Trafficking of plasmepsin II to the food vacuole of the malaria parasite Plasmodium falciparum

A family of aspartic proteases, the plasmepsins (PMs), plays a key role in the degradation of hemoglobin in the Plasmodium falciparum food vacuole. To study the trafficking of proPM 11, we have modified the chromosomal PM 11 gene in P falciparum to encode a proPM II-GFP chimera. By taking advantage of green fluorescent protein fluorescence in live parasites, the ultrastructural resolution of immunoelectron microscopy, and inhibitors of trafficking and PM maturation, we have investigated the biosynthetic path leading to mature PM 11 in the food vacuole. Our data support a model whereby proPM 11 is transported through the secretory system to cytostomal vacuoles and then is carried along with its substrate hemoglobin to the food vacuole where it is proteolytically processed to mature PM II.