[Isoform 1]: Ca(2+-binding protein that plays a key role in store-operated Ca(2+ entry (SOCE in T-cells by regulating CRAC channel activation. Acts as a cytoplasmic calcium-sensor that facilitates the clustering of ORAI1 and STIM1 at the junctional regions between the plasma membrane and the endoplasmic reticulum upon low Ca(2+ concentration. It thereby regulates CRAC channel activation, including translocation and clustering of ORAI1 and STIM1. Upon increase of cytoplasmic Ca(2+ resulting from opening of CRAC channels, dissociates from ORAI1 and STIM1, thereby destabilizing the ORAI1-STIM1 complex.,CRACR2A,EFCAB4B,Signal Transduction,Neuroscience,Calcium Signaling,CRACR2A