Rapid degradation of the G1 cyclin Cln2 induced by CDK-dependent phosphorylation.
Cyclins regulate the major cell cycle transitions in eukaryotes through association with cyclin-dependent protein kinases (CDKs). In yeast, G1 cyclins are essential, rate-limiting activators of cell cycle initiation. G1-specific accumulation of one G1 cyclin, Cln2, results from periodic gene expression coupled with rapid protein turnover. Site-directed mutagenesis of CLN2 revealed that its phosphorylation provides a signal that promotes rapid degradation. Cln2 phosphorylation is dependent on the Cdc28 protein kinase, the CDK that it activates. These findings suggest that Cln2 is rendered self-limiting by virtue of its ability to activate its cognate CDK subunit.
Lanker
S
S
Department of Molecular Biology, Scripps Research Institute, La Jolla, CA 92037, USA.
Valdivieso
M H
MH
Wittenberg
C
C
D000595:Amino Acid Sequence; D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism*; D016213:Cyclins / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D016193:G1 Phase; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010641:Phenotype; D010766:Phosphorylation; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
C082721:CLN2 protein, S cerevisiae; D016213:Cyclins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D017489:CDC28 Protein Kinase, S cerevisiae