Expression and activation of CKLiK in human eosinophils and neutrophils. (A) CKLiK was immune-precipitated with CKLiK antibody from stem cells differentiated toward neutrophils (neutro; 2.5 × 10⁷ and 1.5 × 10⁷ as indicated) and eosinophils (eo; 1.5 × 10⁷) (left) and from peripheral blood neutrophils (2 × 10⁷) and eosinophils (10⁷) (right, with a longer exposure below) and separated by SDS-PAGE. Western blot analysis was performed with the CKLiK antibody. Heavy and light chains of CKLiK antibody and immune-precipitated CKLiK are indicated. (B) Kinase activity of CKLiK is dependent on Ca²⁺/calmodulin (Ca2+/CaM). Kinase assays were performed in the absence or presence of Ca²⁺ and calmodulin with CKLiK immune-precipitated from stem cells differentiated toward neutrophils and eosinophils (top) and with CKLiK obtained from peripheral blood eosinophils and neutrophils (bottom). Data are representative of 3 independent experiments.