Figure 2: Biochemical characterization of plasmodial lactate transporter candidates in yeast.
From: Identity of a Plasmodium lactate/H+ symporter structurally unrelated to human transporters
(a) L-Lactate uptake of jen1Δ ady2Δ yeast19 expressing yeast Jen1 (green) or no transporter (blue). (b) L-Lactate uptake after expression of plasmodial PfFNT (orange), PfB0465c (purple) or PFI1295c (red). The bar graph indicates uptake rates via untreated PfFNT and after chemical blockage by DEPC. (c) Concentration dependency of PfFNT L-lactate transport (orange squares: external pH 6.8; open symbols: pH 4.8) versus nonexpressing controls (blue). (d) pH dependency of L-lactate transport via PfFNT (orange squares; nonexpressing controls: blue). The inset shows correlation of pH and lactate transport after correction for the pH-dependent lactate/lactic acid ratio. Open circles depict transport reduction by proton gradient decouplers (2,4-dinitrophenol, carbonylcyanide-3-chlorophenylhydrazone). (e) Alkalization of the external buffer due to lactate/proton symport in PfFNT-expressing yeast at 10 mM (circles), 20 mM (diamonds) and 40 mM (triangles) inward lactate gradients. The inset depicts the initial, concentration-dependent proton uptake kinetics. (f) PfFNT monocarboxylate selectivity (orange) versus nonexpressing controls (blue) measured in jen1Δ ady2Δ yeast19 using various 14C-labelled substrates. Throughout, data were normalized to 1 mg of dry yeast; error bars denote s.e.m. from 3 to 6 measurements.
