NEGATIVE REGULATION OF ARMADILLO, A WINGLESS EFFECTOR IN DROSOPHILA

Citation
Lm. Pai et al., NEGATIVE REGULATION OF ARMADILLO, A WINGLESS EFFECTOR IN DROSOPHILA, Development, 124(11), 1997, pp. 2255-2266
Citations number
47
Categorie Soggetti
Developmental Biology
Journal title
ISSN journal
09501991
Volume
124
Issue
11
Year of publication
1997
Pages
2255 - 2266
Database
ISI
SICI code
0950-1991(1997)124:11<2255:NROAAW>2.0.ZU;2-I
Abstract
Drosophila Armadillo and its vertebrate homolog beta-catenin play esse ntial roles both in the transduction of Wingless/Wnt cell-cell signals and in the function of cell-cell adherens junctions, Wingless and Wnt s direct numerous cell fate choices during development, We generated a mutant protein, Armadillo(S10), with a 54 amino acid deletion in its N-terminal domain. This mutant is constitutively active in Wingless si gnaling; its activity is independent of both Wingless signal and endog enous wild-type Armadillo. Armadillo's role in signal transduction is normally negatively regulated by Zeste-white 3 kinase, which modulates Armadillo protein stability. Armadillo(S10) is more stable than wild- type Armadillo, suggesting that it is less rapidly targeted for degrad ation. We show that Armadillo(S10) has escaped from negative regulatio n by Zeste white-3 kinase, and thus accumulates outside junctions even in the absence of Wingless signal, Finally, we present data implicati ng kinases in addition to Zeste white-3 in Armadillo phosphorylation, We discuss two models for the negative regulation of Armadillo in norm al development and discuss how escape from this regulation contributes to tumorigenesis.