APEX-based proximity labeling in Plasmodium identifies a membrane protein with dual functions during mosquito infection

PLoS Pathog. 2024 Dec 18;20(12):e1012788. doi: 10.1371/journal.ppat.1012788. eCollection 2024 Dec.

Abstract

Transmission of the malaria parasite Plasmodium to mosquitoes necessitates gamete egress from red blood cells to allow zygote formation and ookinete motility to enable penetration of the midgut epithelium. Both processes are dependent on the secretion of proteins from distinct sets of specialized vesicles. Inhibiting some of these proteins has shown potential for blocking parasite transmission to the mosquito. To identify new transmission blocking vaccine candidates, we aimed to define the microneme content from ookinetes of the rodent model organism Plasmodium berghei using APEX2-mediated rapid proximity-dependent biotinylation. Besides known proteins of ookinete micronemes, this identified over 50 novel candidates and sharpened the list of a previous survey based on subcellular fractionation. Functional analysis of a first candidate uncovered a dual role for this membrane protein in male gametogenesis and ookinete midgut traversal. Mutation of a putative trafficking motif in the C-terminus affected ookinete to oocyst transition but not gamete formation. This suggests the existence of distinct functional and transport requirements for Plasmodium proteins in different parasite stages.

MeSH terms

  • Animals
  • Culicidae / metabolism
  • Culicidae / parasitology
  • Female
  • Malaria* / metabolism
  • Malaria* / parasitology
  • Male
  • Membrane Proteins* / metabolism
  • Mice
  • Plasmodium berghei* / metabolism
  • Protozoan Proteins* / genetics
  • Protozoan Proteins* / metabolism

Substances

  • Protozoan Proteins
  • Membrane Proteins

Grants and funding

This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Project-number 240245660 - SFB 1129 (to FF) and SPP 2225 (to FF and TG), Human Frontier Science Program (HFSP) Young Investigator grant RGY066 (to FF) and the European Research Council (StG 281719) (to FF). JK received part of her salary from funding by the DFG (SFB 1129), the HFSP and ERC. EP received part of her salary from funding by the DFG (SPP 2225). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.