FAR1 links the signal transduction pathway to the cell cycle machinery in yeast.
Alpha factor induces arrest of yeast a cells in G1 and transcription of genes involved in mating. Prior work indicates that FUS3, a member of the MAP kinase family, and FAR1, whose molecular activity is unknown, contribute to cell cycle arrest by inhibiting G1 cyclins. Here we show that FAR1 is a substrate for FUS3 and that this phosphorylation regulates association of FAR1 with CDC28-CLN2 kinase. We show also that FAR1 is phosphorylated in vitro by the CDC28-CLN2 complex and in vivo in a CDC28-dependent manner. Mutational analysis of FAR1 reveals a correlation between its ability to associate with CDC28-CLN2 and to arrest the cell cycle. These results suggest that FAR1 protein is the link between the signaling pathway and the cell cycle machinery.
Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0448.
M
M
Peter
A
A
Gartner
J
J
Horecka
G
G
Ammerer
I
I
Herskowitz
D000595:Amino Acid Sequence; D001483:Base Sequence; D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins; D050756:Cyclin-Dependent Kinase Inhibitor Proteins; D004252:DNA Mutational Analysis; D005656:Fungal Proteins / Q000378:metabolism*; D000072235:Mating Factor; D020928:Mitogen-Activated Protein Kinases; D008969:Molecular Sequence Data; D010455:Peptides; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding; D012097:Repressor Proteins; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction / Q000502:physiology*
D018797:Cell Cycle Proteins; D050756:Cyclin-Dependent Kinase Inhibitor Proteins; C081353:FAR1 protein, S cerevisiae; D005656:Fungal Proteins; D010455:Peptides; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D000072235:Mating Factor; D017489:CDC28 Protein Kinase, S cerevisiae; C075580:FUS3 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases