Functional Complementation by Wheat eIF2α in the Yeast GCN2-Mediated Pathway

Chang, Liyun; Yang, Woo Young; Roth, Don A.

doi:10.1006/bbrc.2000.3964

Cited by 15 publications

(7 citation statements)

References 23 publications

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“…Wheat eIF2α is also phosphorylated at Ser51 and this correlates with decreased translational rates in vitro (Langland et al, 1996;Chang et al, 1999). Although no changes in the level of eIF2α were observed following heat shock (Gallie et al, 1997), wheat eIF2α was phosphorylated and could functionally complement the corresponding yeast mutant under amino acid starvation conditions, suggesting a conserved role for plant eIF2 in translational regulation (Chang et al, 2000). However, whether the possible involvement of eIF2α phosphorylation in translational control is mediated through differential interaction with eIF2B or through some other mechanism remains to be determined.…”

Section: Eifsmentioning

confidence: 97%

“…Arabidopsis GCN2 (AtGCN2) is able to complement its corresponding yeast mutant under amino acid starvation conditions (Zhang et al, 2003), and conversely, yeast GCN2 phosphorylates wheat eIF2α (Chang et al, 1999;Chang et al, 2000). Furthermore, eIF2α is phosphorylated in response to several stresses and this activation is absent in Arabidopsis gcn2 mutants (Lageix et al, 2008;.…”

Section: Gcn2 (General Control Non-repressed 2)mentioning

confidence: 99%

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Energy Signaling in the Regulation of Gene Expression during Stress

2010

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Maintenance of homeostasis is pivotal to all forms of life. In the case of plants, homeostasis is constantly threatened by the inability to escape environmental fluctuations, and therefore sensitive mechanisms must have evolved to allow rapid perception of environmental cues and concomitant modification of growth and developmental patterns for adaptation and survival. Re-establishment of homeostasis in response to environmental perturbations requires reprogramming of metabolism and gene expression to shunt energy sources from growth-related biosynthetic processes to defense, acclimation, and, ultimately, adaptation. Failure to mount an initial 'emergency' response may result in nutrient deprivation and irreversible senescence and cell death. Early signaling events largely determine the capacity of plants to orchestrate a successful adaptive response. Early events, on the other hand, are likely to be shared by different conditions through the generation of similar signals and before more specific responses are elaborated. Recent studies lend credence to this hypothesis, underpinning the importance of a shared energy signal in the transcriptional response to various types of stress. Energy deficiency is associated with most environmental perturbations due to their direct or indirect deleterious impact on photosynthesis and/or respiration. Several systems are known to have evolved for monitoring the available resources and triggering metabolic, growth, and developmental decisions accordingly. In doing so, energy-sensing systems regulate gene expression at multiple levels to allow flexibility in the diversity and the kinetics of the stress response.

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Section: Eifsmentioning

confidence: 97%

Section: Gcn2 (General Control Non-repressed 2)mentioning

confidence: 99%

Energy Signaling in the Regulation of Gene Expression during Stress

2010

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“…Yeast GCN2 has been shown to phosphorylate wheat eIF2α in vitro at this site (Chang et al. , 1999) and wheat eIF2α complements eIF2α deletion mutants of yeast, restoring a fully functional general amino acid control system (Chang et al. , 2000).…”

Section: Introductionmentioning

confidence: 99%

Overexpression of GCN2‐type protein kinase in wheat has profound effects on free amino acid concentration and gene expression

Byrne

Prosser

Muttucumaru

et al. 2011

Plant Biotechnology Journal

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SummaryA key point of regulation of protein synthesis and amino acid homoeostasis in eukaryotes is the phosphorylation of the a subunit of eukaryotic translation initiation factor 2 (eIF2a) by protein kinase general control nonderepressible (GCN)-2. In this study, a GCN2-type PCR product (TaGCN2) was amplified from wheat (Triticum aestivum) RNA, while a wheat eIF2a homologue was identified in wheat genome data and found to contain a conserved target site for phosphorylation by GCN2. TaGCN2 overexpression in transgenic wheat resulted in significant decreases in total free amino acid concentration in the grain, with free asparagine concentration in particular being much lower than in controls. There were significant increases in the expression of eIF2a and protein phosphatase PP2A, as well as a nitrate reductase gene and genes encoding phosphoserine phosphatase and dihydrodipicolinate synthase, while the expression of an asparagine synthetase (AS1) gene and genes encoding cystathionine gamma-synthase and sulphur-deficiency-induced-1 all decreased significantly. Sulphur deficiency-induced activation of these genes occurred in wild-type plants but not in TaGCN2 overexpressing lines. Under sulphur deprivation, the expression of genes encoding aspartate kinase ⁄ homoserine dehydrogenase and 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase was also lower than in controls. The study demonstrates that TaGCN2 plays an important role in the regulation of genes encoding enzymes of amino acid biosynthesis in wheat and is the first to implicate GCN2-type protein kinases so clearly in sulphur signalling in any organism. It shows that manipulation of TaGCN2 gene expression could be used to reduce free asparagine accumulation in wheat grain and the risk of acrylamide formation in wheat products.

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“…Phosphorylation of eIF2a inhibits the recycling of bound GDP to GTP, decreasing the rate of protein synthesis. The phosphorylation site at serine-51 is conserved in eIF2a homologues from a wide range of eukaryotes, including wheat, and yeast GCN2 will phosphorylate wheat eIF2a at this position (Chang et al 1999(Chang et al , 2000.…”

Section: Introductionmentioning

confidence: 99%

Molecular cloning of an arabidopsis homologue of GCN2, a protein kinase involved in co-ordinated response to amino acid starvation

Zhang

Dickinson

Paul

et al. 2003

Planta

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DNA homologous to the yeast ( Saccharomyces cerevisiae) protein kinase gene, GCN2, was amplified from arabidopsis [ Arabidopsis thaliana (L.) Heynh.] RNA and given the name AtGCN2. The AtGCN2 peptide sequence included adjacent protein kinase and histidyl tRNA synthetase-like domains and showed 45% sequence identity with the GCN2 peptide sequence in the protein kinase domain. AtGCN2 transcripts were detectable in RNA from roots, leaves, stems, buds, flowers, siliques and seedlings. GCN2 is required for yeast cells to respond to amino acid starvation. Expression of AtGCN2 in yeast gcn2 mutants complemented the mutation, enabling growth in the presence of sulfometuron methyl, an inhibitor of branched-chain amino acid biosynthesis, and 3-aminotriazole, an inhibitor of histidine biosynthesis.

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Functional Complementation by Wheat eIF2α in the Yeast GCN2-Mediated Pathway

Cited by 15 publications

References 23 publications

Energy Signaling in the Regulation of Gene Expression during Stress

Energy Signaling in the Regulation of Gene Expression during Stress

Overexpression of GCN2‐type protein kinase in wheat has profound effects on free amino acid concentration and gene expression

Molecular cloning of an arabidopsis homologue of GCN2, a protein kinase involved in co-ordinated response to amino acid starvation

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