Ribosome collisions in bacteria promote ribosome rescue by triggering mRNA cleavage by SmrB
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ABSTRACT:
ORGANISM(S): Escherichia coli str. K-12 substr. MG1655
PROVIDER: GSE179691 | GEO | 2022/08/01
REPOSITORIES: GEO
Similar Datasets
Project description:Although many clinically important antibiotics inhibit bacterial ribosomes, the mechanisms by which bacterial cells rescue ribosomes stalled by antibiotics remain poorly understood. Ribosome stalling leads to collisions that recruit ribosome quality control (RQC) factors that recycle the ribosome subunits and target nascent proteins for degradation. Surprisingly, loss of known RQC factors in E. coli does not lead to significant antibiotic sensitivity, even though antibiotics stall ribosomes and induce collisions, suggesting the existence of additional, uncharacterized RQC mechanisms. Here we report a novel mechanism for ribosome quality control (RQC) in bacteria in which the DExH-box ATPase HrpA splits stalled ribosomes into subunits. HrpA selectively acts on collided ribosomes and its activity is dependent on ATP hydrolysis. The cryo-EM structure of HrpA bound to collided ribosomes reveals insight into its selectivity and mechanism: the C-terminal domain of HrpA senses the collision and its helicase domain bind mRNA downstream of the ribosomes, where it likely exerts a pulling force that destabilizes the stalled ribosome. These studies highlight the importance of ribosome splitting as a highly conserved RQC mechanism across all three domains of life and identify an important pathway in proteobacteria that allows proteobacteria to tolerate ribosome-targeting antibiotics.
2024-10-10 | GSE270401 | GEO
Project description:The ribosome-associated protein quality control (RQC) system that resolves stalled translation events is activated when ribosomes collide and form disome, trisome or higher order complexes. However, it is unclear whether this system distinguishes collision complexes formed on defective mRNAs from those with functional roles on endogenous transcripts. Here, we performed disome and trisome footprint profiling in yeast and found collisions were enriched on diverse sequence motifs known to slow translation. When 60S recycling was inhibited, disomes accumulated at stop codons and could move into the 3’UTR to reinitiate translation. The ubiquitin ligase and RQC factor Hel2/ZNF598 generally recognized collisions but did not trigger degradation of endogenous transcripts. However, loss of Hel2 triggered the integrated stress response, via phosphorylation of eIF2alpha, thus linking these pathways. Our results suggest that Hel2 has a role in sensing ribosome collisions on endogenous mRNAs and such events may be important for cellular homeostasis.
2020-05-26 | GSE139036 | GEO
Project description:Ribosome stalling at problematic sequences in mRNAs leads to collisions that trigger a collection of quality control events including ribosome rescue, targeting the nascent polypeptide for decay (Ribosome-mediated Quality Control or RQC), and targeting of the mRNA for decay (No Go Decay or NGD). Using a reverse genetic screen in yeast, we identify Cue2 as the endonuclease that is recruited to stalled ribosomes to promote NGD. Following Cue2-mediated cleavage, ribosomes upstream of the cleavage site translate to the end of the truncated mRNA and are rescued by the Dom34:Hbs1 complex. We also show that the putative helicase Slh1 (part of the RQC Trigger or RQT complex) removes collided ribosomes behind the lead stalled ribosome and thereby reduces endonucleolytic cleavage by Cue2. The synergistic activities of Cue2 and Slh1 define two parallel pathways that allow cells to recognize and respond to ribosomes trapped on problematic mRNAs.
2019-06-25 | GSE129128 | GEO
Project description:Problems arising during translation of mRNAs lead to ribosome stalling and collisions with trailing ribosomes. These collisions are known to trigger a series of events including degradation of the stalled nascent polypeptide, decay of the problematic mRNAs, and ribosome rescue. However, the systemic cellular response of ribosome collision has not been explored. Here, we uncover a novel function for ribosome collisions in signal transduction. Using multiple translation elongation inhibitors and cellular stress conditions, we show that ribosome collisions activate both the SAPK (Stress Activated Protein Kinase) and GCN2-mediated cellular stress response pathways that lead to apoptosis and the integrated stress response (ISR), respectively. We further show that the MAPKKK ZAK functions as the sentinel for ribosome collisions, and ZAK is required for activation of both SAPKs p38/JNK and GCN2 signaling pathways. Selective ribosome profiling and biochemistry demonstrate that ZAK preferentially associates with the minimal unit of colliding ribosomes, the disome, inducing ZAK phosphorylation. While ZAK associates with elongating ribosomes under non-stressed conditions, activation of ZAK is specifically trigger by colliding ribosomes. Together, these results provide new insights into how perturbation of translational homeostasis, as read-out by colliding ribosomes, regulates cell fate.
2020-08-18 | GSE141459 | GEO
Project description:Translation elongation stalling has the potential to produce toxic truncated protein fragments. Translation of either non-stop mRNA or transcripts coding for poly-basic sequences induces ribosome stalling, and the arrest product is degraded by the ribosome-mediated quality control (RQC) system. During this process, the stalled ribosome is dissociated into subunits, and the polypeptide is ubiquitinated by the E3 ubiquitin ligase Listerin on the 60S large ribosomal subunit, leading to subsequent proteasomal degradation. However, it is largely unknown how the specific stalled ribosomes are recognized as aberrant to engage the RQC system. Here, we report that ubiquitination of the ribosomal protein uS10 of the 40S small ribosomal subunit, by the E3 ubiquitin ligase Hel2 (or RQC-trigger (Rqt) 1) initiates RQC. We identified a novel RQC-trigger (RQT) complex composed of the RNA helicase-family protein Slh1/Rqt2, the ubiquitin binding protein Cue3/Rqt3, and yKR023W/Rqt4 that is required for RQC. The defects in RQC of the RQT mutants correlated with sensitivity to anisomycin, which stalls ribosome at the rotated form, suggesting that RQT factors rescue ribosomes stalled by this drug. Our un-biased survey by ribosome profiling revealed that ribosomes stalled at the rotated state with specific pairs of codons at P-A sites serve as RQC substrates. Rqt1 specifically ubiquitinates these arrested ribosomes to target them to the RQT complex, allowing subsequent RQC reactions including dissociation of the stalled ribosome into subunits. Our results provide mechanistic insight into the surveillance system for aberrant proteins induced by ribosome stalling and mediated by ribosome ubiquitination.
2017-07-31 | GSE90919 | GEO
Project description:Cells can respond to stalled ribosomes by sensing ribosome collisions and employing quality control pathways. How ribosome stalling is resolved without collisions, however, has remained elusive. Here, focusing on non-colliding stalling exhibited by decoding-defective ribosomes, we identified Fap1 as a stalling sensor triggering 18S non-functional rRNA decay via poly-ubiquitination of uS3. Ribosome profiling revealed an enrichment of Fap1 at the translation initiation site but also association with elongating individual ribosomes. Cryo-EM structures of Fap1-bound ribosomes elucidated Fap1 probing the mRNA simultaneously at both the entry and exit channels suggesting a mRNA stasis sensing activity, and Fap1 sterically hinders formation of canonical collided di-ribosomes. Our findings indicate that individual stalled ribosomes are the potential signal for ribosome dysfunction, leading to accelerated turnover of the ribosome itself.
2022-09-15 | GSE159329 | GEO
Project description:Translation of poly(A) tails leads to mRNA cleavage but the mechanism and global pervasiveness of this “nonstop/no-go” decay process is not understood. Here we performed ribosome profiling of short 15-18 nt mRNA footprints to identify ribosomes stalled at 3’ ends of mRNA decay intermediates. We found mRNA cleavage extending hundreds of nucleotides upstream of ribosome stalling in poly(A) and predominantly in one reading frame. These observations suggest that cleavage is closely associated with the ribosome. Surprisingly, ribosomes appeared to stall when as few as 3 consecutive ORF-internal lysine codons were positioned in the A, P, and E sites though significant mRNA degradation was not observed. Endonucleolytic cleavage was widespread, however, at sites of premature polyadenylation and rescue of the ribosomes stalled at these sites was dependent on Dom34. These results suggest this process may be critical when changes in polyadenylation occur during development, tumorigenesis, or when translation termination/recycling is impaired.
2017-01-22 | GSE85944 | GEO
Project description:Ribosome-associated quality control (RQC) represents a rescue pathway in eukaryotic cells triggered upon translational stalling. Collided ribosomes are recognized for subsequent dissociation followed by targeting of the faulty nascent peptides for degradation. However, endogenous RQC inducing sequences and the mechanism underlying the ubiquitin-dependent ribosome dissociation remain poorly understood. Here, we identified the SDD1 mRNA from S. cerevisiae as an endogenous RQC substrate and reveal its mRNA and nascent peptide dependent stalling mechanism by mutational and cryo-EM analyses. In vitro translation of SDD1 mRNA enabled the reconstitution of Hel2-dependent poly-ubiquitination of colliding di- and preferentially tri-ribosomes. Their distinct architecture is visualized by cryo-EM and provides the structural basis for more efficient recognition by Hel2 over disomes. Subsequently, the Slh1/Rqt2 helicase subunit of the RQC trigger (RQT) complex preferentially dissociates the first stalled poly-ubiquitinated ribosome in an ATP dependent manner. Together, these findings provide fundamental mechanistic insights into RQC and its physiological role in dealing with endogenous substrates to maintain cellular protein homeostasis.
2020-02-24 | PXD017196 | Pride
Project description:Loss of functional fragile X mental retardation protein (FMRP) causes fragile X syndrome (FXS) and is the leading monogenic cause of autism spectrum disorders and intellectual disability. FMRP is most notably a translational repressor and is thought to inhibit translation elongation by stalling ribosomes as FMRP-bound polyribosomes from brain tissue are resistant to puromycin and nuclease treatment. Here, we present data showing that the C-terminal non-canonical RNA-binding domain of FMRP is essential and sufficient to induce puromycin-resistant mRNA•ribosome complexes. Given that stalled ribosomes can stimulate ribosome collisions and no-go mRNA decay (NGD), we tested the ability of FMRP to drive NGD of its target transcripts in neuroblastoma cells. Indeed, FMRP and ribosomal proteins, but not PABPC1, were enriched in isolated nuclease-resistant disomes compared to controls. Using siRNA knockdown and RNA-seq, we identified 16 putative FMRP-mediated NGD substrates, many of which encode proteins involved in neuronal development and function. Increased mRNA stability of the putative substrates was also observed when either FMRP was depleted or NGD was prevented via RNAi. Taken together, these data support that FMRP stalls ribosomes and can stimulate NGD in cells, albeit on a small number of transcripts, revealing an unappreciated role of FMRP that would be misregulated in FXS when FMRP is lost.
2024-08-28 | GSE254586 | GEO
Project description:Ribosome collisions in bacteria promote ribosome rescue by triggering mRNA cleavage by SmrB
| PRJNA744552 | ENA