Citation/Abstract

Frazzled is a chemoattractive guidance receptor which initiates signals to the cytoskeleton via three conserved P-motifs in its cytoplasmic domain. Here, we genetically evaluate the contribution of each P-motif to Frazzled signaling in vivo and identify Abl and Rho signaling pathways that operate during Frazzled signaling in the formation of axon pathways. Rescue of axon pathway formation in frazzled mutant embryos requires the P3 and P1-motifs but not P2. The P3-motif may initiate a Rho dependent pathway to regulate myosin activity as expression of a Frazzled receptor lacking the P3-motif does not enhance Rho induced crossover defects as well as a wild type Frazzled receptor. Frazzled also sends signals to regulate how the cytoplasmic tyrosine kinase Abelson is used during commissure formation as expression of Abelson in the absence of Frazzled protein prevents commissure formation. Together, this data points to the importance of the P1 and P3-motifs and suggests that Rho and Abl pathways are important during Fra signaling.