Fission yeast Fizzy-related protein srw1p is a G(1)-specific promoter of mitotic cyclin B degradation.
Downregulation of cyclin-dependent kinase (Cdk)-mitotic cyclin complexes is important during cell cycle progression and in G(1) arrested cells undergoing differentiation. srw1p, a member of the Fizzy-related protein family in fission yeast, is required for the degradation of cdc13p mitotic cyclin B during G(1) arrest. Here we show that srw1p is not required for the degradation of cdc13p during mitotic exit demonstrating that there are two systems operative at different stages of the cell cycle for cdc13p degradation, and that srw1p is phosphorylated by Cdk-cdc13p only becoming dephosphorylated during G(1) arrest. We propose that this phosphorylation targets srw1p for proteolysis and inhibits its activity to promote cdc13p turnover.
Cell Cycle Laboratory, Imperial Cancer Research Fund, 44 Lincoln's Inn Fields, London WC2A 3PX, UK.
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Yamaguchi
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Okayama
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Nurse
D016203:CDC2 Protein Kinase / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D019926:Cyclin B / Q000378:metabolism*; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D016193:G1 Phase / Q000502:physiology*; D010766:Phosphorylation; D012568:Schizosaccharomyces / Q000166:cytology / Q000502:physiology*; D029702:Schizosaccharomyces pombe Proteins
D018797:Cell Cycle Proteins; D019926:Cyclin B; D005656:Fungal Proteins; D029702:Schizosaccharomyces pombe Proteins; C113000:srw1 protein, S pombe; D016203:CDC2 Protein Kinase; D018844:Cyclin-Dependent Kinases