IL3 stimulation induces rapid and transient tyrosine-phosphorylation of Vav and the binding of Vav to Tec kinase through Tec homology domains. (Machide et al. 1995). Vav1 and Tec were seen to associate into a complex with the activated prolactin receptor (Kline et al. 2001). These reports were interpreted as Tec enhancing Vav GEF activity, but it has been suggested that Vav might contribute to Tec activation in T cell signaling (Reynolds et al. 2002). Tec kinases generally require PI3K-dependent membrane translocation and phosphorylation of the kinase domain, often by an Src family kinase, for activation (Takesono et al. 2002).