title: WNT-1 and HGF regulate GSK3 beta activity and beta-catenin signaling in mammary epithelial cells.
abstract: Wnt-1, a secreted glycoprotein, participates in development of the nervous system and contributes to mammary oncogenesis when overexpressed. We show that GSK3 activity is decreased in mouse mammary cells transformed by Wnt-1. These cells also exhibit a substantial Wnt-1 dependent increase in the uncomplexed population of beta-catenin. Wnt-1 signaling does not change the steady state level of either GSK3 alpha or GSK3 beta but instead leads to an increased association between GSK3 beta and beta-catenin. HGF/SF treatment of mouse mammary cells also leads to a transient decrease in GSK3 activity and a parallel, selective increase in the uncomplexed pool of beta-catenin. Both Wnt-1 and HGF/SF lead to nuclear accumulation of beta-catenin and activation of a LEF/Tcf responsive reporter gene. This study defines a pivotal signal transduction pathway, activated by both Wnt-1 and HGF/SF, leading to decreased GSK3 beta activity and consequently an increase in the free pool and nuclear accumulation of beta-catenin and changes in gene expression.
authors.affiliation: Department of Molecular Oncology, Megabios Corporation, Burlingame, California 94010, USA.
authors.forename: J
authors.initials: J
authors.lastname: Papkoff
authors.forename: M
authors.initials: M
authors.lastname: Aikawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D017930:Genes, Reporter / Q000235:genetics; D038362:Glycogen Synthase Kinase 3; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D051821:Lymphoid Enhancer-Binding Factor 1; D051379:Mice; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D015534:Trans-Activators; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation / Q000502:physiology; D014170:Transformation, Genetic / Q000235:genetics; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029961:Zebrafish Proteins; D051176:beta Catenin
chemical_list: C495267:CTNNB1 protein, mouse; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D051821:Lymphoid Enhancer-Binding Factor 1; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D051153:Wnt Proteins; D051155:Wnt1 Protein; C495246:Wnt1 protein, mouse; D029961:Zebrafish Proteins; D051176:beta Catenin; D017228:Hepatocyte Growth Factor; D019859:Proto-Oncogene Proteins c-met; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3