title: Exit from mitosis in budding yeast: biphasic inactivation of the Cdc28-Clb2 mitotic kinase and the role of Cdc20.
abstract: Cdc20, an activator of the anaphase-promoting complex (APC), is also required for the exit from mitosis in Saccharomyces cerevisiae. Here we show that during mitosis, both the inactivation of Cdc28-Clb2 kinase and the degradation of mitotic cyclin Clb2 occur in two steps. The first phase of Clb2 proteolysis, which commences at the metaphase-to-anaphase transition when Clb2 abundance is high, is dependent on Cdc20. The second wave of Clb2 destruction in telophase requires activation of the Cdc20 homolog, Hct1/Cdh1. The first phase of Clb2 destruction, which lowers the Cdc28-Clb2 kinase activity, is a prerequisite for the second. Thus, Clb2 proteolysis is not solely mediated by Hct1 as generally believed; instead, it requires a sequential action of both Cdc20 and Hct1.
authors.affiliation: Institute of Molecular and Cell Biology, Singapore.
authors.forename: F M
authors.initials: FM
authors.lastname: Yeong
authors.forename: H H
authors.initials: HH
authors.lastname: Lim
authors.forename: C G
authors.initials: CG
authors.lastname: Padmashree
authors.forename: U
authors.initials: U
authors.lastname: Surana
mesh_terms: D000705:Anaphase / Q000502:physiology; D064173:Anaphase-Promoting Complex-Cyclosome; D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism*; D064199:Cdc20 Proteins; D064200:Cdh1 Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D019926:Cyclin B / Q000378:metabolism*; D005656:Fungal Proteins; D019204:GTP-Binding Proteins / Q000235:genetics; D008025:Ligases / Q000378:metabolism; D008938:Mitosis / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D013692:Telophase / Q000502:physiology; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases
chemical_list: C082279:CDC15 protein; C577495:CDC20 protein, S cerevisiae; C577583:CDH1 protein, S cerevisiae; C093749:CLB2 protein, S cerevisiae; C076558:CLB5 protein, S cerevisiae; D064199:Cdc20 Proteins; D064200:Cdh1 Proteins; D018797:Cell Cycle Proteins; D019926:Cyclin B; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D044767:Ubiquitin-Protein Ligases; D017489:CDC28 Protein Kinase, S cerevisiae; D019204:GTP-Binding Proteins; D008025:Ligases