Dom34:Hbs1 Plays a General Role in Quality-Control Systems by Dissociation of a Stalled Ribosome at the 3′ End of Aberrant mRNA

Graduate School of Pharmaceutical Science, Tohoku University, Sendai, Japan.
Molecular cell (Impact Factor: 14.02). 04/2012; 46(4):518-29. DOI: 10.1016/j.molcel.2012.03.013
Source: PubMed


Translation arrest leads to an endonucleolytic cleavage of mRNA that is termed no-go decay (NGD). It has been reported that the Dom34:Hbs1 complex stimulates this endonucleolytic cleavage of mRNA induced by translation arrest in vivo and dissociates subunits of a stalled ribosome in vitro. Here we report that Dom34:Hbs1 dissociates the subunits of a ribosome that is stalled at the 3' end of mRNA in vivo, and has a crucial role in both NGD and nonstop decay. Dom34:Hbs1-mediated dissociation of a ribosome that is stalled at the 3' end of mRNA is required for degradation of a 5'-NGD intermediate. Dom34:Hbs1 facilitates the decay of nonstop mRNAs from the 3' end by exosomes and is required for the complete degradation of nonstop mRNA decay intermediates. We propose that Dom34:Hbs1 stimulates degradation of the 5'-NGD intermediate and of nonstop mRNA by dissociating the ribosome that is stalled at the 3' end of the mRNA.

Download full-text


Available from: Toshifumi Inada, Apr 01, 2014
37 Reads
  • Source
    • "These observations strongly suggest oxidized mRNA is a primary target of ribosome-based mRNA quality-control processes. We note that NGD and in particular Dom34 has been implicated in a number of processes; for example, Inada and colleagues have shown the factor to be important in rescuing ribosomes trapped on truncated mRNA (Tsuboi et al., 2012). Recently, Guydosh and Green used ribosomal profiling to show that in the absence of the factor, ribosomes venture into the 3 0 UTR (Guydosh and Green, 2014). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Chemical damage to RNA affects its functional properties and thus may pose a significant hurdle to the translational apparatus; however, the effects of damaged mRNA on the speed and accuracy of the decoding process and their interplay with quality-control processes are not known. Here, we systematically explore the effects of oxidative damage on the decoding process using a well-defined bacterial in vitro translation system. We find that the oxidative lesion 8-oxoguanosine (8-oxoG) reduces the rate of peptide-bond formation by more than three orders of magnitude independent of its position within the codon. Interestingly, 8-oxoG had little effect on the fidelity of the selection process, suggesting that the modification stalls the translational machinery. Consistent with these findings, 8-oxoG mRNAs were observed to accumulate and associate with polyribosomes in yeast strains in which no-go decay is compromised. Our data provide compelling evidence that mRNA-surveillance mechanisms have evolved to cope with damaged mRNA. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.
    Cell Reports 11/2014; 9(4):1256-64. DOI:10.1016/j.celrep.2014.10.042 · 8.36 Impact Factor
  • Source
    • "Nonsense-mediated mRNA decay (NMD) is one of three conserved eukaryotic surveillance pathways ensuring mRNA quality control in the cytoplasm [1] [2] [3] [4]. NMD is activated by mechanistic differences between normal and premature translation termination and utilizes three conserved factors (Upf1, Upf2, and Upf3) [5] [6] [7] to couple nonsense codon recognition to the release factors (eRF1 and eRF3), the ribosome, and the mRNA decapping complex [8] [9] [10] [11] [12] [13] [14]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Upf1, Upf2, and Upf3 are the principal regulators of Nonsense-mediated mRNA Decay (NMD), a cytoplasmic surveillance pathway that accelerates the degradation of mRNAs undergoing premature translation termination. These three proteins interact with each other, the ribosome, the translation termination machinery, and multiple mRNA decay factors, but the precise mechanism allowing the selective detection and degradation of nonsense-containing transcripts remains elusive. Here we have determined the crystal structure of the N-terminal mIF4G domain from Saccharomyces cerevisiae Upf2 and identified a highly conserved region in this domain that is essential for NMD and independent of Upf2's binding sites for Upf1 and Upf3. Mutations within this conserved region not only inactivate NMD, but also disrupt Upf2 binding to specific proteins, including Dbp6, a DEAD-box helicase. Although current models indicate that Upf2 functions principally as an activator of Upf1 and a bridge between Upf1 and Upf3, our data suggest that it may also serve as a platform for the association of additional factors that play roles in premature translation termination and NMD.
    Journal of Molecular Biology 09/2014; 426(22). DOI:10.1016/j.jmb.2014.09.015 · 4.33 Impact Factor
  • Source
    • "In our study, we split ribosomes using Pelota, Hbs1, and ABCE1, factors identified to recycle empty and stalled 80S ribosomes in earlier in vitro experiments (Pisareva et al., 2011). The physiologic targets of these factors are only now emerging and clearly include ribosomes at the end of truncated mRNAs (Guydosh and Green, 2014; Tsuboi et al., 2012). Because we employed a truncated mRNA in our experiments, the use of Pelota/Hbs1/ABCE1 is appropriate and physiologically relevant. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Ribosomes stalled on aberrant mRNAs engage quality control mechanisms that degrade the partially translated nascent polypeptide. Ubiquitination of the nascent protein is mediated by the E3 ligase Listerin via a mechanism involving ribosome subunit dissociation. Here, we reconstitute ribosome-associated ubiquitination with purified factors to define the minimal components and essential steps in this process. We find that the primary role of the ribosome splitting factors Hbs1, Pelota, and ABCE1 is to permit Listerin access to the nascent chain. Listerin alone can discriminate 60S- from 80S-nascent chain complexes to selectively ubiquitinate the former. Splitting factors can be bypassed by artificially removing the 40S subunit, suggesting that mere steric hindrance impedes Listerin recruitment. This was illustrated by a cryo-EM reconstruction of the 60S-Listerin complex that identifies a binding interface that clashes with the 40S ribosomal subunit. These results reveal the mechanistic logic of the core steps in a ribosome-associated quality control pathway.
    Molecular Cell 08/2014; 55(6). DOI:10.1016/j.molcel.2014.07.006 · 14.02 Impact Factor
Show more