pH-dependent uncoupled cation fluxes through R477H. (A–D) Current-voltage relationships for WT EAAT1 and R477H elicited by submaximal l-glutamate in 96 mM Cl⁻-based buffer (A and C) and 96 mM gluconate-based buffer (B and D) at pH 5.5 (black circles), 6.5 (orange triangles), 7.5 (blue triangles), and 8.5 (red squares). (E) Current at 60 mV for WT EAAT1 and R477H at pH 5.5 (black) and 8.5 (red) in 96 mM gluconate-based buffer (open bars) and 96 mM Cl⁻-based buffer (closed bars). Data shown represent the mean ± SEM (n ≥ 4). Where error bars cannot be seen, they lie within the symbol. Note the scale difference in the y axes.