A functional connection between translation elongation and protein folding at the ribosome exit tunnel in Saccharomyces cerevisiae
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ABSTRACT:
PROVIDER: PRJNA636675 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR11906947_1.fastq.gz | Fastqsanger.gz | |||
| SRR11906947_2.fastq.gz | Fastqsanger.gz | |||
| SRR11906948_1.fastq.gz | Fastqsanger.gz | |||
| SRR11906948_2.fastq.gz | Fastqsanger.gz | |||
| SRR11906949_1.fastq.gz | Fastqsanger.gz |
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Project description:Proteostasis is a fundamental network of cellular pathways that ensures the optimal concentration and composition of correctly folded proteins within cells in normal and stress conditions. Among key components of this network are the molecular chaperones, which mediate protein folding but also act as modulators of protein synthesis. We have reported on a functional link between translation and de novo folding of proteins in the yeast Saccharomyces cerevisiae by uncovering a specific synthetic-lethal interaction between apparent unrelated mutant variants, the uL3[W255C] variant of the ribosomal protein uL3 and the null mutants of Zuo1 and Ssz1. Zuo1 and Ssz1 are components of the chaperone system named as ribosome-associated complex. Here, we performed a genome-wide analysis of ribosome dynamics by 5PSeq (Pelechano et al. 2015 PMID 2604644) in strains harbouring either wild-type uL3 or mutant uL3[W255C] in the presence or absence of Zuo1 or Ssz1. This method allows the study of ribosome dynamics, by sequencing 5’ phosphorylated mRNA co-translational degradation intermediates. Our results indicate that the rpl3[W255C] mutant is slightly impaired in translation elongation, defect that is significantly enhanced when combined with the deprivation of either Zuo1 or Ssz1.
2020-11-25 | GSE151632 | GEO
Project description:Understanding the conformational sampling of translation-arrested ribosome nascent chain complexes is key to understand co-translational folding. Up to now, coupling of cysteine oxidation, disulfide bond formation and structure formation in nascent chains has remained elusive. Here, we investigate the eye-lens protein γB-crystallin in the ribosomal exit tunnel. Using mass spectrometry, theoretical simulations, dynamic nuclear polarization-enhanced solid-state nuclear magnetic resonance and cryo-electron microscopy, we show that thiol groups of cysteine residues undergo S-glutathionylation and S-nitrosylation and form non-native disulfide bonds. Thus, covalent modification chemistry occurs already prior to nascent chain release as the ribosome exit tunnel provides sufficient space even for disulfide bond formation which can guide protein folding.
2020-11-09 | PXD021574 | Pride
Project description:Continuous translation elongation, irrespective of amino acid sequences, is a prerequisite for living organisms to produce their proteomes. However, the risk of elongation abortion is concealed within nascent polypeptide products. For example, negatively charged sequences with occasional intermittent prolines, termed intrinsic ribosome destabilization (IRD) sequences, destabilizes the translating ribosomal complex. Thus, some nascent chain sequences lead to premature translation cessation. Here, we show that most potential IRD sequences in the middle of open reading frames remain cryptic by two mechanisms: the nascent polypeptide itself that spans the exit tunnel and its bulky amino acid residues that occupy the tunnel entrance region. Thus, nascent polypeptide products have a built-in ability to ensure elongation continuity by serving as a bridge and thus by protecting the large and small ribosomal subunits from dissociation.
2021-12-08 | GSE184331 | GEO
Project description:Proteostasis needs to be tightly controlled to meet the cellular demand for correctly de novo folded proteins and to avoid protein aggregation. While a coupling between translation rate and co-translational folding, likely involving an interplay between the ribosome and its associated chaperones, clearly appears to exist, the underlying mechanisms and the contribution of ribosomal proteins remain to be explored. The ribosomal protein uL3 contains a long internal loop whose tip region is in close proximity to the ribosomal peptidyl transferase center. Intriguingly, the rpl3[W255C] allele, in which the residue making the closest contact to this catalytic site is mutated, affects diverse aspects of ribosome biogenesis and function. Here, we have uncovered, by performing a synthetic lethal screen with this allele, an unexpected link between translation and the folding of nascent proteins by the ribosome-associated Ssb-RAC chaperone system. Our results reveal that uL3 and Ssb-RAC cooperate to prevent 80S ribosomes from piling up within the 5' region of mRNAs early on during translation elongation. Together, our study provides compelling in vivo evidence for a functional connection between peptide bond formation at the peptidyl transferase center and chaperone-assisted de novo folding of nascent polypeptides at the solvent-side of the peptide exit tunnel.
| S-EPMC7797049 | biostudies-literature
Project description:Transcription elongation rates influence RNA processing, but sequence-specific regulation is poorly understood. We addressed this in vivo, analyzing RNAPI in S. cerevisiae. Mapping RNAPI by Miller chromatin spreads or UV crosslinking revealed 5′ enrichment and strikingly uneven local polymerase occupancy along the rDNA, indicating substantial variation in transcription speed. Two features of the nascent transcript correlated with RNAPI distribution: folding energy and GC content in the transcription bubble. In vitro experiments confirmed that strong RNA structures close to the polymerase promote forward translocation and limit backtracking, whereas high GC in the transcription bubble slows elongation. A mathematical model for RNAPI elongation confirmed the importance of nascent RNA folding in transcription. RNAPI from S. pombe was similarly sensitive to transcript folding, as were S. cerevisiae RNAPII and RNAPIII. For RNAPII, unstructured RNA, which favors slowed elongation, was associated with faster cotranscriptional splicing and proximal splice site use, indicating regulatory significance for transcript folding.
2020-06-24 | GSE136056 | GEO
Project description:Proteostasis must be finely tuned in the nervous system, as it represents an essential feature of neurodevelopment, and dominant pathology in neurodegenerative disease. At the gateway of proteostasis is the ribosome; however, the architecture of ribosomal complexes in the developing mammalian brain has not been visualized. In this study, we analyze the molecular architecture of ex vivo embryonic and perinatal mouse neocortical ribosomes, revealing Ebp1 as a 60S peptide tunnel exit binding factor at near-atomic resolution by multiparticle cryo-electron microscopy. The impact of Ebp1 on the neuronal proteome was analyzed by pSILAC and BONCAT coupled mass spectrometry, implicating Ebp1 in neurite outgrowth proteostasis, with in vivo embryonic Ebp1 knockdown resulting in neurite outgrowth dysregulation. This study constitutes the first near-atomic resolution structure of actively translating ribosomes ex vivo from the nervous system, and visualizes Ebp1 as a chaperone of protein synthesis at the 60S peptide tunnel exit in neocortical neurogenesis.
2021-01-04 | PXD014841 | Pride
Project description:Proteostasis must be finely tuned in the nervous system, as it represents an essential feature of neurodevelopment, and dominant pathology in neurodegenerative disease. At the gateway of proteostasis is the ribosome; however, the architecture of ribosomal complexes in the developing mammalian brain has not been visualized. In this study, we analyze the molecular architecture of ex vivo embryonic and perinatal mouse neocortical ribosomes, revealing Ebp1 as a 60S peptide tunnel exit binding factor at near-atomic resolution by multiparticle cryo-electron microscopy. The impact of Ebp1 on the neuronal proteome was analyzed by pSILAC and BONCAT coupled mass spectrometry, implicating Ebp1 in neurite outgrowth proteostasis, with in vivo embryonic Ebp1 knockdown resulting in neurite outgrowth dysregulation. This study constitutes the first near-atomic resolution structure of actively translating ribosomes ex vivo from the nervous system, and visualizes Ebp1 as a chaperone of protein synthesis at the 60S peptide tunnel exit in neocortical neurogenesis.
2021-01-04 | PXD014740 | Pride
Project description:Nascent polypeptide within the exit tunnel stabilizes the ribosome to counteract risky translation
| PRJNA764085 | ENA
Project description:At what point during translation do proteins fold? It is well established that proteins can fold cotranslationally outside the ribosome exit tunnel, whereas studies of folding inside the exit tunnel have so far detected only the formation of helical secondary structure and collapsed or partially structured folding intermediates. Here, using a combination of cotranslational nascent chain force measurements, inter-subunit fluorescence resonance energy transfer studies on single translating ribosomes, molecular dynamics simulations, and cryoelectron microscopy, we show that a small zinc-finger domain protein can fold deep inside the vestibule of the ribosome exit tunnel. Thus, for small protein domains, the ribosome itself can provide the kind of sheltered folding environment that chaperones provide for larger proteins.
| S-EPMC4571824 | biostudies-literature
Project description:Protein folding is assisted by molecular chaperones that bind nascent polypeptides during mRNA translation. Several structurally-distinct classes of chaperone promote de novo folding, suggesting that their activities are coordinated at the ribosome. We used biochemical reconstitution and structural proteomics to explore the molecular basis for cotranslational chaperone action in bacteria. We found that chaperone binding is disfavoured close to the ribosome, allowing folding to precede chaperone recruitment. Trigger factor recognises compact folding intermediates exposing extensive unfolded surface and dictates DnaJ access to nascent chains. DnaJ uses a large surface to bind structurally diverse intermediates, and recruits DnaK to sequence-diverse solvent-accessible sites. Neither Trigger factor, DnaJ nor DnaK destabilize cotranslational folding intermediates. Instead, the chaperones collaborate to protect incipient structure in the nascent polypeptide well beyond the ribosome exit tunnel. Our findings show how the chaperone network selects and modulates cotranslational folding intermediates.
2024-07-03 | PXD048623 | Pride