Glucose inhibits meiotic DNA replication through SCFGrr1p-dependent destruction of Ime2p kinase.
In the budding yeast Saccharomyces cerevisiae, the cell division cycle and sporulation are mutually exclusive cell fates; glucose, which stimulates the cell division cycle, is a potent inhibitor of sporulation. Addition of moderate concentrations of glucose (0.5%) to sporulation medium did not inhibit transcription of two key activators of sporulation, IME1 and IME2, but did increase levels of Sic1p, a cyclin-dependent kinase inhibitor, resulting in a block to meiotic DNA replication. The effects of glucose on Sic1p levels and DNA replication required Grr1p, a component of the SCF(Grr1p) ubiquitin ligase. Sic1p is negatively regulated by Ime2p kinase, and several observations indicate that glucose inhibits meiotic DNA replication through SCF(Grr1p)-mediated destruction of this kinase. First, Ime2p was destabilized in the presence of glucose, and this turnover required Grr1p, a second component of SCF(Grr1p), Cdc53p, and an SCF(Grr1p)-associated E2 enzyme, Cdc34p. Second, Ime2p-ubiquitin conjugates were detected under conditions of rapid Ime2p turnover, and conjugation of Ime2p to ubiquitin required GRR1. Third, a mutant form of Ime2p (Ime2(DeltaPEST)), in which a putative Grr1p-interacting sequence was deleted, was more stable than wild-type Ime2p. Finally, expression of the IME2(DeltaPEST) allele bypassed the block to meiotic DNA replication caused by 0.5% glucose. In addition, Grr1p is required for later events in sporulation independently of its role in Ime2p turnover.
Purnapatre
Kedar
K
Division of Cell Biology and Biophysics, University of Missouri-Kansas City, 5007 Rockhill Road., Kansas City, MO 64110, USA.
Gray
Misa
M
Piccirillo
Sarah
S
Honigberg
Saul M
SM
D000483:Alleles; D064173:Anaphase-Promoting Complex-Cyclosome; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D002469:Cell Separation; D003001:Cloning, Molecular; D003470:Culture Media / Q000378:metabolism / Q000494:pharmacology; D050756:Cyclin-Dependent Kinase Inhibitor Proteins; D004247:DNA / Q000378:metabolism; D004261:DNA Replication; D044783:F-Box Proteins; D005434:Flow Cytometry; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008540:Meiosis; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D012313:RNA / Q000378:metabolism; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D013997:Time Factors; D014158:Transcription, Genetic; D025801:Ubiquitin / Q000378:metabolism; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000502:physiology*
D018797:Cell Cycle Proteins; D003470:Culture Media; D050756:Cyclin-Dependent Kinase Inhibitor Proteins; D044783:F-Box Proteins; D047908:Intracellular Signaling Peptides and Proteins; C086926:SIC1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D025801:Ubiquitin; C071032:GRR1 protein, S cerevisiae; D012313:RNA; D004247:DNA; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D044767:Ubiquitin-Protein Ligases; D011494:Protein Kinases; C064979:IME2 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D005947:Glucose