scholarly journals The Role of Ribosomal Protein L11 in Class I Release Factor-mediated Translation Termination and Translational Accuracy

2006 ◽  
Vol 281 (7) ◽  
pp. 4548-4556 ◽  
Author(s):  
Lamine Bouakaz ◽  
Elli Bouakaz ◽  
Emanuel J. Murgola ◽  
Måns Ehrenberg ◽  
Suparna Sanyal
Keyword(s):  
Ribosomal Protein ◽  
Translation Termination ◽  
Class I ◽  
Release Factor ◽  
Translational Accuracy ◽  
Ribosomal Protein L11

scholarly journals Inhibition of Translation Termination Mediated by an Interaction of Eukaryotic Release Factor 1 with a Nascent Peptidyl-tRNA

2002 ◽  
Vol 22 (24) ◽  
pp. 8562-8570 ◽  
Author(s):  
Deanna M. Janzen ◽  
Lyudmila Frolova ◽  
Adam P. Geballe
Keyword(s):  
Translation Termination ◽  
Open Reading Frame ◽  
Upstream Open Reading Frame ◽  
Dependent Manner ◽  
Release Factor ◽  
Inhibitory Mechanism ◽  
Reading Frame ◽  
Nascent Peptide ◽  
Peptide Product

ABSTRACT Expression of the human cytomegalovirus UL4 gene is inhibited by translation of a 22-codon-upstream open reading frame (uORF2). The peptide product of uORF2 acts in a sequence-dependent manner to inhibit its own translation termination, resulting in persistence of the uORF2 peptidyl-tRNA linkage. Consequently, ribosomes stall at the uORF2 termination codon and obstruct downstream translation. Since termination appears to be the critical step affected by translation of uORF2, we examined the role of eukaryotic release factors 1 and 3 (eRF1 and eRF3) in the inhibitory mechanism. In support of the hypothesis that an interaction between eRF1 and uORF2 contributes to uORF2 inhibitory activity, specific residues in each protein, glycines 183 and 184 of the eRF1 GGQ motif and prolines 21 and 22 of the uORF2 peptide, were found to be necessary for full inhibition of downstream translation. Immunoblot analyses revealed that eRF1, but not eRF3, accumulated in the uORF2-stalled ribosome complex. Finally, increased puromycin sensitivity was observed after depletion of eRF1 from the stalled ribosome complex, consistent with inhibition of peptidyl-tRNA hydrolysis resulting from an eRF1-uORF2 peptidyl-tRNA interaction. These results reveal the paradoxical potential for interactions between a nascent peptide and eRF1 to obstruct the translation termination cascade.

scholarly journals Essential role of ribosomal protein L11 in mediating growth inhibition-induced p53 activation

2004 ◽  
Vol 23 (12) ◽  
pp. 2402-2412 ◽  
Author(s):  
Krishna P Bhat ◽  
Koji Itahana ◽  
Aiwen Jin ◽  
Yanping Zhang
Keyword(s):  
Growth Inhibition ◽  
Ribosomal Protein ◽  
Essential Role ◽  
P53 Activation ◽  
Ribosomal Protein L11

scholarly journals Methylation of E. coli Class I Release Factors Increases the Accuracy of Translation Termination in vitro

2018 ◽  
Author(s):  
Gürkan Korkmaz
Keyword(s):  
Translation Termination ◽  
Class I ◽  
Release Factor ◽  
E Coli ◽  
Release Factors ◽  
Peptide Release ◽  
Ribosomal Protein Synthesis ◽  
Uncompetitive Inhibitor ◽  
Menten Constant

ABSTRACTRibosomal protein synthesis (translation) is a highly accurate process. Translation termination, in particular, must be accurate to prevent truncated proteins. How this accuracy is achieved is not fully understood in all its details. Using an E. coli in vitro system, I explore novel mechanisms that contribute to the high accuracy of translation termination. By comparing the Michaelis-Menten parameters of methylated and non-methylated release factors on cognate and non-cognate codons. Post-translational methylation of a strictly conserved GGQ motif in class I release factors increases the accuracy of termination by up to 5-fold. This happens by increasing both the maximum rate of peptide release (kcat) and Michaelis-Menten constant (KM). Further, I demonstrate here that a non-methylated release factor acts like an uncompetitive inhibitor of enzyme reactions. Overall, this study shows that the methylation of class I release factors is a novel mechanism contributing to highly accurate translation termination.AbbreviationsRFrelease factorRCrelease complex

scholarly journals Bacterial ribosome conformational dynamics during translation termination and rescue

2017 ◽  
Author(s):  
◽  
Widler Casy
Keyword(s):  
Stop Codon ◽  
Translation Termination ◽  
Conformational Dynamics ◽  
Class I ◽  
Translation Inhibition ◽  
Release Factors ◽  
Bacterial Ribosome ◽  
A Site ◽  
Hydrolysis Of

Hydrolysis of polypeptide from the ribosome is a critical step that must occur prior to the ribosome recycling phase of translation. Inability of cells to do so can result in translation inhibition and eventually leading to cell death. In bacteria, class one release factors bind to the ribosome to catalyze the release of the mature polypeptide during translation termination. However, in the event of ribosome stalling as a result of mRNA truncation, ribosome rescue factors bind to the ribosome to catalyze the release of the growing polypeptide from the stalled complex. This rescue process is then followed by ribosome recycling. Here we employ smFRET to study the effects of the class I release factors, RF1 and RF2, and an alternative release factor known as YaeJ on the conformational dynamics of the ribosome following hydrolysis of peptidyl tRNAs. Further, we investigated the role of A-site mRNA on the global conformation of the ribosome. Our results demonstrate that upon binding to their cognate stop codon, the class I release factors stabilize ribosome complexes in the non-rotated state. Similarly, binding of YaeJ to complexes that are assembled on truncated mRNAs resulted in ribosomes that occupy primarily the non-rotated state. We also observe that absence of mRNA in the A-site induces a hyper-rotated conformation between the two subunits. Together, these findings further characterize the interactions between these different ligands and the bacterial ribosome. In addition, these results suggest that stabilization of the ribosome in the non-rotated state is critical for priming the ribosome for the recycling phase of translation.

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