Ras target protein canoe is a substrate for Cdc2 and Cdk5 kinases

Mutations in the canoe locus of Drosophila lead to failure in the dorsal closure of the embryonic epidermis and pattern formation defects in imaginal eyes and wings. In the wing, the canoe mutants develop extra veins when they are heterozygous for shaggy, a mutation in the locus encoding the glycogen synthase kinase 3 beta (Gsk3 beta), which has been known to phosphorylate the Armadillo protein. Although Canoe has a putative target sequence for phosphorylation by Gsk3 beta similar to that found in Armadillo, in vitro experiments indicate that Canoe is not phosphorylated by Gsk3 beta . Instead, Canoe is demonstrated to be a good substrate of Cdc2 and Cdk5 kinases. Thus, Cdc2 and Cdk5 kinases are the potential regulators of the function of Canoe in morphogenesis. Arch.