title: Cdc20 is essential for the cyclosome-mediated proteolysis of both Pds1 and Clb2 during M phase in budding yeast.
abstract: Chromosome separation during the cell-cycle transition from metaphase to anaphase requires the proteolytic destruction of anaphase inhibitors such as Pds1 [1-3]. Proteolysis of Pds1 is mediated by a ubiquitin-protein ligase, the anaphase-promoting complex (APC) or cyclosome [4,5]. The APC is also necessary for the ubiquitin-dependent degradation of mitotic cyclins in late telophase as cells exit mitosis [6-9]. Although phosphorylation seems to be involved [10], it is not clear what activates the APC at the onset of anaphase. In Saccharomyces cerevisiae, chromosome segregation also requires the CDC20 gene, whose product contains WD40 repeats [11,12]. We have investigated the functional relationship between the APC and the Cdc20 protein. We present evidence that strongly suggests that Cdc20 is an essential regulator of APC-dependent proteolysis such that in the absence of Cdc20, cells are unable to degrade either Pds1 at the onset of anaphase or the mitotic cyclin Clb2 during telophase. This notion is consistent with our observations that Cdc20 is localized in the nucleus and co-immunoprecipitates with an APC component, Cdc23.
authors.affiliation: Institute of Molecular and Cell Biology, Singapore.
authors.forename: H H
authors.initials: HH
authors.lastname: Lim
authors.forename: P Y
authors.initials: PY
authors.lastname: Goh
authors.forename: U
authors.initials: U
authors.lastname: Surana
mesh_terms: D064173:Anaphase-Promoting Complex-Cyclosome; D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism*; D019926:Cyclin B; D016213:Cyclins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D006868:Hydrolysis; D008025:Ligases / Q000378:metabolism*; D008938:Mitosis; D009687:Nuclear Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D064249:Securin; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases
chemical_list: D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; C577495:CDC20 protein, S cerevisiae; C577441:CDC23 protein, S cerevisiae; C093749:CLB2 protein, S cerevisiae; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D019926:Cyclin B; D016213:Cyclins; D005656:Fungal Proteins; D009687:Nuclear Proteins; C578004:PDS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D064249:Securin; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D044767:Ubiquitin-Protein Ligases; D008025:Ligases