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Svetlov MS, Dunand CF, Nakamoto JA, Atkinson GC, Safdari HA, Wilson DN, Vázquez-Laslop N, Mankin AS. Peptidyl-tRNA hydrolase is the nascent chain release factor in bacterial ribosome-associated quality control. Mol Cell 2024; 84:715-726.e5. [PMID: 38183984 DOI: 10.1016/j.molcel.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/08/2023] [Accepted: 12/01/2023] [Indexed: 01/08/2024]
Abstract
Rescuing stalled ribosomes often involves their splitting into subunits. In many bacteria, the resultant large subunits bearing peptidyl-tRNAs are processed by the ribosome-associated quality control (RQC) apparatus that extends the C termini of the incomplete nascent polypeptides with polyalanine tails to facilitate their degradation. Although the tailing mechanism is well established, it is unclear how the nascent polypeptides are cleaved off the tRNAs. We show that peptidyl-tRNA hydrolase (Pth), the known role of which has been to hydrolyze ribosome-free peptidyl-tRNA, acts in concert with RQC factors to release nascent polypeptides from large ribosomal subunits. Dislodging from the ribosomal catalytic center is required for peptidyl-tRNA hydrolysis by Pth. Nascent protein folding may prevent peptidyl-tRNA retraction and interfere with the peptide release. However, oligoalanine tailing makes the peptidyl-tRNA ester bond accessible for Pth-catalyzed hydrolysis. Therefore, the oligoalanine tail serves not only as a degron but also as a facilitator of Pth-catalyzed peptidyl-tRNA hydrolysis.
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Affiliation(s)
- Maxim S Svetlov
- Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA; Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA.
| | - Clémence F Dunand
- Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA; Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Jose A Nakamoto
- Department of Experimental Medicine, University of Lund, 221 00 Lund, Sweden
| | - Gemma C Atkinson
- Department of Experimental Medicine, University of Lund, 221 00 Lund, Sweden
| | - Haaris A Safdari
- Institute for Biochemistry and Molecular Biology, University of Hamburg, 20146 Hamburg, Germany
| | - Daniel N Wilson
- Institute for Biochemistry and Molecular Biology, University of Hamburg, 20146 Hamburg, Germany
| | - Nora Vázquez-Laslop
- Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA; Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Alexander S Mankin
- Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA; Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA.
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Filbeck S, Cerullo F, Paternoga H, Tsaprailis G, Joazeiro CAP, Pfeffer S. Mimicry of Canonical Translation Elongation Underlies Alanine Tail Synthesis in RQC. Mol Cell 2020; 81:104-114.e6. [PMID: 33259811 DOI: 10.1016/j.molcel.2020.11.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/06/2020] [Accepted: 10/29/2020] [Indexed: 12/21/2022]
Abstract
Aborted translation produces large ribosomal subunits obstructed with tRNA-linked nascent chains, which are substrates of ribosome-associated quality control (RQC). Bacterial RqcH, a widely conserved RQC factor, senses the obstruction and recruits tRNAAla(UGC) to modify nascent-chain C termini with a polyalanine degron. However, how RqcH and its eukaryotic homologs (Rqc2 and NEMF), despite their relatively simple architecture, synthesize such C-terminal tails in the absence of a small ribosomal subunit and mRNA has remained unknown. Here, we present cryoelectron microscopy (cryo-EM) structures of Bacillus subtilis RQC complexes representing different Ala tail synthesis steps. The structures explain how tRNAAla is selected via anticodon reading during recruitment to the A-site and uncover striking hinge-like movements in RqcH leading tRNAAla into a hybrid A/P-state associated with peptidyl-transfer. Finally, we provide structural, biochemical, and molecular genetic evidence identifying the Hsp15 homolog (encoded by rqcP) as a novel RQC component that completes the cycle by stabilizing the P-site tRNA conformation. Ala tailing thus follows mechanistic principles surprisingly similar to canonical translation elongation.
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Affiliation(s)
- Sebastian Filbeck
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Federico Cerullo
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Helge Paternoga
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | | | - Claudio A P Joazeiro
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany; Department of Molecular Medicine, Scripps Research, Jupiter, FL 33458, USA.
| | - Stefan Pfeffer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
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