Codon-specific interaction of uncharged transfer-RNA with eukaryotic ribosomes

Murchie, Margaret-Jean; Leader, David P.

doi:10.1016/0005-2787(78)90024-2

Cited by 12 publications

(6 citation statements)

References 12 publications

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“…Competition assays have indicated that aminoacylated tRNA Phe binds the enzymatically inactive HisRS-like domain of GCN2 less efficiently than deacylated tRNA Phe , suggesting GCN2 preferentially binds uncharged tRNAs ( Dong et al, 2000 ). While not as efficient as acylated tRNAs, deacylated tRNA has been demonstrated to enter the A-site of the ribosome ( Murchie and Leader, 1978 ) where models of GCN2 activation suggest that it is transferred to GCN2, possibly with the assistance of the GCN2 effector protein GCN1 to activate the kinase activity of GCN2 ( Marton et al, 1997 ; Ramirez et al, 1991 ; Wek et al, 1989 ).…”

Section: Discussionmentioning

confidence: 99%

Activation of GCN2 kinase by ribosome stalling links translation elongation with translation initiation

Ishimura

Nagy

Dotú

et al. 2016

eLife

172

141

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Ribosome stalling during translation has recently been shown to cause neurodegeneration, yet the signaling pathways triggered by stalled elongation complexes are unknown. To investigate these pathways we analyzed the brain of C57BL/6J-Gtpbp2nmf205-/- mice in which neuronal elongation complexes are stalled at AGA codons due to deficiencies in a tRNAArgUCU tRNA and GTPBP2, a mammalian ribosome rescue factor. Increased levels of phosphorylation of eIF2α (Ser51) were detected prior to neurodegeneration in these mice and transcriptome analysis demonstrated activation of ATF4, a key transcription factor in the integrated stress response (ISR) pathway. Genetic experiments showed that this pathway was activated by the eIF2α kinase, GCN2, in an apparent deacylated tRNA-independent fashion. Further we found that the ISR attenuates neurodegeneration in C57BL/6J-Gtpbp2nmf205-/- mice, underscoring the importance of cellular and stress context on the outcome of activation of this pathway. These results demonstrate the critical interplay between translation elongation and initiation in regulating neuron survival during cellular stress.DOI: http://dx.doi.org/10.7554/eLife.14295.001

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Section: Discussionmentioning

confidence: 99%

Activation of GCN2 kinase by ribosome stalling links translation elongation with translation initiation

Ishimura

Nagy

Dotú

et al. 2016

eLife

172

141

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“…By analogy with that system, we suggested that GCN2 could be activated by uncharged tRNA in the ribosomal A‐site. Consistent with this idea, it was also shown that in eukaryotes uncharged tRNAs can bind in a codon‐dependent manner to the ribosomal A‐site (Murchie and Leader, 1978). A possible role for GCN1 in facilitating GCN2 activation was prompted by its similarity to EF3 and the known functions of this essential elongation factor in stimulating release of uncharged tRNA from the ribosomal E‐site and in binding charged tRNA complexed with EF1α/GTP to the A‐site (Chakraburtty, 1999).…”

Section: Discussionmentioning

confidence: 99%

Separate domains in GCN1 for binding protein kinase GCN2 and ribosomes are required for GCN2 activation in amino acid-starved cells

2000

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GCN2 stimulates GCN4 translation in amino acid‐starved cells by phosphorylating the α‐subunit of translation initiation factor 2. GCN2 function in vivo requires the GCN1/GCN20 complex, which binds to the N‐terminal domain of GCN2. A C‐terminal segment of GCN1 (residues 2052–2428) was found to be necessary and sufficient for binding GCN2 in vivo and in vitro. Overexpression of this fragment in wild‐type cells impaired association of GCN2 with native GCN1 and had a dominant Gcn− phenotype, dependent on Arg2259 in the GCN1 fragment. Substitution of Arg2259 with Ala in full‐length GCN1 abolished complex formation with native GCN2 and destroyed GCN1 regulatory function. Consistently, the Gcn− phenotype of gcn1‐R2259A, but not that of gcn1Δ, was suppressed by overexpressing GCN2. These findings prove that GCN2 binding to the C‐terminal domain of GCN1, dependent on Arg2259, is required for high level GCN2 function in vivo. GCN1 expression conferred sensitivity to paromomycin in a manner dependent on its ribosome binding domain, supporting the idea that GCN1 binds near the ribosomal acceptor site to promote GCN2 activation by uncharged tRNA.

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“…This idea is also based on findings in prokaryotes where under amino acid starvation tRNA deacyl binds in the A-site in a codon-specific manner (18,19). Interestingly, it was shown that also in eukaryotes tRNA deacyl can enter the A-site in a codon-specific manner (20), suggesting that the mechanism of the starvation signal occurring in the A-site may be conserved from prokaryotes to eukaryotes. Although in prokaryotes tRNA deacyl binding to the A-site then leads to the activation of the ppGpp synthetase RelA and the stringent response (18,19), in eukaryotes this leads to Gcn1-dependent Gcn2 stimulation and the activation of the GAAC.…”

mentioning

confidence: 93%

Overexpression of Eukaryotic Translation Elongation Factor 3 Impairs Gcn2 Protein Activation

Visweswaraiah

Lee

Hinnebusch

et al. 2012

Journal of Biological Chemistry

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Codon-specific interaction of uncharged transfer-RNA with eukaryotic ribosomes

Cited by 12 publications

References 12 publications

Activation of GCN2 kinase by ribosome stalling links translation elongation with translation initiation

Activation of GCN2 kinase by ribosome stalling links translation elongation with translation initiation

Separate domains in GCN1 for binding protein kinase GCN2 and ribosomes are required for GCN2 activation in amino acid-starved cells

Overexpression of Eukaryotic Translation Elongation Factor 3 Impairs Gcn2 Protein Activation

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