Fig. 4

Organization of muscle-specific proteins and of nuclei. Representative images of 10-day-old myotubes cultured on nanopattern surface (a) and adult human muscle tissue (b) immunolabeled for α-actinin (green) and STIM1 (red) (upper lines) and for RyR1 (green) and STIM1 (red) (lower lines). Scale bar: 5 μm. c–e Organization of α-actinin, STIM1, and RyR1 during maturation. Representative images of 4-, 10-, and 12-day-old myotubes immunolabeled for α-actinin (c) STIM1 (d), and RyR1 (e). At 4 days, α-actinin is already perpendicularly oriented, followed at 10 days by STIM1, and in some cells by RyR1 at 12 days. Scale bar: 5 μm. f Representative image of 12-day-old myotubes immunolabeled with STIM1 together with DAPI. White arrows point to peripheral nuclei. Scale bar: 20 μm