title: Phosphorylation of the cohesin subunit Scc1 by Polo/Cdc5 kinase regulates sister chromatid separation in yeast.
abstract: At the onset of anaphase, a caspase-related protease (separase) destroys the link between sister chromatids by cleaving the cohesin subunit Scc1. During most of the cell cycle, separase is kept inactive by binding to an inhibitory protein called securin. Separase activation requires proteolysis of securin, which is mediated by an ubiquitin protein ligase called the anaphase-promoting complex. Cells regulate anaphase entry by delaying securin ubiquitination until all chromosomes have attached to the mitotic spindle. Though no longer regulated by this mitotic surveillance mechanism, sister separation remains tightly cell cycle regulated in yeast mutants lacking securin. We show here that the Polo/Cdc5 kinase phosphorylates serine residues adjacent to Scc1 cleavage sites and strongly enhances their cleavage. Phosphorylation of separase recognition sites may be highly conserved and regulates sister chromatid separation independently of securin.
authors.affiliation: Research Institute of Molecular Pathology (IMP), Dr Bohr-Gasse 7, A-1030, Vienna, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Alexandru
authors.forename: F
authors.initials: F
authors.lastname: Uhlmann
authors.forename: K
authors.initials: K
authors.lastname: Mechtler
authors.forename: M A
authors.initials: MA
authors.lastname: Poupart
authors.forename: K
authors.initials: K
authors.lastname: Nasmyth
mesh_terms: D000595:Amino Acid Sequence; D000705:Anaphase / Q000502:physiology; D064173:Anaphase-Promoting Complex-Cyclosome; D016203:CDC2 Protein Kinase / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002503:Centromere / Q000235:genetics / Q000378:metabolism; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone; D017124:Conserved Sequence; D029721:Drosophila Proteins; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D008025:Ligases / Q000235:genetics / Q000378:metabolism; D008677:Metaphase / Q000502:physiology; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D064249:Securin; D012694:Serine; D012854:Sister Chromatid Exchange / Q000502:physiology*; D016615:Telomere / Q000235:genetics / Q000378:metabolism; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases; D015003:Yeasts / Q000201:enzymology / Q000235:genetics; D000097722:Cohesins
chemical_list: D064173:Anaphase-Promoting Complex-Cyclosome; D016203:CDC2 Protein Kinase; D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D010450:Endopeptidases; D005656:Fungal Proteins; D008025:Ligases; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D029701:Saccharomyces cerevisiae Proteins; D064249:Securin; D012694:Serine; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases; D000097722:Cohesins; C490529:MCD1 protein, S cerevisiae; C578004:PDS1 protein, S cerevisiae; C081927:CDC5 protein, S cerevisiae