Figure 2.

Interleukin-8 (CXCL8) induces tyrosine phosphorylation and tyrosine kinase activity of proline-rich tyrosine kinase 2 (Pyk2) in human polymorphonuclear neutrophils (PMNs). PMNs were stimulated with vehicle, CXCL8 (400 ng/ml; 15 seconds at 37°) or saturating concentrations of anti-β₂ (30 min at 4°). The lysate was immunoprecipitated using antibody to proline-rich tyrosine kinase 2 (anti-Pyk2) (600). (a) The immunoprecipitate was immunoblotted by antibody to phosphotyrosine (anti-pTyr) (upper panel). The same filter was probed with anti-Pyk2 (N19; lower panel). (b) Tyrosine kinase activity was evaluated in the immunoprecipitate, as described in the Materials and methods. Data shown in the figure represent one of three independent experiments, with similar results obtained in each. IP, immunoprecipitate; MW, molecular weight.