The Plasmodium translocon of exported proteins component EXP2 is critical for establishing a patent malaria infection in mice.
Export of most malaria proteins into the erythrocyte cytosol requires the Plasmodium translocon of exported proteins (PTEX) and a cleavable Plasmodium export element (PEXEL). In contrast, the contribution of PTEX in the liver stages and export of liver stage proteins is unknown. Here, using the FLP/FRT conditional mutatagenesis system, we generate transgenic Plasmodium berghei parasites deficient in EXP2, the putative pore-forming component of PTEX. Our data reveal that EXP2 is important for parasite growth in the liver and critical for parasite transition to the blood, with parasites impaired in their ability to generate a patent blood-stage infection. Surprisingly, whilst parasites expressing a functional PTEX machinery can efficiently export a PEXEL-bearing GFP reporter into the erythrocyte cytosol during a blood stage infection, this same reporter aggregates in large accumulations within the confines of the parasitophorous vacuole membrane during hepatocyte growth. Notably HSP101, the putative molecular motor of PTEX, could not be detected during the early liver stages of infection, which may explain why direct protein translocation of this soluble PEXEL-bearing reporter or indeed native PEXEL proteins into the hepatocyte cytosol has not been observed. This suggests that PTEX function may not be conserved between the blood and liver stages of malaria infection.
Molecular and Medical Research Unit, School of Medicine, Deakin University, Waurn Ponds, Geelong, Victoria, 3216, Australia.
Ming
M
Kalanon
Unité de Biologie et Génétique du Paludisme, Institut Pasteur, Paris, France.|Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Daniel
D
Bargieri
School of BioSciences, The University of Melbourne, Parkville, Victoria, 3010, Australia.
Angelika
A
Sturm
Molecular and Medical Research Unit, School of Medicine, Deakin University, Waurn Ponds, Geelong, Victoria, 3216, Australia.
Kathryn
K
Matthews
Molecular and Medical Research Unit, School of Medicine, Deakin University, Waurn Ponds, Geelong, Victoria, 3216, Australia.
Sreejoyee
S
Ghosh
School of BioSciences, The University of Melbourne, Parkville, Victoria, 3010, Australia.
Christopher D
CD
Goodman
Unité de Biologie et Génétique du Paludisme, Institut Pasteur, Paris, France.
Sabine
S
Thiberge
School of BioSciences, The University of Melbourne, Parkville, Victoria, 3010, Australia.
Vanessa
V
Mollard
School of BioSciences, The University of Melbourne, Parkville, Victoria, 3010, Australia.
Geoffrey I
GI
McFadden
Unité de Biologie et Génétique du Paludisme, Institut Pasteur, Paris, France.
Robert
R
Ménard
Molecular and Medical Research Unit, School of Medicine, Deakin University, Waurn Ponds, Geelong, Victoria, 3216, Australia.
Tania F
TF
de Koning-Ward
D000818:Animals; D030801:Animals, Genetically Modified; D005786:Gene Expression Regulation / Q000187:drug effects; D055785:Gene Knockdown Techniques; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D006790:Host-Parasite Interactions; D008099:Liver / Q000469:parasitology; D008288:Malaria / Q000469:parasitology*; D051379:Mice; D010962:Plasmodium berghei / Q000235:genetics / Q000472:pathogenicity*; D021381:Protein Transport / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D013754:Tetracyclines / Q000494:pharmacology
D006360:Heat-Shock Proteins; D015800:Protozoan Proteins; D013754:Tetracyclines; D049452:Green Fluorescent Proteins; C016229:4-epianhydrotetracycline