Plasmodium falciparum antigen 332 is a resident peripheral membrane protein of Maurer's clefts

PLoS One. 2012;7(11):e46980. doi: 10.1371/journal.pone.0046980. Epub 2012 Nov 20.

Abstract

During the intraerythrocytic development of Plasmodium falciparum, the malaria parasite remodels the host cell cytosol by inducing membranous structures termed Maurer's clefts and inserting parasite proteins into the red blood cell cytoskeleton and plasma membrane. Pf332 is the largest known asexual malaria antigen that is exported into the red blood cell cytosol where it associates with Maurer's clefts. In the current work, we have utilized a set of different biochemical assays to analyze the solubility of the endogenous Pf332 molecule during its trafficking from the endoplasmic reticulum within the parasite to the host cell cytosol. Solubilization studies demonstrate that Pf332 is synthesized and trafficked within the parasite as a peripheral membrane protein, which after export into the host cell cytosol associates with the cytoplasmic side of Maurer's clefts in a peripheral manner. By immunofluorescence microscopy and flow cytometry, we show that Pf332 persists in close association with Maurer's clefts throughout trophozoite maturation and schizogony, and does not become exposed at the host cell surface. Our data also indicate that Pf332 interacts with the host cell cytoskeleton, but only in very mature parasite stages. Thus, the present study describes Pf332 as a resident peripheral membrane protein of Maurer's clefts and suggests that the antigen participates in host cytoskeleton modifications at completion of the intraerythrocytic developmental cycle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carbonates
  • Cytosol / parasitology
  • Erythrocyte Membrane / metabolism
  • Erythrocyte Membrane / parasitology
  • Erythrocytes / cytology*
  • Erythrocytes / metabolism*
  • Erythrocytes / parasitology
  • Host-Parasite Interactions
  • Humans
  • Membrane Proteins / metabolism*
  • Models, Biological
  • Octoxynol
  • Parasites / cytology
  • Parasites / metabolism
  • Plasmodium falciparum / metabolism*
  • Protein Biosynthesis
  • Protein Transport
  • Protozoan Proteins / isolation & purification
  • Protozoan Proteins / metabolism*
  • Schizonts / metabolism
  • Solubility
  • Trophozoites / metabolism
  • Urea

Substances

  • Carbonates
  • Membrane Proteins
  • Protozoan Proteins
  • antigen Pf332, Plasmodium
  • sodium carbonate
  • Urea
  • Octoxynol

Grants and funding

This study was carried out with support from a European Malaria Consortium (EVIMalaR) grant (242095), Swedish Research Council, SIDA/SAREC, Karolinska Institutet (6110/06-225), the National Basic Research Program of China (973 Program, number 2007CB513100) and the Chinese National Natural Science Foundation of China (NSFC) program (81130033, 81171592). The research leading to these results has received funding from the European Community's Seventh Framework Program (FP7/2007–2013) under grant agreement number 242095. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.