The Tec family of tyrosine kinases in T cells, amplifiers of T cell receptor signals

ITK and Rlk/Txk are the predominant Tec family of tyrosine kinases expressed in T cells, and are involved in T cell antigen receptor mediated activation of T cells. These kinases require prior activation of Lck, Zap-70 and PI3-kinase for efficient activation. They share major substrates with both Lck and Zap-70, however the pathways they regulate are unclear. Recent evidence suggests that these kinases may not activate unique pathways, but instead serve as amplifiers for the upstream kinases Lck and Zap-70. This review will discuss the evidence for this view.