Figure 2.

Size of the ER/SR Ca²⁺ stores in control and DM1 myotubes at progressive stages of differentiation. Depletion of ER/SR Ca²⁺ stores in myotubes at 10 (T10, A) and 15 days (T15, B) of differentiation was induced by the SERCA inhibitor tert-butylhydroquinone (tBHQ) at indicated time points. [Ca²⁺] was assessed by measuring Fura-2 ratios at 340 nm and 380 nm excitation as described in the Methods section. Representative traces of n > 8 experiments are shown. (C) Quantification of the Ca²⁺ peaks induced by tBHQ in control and DM1 myotubes. (D) Quantification of the area under the curves (AUC). Data represent mean ± SD. *** p < 0.001 as compared to controls by Students’ t test.