Plasmepsin V, a Secret Weapon Against Malaria
Plasmodium falciparum and Plasmodium vivax are single-celled parasites that, between them, are responsible for the vast majority of malaria cases in humans. Of the two, P. falciparum often provokes the most acute symptoms, whereas P. vivax is associated with a recurring, chronic version of malarial disease. Both parasites spend a large portion of their life cycle living and replicating within human red blood cells (erythrocytes).
While inside erythrocytes, the parasites express and secrete more than 450 proteins. Each of these proteins has a different function for the parasite, but many of them share a distinctive feature: an amino-terminal motif called the Plasmodium EXport ELement (PEXEL). This special sequence of amino acids directs proteins into the export pathway, but it is partially removed while the protein is still within the parasite’s endoplasmic reticulum by an enzyme called Plasmepsin V (PMV). On the basis of this prominent function, it seems likely that PMV is important for parasite survival and may therefore be a good target for antimalarial drugs.
Citation: Sedwick C (2014) Plasmepsin V, a Secret Weapon Against Malaria. PLoS Biol 12(7): e1001898. doi:10.1371/journal.pbio.1001898
Figure 1. Malaria parasites survive inside red blood cells by exporting proteins that renovate the cell. Inhibition of the export process, by blocking the malarial enzyme, Plasmepsin V, prevents red cell remodeling and kills the parasite.
Image credit: Justin Boddey. doi:10.1371/journal.pbio.1001898.g001