Abstract
Identification of SDD1 mRNA from Saccharomyces cerevisiae as an endogenous RQC substrate allows analysis of the mechanism underlying translational stalling and Hel2-dependent polyubiquitination of collided ribosomes to provide insight into ribosome dissociation. Ribosome-associated quality control (RQC) represents a rescue pathway in eukaryotic cells that is triggered upon translational stalling. Collided ribosomes are recognized for subsequent dissociation followed by degradation of nascent peptides. However, endogenous RQC-inducing sequences and the mechanism underlying the ubiquitin-dependent ribosome dissociation remain poorly understood. Here, we identified SDD1 messenger RNA from Saccharomyces cerevisiae as an endogenous RQC substrate and reveal the mechanism of its mRNA-dependent and nascent peptide-dependent translational stalling. In vitro translation of SDD1 mRNA enabled the reconstitution of Hel2-dependent polyubiquitination of collided disomes and, preferentially, trisomes. The distinct trisome architecture, visualized using cryo-EM, provides the structural basis for the more-efficient recognition by Hel2 compared with that of disomes. Subsequently, the Slh1 helicase subunit of the RQC trigger (RQT) complex preferentially dissociates the first stalled polyubiquitinated ribosome in an ATP-dependent manner. Together, these findings provide fundamental mechanistic insights into RQC and its physiological role in maintaining cellular protein homeostasis.
| Dokumententyp: | Zeitschriftenartikel |
|---|---|
| Fakultät: | Chemie und Pharmazie > Department Biochemie |
| Themengebiete: | 500 Naturwissenschaften und Mathematik > 540 Chemie |
| ISSN: | 1545-9993 |
| Sprache: | Englisch |
| Dokumenten ID: | 89741 |
| Datum der Veröffentlichung auf Open Access LMU: | 25. Jan. 2022, 09:32 |
| Letzte Änderungen: | 25. Jan. 2022, 09:32 |
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