Far1 and Fus3 link the mating pheromone signal transduction pathway to three G1-phase Cdc28 kinase complexes.
In the yeast Saccharomyces cerevisiae, the Cdc28 protein kinase controls commitment to cell division at Start, but no biologically relevant G1-phase substrates have been identified. We have studied the kinase complexes formed between Cdc28 and each of the G1 cyclins Cln1, Cln2, and Cln3. Each complex has a specific array of coprecipitated in vitro substrates. We identify one of these as Far1, a protein required for pheromone-induced arrest at Start. Treatment with alpha-factor induces a preferential association and/or phosphorylation of Far1 by the Cln1, Cln2, and Cln3 kinase complexes. This induced interaction depends upon the Fus3 protein kinase, a mitogen-activated protein kinase homolog that functions near the bottom of the alpha-factor signal transduction pathway. Thus, we trace a path through which a mitogen-activated protein kinase regulates a Cdc2 kinase.
Banting and Best Department of Medical Research, University of Toronto, Ontario, Canada.
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Tyers
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Futcher
D000595:Amino Acid Sequence; D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D050756:Cyclin-Dependent Kinase Inhibitor Proteins; D016213:Cyclins / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D000072235:Mating Factor; D020928:Mitogen-Activated Protein Kinases; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism; D012097:Repressor Proteins; D012441:Saccharomyces cerevisiae / Q000166:cytology*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction
C082719:CLN1 protein, S cerevisiae; C082721:CLN2 protein, S cerevisiae; C079895:CLN3 protein, S cerevisiae; D018797:Cell Cycle Proteins; D050756:Cyclin-Dependent Kinase Inhibitor Proteins; D016213:Cyclins; C081353:FAR1 protein, S cerevisiae; D005656:Fungal Proteins; D046911:Macromolecular Substances; D010455:Peptides; D010750:Phosphoproteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D000072235:Mating Factor; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D017489:CDC28 Protein Kinase, S cerevisiae; C075580:FUS3 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases