title: Protein kinase activity associated with the IME2 gene product, a meiotic inducer in the yeast Saccharomyces cerevisiae.
abstract: The IME2 gene product (Ime2) is required for entry into meiosis and sporulation in S. cerevisiae. It has been predicted to be composed of two domains, an amino-terminal domain with homology to protein kinases and a carboxy-terminal acidic domain. The Ime2 was identified in extracts of meiotic cells carrying multi- but not low-copy IME2 in immunoblot analysis using an Ime2-specific antibody. Immune complexes were found to phosphorylate Ime2 and several exogenous proteins. Low-copy plasmids expressing truncated Ime2 proteins that lack part of or the entire carboxy-terminal domain enabled cells to undergo sporulation even under a certain repressive nutritional condition. These cells contained increased levels of protein kinase activity compared with control cells. These results suggest that the amino-terminal domain has a protein kinase activity and that the acidic tail is not essential for either the kinase activity or sporulation but serves in a negative role. An Ime2-beta-galactosidase fusion was shown by immunofluorescence microscopy to be localized predominantly to the nucleus, suggesting a nuclear function of Ime2.
authors.affiliation: Center for Gene Science, Hiroshima University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kominami
authors.forename: Y
authors.initials: Y
authors.lastname: Sakata
authors.forename: M
authors.initials: M
authors.lastname: Sakai
authors.forename: I
authors.initials: I
authors.lastname: Yamashita
mesh_terms: D000936:Antigen-Antibody Complex; D001483:Base Sequence; D018797:Cell Cycle Proteins; D003470:Culture Media; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins; D008540:Meiosis; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010957:Plasmids; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D013050:Spectrometry, Fluorescence; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D000936:Antigen-Antibody Complex; D018797:Cell Cycle Proteins; D003470:Culture Media; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; C064979:IME2 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D001616:beta-Galactosidase