The Fbw7 tumor suppressor regulates glycogen synthase kinase 3 phosphorylation-dependent c-Myc protein degradation.
Myc proteins regulate cell growth and division and are implicated in a wide range of human cancers. We show here that Fbw7, a component of the SCF(Fbw7) ubiquitin ligase and a tumor suppressor, promotes proteasome-dependent c-Myc turnover in vivo and c-Myc ubiquitination in vitro. Phosphorylation of c-Myc on threonine-58 (T58) ... by glycogen synthase kinase 3 regulates the binding of Fbw7 to c-Myc as well as Fbw7-mediated c-Myc degradation and ubiquitination. T58 is the most frequent site of c-myc mutations in lymphoma cells, and our findings suggest that c-Myc activation is one of the key oncogenic consequences of Fbw7 loss in cancer. Because Fbw7 mediates the degradation of cyclin E, Notch, and c-Jun, as well as c-Myc, the loss of Fbw7 is likely to elicit profound effects on cell proliferation during tumorigenesis.
Mesh Terms:
Base Sequence, Cell Cycle Proteins, Cell Line, F-Box Proteins, Fibroblasts, Glycogen Synthase Kinase 3, Hela Cells, Humans, Phosphorylation, Proto-Oncogene Proteins c-myc, Recombinant Proteins, Sequence Alignment, Transduction, Genetic, Transfection, Tumor Suppressor Proteins, Ubiquitin, Ubiquitin-Protein Ligases
Base Sequence, Cell Cycle Proteins, Cell Line, F-Box Proteins, Fibroblasts, Glycogen Synthase Kinase 3, Hela Cells, Humans, Phosphorylation, Proto-Oncogene Proteins c-myc, Recombinant Proteins, Sequence Alignment, Transduction, Genetic, Transfection, Tumor Suppressor Proteins, Ubiquitin, Ubiquitin-Protein Ligases
Proc. Natl. Acad. Sci. U.S.A.
Date: Jun. 15, 2004
PubMed ID: 15150404
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