Plasmodium falciparum infected erythrocytes (IEs) persist in the host and avoid clearance in the spleen by varying expression of a family of cytoadhesion proteins at the IE surface called P. falciparum erythrocyte membrane protein 1 (PfEMP1). Different PfEMP1s bind to different host receptors and thereby target IEs to sequester in the microvasculature of different organs, which in turn determines disease severity. PfEMP1 surface transport is a multi-step process that involves protein export across the parasitophorus vacuole membrane (PVM) (early transport) and protein transfer through the erythrocyte cytoplasm (via Maurer's cleft organelles) to the IE surface (late transport). Each parasite genome encodes ~60 PfEMP1 proteins that are expressed in a mutually exclusion fashion. Most proteins bind to the host receptor CD36, except for an unusually conserved PfEMP1 variant that mediates infected erythrocyte sequestration in the placenta. This project is designed to elucidate important determinants in PfEMP1 transport and assembly at the IE surface and define how PfEMP1 proteins have evolved to maintain key binding interactions despite intense antibody pressure. A combination of in vitro and in vivo assays employing heterologous recombinant proteins and parasite lines expressing transgenic miniPfEMP1 proteins will be used to define accessory proteins involved in PfEMP1 transport and function and to map critical interaction residues in cytoadhesion. These studies will contribute to a detail characterization of the cytoadhesive properties of P. falciparum infected erythrocytes and enable a greater understanding of the molecular basis of malaria pathogenesis.

Public Health Relevance

Plasmodium falciparum is a major cause of human disease and the most lethal form of Plasmodium that infects humans. The virulence of P. falciparum is linked to the ability of infected erythrocytes (IEs) to sequester in and obstruct the microvasculature mediated by a family of cytoadhesive parasite proteins. The long-term goal of these studies is to understand the trafficking and function of PfEMP1 proteins as an important prerequisite for rational drug and vaccine interventions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI047953-14
Application #
8602777
Study Section
Special Emphasis Panel (ZRG1-IDM-B (02))
Program Officer
Rogers, Martin J
Project Start
2001-07-01
Project End
2016-12-31
Budget Start
2014-01-01
Budget End
2014-12-31
Support Year
14
Fiscal Year
2014
Total Cost
$448,589
Indirect Cost
$214,949
Name
Seattle Biomedical Research Institute
Department
Type
DUNS #
070967955
City
Seattle
State
WA
Country
United States
Zip Code
98109
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McMillan, Paul J; Millet, Coralie; Batinovic, Steven et al. (2013) Spatial and temporal mapping of the PfEMP1 export pathway in Plasmodium falciparum. Cell Microbiol 15:1401-18

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