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. 2021 Nov 27;11(12):1781. doi: 10.3390/biom11121781

Figure 4.

Figure 4

Comparison between ICRAC and ISOC in HEK cells transfected with STIM1 + Orai1. Cells were transfected with Orai1 and STIM1 plasmids 24 h before electrophysiological recordings. (A) Representative ICRAC produced by STIM1+Orai1, inward rectifier current with almost no inward potential. In more than 60% of cells displaying ICRAC. (B) Representative ISOC produced by mixing STIM1+Orai1 and endogenous TRPC channels (linear current with inward potential close to 0 mV). In almost 40% of cells displaying ISOC. Patch-clamp recordings were performed in whole-cell mode using electrodes of resistance between 2.5–3 MΩ. The pipette solution contained (in mM) 130 caesium methansulfonate, 8 MgCl2, 10 HEPES, 10 BAPTA, and 0.001 thapsigargin, pH 7.2 (CsOH). Extracellular solution contained (in mM): 135 NaCl, 10 CsCl, 4.4 MgCl2, 2.8 KCl, 10 Hepes, 0.5 EDTA, 0.5 EGTA, 10 glucose, and 11 CaCl2, pH 7.4 (NaOH). After measuring the maximal current amplitude, 10 μM Gd3+ was added at the end of the recording to block the current and estimate the leak. Currents were recorded during a 1 s ramp of potentials ranging from −130 mV to +85 mV applied with low-pass filtering at 1 kHz.