Stim1^−/−neutrophils show defective SOCE in response to integrin-mediated adhesion. (A) WT or CD18^–/– neutrophils were labeled with fluo-4 and then plated on pRGD-coated or 0.2% milk–coated plates, and the fluorescence was read by a Spectramax M5 reader every 6 seconds for 15 minutes. (B) WT and stim1^−/− neutrophils were plated on pRGD-coated plates, and calcium flux was recorded. Cells in (A) and (B) were added at time 0. (C) Neutrophils from WT and stim1^−/− littermate chimeras were plated on pRGD-coated plates for 15 minutes; adherent cells were lysed and the lysates were then immunoprecipitated with anti-PLCγ₂ antibody followed by blotting with 4G10 antibody to detect p-PLCγ or total PLCγ antibody to normalize for protein levels. (D) Neutrophils from WT and stim1^−/− littermate chimeras were plated on pRGD surfaces for 15 minutes and lysed; IP₃ levels were then determined by HitHunter fluorescence polarization assay. ***P < .001. Data shown are representative of 3 to 4 independent experiments.