FIGURE 3.
The action of GMQ is determined by residues in the central cavity of the palm domain. A, structure and key residues in the palm domain. The palm domains of subunits A, B, and C are colored yellow, pink, and blue (left panel), respectively. Only two of the three subunits are shown for clarity (right panel). B, EC50 values and maximal currents of GMQ (means ± S.E., n = 4–10) for point mutations. The values of E423A, E423D, E423L, E423Q, E423R, and E79A were derived from previously published data (7), shown here as white bars for comparison. *, p < 0.05; **, p < 0.001 versus WT ASIC3 (dashed line). #, maximal currents of GMQ were not normalized to IpH5.0 because of the markedly reduced IpH5.0 resulting from the mutation-induced steady-state desensitization at the neutral pH. The WT EC50, taken from Fig. 2B, is regraphed again for comparison.