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. Author manuscript; available in PMC: 2013 May 25.
Published in final edited form as: Circ Res. 2012 Apr 24;110(11):1435–1444. doi: 10.1161/CIRCRESAHA.112.269506

Figure 4. Orai1 regulates TRPC1/4 channel amplitude and calcium selectivity.

Figure 4

[A] Control pulmonary artery endothelial cells were treated with doxycycline and the TRPC1/4 current density tested. Thapsigargin (1 μM) was applied in the patch pipette, and induced a calcium selective current with a typical peak current (≈ −45 pA at −100 mV) and reversal potential (+40 mV). [B] Cells were engineered using a Tet-On system for doxycyline induction of Orai1 shRNA. Orai1 downregulation decreased the peak current and left shifted the reversal potential, effects that were reversed following doxycycline withdrawal and the re-emergence of Orai1. [C] Time-dependent inactivation of the thapsigargin-induced current was measured for 60 seconds, from the standard ramp protocol11-12, 14-15. Whereas the current density decreased in control cells, this effect was reduced in doxycycline-treated cells lacking Orai1. Following doxycycline withdrawal, the time dependent current inactivation was recovered.