Figure 7.

Uptake of pyridoxine and thiamine by various mutants derived from mSlc19a3-hTMD3+6 in transiently transfected HEK293 cells.A, schematic representation of various mutants derived from mSlc19a3-hTMD3+6, the mSlc19a3 mutant that has hTMDs 3 and 6 together in place of their respective mTMD counterparts. All the transporters and mutants 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. D, the uptake ratio was calculated by dividing pyridoxine uptake by thiamine uptake, using uptake values in percent of control. The uptake of pyridoxine and thiamine by hSLC19A3 as a control was 46.3 and 62.6 fmol/min/mg protein, respectively. Data are presented as means ± SD (n = 3). ∗p < 0.05 compared with control. EGFP, enhanced GFP; HEK293, human embryonic kidney 293 cell line; hSLC19A3, human solute carrier SLC19A3; hTMD, TMD in hSLC19A3; mSlc19a3, mouse Slc19a3; mTMD, TMD in mSlc19a3; ND, not detected; TMD, transmembrane domain.