title: Trafficking of plasmepsin II to the food vacuole of the malaria parasite Plasmodium falciparum.
abstract: 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 II, we have modified the chromosomal PM II 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 II in the food vacuole. Our data support a model whereby proPM II 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.
authors.affiliation: Department of Molecular Microbiology, Washington University School of Medicine, 660 S. Euclid Ave., Box 8230, St. Louis, MO 63110, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Klemba
authors.forename: Wandy
authors.initials: W
authors.lastname: Beatty
authors.forename: Ilya
authors.initials: I
authors.lastname: Gluzman
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Goldberg
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics / Q000378:metabolism; D016282:Aspartic Acid Endopeptidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004792:Enzyme Precursors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006454:Hemoglobins / Q000378:metabolism; D007150:Immunohistochemistry; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008854:Microscopy, Electron; D008954:Models, Biological; D009685:Nuclear Envelope / Q000378:metabolism / Q000648:ultrastructure; D010963:Plasmodium falciparum / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D021381:Protein Transport / Q000235:genetics; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D004791:Enzyme Inhibitors; D004792:Enzyme Precursors; D006454:Hemoglobins; D008164:Luminescent Proteins; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D016282:Aspartic Acid Endopeptidases; C116755:proplasmepsin II; C100637:plasmepsin II