STIM1 and osteosarcoma: Consequently, we overexpressed different fluorescent protein-tagged STIM1 variants, including SIMT1-wild-type (WT)-enhanced green fluorescent protein (EGFP), STIM1-D76A-EGFP (constitutively active), and STIM1-D76A-ΔERM-enhanced yellow fluorescent protein (EYFP) (dominant negative) in U2OS osteosarcoma cell lines to further investigate whether cancer cell migration can be affected by manipulating SOCE levels through STIM1 activity.