Fig. 2.

Store-operated Ca²⁺ entry and I_CRAC is enhanced in patients with Stormorken syndrome. (A) Store-operated Ca²⁺ entry in lymphocytes obtained from an unaffected individual (control; black, n = 127 cells) or a patient with Stormorken syndrome (patient; red, n = 288 cells) using single-cell Ca²⁺ imaging. Cells were loaded with 2 µM Fura-2/AM and placed in an extracellular solution (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. (B) Time course of I_CRAC in lymphocytes from a control subject (black, n = 11 cells) and patient with Stormorken syndrome (red, n = 16 cells) induced by 10 mM EGTA in the recording pipette and blocked by 20 µM La³⁺ in the ECS. (C) Current–voltage curves taken at 50 s or 400 s after “break-in” in control cells and cells from a patient with Stormorken syndrome. (D) Quantification of inactivation as determined by the ratio (R195ms) of the peak current at the beginning of a hyperpolarizing pulse (I₀) to tail current at the end of the pulse (I₁₉₅) in cells from a healthy individual (black, n = 11 cells) and a patient with Stormorken syndrome (red, n = 16 cells). Representative step currents generated from hyperpolarizing pulses at the indicated test potentials at 400 s following break-in in a control subject and a patient (Stormorken) cell. Duration of the pulse was 200 ms.