Phosphorylation by Cdc28 activates the Cdc20-dependent activity of the anaphase-promoting complex.
Budding yeast initiates anaphase by activating the Cdc20-dependent anaphase-promoting complex (APC). The mitotic activity of Cdc28 (Cdk1) is required to activate this form of the APC, and mutants that are impaired in mitotic Cdc28 function have difficulty leaving mitosis. This defect can be explained by a defect in APC phosphorylation, which depends on mitotic Cdc28 activity in vivo and can be catalyzed by purified Cdc28 in vitro. Mutating putative Cdc28 phosphorylation sites in three components of the APC, Cdc16, Cdc23, and Cdc27, makes the APC resistant to phosphorylation both in vivo and in vitro. The nonphosphorylatable APC has normal activity in G1, but its mitotic, Cdc20-dependent activity is compromised. These results show that Cdc28 activates the APC in budding yeast to trigger anaphase. Previous reports have shown that the budding yeast Cdc5 homologue, Plk, can also phosphorylate and activate the APC in vitro. We show that, like cdc28 mutants, cdc5 mutants affect APC phosphorylation in vivo. However, although Cdc5 can phosphorylate Cdc16 and Cdc27 in vitro, this in vitro phosphorylation does not occur on in vivo sites of phosphorylation.
Rudner
A D
AD
Department of Physiology, University of California, San Francisco, California 94143-0444, USA.
Murray
A W
AW
D048868:Adaptor Proteins, Signal Transducing; D000705:Anaphase / Q000502:physiology*; D064173:Anaphase-Promoting Complex-Cyclosome; D064191:Apc3 Subunit, Anaphase-Promoting Complex-Cyclosome; D064194:Apc6 Subunit, Anaphase-Promoting Complex-Cyclosome; D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; D001665:Binding Sites / Q000502:physiology; D042846:CDC2-CDC28 Kinases; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism; D016193:G1 Phase / Q000502:physiology; D008938:Mitosis / Q000502:physiology*; D009154:Mutation / Q000235:genetics*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism*; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D004718:Saccharomycetales / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D013997:Time Factors; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases
D048868:Adaptor Proteins, Signal Transducing; D064191:Apc3 Subunit, Anaphase-Promoting Complex-Cyclosome; D064194:Apc6 Subunit, Anaphase-Promoting Complex-Cyclosome; D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; C577397:CDC16 protein, S cerevisiae; C577495:CDC20 protein, S cerevisiae; C577441:CDC23 protein, S cerevisiae; C577355:CDC27 protein, S cerevisiae; C513239:CEF1 protein, S cerevisiae; C081185:CKS1 protein, S cerevisiae; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D044767:Ubiquitin-Protein Ligases; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases