Figure 5

Store-operated Ca²⁺ entry (SOCE) induced by application of thapsigargin in Ca²⁺-free buffer and subsequent readdition of extracellular Ca²⁺ in TRPC1/6− (TRPC1/6^−/−) (a,c), STIM1/2− (STIM1/2^ΔpmLF) (b,c) and STIM1/2−TRPC1/6− (TRPC1/6^−/− STIM1/2^ΔpmLF) deficient primary murine pulmonary fibroblasts (pmLF) (a,c). (a,b) Wild-type fibroblasts infected with recombinant lentiviruses expressing Cre recombinase (Wt Cre) served as controls. Internal Ca²⁺ stores of fura-2-loaded pmLF were emptied by application of thapsigargin followed by recalcification. Intracellular Ca²⁺ levels ([Ca²⁺]_i) were quantified by analysis of fluorescence ratios at excitation wavelengths of 340 and 380 nm (ratio 340/380 nm) and normalized to initial values. Lines represent calculated means and light grey areas indicate standard error of the mean (SEM) of more than three independent experiments of at least three mice. Calculation of the areas under the curves (AUC) in Fig. 6a,b was used to quantify SOCE (c). One single dot represents the mean of at least 20 cells from one cell isolation. Asterisks mark from left to right significant differences (*P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001) between ratios of deficient cells compared to control cells.