STIM2 is an endoplasmic reticulum (ER)-resident calcium sensor that regulates store-operated calcium entry (SOCE), a critical mechanism for maintaining intracellular calcium homeostasis 1. Unlike STIM1, STIM2 functions as a highly sensitive detector of mild ER calcium variations, translocating to ER-plasma membrane junctions to activate ORAI calcium channels and sustain basal cytosolic and ER calcium concentrations 2. STIM2 plays complex roles beyond SOCE, regulating intracellular signaling and gene expression across multiple tissues, including the immune and nervous systems 23. Dysfunction of STIM2 is implicated in several pathological conditions. In Sjögren's disease, loss of STIM2 in regulatory T cells impairs their function, promoting pathogenic TH1 cell differentiation and IFN-γ production that drives glandular inflammation and destruction 4. In colorectal cancer, STIM2 downregulation promotes metabolic reprogramming and ER stress responses through the ATF4 pathway, enhancing tumor metastasis and correlating with poor prognosis 5. STIM2 loss also contributes to calcium store depletion and increased cancer cell survival 6. These findings position STIM2 as essential for normal physiology and a key player in autoimmune and neoplastic disease pathogenesis 2.