Figure 6.

Inhibition of PfCRT-mediated fluxes and cRNA dependence. A and B, effect of verapamil (100 μm) on the uptake of ferrous (A) or ferric (B) iron from an external concentration of 50 μm by water-injected oocytes and PfCRT^HB3- and PfCRT^Dd2-expressing oocytes. Oocytes were analyzed after 60 min of incubation in the respective uptake buffer. The means ± S.E. of N_BR = 7–10 independent biological determinations are shown. Statistical significance was evaluated using the two-tailed t test, and the p values are indicated on the graph. C, effect of increasing concentrations of ferrous iron (gray circle) or ferric iron (black circle) on PfCRT^Dd2-mediated chloroquine uptake. Data were normalized to the amount of PfCRT-mediated chloroquine uptake in the absence of iron. The means ± S.E. of N_BR = 3–5 independent biological determinations are shown. D, effect of increasing amounts of cRNA injected on the amount of PfCRT-mediated chloroquine and ferrous iron uptake. Chloroquine and ferrous iron uptake (at the 60-min time point) were measured in parallel assays. The means ± S.E. (error bars) of N_BR = 3 independent biological determinations are shown.