Affinage · Plasmodium

AP2-G5

PF3D7_1139300 · AP2 domain transcription factor AP2-G5

Annotated
2026-09-08
76 papers in source corpus 2 papers cited in narrative 2 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

AP2-G5 (PF3D7_1139300) is an ApiAP2 transcription factor in Plasmodium falciparum that acts as a gatekeeper of sexual commitment by transcriptionally restraining the master sexual-commitment regulator pfap2-g (PMID:34365503). It binds both the upstream regulatory region and the exonic gene body of pfap2-g, with the exonic binding linked to maintenance of local heterochromatin, thereby repressing pfap2-g transcription and preventing premature initiation of sexual commitment; loss of AP2-G5 disrupts the asexual cycle, de-represses pfap2-g, and drives sexual commitment (PMID:34365503). Beyond this repressive role, AP2-G5 is separately required for the maturation of committed gametocytes: in its absence, gametocytes form but fail to mature fully, coincident with down-regulation of pfap2-g and a set of early gametocyte genes normally activated by PfAP2-G (PMID:34365503). AP2-G5 physically associates with the ApiAP2 repressor PfAP2-G2 in a chromatin-regulatory complex that also contains chromatin remodeling proteins and a MORC protein (PMID:33368818). Beyond these transcriptional and complex-association findings, no further mechanistic detail on AP2-G5 has been characterized in the available corpus.

Mechanistic history

Synthesis pass · year-by-year structured walk · 2 steps
  1. 2021 High

    Established that AP2-G5 is a direct transcriptional repressor of the sexual-commitment master regulator pfap2-g, answering how the initiation of gametocytogenesis is held in check during asexual growth.

    Evidence CRISPR/Cas9 and homologous-recombination knockout of pfap2-g5 with ChIP-seq mapping of AP2-G5 to pfap2-g upstream and exonic regions plus transcriptomic and gametocyte-development phenotyping in P. falciparum

    PMID:34365503

    Open questions at the time
    • The precise DNA motif recognized by AP2-G5 and how exonic binding mechanistically nucleates heterochromatin are not resolved
    • How AP2-G5's dual role as pfap2-g repressor and gametocyte-maturation factor is coordinated is not explained
    • The chromatin-modifying enzymes AP2-G5 recruits are not identified in this study
  2. 2021 Medium

    Placed AP2-G5 within a defined repressor complex by showing it physically associates with the ApiAP2 repressor PfAP2-G2, linking AP2-G5 to a broader chromatin-regulatory machinery.

    Evidence Co-immunoprecipitation/affinity purification of PfAP2-G2-associated proteins with mass-spectrometry identification of PF3D7_1139300 in P. falciparum

    PMID:33368818

    Open questions at the time
    • Single AP-MS pulldown without reciprocal Co-IP or functional validation specific to AP2-G5
    • The stoichiometry and direct versus indirect nature of the AP2-G5–PfAP2-G2 interaction are unknown
    • Whether this complex mediates the pfap2-g repression observed genetically is not tested

Open questions

Synthesis pass · forward-looking unresolved questions
  • How AP2-G5 mechanistically toggles between repressing pfap2-g early and supporting gametocyte maturation later, and how its DNA-binding is coupled to heterochromatin maintenance within the PfAP2-G2 complex, remains open.
  • No structural characterization of AP2-G5 or its DNA-binding specificity
  • No delineation of the effector chromatin enzymes recruited by AP2-G5
  • Temporal regulation distinguishing its repressive and maturation-promoting functions is uncharacterized

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Partners
PFAP2-G2 [#1]
Complex memberships
PfAP2-G2 chromatin-regulatory repressor complex (includes chromatin remodeling proteins and a MORC protein) [#1]

Evidence

Reading pass · 2 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2021 PF3D7_1139300 (AP2-G5) is indispensable for gametocytogenesis in P. falciparum. Knockout of pfap2-g5 disrupts the asexual replication cycle and promotes sexual commitment accompanied by upregulation of pfap2-g expression, but the gametocytes produced fail to mature fully. AP2-G5 suppresses pfap2-g transcriptional activity by binding to both the upstream region and the exonic gene body of pfap2-g, with the latter binding linked to maintenance of local heterochromatin structure, thereby preventing initiation of sexual commitment. AP2-G5 is also required for gametocyte maturation, causing down-regulation of pfap2-g and a set of early gametocyte genes activated by PfAP2-G prior to gametocyte development. Systematic functional screening of ApiAP2 transcription factors; pfap2-g5 knockout by CRISPR/Cas9 or homologous recombination; ChIP-seq to map AP2-G5 binding to pfap2-g upstream and exonic regions; transcriptomic analysis of knockout lines; assessment of gametocyte development phenotype Nucleic acids research High 34365503
2021 PfAP2-G2 interacts physically with PF3D7_1139300 (AP2-G5), identifying AP2-G5 as a protein partner of the PfAP2-G2 transcriptional repressor complex that also includes chromatin remodeling proteins and a MORC protein. This interaction was detected in the context of PfAP2-G2's role in gametocyte maturation. Co-immunoprecipitation / affinity purification of PfAP2-G2-associated proteins followed by mass spectrometry identification of interactors including PF3D7_1139300 Molecular microbiology Medium 33368818

Source papers

Stage 0 corpus · 76 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2014 A transcriptional switch underlies commitment to sexual development in malaria parasites. Nature 397 24572369
2005 Discovery of the principal specific transcription factors of Apicomplexa and their implication for the evolution of the AP2-integrase DNA binding domains. Nucleic acids research 395 16040597
2014 A cascade of DNA-binding proteins for sexual commitment and development in Plasmodium. Nature 326 24572359
2014 Heterochromatin protein 1 secures survival and transmission of malaria parasites. Cell host & microbe 217 25121746
2018 GDV1 induces sexual commitment of malaria parasites by antagonizing HP1-dependent gene silencing. Science (New York, N.Y.) 195 29590075
2008 Specific DNA-binding by apicomplexan AP2 transcription factors. Proceedings of the National Academy of Sciences of the United States of America 193 18541913
2014 A Plasmodium falciparum histone deacetylase regulates antigenic variation and gametocyte conversion. Cell host & microbe 174 25121747
2017 Single-cell RNA sequencing reveals a signature of sexual commitment in malaria parasites. Nature 168 29094698
2009 Identification of a transcription factor in the mosquito-invasive stage of malaria parasites. Molecular microbiology 164 19220746
2017 A Knockout Screen of ApiAP2 Genes Reveals Networks of Interacting Transcriptional Regulators Controlling the Plasmodium Life Cycle. Cell host & microbe 163 28081440
2010 The Apicomplexan AP2 family: integral factors regulating Plasmodium development. Molecular and biochemical parasitology 156 21126543
2018 Chromatin Accessibility-Based Characterization of the Gene Regulatory Network Underlying Plasmodium falciparum Blood-Stage Development. Cell host & microbe 140 29649445
2010 A major role for the Plasmodium falciparum ApiAP2 protein PfSIP2 in chromosome end biology. PLoS pathogens 134 20195509
2009 Transcription factor AP2-Sp and its target genes in malarial sporozoites. Molecular microbiology 129 20025671
2017 Red Blood Cell Invasion by the Malaria Parasite Is Coordinated by the PfAP2-I Transcription Factor. Cell host & microbe 113 28618269
2020 Dissecting the role of PfAP2-G in malaria gametocytogenesis. Nature communications 108 32198457
2018 Regulation of Sexual Commitment and Gametocytogenesis in Malaria Parasites. Annual review of microbiology 91 29975590
2018 Revisiting the initial steps of sexual development in the malaria parasite Plasmodium falciparum. Nature microbiology 91 30478286
2012 Identification of an AP2-family protein that is critical for malaria liver stage development. PloS one 88 23144823
2015 Global transcriptional repression: An initial and essential step for Plasmodium sexual development. Proceedings of the National Academy of Sciences of the United States of America 84 26417110
2012 A tetracycline-repressible transactivator system to study essential genes in malaria parasites. Cell host & microbe 76 23245327
2021 Higher gametocyte production and mosquito infectivity in chronic compared to incident Plasmodium falciparum infections. Nature communications 73 33903595
2019 Hierarchical transcriptional control regulates Plasmodium falciparum sexual differentiation. BMC genomics 73 31795940
2020 Conditional expression of PfAP2-G for controlled massive sexual conversion in Plasmodium falciparum. Science advances 67 32577509
2017 Systematic CRISPR-Cas9-Mediated Modifications of Plasmodium yoelii ApiAP2 Genes Reveal Functional Insights into Parasite Development. mBio 67 29233900
2018 Inducible developmental reprogramming redefines commitment to sexual development in the malaria parasite Plasmodium berghei. Nature microbiology 65 30177743
2020 Strains used in whole organism Plasmodium falciparum vaccine trials differ in genome structure, sequence, and immunogenic potential. Genome medicine 63 31915075
2014 Endoplasmic reticulum stress triggers gametocytogenesis in the malaria parasite. The Journal of biological chemistry 63 24755215
2016 Proteome-wide analysis reveals widespread lysine acetylation of major protein complexes in the malaria parasite. Scientific reports 62 26813983
2017 Culture adaptation of malaria parasites selects for convergent loss-of-function mutants. Scientific reports 61 28117431
2019 Plasmodium falciparum sexual differentiation in malaria patients is associated with host factors and GDV1-dependent genes. Nature communications 60 31086187
2017 Adaptation of Plasmodium falciparum to its transmission environment. Nature ecology & evolution 59 29255304
2023 Regulators of male and female sexual development are critical for the transmission of a malaria parasite. Cell host & microbe 58 36634679
2017 Laser capture microdissection enables transcriptomic analysis of dividing and quiescent liver stages of Plasmodium relapsing species. Cellular microbiology 54 28256794
2021 A cascade of transcriptional repression determines sexual commitment and development in Plasmodium falciparum. Nucleic acids research 49 34365503
2016 Selective sweep suggests transcriptional regulation may underlie Plasmodium vivax resilience to malaria control measures in Cambodia. Proceedings of the National Academy of Sciences of the United States of America 48 27911780
2010 The construction and use of log-odds substitution scores for multiple sequence alignment. PLoS computational biology 48 20657661
2020 From Genes to Transcripts, a Tightly Regulated Journey in Plasmodium. Frontiers in cellular and infection microbiology 46 33425787
2015 Specific expression and export of the Plasmodium falciparum Gametocyte EXported Protein-5 marks the gametocyte ring stage. Malaria journal 46 26315106
2021 The PfAP2-G2 transcription factor is a critical regulator of gametocyte maturation. Molecular microbiology 44 33368818
2021 A unique GCN5 histone acetyltransferase complex controls erythrocyte invasion and virulence in the malaria parasite Plasmodium falciparum. PLoS pathogens 44 34403450
2018 Characterization of the accessible genome in the human malaria parasite Plasmodium falciparum. Nucleic acids research 44 30016465
2017 An ApiAP2 member regulates expression of clonally variant genes of the human malaria parasite Plasmodium falciparum. Scientific reports 43 29070841
2023 Sexual differentiation in human malaria parasites is regulated by competition between phospholipid metabolism and histone methylation. Nature microbiology 42 37277533
2019 Female-specific gene regulation in malaria parasites by an AP2-family transcription factor. Molecular microbiology 42 31231888
2017 Capturing in vivo RNA transcriptional dynamics from the malaria parasite Plasmodium falciparum. Genome research 40 28416533
2020 RNA-Seq Analysis Illuminates the Early Stages of Plasmodium Liver Infection. mBio 36 32019802
2018 Inducing controlled cell cycle arrest and re-entry during asexual proliferation of Plasmodium falciparum malaria parasites. Scientific reports 35 30409996
2010 Identification and characterization of a liver stage-specific promoter region of the malaria parasite Plasmodium. PloS one 35 21048918
2020 Histone modifications associated with gene expression and genome accessibility are dynamically enriched at Plasmodium falciparum regulatory sequences. Epigenetics & chromatin 34 33225957
2021 Mechanisms of triggering malaria gametocytogenesis by AP2-G. Parasitology international 29 34119684
2023 Plasmodium falciparum adapts its investment into replication versus transmission according to the host environment. eLife 27 36916164
2020 Rrp6 Regulates Heterochromatic Gene Silencing via ncRNA RUF6 Decay in Malaria Parasites. mBio 26 32487761
2023 Characterization of the dual role of Plasmodium falciparum DNA methyltransferase in regulating transcription and translation. Nucleic acids research 25 37026483
2020 Disruption of the Plasmodium falciparum Life Cycle through Transcriptional Reprogramming by Inhibitors of Jumonji Demethylases. ACS infectious diseases 25 32272012
2010 From cradle to grave: RNA biology in malaria parasites. Wiley interdisciplinary reviews. RNA 25 21935891
2021 Single-Cell RNA Sequencing Reveals Cellular Heterogeneity and Stage Transition under Temperature Stress in Synchronized Plasmodium falciparum Cells. Microbiology spectrum 24 34232098
2019 The role of epigenetics and chromatin structure in transcriptional regulation in malaria parasites. Briefings in functional genomics 24 31220857
2017 A disrupted transsulphuration pathway results in accumulation of redox metabolites and induction of gametocytogenesis in malaria. Scientific reports 24 28091526
2024 Unraveling the complexities of ApiAP2 regulation in Plasmodium falciparum. Trends in parasitology 23 39419713
2022 A Dynamic and Combinatorial Histone Code Drives Malaria Parasite Asexual and Sexual Development. Molecular & cellular proteomics : MCP 23 35051657
2019 A patatin-like phospholipase functions during gametocyte induction in the malaria parasite Plasmodium falciparum. Cellular microbiology 23 31734953
2021 A Randomized Clinical Trial to Compare Plasmodium falciparum Gametocytemia and Infectivity After Blood-Stage or Mosquito Bite-Induced Controlled Malaria Infection. The Journal of infectious diseases 22 32239171
2025 High-resolution map of the Plasmodium falciparum genome reveals MORC/ApiAP2-mediated links between distant, functionally related genes. Nature microbiology 5 40588593
2025 Pink or blue: sex determination in malaria gametocytes. Trends in parasitology 2 41107154
2025 Transcription factor 25 modulates gametocytogenesis and ribosome biogenesis in the malaria parasite Plasmodium falciparum. Frontiers in cellular and infection microbiology 2 41210950
2025 Structural characterization of the ACDC domain from ApiAP2 proteins, a potential molecular target against apicomplexan parasites. Acta crystallographica. Section D, Structural biology 1 39820027
2025 Heterochromatin de novo formation and maintenance in Plasmodium falciparum. PLoS pathogens 1 40455742
2026 A single valine to leucine switch disrupts Plasmodium falciparum AP2-G DNA binding and reveals GDV1's role in ap2-g activation. Nature communications 0 41547993
2026 Molecular mechanisms involved in Plasmodium gametocytogenesis. Frontiers in microbiology 0 41716278
2026 A heterologous marker-free selection approach for CRISPR/Cas9-based gene editing in the malaria parasite Plasmodium falciparum. mSphere 0 41885428
2026 A divergent Plasmodium NEK4 acts as a key regulator driving the early events of meiosis. Nature communications 0 42120403
2026 The serine-arginine-rich protein PfSR-X2 modulates human malaria parasite gene expression during the intraerythrocytic developmental cycle. Frontiers in cellular and infection microbiology 0 42272758
2026 Identification of a sequence element regulating H3K9 methylation at the ap2-g locus in Plasmodium falciparum. Scientific reports 0 42443261
2026 Persistence of Plasmodium falciparum DNA detection after antimalarial treatment and the implication of gametocytes: a prospective cohort study in a non-endemic setting. Microbiology spectrum 0 42684939
2025 Circadian Biology in Parasites: Beyond Known Mechanisms. Annual review of microbiology 0 41130920