Fig 4. Na⁺ influx induction is required for cholesterol acquisition by the parasite in PA21A050 and KAE609 treated parasites.

Trophozoite stage P. falciparum parasites (30–34 h post-infection), adapted to grow in low [Na⁺] medium, were treated with the indicated concentration of the PA21A050 (A) or KAE609 (B). Cholesterol acquisition was assessed by sensitivity to saponin-mediated loss of aldolase, which was absent in parasites grown in low [Na⁺] medium but apparent in parasites grown in normal medium. (C) Saponin sensitivity was not induced by the compounds in parasites at the ring stage where the erythrocyte cytosol does not yet contain a high [Na⁺] and the parasites are not exposed to the high [Na⁺] of the medium. Western blots were probed with antibodies to aldolase and Exp2. All western blot images are representative of multiple biological replicates.