N-truncated Orai3 mutants with potentiated currents exhibit coupling similar to STIM1. a, time course of constitutive whole cell inward currents at −74 mV of HEK 293 cells coexpressing CFP-STIM1 233–474 with YFP-Orai3 ΔN1–53 in comparison with wild-type YFP-Orai3 (t = 0 s, p < 0.05). b, current/voltage relationships corresponding to a. c, mean fast inactivation for 100 ms upon voltage steps from a holding potential of 0 to −90 mV of normalized current traces of CFP-STIM1 233–474-mediated Orai3 ΔN1–53 currents compared with Orai3 currents (t = 0 s, p < 0.05). d, localization and overlay of CFP-STIM1 233–474 and YFP-Orai3 or YFP-Orai3 ΔN1–53. e, intensity plots representing the localization of STIM1 233–474 across the cell when coexpressed with Orai3 ΔN1–53 compared with wild-type Orai3. Bars in fluorescence images correspond to 5 μm. pF, picofarad; a.u., arbitrary units. Error bars represent S.E.