Stromal Interaction Molecule 2 (STIM2)

Stromal Interaction Molecule 2 is a member of the stromal interaction molecule (STIM) family and likely arose, along with related family member STIM1, from a common ancestral gene. The encoded protein functions to regulate calcium concentrations in the cytosol and endoplasmic reticulum, and is involved in the activation of plasma membrane Orai Ca(2+) entry channels. This gene initiates translation from a non-AUG (UUG) start site. A signal peptide is cleaved from the resulting protein. Multiple transcript variants result from alternative splicing.Flow cytometry and biotinylation studies showed that STIM2 was expressed intracellularly only, in contrast with the endoplasmic reticulum and plasma membrane expression of STIM1. Confocal microscopy demonstrated coexpression of STIM1 and STIM2 in puncta upon store depletion.