TitleWg/Wnt signal can be transmitted through arrow/LRP5,6 and Axin independently of Zw3/Gsk3beta activity.
Publication TypeJournal Article
Year of Publication2003
AuthorsTolwinski, NS, Wehrli, M, Rives, A, Erdeniz, N, DiNardo, S, Wieschaus, E
JournalDev Cell
Date Published2003 Mar
KeywordsActive Transport, Cell Nucleus, Adaptor Proteins, Signal Transducing, Animals, Armadillo Domain Proteins, Carrier Proteins, Drosophila melanogaster, Drosophila Proteins, Embryo, Nonmammalian, Female, Frizzled Receptors, Gene Expression Regulation, Developmental, Glycogen Synthase Kinase 3, LDL-Receptor Related Proteins, Low Density Lipoprotein Receptor-Related Protein-5, Membrane Proteins, Mutation, Proto-Oncogene Proteins, Receptors, Cell Surface, Receptors, G-Protein-Coupled, Receptors, LDL, Recombinant Fusion Proteins, Signal Transduction, Trans-Activators, Transcription Factors, Wnt1 Protein

Activation of the Wnt signaling cascade provides key signals during development and in disease. Here we provide evidence, by designing a Wnt receptor with ligand-independent signaling activity, that physical proximity of Arrow (LRP) to the Wnt receptor Frizzled-2 triggers the intracellular signaling cascade. We have uncovered a branch of the Wnt pathway in which Armadillo activity is regulated concomitantly with the levels of Axin protein. The intracellular pathway bypasses Gsk3beta/Zw3, the kinase normally required for controlling beta-catenin/Armadillo levels, suggesting that modulated degradation of Armadillo is not required for Wnt signaling. We propose that Arrow (LRP) recruits Axin to the membrane, and that this interaction leads to Axin degradation. As a consequence, Armadillo is no longer bound by Axin, resulting in nuclear signaling by Armadillo.

Alternate JournalDev. Cell