The C-terminal domain of Armadillo binds to hypophosphorylated Teashirt tomodulate Wingless signalling in Drosophila

Wnt signalling is a key pathway for tissue patterning during animal develop ment. In Drosophila, the Wnt protein Wingless acts to stabilize Armadillo i nside cells where it binds to at least two DNA-binding factors which regula te specific target genes. One Armadillo-binding protein in Drosophila is th e zinc finger protein Teashirt. Here we show that Wingless signalling promo tes the phosphorylation and the nuclear accumulation of Teashirt, This proc ess requires the binding of Teashirt to the C-terminal end of Armadillo. Fi nally, we present evidence that the serine/threonine kinase Shaggy is assoc iated with Teashirt in a complex. We discuss these results with respect to current models of Armadillo/beta-catenin action for the transmission of the Wingless/Wnt pathway.