9.B.367. The Plasmodium falciparum virulence factor trafficking system (PfVFTS) Family
After invading human red blood cells (RBCs), the malaria parasite Plasmodium falciparum remodels the host cell by trafficking proteins to the RBC compartment. The virulence protein, P. falciparum erythrocyte membrane protein 1 (PfEMP1; UniProt acc # K9KG67), is responsible for cytoadherence of infected cells to host endothelial receptors. This protein is exported across the parasite plasma membrane and parasitophorous vacuole membrane and inserted into the RBC membrane. PfEMP1 export through the infected RBC has been studied (Knuepfer et al. 2005), showing that a knob-associated histidine-rich protein (KAHRP) N-terminal protein export element appended to the PfEMP1 transmembrane and C-terminal domains is sufficient for efficient trafficking of protein domains to the outside of the P. falciparum-infected RBC. The physical state of the exported proteins suggested trafficking as a complex rather than in vesicles, and supports the hypothesis that endogenous PfEMP1 is trafficked in a similar manner. Also, the sequences required for expression of proteins to the outside of the P. falciparum-infected RBC membrane have been identified (Knuepfer et al. 2005).