Cdc28-Clb mitotic kinase negatively regulates bud site assembly in the budding yeast.
In the budding yeast Saccharomyces cerevisiae, a prospective mother normally commences the formation of a daughter (the bud) only in the G(1) phase of the cell division cycle. This suggests a strict temporal regulation of the processes that initiate the formation of a new bud. Using cortical localization of bud site components Spa2 and Bni1 as an indicator of bud site assembly, we show that cells assemble a bud site following inactivation of the Cdc28-Clb mitotic kinase but prior to START. Interestingly, an untimely inactivation of the mitotic kinase is sufficient to drive cells to assemble a new bud site inappropriately in G(2) or M phases. The induction of Cdc28/Clb kinase activity in G(1), on the other hand, dramatically reduces a cell's ability to construct an incipient bud site. Our findings strongly suggest that the Cdc28-Clb kinase plays a critical role in the mechanism that restricts the timing of bud formation to the G(1) phase of the cell cycle.
Padmashree
C G
CG
Institute of Molecular and Cell Biology, Medical Drive, Singapore 117609.
Surana
U
U
D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism*; D020756:Coatomer Protein; D019926:Cyclin B / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins / Q000378:metabolism; D016193:G1 Phase; D012441:Saccharomyces cerevisiae / Q000254:growth & development*; D029701:Saccharomyces cerevisiae Proteins
C093749:CLB2 protein, S cerevisiae; D020756:Coatomer Protein; D019926:Cyclin B; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; C065889:SPA2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C089602:Sec27 protein, S cerevisiae; D017489:CDC28 Protein Kinase, S cerevisiae