Proteases and chaperones are the most abundant proteins in the parasitophorous vacuole of Plasmodium falciparum-infected erythrocytes

After invasion of erythrocytes, the human malaria parasite Plasmodium falciparum resides within a parasitophorous vacuole (PV) which forms an interface between the host cell cytosol and the parasite surface. This vacuole protects the parasite from potentially harmful substances, but allows access of essential nutrients to the parasite. Furthermore, the vacuole acts as a transit compartment for parasite proteins en route to the host cell cytoplasm. Recently we developed a strategy to biotin label soluble proteins of the PV. Here, we have paired this strategy with a high-throughput MALDI-TOF-MS analysis to identify 27 vacuolar proteins. These proteins fall into the following main classes: chaperones, proteases, and metabolic enzymes, consistent with the expected functions of the vacuole. These proteins are likely to be involved in several processes including nutrient acquisition from the host cytosol, protein sorting within the vacuole, and release of parasites at the end of the intraerythrocytic cycle.