TM23 of Orai3 is responsible for 2-APB sensitization/activation.
Averaged [Ca2+]i traces (±S.E.) without
Ca2+ store depletion in cells transfected with N-Orai3-Orai1
(A), Orai1-TM-Orai3 (B), Orai1-C-Orai3 (C),
Orai1-loop1-Orai3 (D), Orai1-TM12-Orai3 (E),
Orai1-TM23-Orai3 (F), Orai1-TM34-Orai3 (G), and
Orai1-loop2-Orai3 (H). Solution exchanges are indicated.