Drosophila Twins regulates Armadillo levels in response to Wg/Wnt signal

R. Bajpai
2004 Development  
Protein Phosphatase 2A (PP2A) has a heterotrimericsubunit structure, consisting of a core dimer of ~36 kDa catalytic and ~65 kDa scaffold subunits complexed to a third variable regulatory subunit. Several studies have implicated PP2A in Wg/Wnt signaling. However, reports on the precise nature of PP2A role in Wg/Wnt pathway in different organisms are conflicting. We show that twins (tws), which codes for the B/PR55 regulatory subunit of PP2A in Drosophila, is a positive regulator of Wg/Wnt
more » ... ing. In twswing discs both short-and long-range targets of Wingless morphogen are downregulated. Analyses of twsmitotic clones suggest that requirement of Tws in Wingless pathway is cell-autonomous. Epistatic genetic studies indicate that Tws functions downstream of Dishevelled and upstream of Sgg and Armadillo. Our results suggest that Tws is required for the stabilization of Armadillo/β-catenin in response to Wg/Wnt signaling. Interestingly, overexpression of, otherwise normal, Tws protein induce dominant-negative phenotypes. The conflicting reports on the role of PP2A in Wg/Wnt signaling could be due to the dominant-negative effect caused by the overexpression of one of the subunits.
doi:10.1242/dev.00980 pmid:14973271 fatcat:6mkpa2my5vf7blp6e77l6gsxoi