Figure 3. IgG-mediated spreading in BMDM is Ca²⁺-independent; εKO spreading is significantly slower.

WT and εKO BMDM were calcium-depleted in Mg/EGTA (EGTA) or maintained in HBSS⁺⁺ (Ca²⁺). Cells were seeded onto IgG-coated coverslips and allowed to undergo frustrated phagocytosis. At the indicated time, cells were fixed and the exposed IgG visualized with Alexa 488 anti-IgG. Area measurements of black holes (inset) were made from three independent experiments; results are reported as average spread area (μm²) ± sem (>150 total cells/time-point). Frustrated phagocytosis was Ca²⁺-independent. The spread area of εKO was significantly smaller than WT, from 7.5 to 15 min. Statistical differences were calculated by two-way ANOVA with Tukey's post-test. *P < 0.50; ***P < 0.001.