title: The role of phosphorylation and the CDC28 protein kinase in cell cycle-regulated nuclear import of the S. cerevisiae transcription factor SWI5.
abstract: The intracellular localization of the S. cerevisiae transcription factor SWI5 is cell cycle dependent. The protein is nuclear in G1 cells but cytoplasmic in S, G2, and M phase cells. We have identified SWI5's nuclear localization signal (NLS) and show that it can confer cell cycle-dependent nuclear entry to a heterologous protein. Located within or close to the NLS are three serine residues, mutation of which results in constitutive nuclear entry. These residues are phosphorylated in a cell cycle-dependent manner in vivo, being phosphorylated when SWI5 is in the cytoplasm and dephosphorylated when it is in the nucleus. As all three serines are phosphorylated by purified CDC28-dependent H1 kinase activity in vitro, we propose a model in which the CDC28 kinase acts directly to control nuclear entry of SWI5.
authors.affiliation: Institute for Molecular Pathology, Vienna, Austria.
authors.forename: T
authors.initials: T
authors.lastname: Moll
authors.forename: G
authors.initials: G
authors.lastname: Tebb
authors.forename: U
authors.initials: U
authors.lastname: Surana
authors.forename: H
authors.initials: H
authors.lastname: Robitsch
authors.forename: K
authors.initials: K
authors.lastname: Nasmyth
mesh_terms: D000595:Amino Acid Sequence; D002451:Cell Compartmentation; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000378:metabolism*; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D006657:Histones / Q000378:metabolism; D016200:Maturation-Promoting Factor / Q000378:metabolism*; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D006656:Protamine Kinase / Q000378:metabolism*; D011494:Protein Kinases / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D006657:Histones; D010750:Phosphoproteins; C080218:SWI5 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D011494:Protein Kinases; D006656:Protamine Kinase; D016200:Maturation-Promoting Factor