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. 2014 Mar;143(3):325–343. doi: 10.1085/jgp.201311108

Figure 6.

Figure 6.

Blockade of STIM1-activated or 2-APB–activated Orai3 current by La3+. (A and B) Currents in 20 mM Ca2+o through STIM1-gated channels (A) or 2-APB–gated Orai3 channels (B) were blocked with increasing concentrations of La3+. 2-APB–gated currents are depicted at −100 and +100 mV. (C) Dose–response of La3+ blockade of STIM1-activated or 2-APB–activated WT and E85A/D87A/E89A mutant Orai3 currents. The dashed lines are least-squares fit to the Hill equation block = 1/[1 + Ki/(La)n]. Each point is the mean ± SEM of four to five cells. Fit parameters are: WT Orai3 + STIM1: Ki = 470 nM, n = 1.1; WT Orai3 + 2-APB: Ki = 6 µM, n = 0.7 (inward current); triple mutant + STIM1: Ki = 10 µM, n = 0.97; triple mutant+2-APB: Ki = 189 µM, n = 0.96.