Fig. 2. Store-operated entry of Ca²⁺ in control and TRPC1-knockdown myoblasts. Influence of GsMTx4. (A) Store-operated entry of Ca²⁺ was triggered by depletion of the stores with 1 µM thapsigargin (TG) in the absence of external Ca²⁺ (0.1 mM EGTA). 1.8 mM Ca²⁺ was then re-added to the extracellular medium as indicated, inducing a second peak of [Ca²⁺]_i. Comparison of the response in C2C12 myoblasts (1 day post differentiation) transfected with control shRNA or TRPC1 shRNA (efficiency of transfection checked by EGFP fluorescence emission). Traces are representative of up to 11 experiments. (B-D) Results of similar experiments obtained in myoblasts treated with TRPC1 shRNA or TRPC1 siRNA and myoblasts treated with 5 µM GsMTx4. SOCE, store-operated Ca²⁺ entry. Results are mean ± s.e.m. Student's t-test: *P<0.05 vs control; n=6-12.