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. Author manuscript; available in PMC: 2017 Oct 31.
Published in final edited form as: Curr Biol. 2007 Apr 19;17(9):794–800. doi: 10.1016/j.cub.2007.03.065

Figure 4.

Figure 4

CRACM Homologs Have Distinct Ion Selectivity and Pharmacology

(A) Average normalized CRAC currents at −80 mV induced by IP3 (20 μM) in stable STIM1-expressing HEK293 cells transiently overexpressing CRACM1 (black, n = 12, data taken from [5]) CRACM2 (blue, n = 8), or CRACM3 (red, n = 10). Currents of individual cells were normalized to the current before solution change at 120 s (I/I120s). [Ca2+]i was clamped to near zero with 20 mM BAPTA. The bar indicates application of nominally Ca2+-free external solution. Error bars indicate SEM.

(B) Average I/V relationships of CRACM2 currents extracted from representative cells shown in (A) obtained at 120 s and 180 s (n = 7). Data represent leak-subtracted current densities (pA/pF) evoked by 50 ms voltage ramps from −150 to +150 mV.

(C) Average I/V relationships of CRACM3 currents extracted from representative cells shown in (A) at 120 s and 180 s into the experiment (n = 9).

(D) Average normalized CRAC currents (I/I120s) at −80 mV induced by IP3 (20 μM) in stable STIM1-expressing HEK293 cells transiently overexpressing CRACM1 (black, n = 5), CRACM2 (blue, n = 7), or CRACM3 (red, n = 10). The bar indicates application of an external solution containing 10 mM Ba2+ in the presence of Na+. Error bars indicate SEM.

(E) Average normalized CRAC currents (I/I120s) at −80 mV induced by IP3 (20 μM) in stable STIM1-expressing HEK293 cells transiently overexpressing CRACM1 (black, n = 9; data taken from [5]), CRACM2 (blue, n = 6), or CRACM3 (red, n = 6). The bar indicates application of an external solution containing 10 mM Ba2+ with external Na+ being replaced by TEA+. Error bars indicate SEM.

(F) Average normalized CRAC currents (I/I120s) at −80 mV induced by IP3 (20 μM) in stable STIM1-expressing HEK293 cells transiently overexpressing CRACM1 (black, n = 3, data taken from [5]), CRACM2 (blue, n = 5), or CRACM3 (red, n = 10). The bar indicates application of divalent-free external solution. Error bars indicate SEM.

(G) Average normalized CRAC currents (I/I120s) at −80 mV induced by IP3 (20 μM) in stable STIM1-expressing HEK293 cells transiently over-expressing CRACM1 (black, n = 8), CRACM2 (blue, n = 4), or CRACM3 (n = 9). The bar indicates application of external solution containing 50 μM 2-APB. Error bars indicate SEM.