Juxtaposition of domains homologous to protein kinase and histidyl-tRNA synthetases in GCN2 protein suggests a mechanism for coupling GCN4 expression to amino acid availability

Ronald Wek, B. M. Jackson, A. G. Hinnebusch

Research output: Contribution to journalArticle

178 Citations (Scopus)

Abstract

The GCN2 protein of Saccharomyces cerevisiae stimulates the expression of amino acid biosynthetic genes under conditions of amino acid starvation by derepressing GCN4, a transcriptional activator of these genes. GCN2 contains sequences homologous to the catalytic domain of protein kinases. We show here that substitution of a highly conserved lysine in the presumed ATP-binding site of this domain impairs the derepression of histidine biosynthetic genes under GCN4 control. This result supports the idea that protein kinase activity is required for GCN2 positive regulatory function. Determination of the nucleotide sequence of the entire GCN2 complementation unit, and measurement of the molecular weight of GCN2 protein expressed in vivo, indicate that GCN2 is a M(r) ~ 180,000 protein and contains a M(r) ~ 60,000 segment homologous to histidyl-tRNA synthetases (HisRSs) juxtaposed to the protein kinase domain. Several two-codon insertion mutations in the HisRS-related coding sequences inactivate GCN2 regulatory function. Based on these results, we propose that the GCN2 HisRS domain responds to the presence of uncharged tRNA by activating the adjacent protein kinase moiety, thus providing a means of coupling GCN2-mediated derepression of GCN4 expression to the availability of amino acids.

Original languageEnglish (US)
Pages (from-to)4579-4583
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume86
Issue number12
StatePublished - 1989
Externally publishedYes

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Histidine-tRNA Ligase
Protein Kinases
Amino Acids
Proteins
Genes
Saccharomyces cerevisiae Proteins
Insertional Mutagenesis
Sequence Homology
Starvation
Transfer RNA
Histidine
Codon
Lysine
Catalytic Domain
Adenosine Triphosphate
Molecular Weight
Binding Sites

ASJC Scopus subject areas

  • General
  • Genetics

Cite this

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title = "Juxtaposition of domains homologous to protein kinase and histidyl-tRNA synthetases in GCN2 protein suggests a mechanism for coupling GCN4 expression to amino acid availability",
abstract = "The GCN2 protein of Saccharomyces cerevisiae stimulates the expression of amino acid biosynthetic genes under conditions of amino acid starvation by derepressing GCN4, a transcriptional activator of these genes. GCN2 contains sequences homologous to the catalytic domain of protein kinases. We show here that substitution of a highly conserved lysine in the presumed ATP-binding site of this domain impairs the derepression of histidine biosynthetic genes under GCN4 control. This result supports the idea that protein kinase activity is required for GCN2 positive regulatory function. Determination of the nucleotide sequence of the entire GCN2 complementation unit, and measurement of the molecular weight of GCN2 protein expressed in vivo, indicate that GCN2 is a M(r) ~ 180,000 protein and contains a M(r) ~ 60,000 segment homologous to histidyl-tRNA synthetases (HisRSs) juxtaposed to the protein kinase domain. Several two-codon insertion mutations in the HisRS-related coding sequences inactivate GCN2 regulatory function. Based on these results, we propose that the GCN2 HisRS domain responds to the presence of uncharged tRNA by activating the adjacent protein kinase moiety, thus providing a means of coupling GCN2-mediated derepression of GCN4 expression to the availability of amino acids.",
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T1 - Juxtaposition of domains homologous to protein kinase and histidyl-tRNA synthetases in GCN2 protein suggests a mechanism for coupling GCN4 expression to amino acid availability

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AU - Jackson, B. M.

AU - Hinnebusch, A. G.

PY - 1989

Y1 - 1989

N2 - The GCN2 protein of Saccharomyces cerevisiae stimulates the expression of amino acid biosynthetic genes under conditions of amino acid starvation by derepressing GCN4, a transcriptional activator of these genes. GCN2 contains sequences homologous to the catalytic domain of protein kinases. We show here that substitution of a highly conserved lysine in the presumed ATP-binding site of this domain impairs the derepression of histidine biosynthetic genes under GCN4 control. This result supports the idea that protein kinase activity is required for GCN2 positive regulatory function. Determination of the nucleotide sequence of the entire GCN2 complementation unit, and measurement of the molecular weight of GCN2 protein expressed in vivo, indicate that GCN2 is a M(r) ~ 180,000 protein and contains a M(r) ~ 60,000 segment homologous to histidyl-tRNA synthetases (HisRSs) juxtaposed to the protein kinase domain. Several two-codon insertion mutations in the HisRS-related coding sequences inactivate GCN2 regulatory function. Based on these results, we propose that the GCN2 HisRS domain responds to the presence of uncharged tRNA by activating the adjacent protein kinase moiety, thus providing a means of coupling GCN2-mediated derepression of GCN4 expression to the availability of amino acids.

AB - The GCN2 protein of Saccharomyces cerevisiae stimulates the expression of amino acid biosynthetic genes under conditions of amino acid starvation by derepressing GCN4, a transcriptional activator of these genes. GCN2 contains sequences homologous to the catalytic domain of protein kinases. We show here that substitution of a highly conserved lysine in the presumed ATP-binding site of this domain impairs the derepression of histidine biosynthetic genes under GCN4 control. This result supports the idea that protein kinase activity is required for GCN2 positive regulatory function. Determination of the nucleotide sequence of the entire GCN2 complementation unit, and measurement of the molecular weight of GCN2 protein expressed in vivo, indicate that GCN2 is a M(r) ~ 180,000 protein and contains a M(r) ~ 60,000 segment homologous to histidyl-tRNA synthetases (HisRSs) juxtaposed to the protein kinase domain. Several two-codon insertion mutations in the HisRS-related coding sequences inactivate GCN2 regulatory function. Based on these results, we propose that the GCN2 HisRS domain responds to the presence of uncharged tRNA by activating the adjacent protein kinase moiety, thus providing a means of coupling GCN2-mediated derepression of GCN4 expression to the availability of amino acids.

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