Figure 9.

Uptake of pyridoxine and thiamine by hSLC19A2-ma3-7AA in transiently transfected HEK293 cells.A, schematic representation of hSLC19A2-ma3-7AA, the hSLC19A2 mutant in which the seven amino acid residues corresponding to the hSLC19A3 residues required for the pyridoxine transport function (Fig. 7) are replaced with their mSlc19a3 counterparts. The residues are indicated by dots. hSLC19A2 and the mutant were tagged with EGFP at the N terminus. B, the specific uptake of [³H]pyridoxine (5 nM) was evaluated for 2 min at pH 5.5 and 37 °C. C, the specific uptake of [³H]thiamine (5 nM) was evaluated for 2 min at pH 7.4 and 37 °C. The uptake of pyridoxine and thiamine by hSLC19A2 as a control was 36.6 and 70.5 fmol/min/mg protein, respectively. Data are presented as means ± SD (n = 3). EGFP, enhanced GFP; HEK293, human embryonic kidney 293 cell line; hSLC19A2, human solute carrier SLC19A3; mSlc19a3, mouse Slc19a3; ND, not detected.