Figure 4
Concentration-dependent effects of protons on Orai1/STIM1 WT channel and mutants.
(A1–A5), Typical recordings of each mutant at pHo 5.5, 7.4 and 9.5. (B1–B5) Concentration-dependent effects of various pHs on current amplitude of each mutant in comparison with WT. The changes of current amplitude were obtained by normalizing current amplitude at each pHo to the value at pHo 7.4. The pKa of each mutant was obtained by best fit of the dose-response curves. (C1–C5) Dose-response curves constructed using the normalized current amplitude to the maximal current amplitude. The best fit of the dose-response curves generated pKa of 8.43 ± 0.1 (n = 8) for WT, 8.17 ± 0.13 (n = 9, p > 0.05) for E106D, 8.37 ± 0.09 (p > 0.05, n = 8) for D110N, 8.10 ± 0.18 (n = 12, p > 0.05) for D112/114N, 8.74 ± 0.08 (n = 4 ~ 6, P > 0.05) for E190Q and 6.73 ± 0.08 (n = 8, p < 0.05) for E190D.
