Affinage · Plasmodium

BTP1

PF3D7_0611600 · basal complex transmembrane protein 1

Annotated
2026-09-08
14 papers in source corpus 5 papers cited in narrative 5 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

BTP1 (PF3D7_0611600) is a Plasmodium falciparum transmembrane protein of the basal complex, the ring-shaped structure at the leading edge of the inner membrane complex (IMC) that drives daughter cell formation during schizogony (PMID:26763910). It colocalizes with the basal complex marker MORN1 and is recovered biochemically as part of the PfCINCH-containing basal complex, establishing it as a bona fide component of this division machinery (PMID:26763910, PMID:31097714). Live imaging showed that basal complex dynamics marked by BTP1 track plasma membrane invagination during the final steps of cell division, indicating a role at the interface between the invaginating plasma membrane and the IMC (PMID:26763910). High-resolution imaging by expansion microscopy and DNA-PAINT confirmed its basal complex localization, and BTP1 has been used as a spatial reference to mark the region where ER-IMC membrane contact sites reside (PMID:41706859, PMID:41904125). Its phosphorylation state is altered upon depletion of the phosphatase PfPPM2, placing BTP1 within a phosphoregulated pathway governing IMC formation (PMID:40410154). Beyond its membership in the basal complex and correlation of its dynamics with membrane invagination, no direct enzymatic activity or independent loss-of-function phenotype has been established for BTP1 itself in the available corpus.

Mechanistic history

Synthesis pass · year-by-year structured walk · 4 steps
  1. 2016 Medium

    Establishing whether a novel transmembrane protein participates in Plasmodium cell division required localizing it and correlating its behavior with the division machinery; this identified BTP1 as a basal complex protein whose dynamics track plasma membrane invagination.

    Evidence Fluorescence and live imaging of epitope-tagged BTP1 lines with MORN1 co-localization and a plasma membrane marker in P. falciparum

    PMID:26763910

    Open questions at the time
    • No loss-of-function analysis of BTP1 itself
    • Correlation with membrane invagination does not demonstrate a causal or mechanical role
    • Molecular partners not yet defined
  2. 2019 Medium

    Whether BTP1's basal complex localization reflected physical membership in a defined protein complex was unresolved; biochemical recovery placed BTP1 within the PfCINCH-containing basal complex.

    Evidence Co-immunoprecipitation of PfCINCH complexes with mass spectrometry plus MORN1 co-localization in P. falciparum 3D7

    PMID:31097714

    Open questions at the time
    • No mutagenesis of BTP1 to test complex assembly dependence
    • Direct binding partners of BTP1 within the complex not resolved
    • Functional contribution of BTP1 to complex activity untested
  3. 2025 Low

    How basal complex/IMC formation is regulated post-translationally was unclear; phosphoproteomics identified BTP1 as a differentially phosphorylated target downstream of the phosphatase PfPPM2.

    Evidence Phosphoproteomics on PfPPM2-depleted P. falciparum parasites

    PMID:40410154

    Open questions at the time
    • Direct writer/eraser relationship for BTP1 phosphosites not experimentally confirmed
    • Functional consequence of BTP1 phosphorylation unknown
    • Distinction between direct and indirect PfPPM2 targeting not established
  4. 2026 Low

    Confirming BTP1's precise localization and its spatial relationship to membrane biogenesis required higher resolution; nanoscopy and co-localization with VPS13L1 confirmed BTP1 as a transmembrane basal complex marker at ER-IMC membrane contact regions.

    Evidence Expansion microscopy (U-ExM), DNA-PAINT nanoscopy, and co-localization of BTP1-mNeonGreen with PfVPS13L1-Halo in P. falciparum

    PMID:41706859 PMID:41904125

    Open questions at the time
    • BTP1 used as a marker rather than functionally interrogated
    • No direct interaction between BTP1 and VPS13L1 demonstrated
    • Role of BTP1 in membrane contact site formation untested

Open questions

Synthesis pass · forward-looking unresolved questions
  • The direct molecular function of BTP1 and its independent contribution to basal complex biology remain unknown.
  • No BTP1 knockout/knockdown phenotype established
  • No direct enzymatic or mechanical activity assigned
  • Functional significance of its phosphorylation and membrane-invagination correlation undefined

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Partners
MORN1 (CO-LOCALIZATION)PFCINCH COMPLEX (CO-IP MEMBERSHIP)PFVPS13L1 (CO-LOCALIZATION)
Complex memberships
PfCINCH-containing basal complex

Evidence

Reading pass · 5 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2016 BTP1 (PF3D7_0611600) is a novel transmembrane protein that localizes to the basal complex of P. falciparum, colocalizing with the known basal complex marker MORN1. It shows distinct dynamics compared to other IMC proteins during schizogony, and live-imaging with a parasite plasma membrane marker demonstrated that basal complex dynamics (including BTP1 localization) are correlated with plasma membrane invagination during the final steps of cell division, suggesting BTP1 may be involved in interactions between the invaginating plasma membrane and the IMC. Fluorescence microscopy / live imaging, transgenic parasite lines with epitope-tagged BTP1, co-localization with MORN1 marker Journal of cell science Medium 26763910
2019 BTP1 (PF3D7_0611600) colocalizes with MORN1 at the basal complex during segmentation in P. falciparum, and is recovered as part of the PfCINCH-containing basal complex by co-immunoprecipitation, establishing its membership in the basal complex protein complex. Immunofluorescence co-localization with MORN1; co-immunoprecipitation of PfCINCH-containing complexes followed by mass spectrometry Nature communications Medium 31097714
2026 BTP1 (PF3D7_0611600) is a transmembrane basal complex protein in P. falciparum whose localization was directly visualized by expansion microscopy (U-ExM) and DNA-PAINT nanoscopy. BTP1-mNeonGreen was also used as a basal complex marker to co-localize with PfVPS13L1-Halo, showing overlap during IMC formation, confirming BTP1's role as a bona fide basal complex transmembrane component during daughter cell formation. Expansion microscopy (U-ExM), DNA-PAINT (PAINT nanoscopy), fluorescence co-localization with tagged BTP1 Science advances Medium 41706859
2025 BTP1 (PF3D7_0611600) is among the differentially phosphorylated proteins detected in P. falciparum parasites depleted of PfPPM2 (a protein phosphatase), identifying BTP1 as a substrate (or indirect target) in a phosphorylation-regulated pathway governing IMC formation during parasite division. Phosphoproteomics on PfPPM2-depleted parasites Nature communications Low 40410154
2026 BTP1-mNeonGreen (BTP1-mNG) co-localizes with PfVPS13L1-Halo during IMC formation in P. falciparum schizonts, establishing that BTP1 marks the basal complex region where ER-IMC membrane contact sites (bridged by VPS13L1) are found, and confirming BTP1 as a spatial reference for the basal complex during IMC biogenesis. Fluorescence co-localization microscopy of episomally expressed BTP1-mNG with endogenously tagged PfVPS13L1-Halo Nature communications Low 41904125

Source papers

Stage 0 corpus · 14 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2016 Pellicle formation in the malaria parasite. Journal of cell science 30 26763910
2026 Transmembrane proteins mediate basal complex assembly and individual daughter cell formation in malaria parasites. Science advances 1 41706859
2026 A bridge-like lipid transfer protein is critical for generation of invasive stages in malaria parasites. Nature communications 0 41904125
2025 SIP2 is the master transcription factor of Plasmodium merozoite formation. Science advances 0 40117352
2025 PfPPM2 signalling regulates asexual division and sexual conversion of human malaria parasite Plasmodium falciparum. Nature communications 0 40410154
2024 An inner membrane complex protein IMC1g in Plasmodium berghei is involved in asexual stage schizogony and parasite transmission. mBio 0 39576115
2023 A PPP-type pseudophosphatase is required for the maintenance of basal complex integrity in Plasmodium falciparum. Nature communications 0 37400439
2022 Identification of basal complex protein that is essential for maturation of transmission-stage malaria parasites. Proceedings of the National Academy of Sciences of the United States of America 0 35972967
2021 The Dynamic Roles of the Inner Membrane Complex in the Multiple Stages of the Malaria Parasite. Frontiers in cellular and infection microbiology 0 33489940
2021 The Ringleaders: Understanding the Apicomplexan Basal Complex Through Comparison to Established Contractile Ring Systems. Frontiers in cellular and infection microbiology 0 33954122
2021 The Basal Complex Protein PfMORN1 Is Not Required for Asexual Replication of Plasmodium falciparum. mSphere 0 34878291
2019 An essential contractile ring protein controls cell division in Plasmodium falciparum. Nature communications 0 31097714
2019 Who Needs a Contractile Actomyosin Ring? The Plethora of Alternative Ways to Divide a Protozoan Parasite. Frontiers in cellular and infection microbiology 0 31824870
2017 Photosensitized INA-Labelled protein 1 (PhIL1) is novel component of the inner membrane complex and is required for Plasmodium parasite development. Scientific reports 0 29138437