Calcium Imaging of SOCE and ER Store Depletion

Cells were seeded into black-walled 96-well plates (CellBIND; Corning, Corning, NY, USA, CLS3340) at a density of 20 × 10³ cells per well, and Ca²⁺ imaging was performed 24 h later using FLIPR^TETRA (Molecular Devices, San Jose, CA, USA). Cyclopiazonic acid (CPA; Sigma-Aldrich, St. Louis, MI, USA, C153P)-induced SOCE was performed as previously described [55 (link)]. For thapsigargin (Sigma-Aldrich, St. Louis, MI, USA, T9033)-induced ER store depletion, 1 µM of thapsigargin in either nominal or 1.8 mM CaCl₂ PSS was added after 10 s and assessed for an additional 600 s. Changes in fluorescence intensity relative to baseline fluorescence over time were expressed as cytosolic Ca²⁺ changes (ΔF/F₀).