Fig. 5.

ORAI1_P245L suppresses slow CDI of I_CRAC. (A) Time course of I_CRAC in HEK293 cells transiently cotransfected with STIM1_WT plus WT ORAI1 (S_WT/O_WT; black, n = 5) or STIM1_WT plus ORAI1_P245L (S_WT/O_P245L; dark cyan, n = 8) induced by 10 mM EGTA and suppressed by 20 µM La³⁺. (B) Normalized whole-cell currents measured at −80 mV of cells transfected with STIM1_WT plus ORAI1_WT (black, n = 10) or STIM1_WT plus ORAI1_P245L (dark cyan, n = 14) in the presence of 2 mM EGTA in the pipette solution. (C) Normalized whole-cell currents measured at −80 mV of cells transfected with STIM1_WT plus ORAI1_WT (black, n = 8) or STIM1_WT plus ORAI1_P245L (dark cyan, n = 9) in the presence of 10 mM BAPTA in the pipette solution. (D) Store-operated Ca²⁺ entry is enhanced in a patient with congenital miosis and TAM. Store-operated Ca²⁺ entry in lymphocytes obtained from an unaffected individual (control; black, n = 146 cells) or a patient (patient; red, n = 302 cells) using single-cell Ca²⁺ imaging. Cells were loaded with 2 µM Fura-2/AM and placed in an ECS containing 0 mM Ca²⁺. Stores were depleted with 2 µM TG, and Ca²⁺ influx was stimulated by the addition of 2 mM Ca²⁺ in the ECS.