Figure 3. CAR promotes Ca²⁺ permeation through the Orai2 channel.

(A) Whole-cell patch-clamp experiments show time course of currents mediated mCherry-tagged STIM1 coexpressed with wild-type or mutant eYFP-tagged Orai2 as indicated in HEK cells exposed to 20 mM EGTA in the patch pipette and then stepwise increase in Ca²⁺ concentration with Na⁺-containing solution (n = 8 – 9). Wild-type Orai2 and mutant Orai2 were analyzed by t-test for statistical significance for their maximum currents at various extracellular Ca²⁺ concentrations. Their currents are significantly different (p < 0.05) in a 1, 10, and 110 mM Ca²⁺ solution. (B, C) Representative current-voltage relationship of Orai2- or Orai2-E84Q-mediated SOCE currents for experiments shown in (A).