FIGURE 4.

preSTIM2 regulates Ca²⁺ dynamics in HEK293T cells. A–I, [Ca²⁺]_i measurements in HEK293T cells transiently transfected (24 h) with empty vector (black), STIM2^FLAG (red), STIM2^L89H (green), or SPF⁹¹ (blue) are shown. A and B, basal Ca²⁺ entry measurements in 2 mm (A) or 20 mm (B) Ca²⁺ are shown. Traces are the mean for n = 3 (A) or n = 4 (B) individual wells per construct. C is a summary of peak basal Ca²⁺ entry from A and B; data are the mean ± S.D. for n = 3 (A) and n = 4 (B) individual wells. Data represent six individual experiments. D, shown are resting [Ca²⁺]_i measurements in 0 or 2 mm [Ca²⁺]_ext. Data are the mean ± S.E. for n = 4 individual wells per construct and are representative of 2 individual experiments. E, Ca²⁺ influx measurements in 2 mm [Ca²⁺]_ext are shown. Cch, carbachol; Tg, thapsigargin. F, a summary of peak and plateau [Ca²⁺]_i from E; data are the mean ± S.E. for n = 4 (vector, STIM2^FLAG, STIM2^L89H) or n = 3 (SPF⁹¹) individual wells. Data represent three individual experiments. G, ER store release measurements in 0 [Ca²⁺]_ext is shown. H, SOCe measurements in store-depleted cells are shown. I, shown is a summary of peak ER store release and SOCe from G and H; data are the mean ± S.D. for n = 4 (vector and SPF⁹¹) and n = 2 (STIM2^FLAG and STIM2^L89H) individual wells. Data represent four individual experiments. ns, not significant; *, p < 0.05; **, p < 0.01.