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PMID:21098119

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Citation

Liu, Q, Larsen, B, Ricicova, M, Orlicky, S, Tekotte, H, Tang, X, Craig, K, Quiring, A, Le Bihan, T, Hansen, C, Sicheri, F and Tyers, M (2011) SCFCdc4 enables mating type switching in yeast by cyclin-dependent kinase-mediated elimination of the Ash1 transcriptional repressor. Mol. Cell. Biol. 31:584-98

Abstract

In the budding yeast Saccharomyces cerevisiae, mother cells switch mating types between a and α forms, whereas daughter cells do not. This developmental asymmetry arises because the expression of the HO endonuclease, which initiates the interconversion of a and α mating type cassettes, is extinguished by the daughter-specific Ash1 transcriptional repressor. When daughters become mothers in the subsequent cell cycle, Ash1 must be eliminated to enable a new developmental state. Here, we report that the ubiquitin ligase SCF(Cdc4) mediates the phosphorylation-dependent elimination of Ash1. The inactivation of SCF(Cdc4) stabilizes Ash1 in vivo, and consistently, Ash1 binds to and is ubiquitinated by SCF(Cdc4) in a phosphorylation-dependent manner in vitro. The mutation of a critical in vivo cyclin-dependent kinase (CDK) phosphorylation site (Thr290) on Ash1 reduces its ubiquitination and rate of degradation in vivo and decreases the frequency of mating type switching. Ash1 associates with active Cdc28 kinase in vivo and is targeted to SCF(Cdc4) in a Cdc28-dependent fashion in vivo and in vitro. Ash1 recognition by Cdc4 appears to be mediated by at least three phosphorylation sites that form two redundant diphosphorylated degrons. The phosphorylation-dependent elimination of Ash1 by the ubiquitin-proteasome system thus underpins developmental asymmetry in budding yeast.

Links

PubMed PMC3028614 Online version:10.1128/MCB.00845-10

Keywords

Amino Acid Sequence; CDC28 Protein Kinase, S cerevisiae/metabolism; Cell Cycle; Cell Cycle Proteins/metabolism; Cyclin-Dependent Kinases/metabolism; F-Box Proteins/metabolism; Gene Silencing; Genes, Mating Type, Fungal; Molecular Sequence Data; Phosphorylation; Phosphothreonine/metabolism; Protein Binding; Protein Processing, Post-Translational; Protein Stability; Protein Transport; Repressor Proteins/chemistry; Repressor Proteins/metabolism; Saccharomyces cerevisiae/cytology; Saccharomyces cerevisiae/enzymology; Saccharomyces cerevisiae/genetics; Saccharomyces cerevisiae Proteins/chemistry; Saccharomyces cerevisiae Proteins/metabolism; Transcription, Genetic; Ubiquitin-Protein Ligases/metabolism; Ubiquitination

Significance

Annotations

Gene product Qualifier GO Term Evidence Code with/from Aspect Extension Notes Status

YEAST:CDK1

involved_in

GO:0044257: cellular protein catabolic process

ECO:0000315: mutant phenotype evidence used in manual assertion

P

  • has_input:(UniProtKB:P34233)

Seeded From UniProt

complete

YEAST:CDC4

contributes_to

GO:0061630: ubiquitin protein ligase activity

ECO:0000315: mutant phenotype evidence used in manual assertion

F

  • has_input:(UniProtKB:P34233)

Seeded From UniProt

complete

YEAST:CDK1

involved_in

GO:0044257: cellular protein catabolic process

ECO:0000315: mutant phenotype evidence used in manual assertion

P

has_direct_input:(UniProtKB:P34233)

Seeded From UniProt

complete

Notes

See also

References

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