Couples tyrosine kinase signals with the activation of the Rho/Rac GTPases. Probably plays a pivotal role as a signal transducer protein during fruit fly development. Interacts (via SH2 domain) with Egfr (when phosphorylated on tyrosine residues). Ubiquitous. Expressed both maternally and zygotically in all stages of development. Phosphorylated on tyrosine residues.