CRAC channel blocker Synta66 inhibits x-ray–stimulated increase in Jurkat cell diameter. (A) Jurkat cells exhibit a dose-dependent increase in diameter 24 h after irradiation, which can be abolished by 10 µM CRAC channel inhibitor Synta66. Representative images (left, confocal image of fluorescent stained PM [red]; right, overlay of fluorescent and bright field image) of individual Jurkat cells. Images were taken 24 h after start of experiment with an untreated control cell (ctrl), a cell exposed to 5 Gy x rays alone (5 Gy) or with 10 µM Synta66 (5 Gy + Synta66). (B) Mean diameters ± SD of >300 cells per treatment (N ≥ 5 independent experiments) 24 h after exposure to 0–5 Gy x rays in the absence (black square) or presence (open square) of 10 µM Synta66. Statistical differences between treatments ± Synta66 were analyzed by unpaired Student’s t test, and respective P values are given in the figure. All scale bars, 10 μm.