title: Biochemical interactions in the wnt pathway.
abstract: The wnt signal transduction pathway is involved in many differentiation events during embryonic development and can lead to tumor formation after aberrant activation of its components. The cytoplasmic component beta-catenin is central to the transmission of wnt signals to the nucleus: in the absence of wnts beta-catenin is constitutively degraded in proteasomes, whereas in the presence of wnts beta-catenin is stabilized and associates with HMG box transcription factors of the LEF/TCF family. In tumors, beta-catenin degradation is blocked by mutations of the tumor suppressor gene APC (adenomatous polyposis coli), or of beta-catenin itself. As a consequence, constitutive TCF/beta-catenin complexes are formed and activate oncogenic target genes. This review discusses the mechanisms that silence the pathway in cells that do not receive a wnt signal and goes on to describe the regulatory steps involved in the activation of the pathway.
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13122, Berlin, Germany.
authors.forename: M J
authors.initials: MJ
authors.lastname: Seidensticker
authors.forename: J
authors.initials: J
authors.lastname: Behrens
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D029681:Arabidopsis Proteins; D060466:Axin Protein; D003598:Cytoskeletal Proteins / Q000378:metabolism; D000072261:Dishevelled Proteins; D017491:Genes, APC; D006801:Humans; D051379:Mice; D008817:Mice, Mutant Strains; D010750:Phosphoproteins / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins; D015398:Signal Transduction; D015534:Trans-Activators; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin
chemical_list: C491761:AXIN2 protein, human; D048868:Adaptor Proteins, Signal Transducing; D029681:Arabidopsis Proteins; D060466:Axin Protein; C111729:Axin2 protein, mouse; C495270:CTNNB1 protein, human; C495267:CTNNB1 protein, mouse; D003598:Cytoskeletal Proteins; D000072261:Dishevelled Proteins; D010750:Phosphoproteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin; D011494:Protein Kinases; C101990:CKI1 protein, Arabidopsis