Even though the protein has been identified earlier, its function was unknown until recently. In 2005, it was discovered that STIM1 functions as a calcium sensor in the endoplasmic reticulum.[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. STIM1 activates the "store-operated" ORAI1 calcium ion channels in the plasma membrane, via intracellular STIM1 movement, clustering under plasma membrane and protein interaction with ORAI isoforms.[11][12][13] STIM1-mediated calcium entry is required for thrombin-induced disassembly of VE-cadherinadherens 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.[15]
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Parker NJ, Begley CG, Smith PJ, Fox RM (Oct 1996). "Molecular cloning of a novel human gene (D11S4896E) at chromosomal region 11p15.5". Genomics. 37 (2): 253–6. doi:10.1006/geno.1996.0553. PMID8921403.
^Williams RT, Senior PV, Van Stekelenburg L, Layton JE, Smith PJ, Dziadek MA (Apr 2002). "Stromal interaction molecule 1 (STIM1), a transmembrane protein with growth suppressor activity, contains an extracellular SAM domain modified by N-linked glycosylation". Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology. 1596 (1): 131–7. doi:10.1016/S0167-4838(02)00211-X. PMID11983428.