Effects of external divalent or trivalent cations on both FXYD2 WT and G41R-induced currents. The I-V relationships of the WT and mutant currents: A: 10 mM Ba2+ (WT, n = 6; G41R, n = 8); B: 10 mM Ca2+ (WT, n = 6; G41R, n = 6); C: 10 mM Mg2+ (WT, n = 10; G41R, n = 12); or D: 10 mM La3+ (WT, n = 8; G41R, n = 8). Divalent extracellular and trivalent cations had similar inhibitory effects on both WT and G41R currents. Bars show means ± SE. In all cases, filled and unfilled triangles represent FXYD2WT before and after cation treatment, respectively; filled and unfilled circles represent FXYD2G41R before and after cation treatment.