SIC1 is ubiquitinated in vitro by a pathway that requires CDC4, CDC34, and cyclin/CDK activities
| Autor: | R. M. Renny Feldman, Rati Verma, Raymond J. Deshaies |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1997 |
| Předmět: |
Saccharomyces cerevisiae Proteins
Ubiquitin-Protein Ligases Cyclin D Cyclin A Cyclin B Cell Cycle Proteins Anaphase-Promoting Complex-Cyclosome Fungal Proteins Ligases Cyclin-dependent kinase Cyclins Yeasts Enzyme Inhibitors Phosphorylation Ubiquitins Molecular Biology Cyclin-Dependent Kinase Inhibitor Proteins Cyclin-dependent kinase 1 biology F-Box Proteins Ubiquitin-Protein Ligase Complexes Cell Biology Ubiquitin ligase Cell biology Biochemistry Ubiquitin-Conjugating Enzymes biology.protein Cyclin-dependent kinase complex CDC28 Protein Kinase S cerevisiae Cyclin A2 Caltech Library Services Research Article |
| Popis: | Traversal from G1 to S-phase in cycling cells of budding yeast is dependent on the destruction of the S-phase cyclin/CDK inhibitor SIC1. Genetic data suggest that SIC1 proteolysis is mediated by the ubiquitin pathway and requires the action of CDC34, CDC4, CDC53, SKP1, and CLN/CDC28. As a first step in defining the functions of the corresponding gene products, we have reconstituted SIC1 multiubiquitination in DEAE-fractionated yeast extract. Multiubiquitination depends on cyclin/CDC28 protein kinase and the CDC34 ubiquitin-conjugating enzyme. Ubiquitin chain formation is abrogated in cdc4ts mutant extracts and assembly restored by the addition of exogenous CDC4, suggesting a direct role for this protein in SIC1 multiubiquitination. Deletion analysis of SIC1 indicates that the N-terminal 160 residues are both necessary and sufficient to serve as substrate for CDC34-dependent ubiquitination. The complementary C-terminal segment of SIC1 binds to the S-phase cyclin CLB5, indicating a modular structure for SIC1. |
| Databáze: | OpenAIRE |
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