Figure 2.

SOCE is selectively impaired at low doses of agonists in STIM2-deficient neutrophils. Analysis of SOCE in neutrophils from Stim1^f/f, Stim1^VavCre, Stim2^VavCre, and Stim1/2^VavCre mice measured by flow cytometry. (A) Bone marrow cells loaded with Indo-1 and labeled for Ly6G were stimulated with the indicated doses of fMLF, ionomycin, or thapsigargin. Cells were stimulated first in calcium-free media to analyze ER Ca²⁺ store release, followed by readdition of extracellular calcium. (B) Analysis of SOCE in neutrophils from WT and Stim1/2^VavCre mice stimulated with the indicated agonist. (C) Quantification of ER store release (area under the curve of cells stimulated in 0 mM Ca²⁺) and (D) SOCE (area under the curve of segment after addition of 1 mM Ca²⁺); mean ± SEM from 3 to 4 independent experiments. *P < .05. (E) Calcium flux in cells stimulated with the indicated agonists in media containing physiological calcium (1 mM). To synchronize zymosan particle uptake and calcium flux, cells were incubated with zymosan on ice in media containing 1 mM Ca²⁺ and then placed in a 37°C water bath during flow cytometry to induce stimulation. (F) Quantification of E, area under the curve of indicated time segment represented as mean ± SEM from 3 to 4 independent experiments.