[5][6][7] STIM1 has a single transmembrane domain, and is localized to the endoplasmic reticulum, and to a lesser extent to the plasma membrane.

[9][10] Upon activation of the IP3 receptor, the calcium concentration in the endoplasmic reticulum decreases, which is sensed by STIM1, via its EF hand domain.

[11][12][13] STIM1-mediated calcium entry is required for thrombin-induced disassembly of VE-cadherin adherens junctions.

[14] 2-Aminoethoxydiphenyl borate (2-APB) and 4-chloro-3-ethylphenol (4-CEP) cause STIM1 clustering in a cell and prevent STIM1 moving toward plasma membrane.

[6] STIM1 mutations are associated with Immunodeficiency 10, Tubular aggregate myopathy type 1 (TAM1), and Stormorken syndrome.