Our research goal is to understand fundamental mechanisms that guide neuronal processes to correct targets within the developing nervous system. We have used Drosophila genetics to define signaling pathways, from cell surface to cytoskeleton, that growth cones use to accurately interpret guidance information and execute directional axon outgrowth. Our recent work on the receptor protein-tyrosine phosphatase Dlar suggests that motor axon guidance behavior is controlled by a antagonistic balance of tyrosine kinase and phosphatase activity involving the proto-oncogene Abl and other proteins in the Abl pathway that act to control cytoskeletal dynamics. Our current analysis suggests that Enabled, Profilin and CAP collaborate with Abl during axonogenesis. Exactly how extracellular information regulates this process, and how tyrosine phosphorylation influences the activities of the downstream players, is currently under investigation. We anticipate that these studies will provide insights valuable for the understanding of cell motility in a variety of contexts, including cancer cell metastasis.