FIGURE 4.

Potential redundancy of STIM1 and STIM2. A and B, cytoplasmic Ca²⁺ was assessed with Fura-2, 48 h after myoblast transfection. Intracellular Ca²⁺ stores were depleted with 1 μm Tg in a medium containing 250 nm Ca²⁺ (not shown), and 2 mm Ca²⁺ was subsequently added to reveal SOCE (same protocol as in Fig. 1C). In each condition, siRNA and a plasmid were co-transfected. When no specific siRNA and/or plasmid were used, siAllstar siRNA and/or EGFPN3 plasmid were/was added as control. C, transfected myoblasts were kept for 2 days in proliferation medium, and then transferred for 2 more days in differentiation medium. MEF2 and myogenin were stained in red and green, respectively. Nuclei were stained with DAPI. The scale bar represents 50 μm. D, mean myogenin- and MEF2-positive nuclei obtained out of three independent experiments.