title: Phosphorylation-dependent ubiquitination of cyclin E by the SCFFbw7 ubiquitin ligase.
abstract: Cyclin E binds and activates the cyclin-dependent kinase Cdk2 and catalyzes the transition from the G1 phase to the S phase of the cell cycle. The amount of cyclin E protein present in the cell is tightly controlled by ubiquitin-mediated proteolysis. Here we identify the ubiquitin ligase responsible for cyclin E ubiquitination as SCFFbw7 and demonstrate that it is functionally conserved in yeast, flies, and mammals. Fbw7 associates specifically with phosphorylated cyclin E, and SCFFbw7 catalyzes cyclin E ubiquitination in vitro. Depletion of Fbw7 leads to accumulation and stabilization of cyclin E in vivo in human and Drosophila melanogaster cells. Multiple F-box proteins contribute to cyclin E stability in yeast, suggesting an overlap in SCF E3 ligase specificity that allows combinatorial control of cyclin E degradation.
authors.affiliation: Department of Biochemistry and Molecular Biology, Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX, 77030, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Koepp
authors.forename: L K
authors.initials: LK
authors.lastname: Schaefer
authors.forename: X
authors.initials: X
authors.lastname: Ye
authors.forename: K
authors.initials: K
authors.lastname: Keyomarsi
authors.forename: C
authors.initials: C
authors.lastname: Chu
authors.forename: J W
authors.initials: JW
authors.lastname: Harper
authors.forename: S J
authors.initials: SJ
authors.lastname: Elledge
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism; D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D019927:Cyclin E / Q000378:metabolism*; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D029721:Drosophila Proteins; D004331:Drosophila melanogaster; D044783:F-Box Proteins; D000073979:F-Box-WD Repeat-Containing Protein 7; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010453:Peptide Synthases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012330:RNA, Double-Stranded; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D044843:SKP Cullin F-Box Protein Ligases; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D014162:Transfection; D014407:Tumor Cells, Cultured; D044767:Ubiquitin-Protein Ligases; D014452:Ubiquitins / Q000378:metabolism*
chemical_list: C080443:CDC4 protein, S cerevisiae; D018797:Cell Cycle Proteins; D019927:Cyclin E; D029721:Drosophila Proteins; D044783:F-Box Proteins; D000073979:F-Box-WD Repeat-Containing Protein 7; C513273:FBXW7 protein, human; C513272:Fbxw7 protein, mouse; D012330:RNA, Double-Stranded; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014452:Ubiquitins; D044843:SKP Cullin F-Box Protein Ligases; D044767:Ubiquitin-Protein Ligases; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; C495887:cdk2 protein, Drosophila; D010453:Peptide Synthases