Genetic and biochemical evidence for yeast GCN2 protein kinase polymerization

Gene. 1994 May 27;143(1):21-7. doi: 10.1016/0378-1119(94)90599-1.

Abstract

The GCN2 (general control kinase 2) protein is an eIF2-alpha (eukaryotic initiation factor alpha) kinase which mediates translational derepression of the yeast general control transcriptional activator, GCN4, upon amino-acid starvation. We isolated and characterized GCN2 mutations differentially affecting GCN2 function. Mutations mapping in, or close to, the ATP-binding site of the kinase moiety result in constitutively activated GCN2 molecules. A C-terminal regulatory mutation dramatically affects translation initiation rates resulting in pleiotropic phenotypes. The effect of mutations in both regions were found to depend on eIF2-alpha phosphorylation. We have demonstrated that GCN2 mutants have altered autophosphorylation activities in vitro, depending on the presence or absence of a wild-type GCN2 gene and that GCN2 elutes in gel-filtration chromatography fractions with high apparent molecular mass. Both these genetic and biochemical findings suggest that GCN2 functioning might involve polymerization to form dimers or tetramers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / metabolism
  • Chromatography, Gel
  • DNA Mutational Analysis
  • DNA-Binding Proteins*
  • Eukaryotic Initiation Factor-2 / metabolism
  • Fungal Proteins / biosynthesis*
  • Fungal Proteins / genetics
  • Gene Expression Regulation, Enzymologic
  • Gene Expression Regulation, Fungal
  • Genes, Fungal*
  • Mutation
  • Peptide Initiation Factors / metabolism
  • Peptide Mapping
  • Phosphorylation
  • Protein Biosynthesis*
  • Protein Kinases / biosynthesis*
  • Protein Kinases / chemistry
  • Protein Serine-Threonine Kinases
  • RNA, Messenger / metabolism
  • Repressor Proteins / metabolism
  • Ribosomes / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins*
  • Signal Transduction
  • Transcription Factors / genetics*

Substances

  • Amino Acids
  • DNA-Binding Proteins
  • Eukaryotic Initiation Factor-2
  • Fungal Proteins
  • Peptide Initiation Factors
  • RNA, Messenger
  • Repressor Proteins
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • Protein Kinases
  • GCN2 protein, S cerevisiae
  • Protein Serine-Threonine Kinases