Affinage

CENPU

Centromere protein U · UniProt Q71F23

Length
418 aa
Mass
47.5 kDa
Annotated
2026-04-28
26 papers in source corpus 15 papers cited in narrative 15 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

CENP-U is a constitutive inner kinetochore protein that functions as a central scaffold for PLK1 recruitment and kinetochore-microtubule attachment during mitosis. It forms an obligate complex with CENP-Q, with mutual dependence for protein stability and centromere targeting, and its centromeric localization requires the CENP-H/CENP-I complex and CENP-P/CENP-Q subunits (PMID:16287847, PMID:34551298). A CDK1-primed phospho-T78 motif on CENP-U generates a high-affinity polo-box domain docking site that recruits PLK1 to the inner kinetochore; PLK1 subsequently phosphorylates CENP-Q to drive timed delocalization of the CENP-U–CENP-Q complex, resetting PLK1 availability for downstream mitotic substrates (PMID:17081991, PMID:21454580, PMID:25670858, PMID:33248027). CENP-U also directly binds microtubules and cooperates with NDC80/Hec1 to stabilize kinetochore-microtubule attachments, with Aurora B phosphorylation of CENP-U reducing microtubule binding as part of the error-correction mechanism (PMID:21056971). CENP-U and BUB1 act as redundant PLK1 receptors at kinetochores; co-depletion causes severe chromosome mis-segregation, and CENP-U knockout in mice is embryonic lethal at E6.5 (PMID:34551298, PMID:23724000).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 2004 Medium

    Before CENP-U's kinetochore role was recognized, it was identified as a nuclear/cytoplasmic interactor of the leukemia-associated factor MLF1, establishing that the protein existed and had nuclear localization.

    Evidence Yeast two-hybrid and pulldown assays with colocalization by immunofluorescence

    PMID:15116101

    Open questions at the time
    • Interaction identified by yeast two-hybrid without independent in vivo validation
    • Functional significance of MLF1 interaction for kinetochore biology unknown
    • No centromere association yet established
  2. 2005 High

    The discovery that CENP-U is a constitutive centromere component dependent on CENP-H/CENP-I established it as an inner kinetochore protein with a role in sister chromatid cohesion maintenance during spindle stress.

    Evidence Co-immunoprecipitation, DT40 chicken cell knockout, immunofluorescence showing colocalization with CENP-A throughout the cell cycle

    PMID:16287847

    Open questions at the time
    • How CENP-U contributes mechanistically to sister chromatid cohesion was unresolved
    • Direct binding partners at the centromere beyond CENP-H/I complex were unknown
  3. 2006 High

    Identification of the PLK1-CENP-U self-priming loop — where PLK1 phosphorylates T78 to create its own docking site — revealed the molecular mechanism by which PLK1 is recruited to kinetochores and subsequently triggers CENP-U degradation to redistribute PLK1 to other substrates.

    Evidence In vitro kinase assay, mutagenesis of T78, co-immunoprecipitation, live-cell imaging

    PMID:17081991

    Open questions at the time
    • Whether CDK1 also primes T78 was not addressed
    • The role of CENP-Q in this complex was unknown
    • How PLK1-induced CENP-U degradation is executed molecularly was unclear
  4. 2010 High

    Demonstrating that CENP-U directly binds microtubules and cooperates with NDC80/Hec1, with Aurora B phosphorylation reducing this binding, established CENP-U as an active participant in kinetochore-microtubule attachment and error correction rather than merely a PLK1 scaffold.

    Evidence In vitro microtubule cosedimentation, co-immunoprecipitation with Hec1, Aurora B kinase assay, shRNA knockdown with mitotic phenotype analysis

    PMID:21056971

    Open questions at the time
    • Which specific Aurora B phosphosites on CENP-U mediate microtubule release was not mapped
    • Structural basis of CENP-U–microtubule interaction unknown
    • Relative contribution versus NDC80 not quantified in vivo
  5. 2011 High

    Discovery that CENP-U and CENP-Q form an obligate complex — mutually required for stability and centromere targeting — and that PLK1 forms a ternary complex to phosphorylate CENP-Q and drive delocalization, explained how PLK1 activity is temporally coupled to kinetochore remodeling.

    Evidence Co-immunoprecipitation, in vitro binding assays, mutagenesis, phosphorylation analysis

    PMID:21454580

    Open questions at the time
    • Phosphosites on CENP-Q responsible for dissociation were not fully mapped
    • Whether other kinases or phosphatases regulate the ternary complex was unknown
  6. 2013 Medium

    Knockout of CENP-U in mice causing embryonic lethality at E6.5 demonstrated that its kinetochore function is essential for mammalian cell proliferation during early development.

    Evidence Knockout mouse generation with embryonic phenotype analysis and in situ hybridization

    PMID:23724000

    Open questions at the time
    • Single study without conditional knockout to distinguish cell-autonomous from developmental defect
    • Whether lethality is due to mitotic failure specifically was not tested
  7. 2015 High

    Systematic mutagenesis of nine PLK1 phosphosites on CENP-Q showed that both premature and delayed delocalization of the CENP-U–CENP-Q complex cause chromosome segregation defects, establishing that the PLK1-driven dissociation timer is critical for mitotic fidelity.

    Evidence Phosphosite mutagenesis (9A and 9D/E), chromatin fractionation, live-cell imaging, segregation assays

    PMID:25670858

    Open questions at the time
    • Whether individual sites have graded contributions was not resolved
    • How phosphatases counteract PLK1 at the CENP-Q level was not addressed
  8. 2020 High

    Identifying CENP-U and BUB1 as the two main PLK1 kinetochore receptors sharing a conserved motif architecture (PP2A-docking site plus two PLK1-docking sites requiring CDK1 priming) unified the mechanism of PLK1 kinetochore recruitment and revealed that PLK1 dimerization is promoted upon binding these receptors.

    Evidence Ectopic localization assay, in vitro reconstitution, mutagenesis, kinetochore localization studies

    PMID:33248027

    Open questions at the time
    • Whether PLK1 dimerization is functionally required at kinetochores was not shown
    • Relative contributions of CENP-U versus BUB1 at different mitotic stages were not resolved
  9. 2021 High

    Parallel discoveries — that the yeast ortholog Ame1 contains CDK1-dependent phospho-degrons shielded by the Mis12 complex, and that CENP-U and BUB1 act redundantly for PLK1 recruitment — together revealed a conserved regulatory logic in which kinetochore-bound CENP-U is protected from degradation while free CENP-U is cleared, and either receptor suffices for faithful segregation.

    Evidence Budding yeast phosphorylation analysis with SCF-Cdc4 interaction assays (Ame1); siRNA epistasis with chromosome segregation assays in human cells (CENP-U/BUB1)

    PMID:34308839 PMID:34551298

    Open questions at the time
    • Whether the Mis12-shielding mechanism is conserved in human CENP-U is unknown
    • The E3 ligase targeting human CENP-U for degradation has not been identified

Open questions

Synthesis pass · forward-looking unresolved questions
  • Key unresolved questions include the structural basis of the CENP-U–microtubule interaction, identification of the Aurora B phosphosites that regulate it, whether CENP-U's reported roles in non-kinetochore processes (COX-2 stabilization, E2F6 regulation, furin stabilization) reflect moonlighting or indirect cell-cycle effects, and whether the Mis12-mediated degron-shielding mechanism conserved in yeast operates in mammalian cells.
  • No high-resolution structure of CENP-U alone or in complex with microtubules
  • Aurora B phosphosites on CENP-U not individually mapped
  • Cancer-context findings (COX-2, E2F6, furin) each from single studies without independent replication

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060090 molecular adaptor activity 4 GO:0008092 cytoskeletal protein binding 1
Localization
GO:0005694 chromosome 3 GO:0005634 nucleus 2
Pathway
R-HSA-1640170 Cell Cycle 7
Partners
BUB1CENP-HCENP-ICENP-PCENP-QMLF1NDC80PLK1
Complex memberships
CENP-H/CENP-I complexCENP-O complex (CENP-O/P/Q/U)

Evidence

Reading pass · 15 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2006 CENP-U (PBIP1) is phosphorylated at T78 by PLK1, creating a self-tethering PBD-binding site that recruits PLK1 to interphase and mitotic kinetochores. Later in mitosis, PLK1 also induces CENP-U degradation in a T78-dependent manner, enabling PLK1 to interact with other kinetochore components. In vitro kinase assay, mutagenesis, co-immunoprecipitation, live-cell imaging, loss-of-function Molecular cell High 17081991
2005 CENP-U (CENP-50) is a constitutive centromere component that colocalizes with CENP-A and CENP-H throughout the cell cycle. Its centromeric localization depends on CENP-H and CENP-I, and it physically interacts with the CENP-H/CENP-I complex. Loss of CENP-50 causes premature sister chromatid separation when the mitotic checkpoint is activated, indicating a role in recovery from spindle damage. Coimmunoprecipitation, knockout in chicken DT40 cells, immunofluorescence, loss-of-function phenotypic analysis Molecular and cellular biology High 16287847
2004 CENP-U (MLF1IP) specifically associates with MLF1 (myeloid leukemia factor 1) as identified by yeast two-hybrid and pulldown assays, and colocalizes with MLF1 in both the nuclei and cytoplasm of cells. Yeast two-hybrid, pulldown assay, colocalization by immunofluorescence Oncogene Medium 15116101
2010 CENP-U interacts with Hec1 (NDC80), directly binds microtubules, and exhibits cooperative microtubule binding with Hec1 in vitro. Aurora-B phosphorylates CENP-U, and this phosphorylation reduces kinetochore-microtubule interaction, contributing to error-correction. shRNA-mediated suppression of CENP-U causes mitotic defects with impaired kinetochore-microtubule attachment. Co-immunoprecipitation, in vitro microtubule binding assay, in vitro kinase assay, shRNA knockdown with phenotypic analysis The Journal of biological chemistry High 21056971
2011 CENP-U (PBIP1) directly interacts with CENP-Q, and this interaction is mutually required for their stability and centromere localization. PLK1 forms a ternary complex with PBIP1 and CENP-Q via the self-generated p-T78 motif on PBIP1, leading to PLK1-dependent phosphorylation of CENP-Q and delocalization of the PBIP1-CENP-Q complex from mitotic centromeres. Co-immunoprecipitation, in vitro binding assay, mutagenesis, loss-of-function, phosphorylation analysis The Journal of biological chemistry High 21454580
2015 PLK1 phosphorylates CENP-Q (a subunit of the PBIP1/CENP-U·CENP-Q complex) at multiple sites, and mutation of nine PLK1-dependent sites to Ala prolongs CENP-Q kinetochore localization while phosphomimetic mutations dissociate CENP-Q from chromatin. Both mutants cause chromosome segregation defects, demonstrating that timely localization and delocalization of the PBIP1·CENP-Q complex are critical for normal mitosis. Mutagenesis (9A and 9D/E mutants), chromatin fractionation, live-cell imaging, loss-of-function phenotypic analysis The Journal of biological chemistry High 25670858
2020 CENP-U and BUB1 are the two main PLK1 kinetochore receptors in mitosis, with CENP-U recruiting PLK1 at the inner kinetochore. Both proteins share a constellation of sequence motifs (a putative PP2A-docking motif and two PLK1-docking sites) that, contingent on priming phosphorylation by CDK1 and PLK1 itself, bind PLK1 and promote its dimerization. Ectopic localization assay, in vitro reconstitution, kinetochore localization studies, mutagenesis Molecular cell High 33248027
2021 In budding yeast, the CENP-U ortholog Ame1 contains phospho-degrons that are phosphorylated by Cdk1, recognized by the E3 ubiquitin ligase SCF-Cdc4, and targeted for degradation in M-phase. Binding of the Mtw1/Mis12 complex to the proximal phospho-degron of Ame1 shields it from the degradation machinery, protecting kinetochore-bound Ame1. Comprehensive phosphorylation analysis of native subunits, biochemical assays, ubiquitin ligase interaction assays, functional assays in budding yeast eLife High 34308839
2021 CENP-U is recruited to kinetochores by the CENP-P and CENP-Q subunits of the CENP-O complex. CENP-U and BUB1 redundantly recruit PLK1 to kinetochores to stabilize kinetochore-microtubule attachments; depletion of both causes chromosome mis-segregation whereas depletion of either alone does not significantly affect fidelity. siRNA depletion (stable ~95% reduction), epistasis analysis, chromosome segregation assays, kinase inhibitor sensitization Cell reports High 34551298
2013 MLF1-IP (CENP-U) knockout mice fail to develop beyond embryonic day 6.5, with degeneration of epiblasts, demonstrating an essential role during early embryonic development. Knockout mouse generation, in situ hybridization, embryonic phenotype analysis PloS one Medium 23724000
2019 CENPU promotes angiogenesis in triple-negative breast cancer by inhibiting ubiquitination and proteasomal degradation of COX-2, leading to increased activation of the COX-2-p-ERK-HIF-1α-VEGFA signaling pathway. shRNA knockdown, ubiquitination assay, co-immunoprecipitation, xenograft mouse model, Western blot Cancer letters Medium 31705927
2022 CENPU physically interacts with E2F6 and promotes its ubiquitin-mediated degradation, thereby affecting E2F1 transcription levels and accelerating G1/S transition. E2F1 in turn directly binds the CENPU promoter, forming a positive regulatory feedback loop. Co-immunoprecipitation, ubiquitination assay, promoter binding assay, knockdown/overexpression with cell cycle analysis International journal of biological sciences Medium 35844791
2025 CENPU promotes furin activity by inhibiting its lysosomal degradation. Furin, a precursor-processing enzyme of NGF, promotes conversion of pro-NGF to NGF, which promotes breast cancer stem cell properties in TNBC. Co-immunoprecipitation, western blotting, ELISA, xenograft mouse model with furin inhibitor treatment International journal of molecular medicine Medium 41041859
2025 CENP-U contains a single high-affinity master PLK1 docking motif that engages multiple pockets on the PBD surface. The motif is generated by CDK1 priming followed by PLK1 autophosphorylation, and structural/biophysical analysis indicates PBD dimerization is not required for CENP-U docking. Biochemical, biophysical (binding affinity measurements), and structural modelling approaches bioRxivpreprint Medium bio_10.1101_2025.03.28.645803
2024 CENP-U serves as a site of PLK1 recruitment at the inner kinetochore, and this recruitment is driven by CDK1 activity and requires PLK1's polo-box domain. Inhibition of BUB1 or PP2A increases PLK1 recruitment to the inner centromere, revealing counteracting regulatory inputs. Live-cell imaging, kinase inhibitor treatment, siRNA knockdown, fluorescence localization assays bioRxivpreprint Medium bio_10.1101_2024.07.03.601947

Source papers

Stage 0 corpus · 26 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2006 Self-regulated Plk1 recruitment to kinetochores by the Plk1-PBIP1 interaction is critical for proper chromosome segregation. Molecular cell 226 17081991
2020 BUB1 and CENP-U, Primed by CDK1, Are the Main PLK1 Kinetochore Receptors in Mitosis. Molecular cell 88 33248027
2005 The constitutive centromere component CENP-50 is required for recovery from spindle damage. Molecular and cellular biology 66 16287847
2004 cDNA cloning and characterization of a novel gene encoding the MLF1-interacting protein MLF1IP. Oncogene 57 15116101
2010 CENP-U cooperates with Hec1 to orchestrate kinetochore-microtubule attachment. The Journal of biological chemistry 56 21056971
2011 Mammalian polo-like kinase 1-dependent regulation of the PBIP1-CENP-Q complex at kinetochores. The Journal of biological chemistry 43 21454580
2021 Bub1 and CENP-U redundantly recruit Plk1 to stabilize kinetochore-microtubule attachments and ensure accurate chromosome segregation. Cell reports 35 34551298
2019 Centromere protein U (CENPU) enhances angiogenesis in triple-negative breast cancer by inhibiting ubiquitin-proteasomal degradation of COX-2. Cancer letters 32 31705927
2008 Self-regulated mechanism of Plk1 localization to kinetochores: lessons from the Plk1-PBIP1 interaction. Cell division 32 18215321
2022 A positive feedback loop of CENPU/E2F6/E2F1 facilitates proliferation and metastasis via ubiquitination of E2F6 in hepatocellular carcinoma. International journal of biological sciences 27 35844791
2005 Regulation of myeloid leukemia factor-1 interacting protein (MLF1IP) expression in glioblastoma. Brain research 27 15893739
2019 Short communication: A splice site mutation in CENPU is associated with recessive embryonic lethality in Holstein cattle. Journal of dairy science 20 31733857
2015 Mammalian Polo-like kinase 1 (Plk1) promotes proper chromosome segregation by phosphorylating and delocalizing the PBIP1·CENP-Q complex from kinetochores. The Journal of biological chemistry 19 25670858
2022 The centromere-associated protein CENPU promotes cell proliferation, migration, and invasiveness in lung adenocarcinoma. Cancer letters 16 35176420
2019 Reduced CENPU expression inhibits lung adenocarcinoma cell proliferation and migration through PI3K/AKT signaling. Bioscience, biotechnology, and biochemistry 16 30849291
2021 Centromere protein U (CENPU) promotes gastric cancer cell proliferation and glycolysis by regulating high mobility group box 2 (HMGB2). Bioengineered 10 34872447
2017 MLF1IP promotes cells proliferation and apoptosis by regulating CyclinD1 in breast cancer. International journal of clinical and experimental pathology 10 31966511
2017 MLF1IP promotes normal erythroid proliferation and is involved in the pathogenesis of polycythemia vera. FEBS letters 9 28173615
2022 Knockdown of CENPU inhibits cervical cancer cell migration and stemness through the FOXM1/Wnt/β-catenin pathway. Tissue & cell 6 36608638
2013 Investigation of tissue-specific expression and functions of MLF1-IP during development and in the immune system. PloS one 6 23724000
2021 Cdc4 phospho-degrons allow differential regulation of Ame1CENP-U protein stability across the cell cycle. eLife 5 34308839
2022 Overexpression of MLF1IP promotes colorectal cancer cell proliferation through BRCA1/AKT/p27 signaling pathway. Cellular signalling 4 35122991
2021 Mitosis-related gene CENP-U as a potential biomarker in malignancy. Annals of translational medicine 4 35071438
2020 CENP-50 is required for papilloma development in the two-stage skin carcinogenesis model. Cancer science 3 32535988
2025 DPHC from Alpinia officinarum Hance specifically modulates the function of CENPU in the cell cycle and apoptosis to ameliorate hepatocellular carcinoma. Journal of ethnopharmacology 1 40058474
2025 CENPU promotes tumorigenesis and stem cell properties in triple‑negative breast cancer by suppressing lysosomal furin degradation. International journal of molecular medicine 1 41041859