Protein kinase activity associated with the IME2 gene product, a meiotic inducer in the yeast Saccharomyces cerevisiae

Biosci Biotechnol Biochem. 1993 Oct;57(10):1731-5. doi: 10.1271/bbb.57.1731.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigen-Antibody Complex
  • Base Sequence
  • Cell Cycle Proteins*
  • Culture Media
  • Fungal Proteins / chemistry
  • Fungal Proteins / genetics
  • Fungal Proteins / immunology
  • Fungal Proteins / metabolism*
  • Immunoblotting
  • Intracellular Signaling Peptides and Proteins
  • Meiosis
  • Molecular Sequence Data
  • Phosphorylation
  • Plasmids
  • Protein Kinases / chemistry
  • Protein Kinases / genetics
  • Protein Kinases / immunology
  • Protein Kinases / metabolism*
  • Protein-Serine-Threonine Kinases
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins*
  • Spectrometry, Fluorescence
  • Transcription, Genetic
  • beta-Galactosidase / metabolism

Substances

  • Antigen-Antibody Complex
  • Cell Cycle Proteins
  • Culture Media
  • Fungal Proteins
  • Intracellular Signaling Peptides and Proteins
  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • Protein Kinases
  • IME2 protein, S cerevisiae
  • Protein-Serine-Threonine Kinases
  • beta-Galactosidase