CRACR2A is a newly discovered Ca2+-binding protein that regulates store-operated Ca2+ entry (SOCE). CRACR2A enhances SOCE by promoting the binding of the endoplasmic reticulum Ca2+ sensor STIM to Orai, a Ca2+ channel located in the plasma membrane. As intracellular Ca2+ levels rise, CRACR2A binds Ca2+ and triggers SOCE inactivation by dissociating from the Orai–STIM complex.
