Affinage · Plasmodium

PCNA1

PF3D7_1361900 · proliferating cell nuclear antigen 1

Annotated
2026-09-08
14 papers in source corpus 9 papers cited in narrative 9 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

PF3D7_1361900 (PCNA1) is the primary replicative proliferating cell nuclear antigen of Plasmodium falciparum, coordinating DNA replication and the DNA-damage response during intraerythrocytic development (PMID:26251451). It is encoded by a single-exon gene whose protein accumulates from the trophozoite stage and persists through schizogony; although its promoter is transcriptionally active throughout the intraerythrocytic cycle, its protein accumulation is coordinated post-transcriptionally with DNA replication (PMID:8095096, PMID:8855554). During S phase PCNA1 assembles into distinct nuclear replication foci and physically engages the origin recognition complex, co-immunoprecipitating and colocalizing with PfORC5 and colocalizing with PfORC1 at replication onset via a PIP-box in PfORC1 that mediates direct binding, an interaction functional in both yeast and parasite (PMID:18554328, PMID:19633266). PCNA1, but not the sibling PCNA2, complements a yeast PCNA mutant, confirming its role as the principal replicative clamp; both accumulate upon genotoxic stress through regulation of protein stability rather than transcription, and PCNA1 overexpression confers genotoxic resistance (PMID:26251451). Nuclear retention and foci formation depend on the conserved tyrosine 213, whose mutation abolishes function in both yeast and parasite (PMID:30052905). PCNA1 is also phosphorylated in infected erythrocytes and redistributes transiently from cytoplasm to nucleus upon TNF stimulation with accompanying dephosphorylation and turnover (PMID:26893139).

Mechanistic history

Synthesis pass · year-by-year structured walk · 8 steps
  1. 1993 Medium

    Establishing that P. falciparum encodes a PCNA and expresses it in a replication-linked pattern was the first step toward defining the parasite's replicative machinery.

    Evidence molecular characterization of a single-exon chromosome-13 gene with specific antibody detection and stage-resolved northern/western blots

    PMID:8095096

    Open questions at the time
    • Whether the detected protein functions as a replicative clamp not yet tested
    • Interaction partners unknown
  2. 1996 Medium

    Promoter mapping and run-on analysis addressed how PCNA1 expression is temporally coordinated, revealing constitutive transcription with the replication-coupled protein accumulation set post-transcriptionally.

    Evidence RNase protection/primer extension promoter mapping, luciferase reporter deletion analysis, and nuclear run-on transcription assays in synchronised parasites

    PMID:8855554 PMID:8946386

    Open questions at the time
    • Mechanism of post-transcriptional coordination unidentified
    • Trans-acting factors on the promoter not defined
  3. 2008 Medium

    Whether PCNA1 physically couples to replication origins was answered by demonstrating S-phase-specific association with the origin recognition complex.

    Evidence co-immunoprecipitation and immunofluorescence colocalization with PfORC5/PfORC1 in synchronised parasites, disrupted by hydroxyurea

    PMID:18554328

    Open questions at the time
    • Directness of ORC5 interaction not established biochemically
    • Functional consequence of the interaction untested
  4. 2009 Medium

    The mechanism of PCNA1 recruitment to origins was defined by showing a PIP-box motif in PfORC1 mediates direct binding functional in vivo.

    Evidence in vitro pull-down binding assay plus yeast complementation with domain deletion/mutation

    PMID:19633266

    Open questions at the time
    • Structural basis of the PIP-box/PCNA1 contact not resolved
    • Whether other PIP-box proteins compete for PCNA1 unknown
  5. 2011 Medium

    Dissecting the genetic elements controlling PCNA1 expression separated absolute expression level from temporal control, showing temporal regulation is independent of the flanking sequences and HDAC activity tested.

    Evidence Bxb1-integrated luciferase reporter with serial 5'/3' deletions and histone deacetylase inhibitor treatment

    PMID:21354176

    Open questions at the time
    • The actual determinant of temporal control remains unidentified
    • Generalizability to endogenous locus behaviour untested
  6. 2015 High

    Assigning primary replicative function among the two PCNAs and defining a damage response established PCNA1 as the principal clamp and a stability-regulated DDR effector.

    Evidence yeast complementation, replication-foci imaging, DNA-damage western blots with qRT-PCR controls, and genotoxic overexpression challenge

    PMID:26251451

    Open questions at the time
    • The stabilization mechanism upon damage not identified
    • Division of labour between PCNA1 and PCNA2 in the DDR unresolved
  7. 2016 Medium

    Discovery of phosphorylation and TNF-triggered cytoplasm-to-nucleus redistribution linked PCNA1 to host-derived external signalling beyond replication.

    Evidence 2D gel/western, cytoplasm-nucleus fractionation, and mass-spectrometric identification of a triple-serine phosphopeptide

    PMID:26893139

    Open questions at the time
    • Kinase/phosphatase controlling the phospho-switch unknown
    • Functional consequence of TNF-induced nuclear shift undefined
  8. 2018 High

    Identifying tyrosine 213 as essential for nuclear retention pinpointed a residue governing PCNA1 foci formation and replication function, distinct from serine 191 phosphorylation.

    Evidence site-directed mutagenesis (Y213F, S191) with parasite immunofluorescence and yeast complementation

    PMID:30052905

    Open questions at the time
    • Molecular basis by which Y213 controls retention unresolved
    • Whether Y213 is post-translationally modified in vivo not shown

Open questions

Synthesis pass · forward-looking unresolved questions
  • How PCNA1's replication role, damage-induced stabilization, and TNF-responsive relocalization are mechanistically integrated, and what upstream enzymes control its phosphorylation and stability, remains unresolved.
  • No structural model of PCNA1 or its ORC contacts
  • Regulators of PCNA1 protein stability unidentified
  • Kinase for the TNF-linked phospho-switch unknown

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Partners
PFORC1PFORC5

Evidence

Reading pass · 9 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1993 PCNA1 (PfPCNA1) is encoded by a single-exon gene on chromosome 13 of P. falciparum, predicting a 30,586 Da protein; antibodies against a PfPCNA1-GST fusion protein recognize a single ~32 kDa band in western blots, and expression is regulated during intraerythrocytic development, increasing dramatically in late trophozoites and persisting through schizogony. Western blot with anti-PfPCNA1-GST antiserum; northern blot; molecular characterization of coding sequence Nucleic acids research Medium 8095096
1996 The PCNA1 promoter contains a major transcription start site 960 bp upstream of the translational start and a minor site 40 bp further upstream; a 470 bp region encompassing these sites is essential for promoter activity, and a region 290–620 bp upstream of the transcriptional start is required for efficient promoter activity, as determined by transient transfection of luciferase reporter constructs. RNase protection assay; primer extension; transient transfection with luciferase reporter constructs containing serially deleted 5' flanking sequences Molecular and biochemical parasitology Medium 8946386
1996 PCNA1 protein and transcript accumulate at the trophozoite stage and persist in schizonts; nuclear run-on analysis shows that the PCNA1 promoter is active throughout the intraerythrocytic cycle (unlike PfDNA Pol delta, which is absent in rings), suggesting post-transcriptional regulation coordinates PCNA1 expression with DNA replication. Western blot of synchronised parasite extracts; northern blot; nuclear run-on transcription assay Molecular and biochemical parasitology Medium 8855554
2008 PCNA1 (PfPCNA1) colocalizes with PfORC5 in distinct nuclear replication foci during early-to-mid trophozoite stage and co-immunoprecipitates with PfORC5 at this stage; the two proteins separate at the non-replicating late schizont stage. PfORC1 also colocalizes with PCNA1 at the onset of DNA replication. A putative PCNA-interacting protein (PIP) box in PfORC1 may mediate colocalization. The DNA replication inhibitor hydroxyurea disrupts ORC5/PCNA1 foci formation. Co-immunoprecipitation; immunofluorescence colocalization; hydroxyurea inhibitor treatment; bioinformatic identification of PIP box Molecular microbiology Medium 18554328
2009 The putative PIP (PCNA-interacting protein) motif in PfORC1 mediates direct physical interaction with PCNA1 in vitro and is functional in vivo in both yeast and P. falciparum, as shown by biochemical pull-down and yeast complementation. In vitro binding assay (biochemical interaction); yeast genetic complementation; domain deletion/mutation analysis Eukaryotic cell Medium 19633266
2011 The 5' and 3' genetic elements of the PCNA1 (Pfpcna) locus control both the absolute level and temporal pattern of gene expression during the intraerythrocytic cycle; serial deletion of these elements and treatment with histone deacetylase inhibitors perturbed absolute expression but did not affect temporal control, supporting a model in which temporal regulation of PCNA1 (and potentially hundreds of other genes) is independent of histone deacetylase activity and of the flanking regulatory sequences tested. Bxb1 integrase-mediated site-specific integration of luciferase reporter with serial 5'/3' deletions; histone deacetylase inhibitor treatment; quantitative luciferase assay Journal of molecular biology Medium 21354176
2015 PCNA1 (PfPCNA1), but not PfPCNA2, functionally complements a ScPCNA mutant in yeast and forms distinct nuclear replication foci in P. falciparum parasites, establishing PCNA1 as the primary replicative PCNA. Both PfPCNA1 and PfPCNA2 accumulate significantly upon DNA damage induction, participating in an active DNA-damage-response (DDR) pathway. Regulation upon DNA damage occurs at the protein stability level rather than at the transcriptional level. Overexpression of PfPCNA1 confers a survival advantage in a genotoxic environment. Yeast complementation assay; immunofluorescence (replication foci); western blot of DNA-damage-induced parasites; quantitative RT-PCR (ruling out transcriptional regulation); parasite overexpression with genotoxic challenge The Biochemical journal High 26251451
2016 PCNA1 (PfPCNA1) is phosphorylated in P. falciparum-infected erythrocytes; it localizes predominantly to the parasite cytoplasm but transiently shifts to the nucleus upon TNF stimulation, accompanied by dephosphorylation and rapid protein turnover. A triple serine-phosphorylated PCNA1 peptide was identified by mass spectrometry in a high-expressing strain. This response to TNF is part of an external sensing system in the parasite. 2D gel electrophoresis followed by western blot; biochemical fractionation (cytoplasm vs. nucleus); high-resolution mass spectrometry of immune precipitants; real-time qRT-PCR Malaria journal Medium 26893139
2018 Tyrosine 213 (Y213) of PCNA1 is required for nuclear retention and replication foci formation of PfPCNA1 in P. falciparum; a Y213F mutation causes functional loss in both yeast complementation and parasite assays. Serine 191 phosphorylation (reported in phospho-proteome data) was found not to be important for this nuclear localization function. The conserved tyrosine residue is linked to DNA replication and cell proliferation. Site-directed mutagenesis (Y213F, S191); immunofluorescence (nuclear localization and foci formation in parasite); yeast complementation assay FEMS microbiology letters High 30052905

Source papers

Stage 0 corpus · 14 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
1996 Physical and functional mapping of the transcriptional start sites of Plasmodium falciparum proliferating cell nuclear antigen. Molecular and biochemical parasitology 45 8946386
1996 Stage specific expression of proliferating cell nuclear antigen and DNA polymerase delta from Plasmodium falciparum. Molecular and biochemical parasitology 36 8855554
2016 Tumor necrosis factor reduces Plasmodium falciparum growth and activates calcium signaling in human malaria parasites. Biochimica et biophysica acta 34 27080559
1993 Molecular characterisation and stage-specific expression of proliferating cell nuclear antigen (PCNA) from the malarial parasite, Plasmodium falciparum. Nucleic acids research 33 8095096
2008 Plasmodium falciparum origin recognition complex subunit 5: functional characterization and role in DNA replication foci formation. Molecular microbiology 27 18554328
2015 Functional dissection of proliferating-cell nuclear antigens (1 and 2) in human malarial parasite Plasmodium falciparum: possible involvement in DNA replication and DNA damage response. The Biochemical journal 21 26251451
2000 Two genes encoding unique proliferating-cell-nuclear-antigens are expressed in Toxoplasma gondii. Molecular and biochemical parasitology 21 10960171
2011 Analysis of the molecular mechanisms governing the stage-specific expression of a prototypical housekeeping gene during intraerythrocytic development of P. falciparum. Journal of molecular biology 18 21354176
2002 Molecular characterization and expression of an alternate proliferating cell nuclear antigen homologue, PfPCNA2, in Plasmodium falciparum. Biochemical and biophysical research communications 18 12413950
2009 Functional dissection of the catalytic carboxyl-terminal domain of origin recognition complex subunit 1 (PfORC1) of the human malaria parasite Plasmodium falciparum. Eukaryotic cell 14 19633266
2016 An external sensing system in Plasmodium falciparum-infected erythrocytes. Malaria journal 7 26893139
2002 Identification of a second proliferating cell nuclear antigen in the human malarial pathogen Plasmodium falciparum. International journal for parasitology 7 12464414
2019 Molecular characterization and expression profile of an alternate proliferating cell nuclear antigen homolog PbPCNA2 in Plasmodium berghei. IUBMB life 3 30865364
2018 Role of tyrosine residue (Y213) in nuclear retention of PCNA1 in human malaria parasite Plasmodium falciparum. FEMS microbiology letters 2 30052905