Abstract
Control of cyclin levels is critical for proper cell cycle regulation. In yeast, the stability of the G1 cyclin Cln1 is controlled by phosphorylation-dependent ubiquitination. Here it is shown that this reaction can be reconstituted in vitro with an SCF E3 ubiquitin ligase complex. Phosphorylated Cln1 was ubiquitinated by SCF (Skp1-Cdc53-F-box protein) complexes containing the F-box protein Grr1, Rbx1, and the E2 Cdc34. Rbx1 promotes association of Cdc34 with Cdc53 and stimulates Cdc34 auto-ubiquitination in the context of Cdc53 or SCF complexes. Rbx1, which is also a component of the von Hippel-Lindau tumor suppressor complex, may define a previously unrecognized class of E3-associated proteins.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Anaphase-Promoting Complex-Cyclosome
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Animals
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Carrier Proteins / chemistry
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Carrier Proteins / metabolism*
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Cell Cycle Proteins / metabolism
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Cell Line
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Cullin Proteins*
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Cyclins / metabolism*
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F-Box Proteins
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Fungal Proteins / metabolism*
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Ligases / metabolism
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Molecular Sequence Data
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Peptide Synthases / metabolism*
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Phosphorylation
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Recombinant Fusion Proteins / metabolism
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S-Phase Kinase-Associated Proteins
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SKP Cullin F-Box Protein Ligases
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins*
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Sequence Alignment
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Ubiquitin-Conjugating Enzymes
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Ubiquitin-Protein Ligase Complexes*
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Ubiquitin-Protein Ligases
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Ubiquitins / metabolism*
Substances
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CLN1 protein, S cerevisiae
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Carrier Proteins
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Cdc53 protein, S cerevisiae
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Cell Cycle Proteins
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Cullin Proteins
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Cyclins
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F-Box Proteins
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Fungal Proteins
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Recombinant Fusion Proteins
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S-Phase Kinase-Associated Proteins
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Saccharomyces cerevisiae Proteins
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Ubiquitins
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GRR1 protein, S cerevisiae
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CDC34 protein, S cerevisiae
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Ubiquitin-Conjugating Enzymes
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Ubiquitin-Protein Ligase Complexes
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Anaphase-Promoting Complex-Cyclosome
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SKP Cullin F-Box Protein Ligases
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Ubiquitin-Protein Ligases
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Ligases
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Peptide Synthases