The Fc receptor gamma-chain and the tyrosine kinase Syk are essential for activation of mouse platelets by collagen.

Poole, A., Gibbins, J. ORCID: https://orcid.org/0000-0002-0372-5352, Turner, M., van Vugt, M. J., van de Winkel, J. G., Saito, T., Tybulewicz, V. L. and Watson, S. P. (1997) The Fc receptor gamma-chain and the tyrosine kinase Syk are essential for activation of mouse platelets by collagen. The EMBO journal, 16 (9). pp. 2333-2341. ISSN 0261-4189

Abstract/Summary

Activation of mouse platelets by collagen is associated with tyrosine phosphorylation of multiple proteins including the Fc receptor gamma-chain, the tyrosine kinase Syk and phospholipase Cgamma2, suggesting that collagen signals in a manner similar to that of immune receptors. This hypothesis has been tested using platelets from mice lacking the Fc receptor gamma-chain or Syk. Tyrosine phosphorylation of Syk and phospholipase Cgamma2 by collagen stimulation is absent in mice lacking the Fc receptor gamma-chain. Tyrosine phosphorylation of phospholipase Cgamma2 by collagen stimulation is also absent in mice platelets which lack Syk, although phosphorylation of the Fc receptor gamma-chain is maintained. In contrast, tyrosine phosphorylation of platelet proteins by the G protein-coupled receptor agonist thrombin is maintained in mouse platelets deficient in Fc receptor gamma-chain or Syk. The absence of Fc receptor gamma-chain or Syk is accompanied by a loss of secretion and aggregation responses in collagen- but not thrombin-stimulated platelets. These observations provide the first direct evidence of an essential role for the immunoreceptor tyrosine-based activation motif (ITAM) in signalling by a non-immune receptor stimulus.