Figure 1.

Effect of MATE2-K nonsynonymous variants on (a) transport of four compounds by HEK-293 cells expressing MATE2-K reference and (b) protein levels of MATE2-K green fluorescent protein (GFP) chimeras. (a) Functional activities were measured 48 h after transfection of plasmids containing MATE2-K reference or its variants into HEK-293 cells. The cells were incubated with various substrates including tetraethyl ammonium (TEA) (5 µmol/l), metformin (10 µmol/l), amiloride (10 µmol/l), and trospium (10 µmol/l) for 5 min each, and the uptake of each drug was determined. The functional activity of each construct was compared with that of the empty vector (pcDNA5-FRT). The data shown represent mean values ± SE from triplicate wells in a representative experiment. *P < 0.05, +P < 0.01 vs. the reference. (b) MATE2-K protein levels were determined by immunoblotting with an antibody against GFP. Cells were harvested 48 h after transfection of HEK-293 cells with MATE2-K reference or its variants—pcDNA3.1 vectors tagged with GFP. Proteins were blotted with antibodies against GFP, β-actin, and neomycin phosphotransferase II. β-actin was used as an internal control and neomycin phosphotransferase II was used as a cis-transfection marker. Expression levels were compared with that of the reference.