pathway placement or direct binding partners identified
    • Single-lab RNAi study without genetic confirmation
  2. 2014 High

    Defining CEP295 as specifically required for centriole-to-centrosome conversion — rather than cartwheel removal — revealed why centrioles disintegrate without it: they lose both cartwheel and PCM, leaving no stabilizing scaffold.

    Evidence RNAi depletion with live-cell imaging and cell-cycle staging in human cells

    PMID:25131205

    Open questions at the time
    • Molecular partners mediating CCC unknown
    • No direct binding data
    • Mechanism of centriole disintegration not resolved at structural level
  3. 2015 High

    Demonstrating that Ana1/CEP295 forms a molecular bridge from the inner centriole (Cep135) to the outer centriole (Asterless/Cep152) answered how CCC is structurally organized: an engineered Cep135–Asterless linker could bypass Ana1 requirement.

    Evidence Sequential epistasis, engineered protein fragment rescue, immunofluorescence in Drosophila and human cells

    PMID:26595382

    Open questions at the time
    • Direct biochemical binding interface not mapped
    • Whether the bridge model applies to all cell types unresolved
  4. 2016 High

    Three studies collectively established CEP295 as a multifunctional centriole wall scaffold: it directly binds microtubules and promotes distal centriole elongation and post-translational modification (acetylation, glutamylation); it directly binds and recruits CEP192 to endow daughter centrioles with PCM and MTOC activity; and it is irreversibly incorporated during assembly with separable elongation and centrosome/cilium functions.

    Evidence In vitro microtubule-binding assay, super-resolution and immunogold EM, direct CEP192-binding assay, Drosophila ana1 mutants with domain-truncation rescue

    PMID:27185865 PMID:27206860 PMID:27562453

    Open questions at the time
    • Structural basis of CEP295–CEP192 and CEP295–microtubule interactions unknown
    • Stoichiometry of CEP295 on the centriole not determined
    • Regulation of CEP295 incorporation timing unclear
  5. 2017 High

    Placing RTTN upstream of CEP295 in a centriole elongation hierarchy clarified why RTTN loss phenocopies CEP295 depletion for distal centriole protein recruitment (POC1B, POC5).

    Evidence CRISPR knockout of RTTN with epistasis analysis and super-resolution microscopy

    PMID:28811500

    Open questions at the time
    • Whether RTTN directly binds CEP295 or acts indirectly not resolved
    • Other factors between RTTN and CEP295 not excluded
  6. 2018 High

    Identification of PPP1R35 as a required upstream factor for CEP295 recruitment to nascent centrioles extended the pathway order, defining a PPP1R35 → CEP295 → CCC axis.

    Evidence CRISPR knockout and siRNA epistasis with immunofluorescence in human cells

    PMID:30230954

    Open questions at the time
    • Whether PPP1R35 acts via dephosphorylation or scaffolding unknown
    • Direct PPP1R35–CEP295 physical interaction not demonstrated
  7. 2020 High

    Showing that CEP44 depletion blocks CCC even when CEP295 is present demonstrated that proper A-microtubule architecture is a parallel or downstream requirement for CCC, not merely an upstream prerequisite for CEP295 loading.

    Evidence siRNA depletion with epistasis, immunofluorescence and electron microscopy

    PMID:32060285

    Open questions at the time
    • Whether CEP44 and CEP295 physically interact not tested
    • Mechanism by which microtubule integrity enables CCC downstream of CEP295 unknown
  8. 2021 High

    Domain-specific disruption of the Ana1–Polo interaction revealed that Ana1/CEP295 recruits Polo/PLK1 specifically to promote mitotic PCM assembly and centriole elongation in G2, separating this from duplication and cilia functions.

    Evidence Polo-binding-deficient ana1 mutant alleles with rescue and multiple functional readouts in Drosophila

    PMID:34156068

    Open questions at the time
    • Polo-binding site on Ana1 defined genetically but not structurally
    • Whether PLK1 binding to human CEP295 is similarly separable not shown
  9. 2022 High

    Combined modelling and in vivo imaging demonstrated that Ana1–Polo generates a local kinase pulse at the centriole that sets the temporal dynamics of PCM scaffold assembly during mitotic entry, providing a quantitative mechanism for centrosome maturation initiation.

    Evidence Live quantitative fluorescence imaging, mathematical modelling, genetic perturbation in Drosophila syncytial embryos

    PMID:35505659

    Open questions at the time
    • Model not validated in mammalian cells
    • Polo substrates at the centriole downstream of Ana1 not identified
  10. 2022 Medium

    The CPAP-E1235V microcephaly mutation impairs CEP295 recruitment alongside other elongation factors, placing CPAP upstream of CEP295 in the centriole elongation hierarchy and linking CEP295 to a disease-relevant pathway.

    Evidence CRISPR-edited hiPSCs, brain organoids, immunofluorescence

    PMID:35309908

    Open questions at the time
    • CPAP mutation affects multiple downstream proteins simultaneously, so direct relationship to CEP295 is indirect
    • Whether CPAP binds CEP295 directly unknown
  11. 2023 High

    Demonstration that CEP295 loss causes p53-dependent G1 arrest and primary ciliary defects, with rescue by wild-type but not mutant CEP295 in patient-derived fibroblasts, established CEP295 as a ciliopathy gene and connected centriole-to-centrosome conversion to ciliogenesis.

    Evidence siRNA and CRISPR depletion in U2OS/RPE1, patient fibroblasts with complementation, immunofluorescence

    PMID:38154379

    Open questions at the time
    • Patient mutations not structurally mapped onto CEP295 domains
    • Mechanism linking CCC failure to ciliary defects not molecularly dissected
  12. 2024 High

    In vivo tethering experiments demonstrated that Ana1/CEP295 is sufficient to maintain centriole structural integrity even when PCM is downregulated, but centrioles stabilized solely by Ana1 are inactive as MTOCs, cleanly separating structural maintenance from organizing-center function.

    Evidence Conditional expression, tethering constructs, Drosophila oogenesis model

    PMID:38200359

    Open questions at the time
    • What additional factors convert a structurally stable centriole into an active MTOC not identified
    • Whether this structural-only role applies in mammalian systems unknown

Open questions

Synthesis pass · forward-looking unresolved questions
  • Key unresolved questions include: the atomic-level structure of CEP295 and its binding interfaces with CEP192, microtubules, and Polo/PLK1; the mechanism by which PPP1R35 enables CEP295 recruitment; how CEP295-dependent CCC is coupled to ciliogenesis; identification of PLK1 substrates acting downstream of the Ana1/CEP295-generated kinase pulse; and the full genotype–phenotype spectrum of CEP295 mutations in human disease.
  • No structural model of CEP295
  • PPP1R35–CEP295 recruitment mechanism unknown
  • PLK1 substrates downstream of Ana1-recruited Polo unidentified

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0005198 structural molecule activity 4 GO:0008092 cytoskeletal protein binding 3
Localization
GO:0005815 microtubule organizing center 4 GO:0005929 cilium 2 GO:0005856 cytoskeleton 1
Pathway
R-HSA-1852241 Organelle biogenesis and maintenance 6 R-HSA-1640170 Cell Cycle 2
Partners
CEP135CEP152CEP192PLK1POC1BPOC5PPP1R35RTTN

Evidence

Reading pass · 15 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2014 CEP295 (KIAA1731) is specifically required for centriole-to-centrosome conversion (CCC) — the acquisition of PCM-recruiting ability by daughter centrioles — but is dispensable for cartwheel removal. In its absence, centrioles form and lose their cartwheel in mitosis but cannot become centrosomes; without either the cartwheel or PCM, centrioles progressively disintegrate, demonstrating that CEP295-mediated CCC maintains centriole stability. RNAi/siRNA depletion, immunofluorescence, live-cell imaging, cell-cycle staging Cell reports High 25131205
2015 CEP295 (Drosophila Ana1) is sequentially loaded onto daughter centrioles during mitotic progression after Cep135 and before Asterless/Cep152, forming a molecular strut spanning from inner to outer centriole. Ana1 is essential for loading Asterless/Cep152 (the Plk4 partner), and an engineered fragment providing an alternative Asterless–Cep135 linkage can substitute for Ana1's essential role, demonstrating it acts as a structural bridge for centriole-to-centrosome conversion. Epistasis by sequential depletion/overexpression, engineered protein fragments, immunofluorescence in Drosophila and human cells Nature cell biology High 26595382
2010 KIAA1731 (CEP295) localizes to the centrosome when exogenously expressed, and RNAi-mediated knockdown causes centriole formation/stability defects, identifying it as a centrosomal protein required for centriole integrity. Exogenous expression with immunofluorescence, RNAi knockdown with phenotypic readout Molecular biology of the cell Medium 20844083
2016 CEP295 is recruited to the proximal end of procentrioles in early S phase and localizes at the centriolar microtubule wall. It directly interacts with microtubules (shown by in vitro microtubule-binding assay) and is required for building the distal half of centrioles and for post-translational modifications of centriolar microtubules (acetylation and glutamylation). Depletion blocks recruitment of POC5 and POC1B to distal centrioles; overexpression induces overly long centrioles; N-terminal domain acts as dominant negative. Super-resolution and immunogold EM, in vitro microtubule-binding assay, siRNA depletion, overexpression, dominant-negative analysis Journal of cell science High 27185865
2016 CEP295 (Drosophila Ana1) acts as a scaffold at the proximal centriole wall and directly binds to and recruits CEP192 onto the daughter centriole wall, thereby endowing the new mother centriole with PCM assembly capacity, microtubule-organizing centre activity, and the ability to support centriole duplication. Depletion/rescue experiments, direct binding assay, epistasis in human cells and Drosophila Nature communications High 27562453
2016 Drosophila Ana1 (CEP295 ortholog) is irreversibly incorporated into centrioles during assembly, is required for centrosome assembly and cilia formation in vivo, and promotes centriole elongation in a dose-dependent manner. The N-terminal 639 aa region is specifically required for elongation but not for centrosome or cilium function. ana1 loss-of-function mutants, GFP-Ana1 truncation rescue experiments, in vivo imaging in flies Journal of cell science High 27206860
2017 CEP295 acts downstream of RTTN in the centriole elongation pathway: RTTN serves as an upstream effector of CEP295, which in turn mediates the loading of POC1B and POC5 onto distal-half centrioles. CRISPR knockout of RTTN blocks CEP295-dependent distal centriole protein recruitment. CRISPR/Cas9 knockout, epistasis by sequential depletion, super-resolution microscopy Nature communications High 28811500
2018 PPP1R35 acts upstream of CEP295 in centriole-to-centrosome conversion: in PPP1R35-null cells, nascent centrioles cannot recruit CEP295 and therefore fail CCC, placing PPP1R35 as a required upstream factor for CEP295 recruitment. siRNA/CRISPR KO, epistasis by sequential depletion, immunofluorescence Molecular biology of the cell High 30230954
2020 CEP44 promotes centriole structural integrity by binding A-microtubules and interacting with POC1B; depletion of CEP44 prevents centriole-to-centrosome conversion despite CEP295 still binding to centrioles, showing that proper centriole architecture is required downstream of or in parallel with CEP295 for CCC. siRNA depletion, epistasis, immunofluorescence, electron microscopy Nature communications High 32060285
2021 Ana1 (CEP295) recruits Polo kinase to mother centrioles to specifically promote mitotic PCM assembly and centriole elongation in G2; impairment of Ana1-dependent Polo recruitment does not affect centriole duplication, disengagement, or cilia assembly, demonstrating a specific role for the Ana1–Polo interaction in centrosome maturation and elongation. Mutant alleles disrupting Polo-binding, rescue experiments, in vivo Drosophila genetics and live imaging Journal of cell science High 34156068
2022 Centriolar Ana1/CEP295 generates a local pulse of Polo/PLK1 activity at the centriole to initiate mitotic centrosome maturation; mathematical modelling and genetic experiments in Drosophila syncytial embryos indicate that the Ana1–Polo interaction at the centriole drives the temporal dynamics of PCM scaffold assembly. Live imaging, quantitative fluorescence, mathematical modelling, genetic perturbation in Drosophila embryos The EMBO journal High 35505659
2022 The CPAP-E1235V mutant perturbs recruitment of CEP295 (along with CEP120, CENTROBIN, POC5, POC1B) onto nascent centrioles, resulting in short centrioles; this places CEP295 downstream of CPAP in the centriole elongation hierarchy. CRISPR/Cas9 hiPSC editing, immunofluorescence, brain organoids Frontiers in cell and developmental biology Medium 35309908
2023 CEP295 depletion reduces centriole and centrosome numbers and triggers p53-dependent G1 cell cycle arrest; loss of CEP295 also causes extensive primary ciliary defects, demonstrating a role in ciliogenesis. Complementation with wild-type but not mutant CEP295 corrects centrosome/centriole and cilia defects in patient-derived fibroblasts. siRNA depletion, CRISPR KD in U2OS/RPE1 cells, patient-derived fibroblasts, complementation with WT vs. mutant mRNA, immunofluorescence EBioMedicine High 38154379
2024 Ana1/CEP295 expression is essential for maintaining centrosome structural integrity; Polo kinase requires Ana1 to promote centriole stability, and Ana1 overexpression prevents centriole loss observed upon PCM downregulation in Drosophila oogenesis. However, centrioles maintained by tethered Ana1 are inactive MTOCs, distinguishing structural maintenance from MTOC activity. Conditional expression/depletion, tethering constructs, in vivo Drosophila oogenesis model, immunofluorescence EMBO reports High 38200359
2024 Intragenic complementation between N- and C-terminal Ana1 fragments rescues radial centriole expansion, Asl/Cep152 recruitment, and centriole duplication, but not elongation of triplet-microtubule-containing primary spermatocyte centrioles; a specific internal deletion removes elongation capacity without affecting Asl recruitment, demonstrating that radial expansion and centriole elongation have distinct structural requirements within the Ana1/CEP295 primary sequence. Drosophila intragenic complementation genetics, deletion analysis, immunofluorescence, electron microscopy bioRxivpreprint Medium bio_10.1101_2024.10.28.620588

Source papers

Stage 0 corpus · 20 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2015 Conserved molecular interactions in centriole-to-centrosome conversion. Nature cell biology 110 26595382
2014 Stabilization of cartwheel-less centrioles for duplication requires CEP295-mediated centriole-to-centrosome conversion. Cell reports 90 25131205
2010 Centriolar association of ALMS1 and likely centrosomal functions of the ALMS motif-containing proteins C10orf90 and KIAA1731. Molecular biology of the cell 89 20844083
2018 ALMS1 and Alström syndrome: a recessive form of metabolic, neurosensory and cardiac deficits. Journal of molecular medicine (Berlin, Germany) 84 30421101
2016 CEP295 interacts with microtubules and is required for centriole elongation. Journal of cell science 63 27185865
2015 Gene-based meta-analysis of genome-wide association studies implicates new loci involved in obesity. Human molecular genetics 55 26376864
2016 Cep295 is a conserved scaffold protein required for generation of a bona fide mother centriole. Nature communications 53 27562453
2020 CEP44 ensures the formation of bona fide centriole wall, a requirement for the centriole-to-centrosome conversion. Nature communications 40 32060285
2017 Human microcephaly protein RTTN interacts with STIL and is required to build full-length centrioles. Nature communications 39 28811500
2016 Drosophila Ana1 is required for centrosome assembly and centriole elongation. Journal of cell science 34 27206860
2022 Centrioles generate a local pulse of Polo/PLK1 activity to initiate mitotic centrosome assembly. The EMBO journal 23 35505659
2022 Modeling Human Primary Microcephaly With hiPSC-Derived Brain Organoids Carrying CPAP-E1235V Disease-Associated Mutant Protein. Frontiers in cell and developmental biology 22 35309908
2018 PPP1R35 ensures centriole homeostasis by promoting centriole-to-centrosome conversion. Molecular biology of the cell 13 30230954
2021 Ana1 helps recruit Polo to centrioles to promote mitotic PCM assembly and centriole elongation. Journal of cell science 12 34156068
2023 IQUB deficiency causes male infertility by affecting the activity of p-ERK1/2/RSPH3. Human reproduction (Oxford, England) 8 36355624
2024 Ana1/CEP295 is an essential player in the centrosome maintenance program regulated by Polo kinase and the PCM. EMBO reports 7 38200359
2023 Heritable Risk and Protective Genetic Components of Glaucoma Medication Non-Adherence. International journal of molecular sciences 5 36982708
2023 Bi-allelic variants in CEP295 cause Seckel-like syndrome presenting with primary microcephaly, developmental delay, intellectual disability, short stature, craniofacial and digital abnormalities. EBioMedicine 5 38154379
2021 Triple deletion of TP53, PCNT, and CEP215 promotes centriole amplification in the M phase. Cell cycle (Georgetown, Tex.) 5 34233584
2021 Coding variants in the PCNT and CEP295 genes contribute to breast cancer risk in Chinese women. Pathology, research and practice 3 34418690