Poster Presentation 2014 International Biophysics Congress

Unraveling a network of interactions involved in the trafficking of virulence proteins in P. falciparum-infected erythrocytes (#254)

Steven Batinovic 1 2 , Paul J. McMillan 3 , Joseph D. Smith 4 5 , Matthew W.A. Dixon 1 2 , Leann Tilley 1 2
  1. Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, VIC, Australia
  2. ARC Centre of Excellence for Coherent X-ray Science, The University of Melbourne, Parkville, VIC, Australia
  3. Biological Optical Microscopy Platform, The University of Melbourne, Parkville, VIC, Australia
  4. Seattle Biomedical Research Institute, Seattle, WA, USA
  5. Department of Global Health, University of Washington, Seattle, WA, USA

Plasmodium falciparum is the most virulent human malaria parasite, accounting for the overwhelming majority of malaria-related deaths each year. P. falciparum parasites invade red blood cells (RBCs) and extensively modify the structure and morphology of their host cell – including the generation of virulence complexes on the surface of the erythrocyte. These complexes comprise of a collection of exported parasite proteins that assemble at knob-like structures under the surface of the erythrocyte membrane and allow infected RBCs to cytoadhere to the vascular endothelium, a process that leads to sequestration of infected RBCs in the microvasculature of the host. One key parasite protein, P. falciparum Erythrocyte Membrane Protein-1 (PfEMP1), is largely responsible for this adhesion phenotype.  It is becoming clear that PfEMP1 (and other virulence proteins) are trafficked with the aid of a large complement of host and parasite-structures and compartments that are generated de novo during the approximate 48-hour lifecycle of the parasite inside its host RBC. In this work, we have made use of a series of GFP-tagged mini-PfEMP1 constructs to examine this complex export process. We have delineated discrete compartments that these virulence proteins transiently associate with prior to further trafficking, and used immunoprecipitation followed by mass spectrometry to identify the ‘local interactome’ of virulence proteins in these compartments. Live-cell imaging and immunofluorescence assays have been used to complement these findings. Understanding and selectively targeting the export of parasite proteins may allow us to ablate parasite virulence in vivo