A mode of regulation of beta-catenin signaling activity in Xenopus embryos independent of its levels Journal Article
| Authors: | Guger, K. A.; Gumbiner, B. M. |
| Article Title: | A mode of regulation of beta-catenin signaling activity in Xenopus embryos independent of its levels |
| Abstract: | The signaling activity of β-catenin is thought to be regulated by phosphorylation of a cluster of N-terminal serines, putative sites for GSK3β. In the prevailing model in the literature, GSK3β-dependent phosphorylation of these sites targets β-catenin for ubiquitin-mediated degradation. Wnt signaling inhibits GSK3β activity and this blocks degradation, allowing β-catenin to accumulate and signal. We show here that β-catenin activity is not regulated solely by protein stability. Mutations in the putative GSK3β phosphorylation sites of β-catenin enhance its signaling activity, but this cannot be accounted for by accumulation of either total or cadherin-free protein. Instead, the mutant protein has a threefold higher specific activity than the wild type both in vivo and in an in vitro signaling assay. We conclude that the N-terminal serines convey a layer of regulation upon β-catenin signaling in addition to the effects these sites exert upon protein stability. (C) 2000 Academic Press. |
| Keywords: | signal transduction; protein phosphorylation; gene mutation; mutation; nonhuman; ubiquitin; animals; serine; embryo; protein stability; phosphorylation; vertebrata; embryo, nonmammalian; regulatory mechanism; amino acid sequence; molecular sequence data; amino terminal sequence; protein-serine-threonine kinases; gene control; trans-activators; beta catenin; cadherins; body patterning; aspartic acid; microinjections; gene activity; cytoskeletal proteins; xenopus; gsk3β; xenopus proteins; trixis; priority journal; article; wnts |
| Journal Title: | Developmental Biology |
| Volume: | 223 |
| Issue: | 2 |
| ISSN: | 0012-1606 |
| Publisher: | Elsevier Inc. |
| Date Published: | 2000-07-15 |
| Start Page: | 441 |
| End Page: | 448 |
| Language: | English |
| DOI: | 10.1006/dbio.2000.9770 |
| PUBMED: | 10882528 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | Export Date: 18 November 2015 -- Source: Scopus |
