DOMAIN REQUIREMENTS FOR THE DOCK ADAPTER PROTEIN IN GROWTH-CONE SIGNALING

Tyrosine phosphorylation has been implicated in growth-cone guidance t hrough genetic, biochemical, and pharmacological studies. Adapter prot eins containing src homology 2 (SH2) domains and src homology 3 (SH3) domains provide a means of linking guidance signaling through phosphot yrosine to downstream effecters regulating growth-cone motility. The D rosophila adapter, Dreadlocks (Dock), the homolog of mammalian Nck con taining three N-terminal SH3 domains and a single SH2 domain, is highl y specialized for growth-cone guidance. In this paper, we demonstrate that Dock can couple signals in either an SH2-dependent or an SH2-inde pendent fashion in photoreceptor (R cell) growth cones, and that Dock displays different domain requirements in different neurons.