Figure 2.

A scheme illustrating the standard mechanism and molecular components of SOCE in skeletal muscle. At the triad junction, the voltage-sensitive Ca_V1.1 and RyR1 interacts physically. STIM1 and STIM1L are in close proximity or in complex with Orai1 even before store depletion. This pre-localization of STIM1/1L with Orai1 likely facilitates the fast-activation kinetics of SOCE. A similar mechanism involving TRPC channels and STIM1 has also been implicated in Ca²⁺ influx mechanisms. STIM1 interacts with STIM2, which regulates SERCA1-mediated filling of the SR Ca²⁺ store and sustains resting [Ca²⁺] in the cytosol.