Effects of N-terminal region truncations in CRACM1 and CRACM3. Average CRAC current densities at −80 mV induced by 20 µM IP3 in stable STIM1-expressing HEK293 cells transiently overexpressing truncation mutants. (A) CRACM1-wt (black; n = 45), CRACM1-ΔN35 (green; n = 6), CRACM1-ΔN49 (orange; n = 5), CRACM1-ΔN66 (red; n = 5), and CRACM1-ΔN87 (blue; n = 6). (B) Magnified plot of the initial 120-s data from C. (C) CRACM3-wt (black; n = 9), CRACM3-ΔN41 (red; n = 7), and CRACM3-ΔN62 (blue; n = 5). Bars indicate external application of 50 µM 2-APB. (D–F) Average I-V relationships of CRAC currents extracted from representative HEK293 cells shown in A–C obtained at 120 s (D and E) and 180 s (F). Data represent leak-subtracted current densities (pA/pF) evoked by 50-ms voltage ramps from −150 to +150 mV. Error bars indicate SEM.
