Wingless signaling modulates cadherin-mediated cell adhesion in Drosophila imaginal disc cells.
Armadillo, the Drosophila homolog of beta-catenin, plays a crucial role in both the Wingless signal transduction pathway and cadherin-mediated cell-cell adhesion, raising the possibility that Wg signaling affects cell adhesion. Here, we use a tissue culture system that allows conditional activation of the Wingless signaling pathway and modulation of E-cadherin expression levels. We show that activation of the Wingless signaling pathway leads to the accumulation of hypophosphorylated Armadillo in the cytoplasm and in cellular processes, and to a concomitant reduction of membrane-associated Armadillo. Activation of the Wingless pathway causes a loss of E-cadherin from the cell surface, reduced cell adhesion and increased spreading of the cells on the substratum. After the initial loss of E-cadherin from the cell surface, E-cadherin gene expression is increased by Wingless. We suggest that Wingless signaling causes changes in Armadillo levels and subcellular localization that result in a transient reduction of cadherin-mediated cell adhesion, thus facilitating cell shape changes, division and movement of cells in epithelial tissues.
Wodarz
Andreas
A
Howard Hughes Medical Institute and Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA. awodarz@gwdg.de
Stewart
Daniel B
DB
Nelson
W James
WJ
Nusse
Roel
R
D000818:Animals; D051186:Armadillo Domain Proteins / Q000378:metabolism*; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D051177:Catenins / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D004330:Drosophila / Q000166:cytology / Q000502:physiology*; D029721:Drosophila Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics; D051379:Mice; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism*; D051155:Wnt1 Protein
C495305:ARM protein, Drosophila; D051186:Armadillo Domain Proteins; D015820:Cadherins; D051177:Catenins; D029721:Drosophila Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D051155:Wnt1 Protein; C074622:wg protein, Drosophila