Figure 1. An overview of SOCE choreography.
In resting cells with high ER [Ca2+], STIM1 and Orai1 diffuse in the ER and PM, respectively (top). Upon ER Ca2+ depletion, STIM1 becomes activated and accumulates at ER-plasma membrane junctions to bind and trap Orai1 (middle). STIM1 binding opens Orai1 channels and allows extracellular Ca2+ to flow into the cell (bottom).