Fig. 1.
Expression and function of G192 and G189 proton-coupled folate transporter (PCFT) mutants. A: [3H]methotrexate ([3H]MTX) influx was assessed at a concentration of 0.5 μM and at pH 5.5 over 1 min. Influx is indicated as percentage of wild-type (WT)-PCFT activity. Data are the means ± SE from 3 separate experiments. B: expression of the G192V, G192C, G192 C, G189A, and G189V mutants and WT-PCFT in the crude membrane preparation and on the plasma membrane as assessed by surface biotinylation. Expression of actin serves as an internal control for the crude membrane samples. Image represents 2 independent blots.