Deletion of STIM proteins sensitizes cell migration to IP3R inhibition. (A) Indicated compounds were added to either WT or dKO cells, and the number of migrating cells from each group was normalized to that of control (DMSO-treated cells). The following inhibitor concentrations were used: 2-APB at 50 μM (WT, n = 5; dKO, n = 11), nifedipine at 50 μM (WT, n = 5; dKO, n = 10), SKF96365 at 10 μM (WT, n = 5; dKO, n = 10), Xes-C at 5 μM (WT, n = 10; dKO, n = 5), NS8593 at 5 μM (WT, n = 5; dKO, n = 5), and ML-9 at 10 μM (WT, n = 5; dKO, n = 5). Bars show the mean ± SEM. (B) Migration was analyzed as in A using the indicated concentration of Xes-C (WT, n = 11–16; dKO, n = 5–11). (C) (C-left) Representative images (left) of anti-paxillin (red) and phalloidin (F-actin, green) fluorescence in dKO cells treated with Xes-C or DMSO (control). (C-right) Mean ± SEM of FAs per cell in WT (control, n = 9; Xes-C, n = 15) or dKO (control, n = 8; Xes-C, n = 13) cells. Scale bar = 10 μm. (D) Migration analysis (bars show the mean ± SEM) of WT (n = 14), S1KO (n = 11), S2KO (n = 10), or dKO cells (n = 15) treated with the indicated ITPR siRNAs. (E) WB analysis using antibodies for IP3R1, IP3R2, IP3R3, or tubulin of lysates prepared from WT cells treated with siRNAs against IP3R1, IP3R2, or IP3R3, as indicated. Statistics: two-tailed t test; *P < 0.05, **P < 0.01, ***P < 0.001. Source data are available for this figure: SourceData F3.