Protein tyrosine kinases in neutrophil activation and recruitment

Migration of leukocytes into tissue is a key element of innate and adaptive immunity. The first contact of leukocytes with endothelial cells is mediated by engagement of selectins with their counter-receptors which results in leukocyte rolling. During rolling, leukocytes collect different inflammatory signals that activate intracellular signaling pathways. Integration of these signals induces leukocyte activation, firm arrest, post-adhesion strengthening, intravascular crawling, and transmigration. In neutrophils, like in T-cells and platelets, both G-protein-coupled receptor-dependent and -independent activation pathways exist that lead to integrin activation. Accumulating evidence suggests that different protein tyrosine kinases play key roles in signal transduction pathways regulating neutrophil activation and recruitment to inflammatory sites. This review focuses on the role of protein tyrosine kinases of the Src, Syk, and Tec families for neutrophil activation and recruitment.

Research highlights
► Protein tyrosine kinases (PTK) are involved in neutrophil activation and recruitment.
► PTKs participate in signaling downstream of PSGL-1 and β2-integrins in neutrophils.
► Some PTKs have redundant functions, whereas other PTKs have unique functions.