FIGURE 5.
Substrate-evoked anion conductance by WT and S364A, S364T, and S364C mutants. A–D, steady-state currents evoked by 5 mm l-[3H]glutamate (circles), l-[3H]aspartate (squares), and d-[3H]aspartate (triangles) in X. laevis oocytes expressing SLC1A2-WT or the indicated Ser-364 mutants were measured using the voltage clamp protocol described under “Experimental Procedures.” Currents were measured in oocyte buffer, where 20 mm NaCl was replaced by an equimolar concentration of NaSCN. For each substrate, currents were corrected with respect to the background current observed without substrate (Inorm), normalized to the currents obtained with 5 mm l-glutamate in SCN−-free solution (Inorm), and plotted against the holding potential (Vm). The data are means ± S.D. of 3–5 oocytes. Currents at −100 mV induced by 5 mm l-glutamate in SCN−-containing buffer ranged from −100 to −190 nA for WT, from −169 to −625 nA for S364T, from −43 to −188 nA for S364A, and from −114 to −159 nA for S364C.