Syk Is Required for Integrin Signaling in Neutrophils

• Published in: Immunity (Cambridge, Mass.) Mass.), 2002-04, Vol.16 (4), p.547-558
• Main Authors: Mócsai, Attila, Zhou, Meijuan, Meng, Fanying, Tybulewicz, Victor L., Lowell, Clifford A.
• Format: Article
• Language: English
• Subjects: Animals; Antigens, CD - metabolism; Bone marrow; Bone Marrow Cells - cytology; Bone Marrow Cells - metabolism; Bone Marrow Cells - physiology; CD18 Antigens - metabolism; Cell Adhesion - physiology; Cell Movement - physiology; Cloning; Cross-Linking Reagents; Defects; Enzyme Activation; Enzyme Precursors - genetics; Enzyme Precursors - metabolism; Enzyme Precursors - physiology; Experiments; Female; Hematopoietic Stem Cells - cytology; Hematopoietic Stem Cells - metabolism; Hematopoietic Stem Cells - physiology; Immune system; Integrin beta1 - metabolism; Integrin beta3; Intracellular Signaling Peptides and Proteins; Kinases; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Migration; Neutrophils - cytology; Neutrophils - metabolism; Neutrophils - physiology; Platelet Membrane Glycoproteins - metabolism; Protein-Tyrosine Kinases - genetics; Protein-Tyrosine Kinases - metabolism; Protein-Tyrosine Kinases - physiology; Proteins; Signal Transduction; Syk Kinase; Syk protein
• ISSN: 1074-7613; 1097-4180
• DOI: 10.1016/S1074-7613(02)00303-5

The Syk tyrosine kinase plays a critical role in the signaling machinery of various receptors of the adaptive immune system. Here we show that Syk is also an essential component of integrin signaling in neutrophils. syk −/− neutrophils failed to undergo respiratory burst, degranulation, or spreading in response to proinflammatory stimuli while adherent to immobilized integrin ligands or when stimulated by direct crosslinking of integrins. Signaling from the β 1, β 2, or β 3 integrins was defective in syk −/− cells. Syk colocalized with CD18 during cell spreading and initiated downstream signaling events leading to actin polymerization. Surprisingly, these defects in integrin-mediated activation did not impair the integrin-dependent in vitro or in vivo migration of syk −/− neutrophils or of cells deficient in Src-family kinases. Thus, integrins use different signaling mechanisms to support migration and adherent activation.