title: Phosphorylation of the mitotic regulator Pds1/securin by Cdc28 is required for efficient nuclear localization of Esp1/separase.
abstract: Sister chromatid separation at the metaphase-to-anaphase transition is induced by the proteolytic cleavage of one of the cohesin complex subunits. This process is mediated by a conserved protease called separase. Separase is associated with its inhibitor, securin, until the time of anaphase initiation, when securin is degraded in an anaphase-promoting complex/cyclosome (APC/C)-dependent manner. In budding yeast securin/Pds1 not only inhibits separase/Esp1, but also promotes its nuclear localization. The molecular mechanism and regulation of this nuclear targeting are presently unknown. Here we show that Pds1 is a substrate of the cyclin-dependent kinase Cdc28. Phosphorylation of Pds1 by Cdc28 is important for efficient binding of Pds1 to Esp1 and for promoting the nuclear localization of Esp1. Our results uncover a previously unknown mechanism for regulating the Pds1-Esp1 interaction and shed light on a novel role for Cdc28 in promoting the metaphase-to-anaphase transition in budding yeast.
authors.affiliation: The Laboratory of Molecular and Cellular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Ritu
authors.initials: R
authors.lastname: Agarwal
authors.forename: Orna
authors.initials: O
authors.lastname: Cohen-Fix
mesh_terms: D021581:Active Transport, Cell Nucleus; D000409:Alanine / Q000737:chemistry; D000595:Amino Acid Sequence; D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002842:Chromatids / Q000378:metabolism; D004249:DNA Damage; D010450:Endopeptidases; D004926:Escherichia coli / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008938:Mitosis; D008954:Models, Biological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D029701:Saccharomyces cerevisiae Proteins; D064249:Securin; D064247:Separase; D013696:Temperature; D013997:Time Factors; D015003:Yeasts / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; C578004:PDS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D064249:Securin; D017489:CDC28 Protein Kinase, S cerevisiae; D010744:Phosphoric Monoester Hydrolases; D010450:Endopeptidases; C577986:ESP1 protein, S cerevisiae; D064247:Separase; D000409:Alanine