A role for the Tec family tyrosine kinase Txk in T cell activation and thymocyte selection
- J Exp Med. 1999 Nov 15;190(10):1427-38. doi: 10.1084/jem.190.10.1427.
- 1. Laboratory of Mammalian Genes and Development, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA. [email protected]
Recent data indicate that several members of the Tec family of Protein Tyrosine Kinases function in antigen receptor signal transduction. TXK, a Tec family protein tyrosine kinase, is expressed in both immature and mature T cells and in mast cells. By overexpressing TXK in T cells throughout development, we found that TXK specifically augments the Phospholipase C (PLC)-gamma1-mediated calcium signal transduction pathway upon T cell antigen receptor (TCR) engagement. Although TXK is structurally different from inducible T cell kinase (Itk), another Tec family member expressed in T cells, expression of the TXK transgene could partially rescue defects in positive selection and signaling in Itk(-)(/)(-) mice. Conversely, in the Itk(+/+) (wild-type) background, overexpression of TXK inhibited positive selection of TCR transgenic thymocytes, presumably due to induction of cell death. These results identify a role for TXK in TCR signal transduction, T cell development, and selection and suggest that the Tec family Kinases Itk and TXK perform analogous functions.