EF-hand calcium-binding domain-containing protein 4B (CRACR2A)

Ca(2+)-binding protein that plays an integral role in store- operated Ca(2+) entry (SOCE) in T-cells by controlling CRAC channel activation. Acts as a cytoplasmic calcium-sensor that eases the clustering of ORAI1 and STIM1 at the junctional areas between the plasma membrane and the endoplasmic reticulum upon low Ca(2+) concentration.

It consequently regulates CRAC channel activation, including translocation and clustering of ORAI1 and STIM1. Upon increase of cytoplasmic Ca(2+) leading to opening of CRAC channels, dissociates from ORAI1 and STIM1, thereby destabilizing the ORAI1-STIM1 complex.