Fig. 1.

Transporter function and protein expression of OATP1A2 and its variants. a–c Transport of 300 nM [³H] estrone sulfate (E3S), 3 μM [¹⁴C] imatinib, and 5 μM [³H] methotrexate (MTX) in HEK-293 cells transfected with wild type and mutagenized variants of OATP1A2, relative to mock-transfected control (MOCK). Basal rates of substrate uptake by wild-type OATP1A2 were 12.5 pmol/(mg min) for E3S, 57.5 pmol/(mg min) for MTX, and 53.8 pmol/(mg min) for imatinib. d Western blot analysis of cell surface expression of wild-type OATP1A2 and its variant transporters. Upper panel, cells were biotinylated and the labeled cell surface proteins were precipitated with streptavidin beads and separated by gel electrophoresis, followed by Western blotting with anti-OATP1A2 antibody. Bottom panel, densitometric analysis of transporter plasma expression. NC, negative control. Values are mean ± SE (n = 3). Different from wild type, *p < 0.05; **p < 0.01