In 2011 our laboratory identified a longer isoform of STIM1, named STIM1 Long (STIM1L), highly expressed in skeletal muscle. However, the physiological roles of the two isoforms are still to be elucidated as well as the function of SOCE to maintain prolonged excitation-contraction coupling. Moreover, it is still debated in the muscle field whether SOCE is only necessary during early myogenesis or also in adult muscle to refill the SR upon a prolonged stimulation and thus limit muscle fatigue. The aim of the present study was to investigate whether SOCE plays a role to sustain Ca2+ transients evoked by electrical stimulations, and whether the role of SOCE changes during myotube maturation, with a particular focus on the physiological function played by STIM1 and STIM1L.