title: Human APC sequesters beta-catenin even in the absence of GSK-3beta in a Drosophila model.
abstract: There have been conflicting reports on the requirement of GSK-3beta-mediated phosphorylation of the tumor suppressor adenomatous polyposis coli (APC) vis-à-vis its ability to bind and degrade beta-catenin. Using a unique combination of loss of function for Shaggy/GSK-3beta and a gain of function for human APC in Drosophila, we show that misexpressed human APC (hAPC) can still sequester Armadillo/beta-catenin. In addition, human APC could suppress gain of Wnt/Wingless phenotypes associated with loss of Shaggy/GSK-3beta activity, suggesting that sequestered Armadillo/beta-catenin is non-functional. Based on these studies, we propose that binding per se of beta-catenin by APC does not require phosphorylation by GSK-3beta.
authors.affiliation: Centre for Cellular and Molecular Biology, Hyderabad, India. prashanth21676@gmail.com
authors.forename: P R
authors.initials: PR
authors.lastname: Rao
authors.forename: K
authors.initials: K
authors.lastname: Makhijani
authors.forename: L S
authors.initials: LS
authors.lastname: Shashidhara
mesh_terms: D011125:Adenomatous Polyposis Coli / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D023421:Models, Animal; D010641:Phenotype; D011485:Protein Binding; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D051176:beta Catenin; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3