Arap3 is inducibly knocked out in neutrophils. (A) Bone marrow–derived neutrophils were isolated from femurs and tibias of tamoxifen- and mock-induced Arap3^fl/flERT2Cre⁺ (iko), Arap3^+/+ERT2Cre⁺ (iCre), and Arap3^fl/fl (floxed) mice. Cells were boiled in sample buffer and proteins were separated by SDS-PAGE, transferred to PVDF membranes, and subjected to blotting using an anti-ARAP3 antiserum (ARAP3).¹⁰  Blots were reprobed using β-COP as a loading control (β-COP); 1 × 10⁶ cells were loaded per lane. (B) Peripheral blood cells from tamoxifen- and mock-induced Arap3^fl/flERT2Cre⁺ mice were analyzed using a Vet ABC animal blood cell counter. Data shown are pooled from 2 separate experiments (means ± SEM; n = 18).