Fig. 1

Deletion of STIM1 and STIM2 in Treg cells is fatal despite normal Treg numbers in secondary lymphoid organs. a Analysis of Stim1, Stim2, and Foxp3 gene expression in conventional and Treg cells isolated from male WT and Stim1^fl/flStim2^fl/fl Foxp3cre (Stim1/2^Foxp3) mice using qRT-PCR. Means ± SEM of four mice. b Analysis of Ca²⁺ influx in T conventional (Tcon) and Treg cells isolated from male WT and Stim1/2^Foxp3 mice loaded with Fura-2 and stimulated with thapsigargin (TG) in Ca²⁺ free Ringer solution followed by addition of 1 mM Ca²⁺ (left panel). Normalized store depletion (AUC_120s-400s) and SOCE (peak_600s) of T cells calculated as F340/380 emission ratios; means ± SEM of four mice (right panels). c Analysis of Foxp3⁺ Treg cells in secondary lymphoid organs and blood of male WT and Stim1/2^Foxp3 mice using flow cytometry; means of 7–21 mice. d Analysis of naïve and effector Treg cells in spleen and mLNs of male WT and Stim1/2^Foxp3 mice using flow cytometry. Bar graphs represent the means ± SEM of three mice. e Representative pictures of 42 days old male WT and Stim1/2^Foxp3 mice. f Weight of 35–45 days old male WT and Stim1/2^Foxp3 mice; means of eight mice. g Cumulative survival of male WT and Stim1/2^Foxp3 mice; 9–13 mice per cohort. Mean survival time (MST) of Stim1/2^Foxp3 mice 37 days and of WT mice > 100 days. Each dot in c and f represents one mouse. Statistical analysis in a–d, f by unpaired Student’s t-test; in g using the Mantel–Cox test. *p < 0.05; **p < 0.01; ***p < 0.001. AUC, area under the curve