Reduced glycerol incorporation into phospholipids contributes to impaired intra-erythrocytic growth of glycerol kinase knockout Plasmodium falciparum parasites

• Published in: Biochimica et biophysica acta Vol. 1830; no. 11; pp. 5326 - 5334
• Main Authors: Naidoo, Kubendran, Coetzer, Theresa L.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2013
• Subjects: Animals; biogenesis; carbohydrate metabolism; carbon; DNA; Erythrocytes - metabolism; flow cytometry; gene targeting; genes; glycerol; Glycerol - metabolism; Glycerol kinase; Glycerol Kinase - genetics; Glycerol Kinase - metabolism; humans; Knockout parasites; Malaria; messenger RNA; parasites; Parasites - genetics; Parasites - growth & development; Parasites - metabolism; phosphatidylcholines; Phosphatidylcholines - genetics; Phosphatidylcholines - metabolism; phosphatidylethanolamines; Phosphatidylethanolamines - genetics; Phosphatidylethanolamines - metabolism; Phospholipids; Phospholipids - genetics; Phospholipids - metabolism; phosphorylation; Plasmodium falciparum; Plasmodium falciparum - genetics; Plasmodium falciparum - growth & development; Plasmodium falciparum - metabolism; Protozoan Proteins - genetics; Protozoan Proteins - metabolism; RNA, Messenger - genetics; Southern blotting; AQP; hDHFR; Malaria; G3P; Phospholipids; Knockout parasites; EBA-175; Plasmodium falciparum; PC; PE; Glycerol kinase; Pf; 3D7ΔPfGK; 3D7ΔEBA; PL; PfGK; human dihydrofolate reductase; glycerol-3-phosphate; glycerol kinase knockout 3D7 P. falciparum parasites; phosphatidylcholine; erythrocyte binding antigen-175 knockout 3D7 P. falciparum parasites; aquaglyceroporin; P. falciparum glycerol kinase; phosphatidylethanolamine; phospholipid; erythrocyte binding antigen-175
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2013.08.006

Malaria is a devastating disease and Plasmodium falciparum is the most lethal parasite infecting humans. Understanding the biology of this parasite is vital in identifying potential novel drug targets. During every 48-hour intra-erythrocytic asexual replication cycle, a single parasite can produce up to 32 progeny. This extensive proliferation implies that parasites require substantial amounts of lipid precursors for membrane biogenesis. Glycerol kinase is a highly conserved enzyme that functions at the interface of lipid synthesis and carbohydrate metabolism. P. falciparum glycerol kinase catalyzes the ATP-dependent phosphorylation of glycerol to glycerol-3-phosphate, a major phospholipid precursor. The P. falciparum glycerol kinase gene was disrupted using double crossover homologous DNA recombination to generate a knockout parasite line. Southern hybridization and mRNA analysis were used to verify gene disruption. Parasite growth rates were monitored by flow cytometry. Radiolabelling studies were used to assess incorporation of glycerol into parasite phospholipids. Disruption of the P. falciparum glycerol kinase gene produced viable parasites, but their growth was significantly reduced to 56.5±1.8% when compared to wild type parasites. 14C-glycerol incorporation into the major phospholipids of the parasite membrane, phosphatidylcholine and phosphatidylethanolamine, was 48.4±10.8% and 53.1±5.7% relative to an equivalent number of wild type parasites. P. falciparum glycerol kinase is required for optimal intra-erythrocytic asexual parasite development. Exogenous glycerol may be used as an alternative carbon source for P. falciparum phospholipid biogenesis, despite the lack of glycerol kinase to generate glycerol-3-phosphate. These studies provide new insight into glycerolipid metabolism in P. falciparum. •The glycerol kinase gene in P. falciparum was disrupted.•Glycerol kinase knockout parasites grew slower compared to wild type parasites.•Glycerol incorporation into phospholipids of knockout parasites was compromised.•Glycerol metabolism is required for optimal P. falciparum blood stage development.