Signaling through CD16b in human neutrophils involves the Tec family of tyrosine kinases

• Published in: Journal of leukocyte biology Vol. 78; no. 2; pp. 524 - 532
• Main Authors: Fernandes, Maria J. G., Lachance, Geneviève, Paré, Guillaume, Rollet‐Labelle, Emmanuelle, Naccache, Paul H.
• Format: Journal Article
• Language: English
• Published: United States Society for Leukocyte Biology 01.08.2005
• Subjects: Amides - pharmacology; Androstadienes - pharmacology; Antigens, CD - metabolism; Calcium Signaling - drug effects; Calcium Signaling - physiology; Cell Degranulation - drug effects; Cell Degranulation - physiology; Cell Membrane - metabolism; Cells, Cultured; Fc receptors; GPI-Linked Proteins; Humans; N-Formylmethionine Leucyl-Phenylalanine - pharmacology; Neutrophils - metabolism; Nitriles - pharmacology; phagocytes; Phospholipase C gamma; Protein Kinase Inhibitors - pharmacology; Protein Transport - drug effects; Protein Transport - physiology; Protein-Tyrosine Kinases - antagonists & inhibitors; Protein-Tyrosine Kinases - metabolism; Receptors, IgG - metabolism; signal transduction; src-Family Kinases - antagonists & inhibitors; src-Family Kinases - metabolism; Type C Phospholipases - metabolism
• ISSN: 0741-5400; 1938-3673
• DOI: 10.1189/jlb.0804479

Tec kinases belong to the second largest family of nonreceptor tyrosine kinases. Although these kinases are expressed in myeloid cells, little is known about their implication in neutrophil function. We recently reported the participation of Tec kinases in the responses of human neutrophils to the bacterial peptide N‐formyl‐l‐methionyl‐l‐leucyl‐l‐phenylalanine via G‐coupled protein receptors. In this study, we extended our investigations of Tec kinases to the signaling of the glycosylphosphatidylinositol‐linked receptor CD16b, which is highly and specifically expressed in neutrophils. The results obtained indicate that Tec is translocated to the plasma membrane, phosphorylated, and activated upon CD16b cross‐linking and that the activation of Tec is inhibited by Src‐specific inhibitors as well as by the phosphatidylinositol‐3 kinase inhibitor, wortmannin. As no specific inhibitor of Tec exists, the role of Tec kinases was further investigated using a‐Cyano‐b‐hydroxy‐b‐methyl‐N‐(2,5‐dibromophenyl)propenamide (LFM‐A13), a compound known to inhibit Bruton’s tyrosine kinase. We show that this compound also inhibits the kinase activity of Tec and provide evidence that the mobilization of intracellular calcium and the tyrosine phosphorylation of phospholipase Cγ2 (PLCγ2) induced upon CD16b engagement are inhibited by LFM‐A13. We also show that Tec kinases are important for CD16b‐dependent degranulation of neutrophils. In summary, we provide direct evidence for the implication of Tec in CD16b signaling and suggest that Tec kinases are involved in the phosphorylation and activation of PLCγ2 and subsequently, in the mobilization of calcium in human neutrophils.