Figure 2. MCU activity is required for cytosolic Ca²⁺ clearance.

A) PDGF-evoked Ca²⁺ transients in WT and MCU^−/− VSMCs and WT VSMCs pretreated with 100 nM RU360 for 16 h. (Arrow: addition of 10 nM PDGF). B) Area under the curve (AUC) for A. n = 5 independent experiments. C) Peak amplitude for A). n = 5 independent experiments with 8, 7 and 6 biological replicates for WT, MCU^−/− and RU360 treatment). D) Mitochondrial Ca²⁺ uptake by Ca²⁺ Green 5N assay in WT and MCU^−/− skin fibroblasts. Treatment with digitonin (Dig, 0.005%), Ca²⁺ (1 μM) and FCCP (25 μM). Representative of n = 2 independent experiments. E) Thapsigargin-induced Ca²⁺ transients in WT and MCU^−/− VSMCs and WT VSMCs pretreated with 100 nM RU360. (Arrow: addition of 1 μM thapsigargin, Thap). F) Area under the curve in E. n = 5 independent experiment with 6, 7 and 5 replicates for WT, MCU^−/− and RU360 treatment respectively. G) Quantification of baseline Fura signal in untreated WT VSMCs, WT VSMCs transfected with MCU siRNA, and MCU^−/− VSMCs. n = 5 independent experiments with 12, 9, and 8 replicates for WT, MCU^−/− and for WT VSMCs transfected with MCU siRNA respectively. * p < 0.05, ** p < 0.01compared to WT untreated by Kruskal-Willis test (B), 1-way ANOVA (C, F, G). H) Cytosolic Ca²⁺ levels by Fura recording in WT and MCU^−/− VSMC after PDGF treatment (arrows) recorded over 3000 s. (n=4 independent experiments).