An E3 ligase network engages GCN1 to promote elongation factor-1α degradation on stalled ribosomes

• Published in: bioRxiv
• Main Authors: Oltion, Keely, Carelli, Jordan D, Yang, Tangpo, See, Stephanie K, Hao-Yuan, Wang, Kampmann, Martin, Taunton, Jack
• Format: Paper
• Language: English
• Published: Cold Spring Harbor Cold Spring Harbor Laboratory Press 22.03.2022
• Subjects: Allosteric properties; Degradation; Gene regulation; mRNA; Patent applications; Proteomics; Quality control; Ribosomal proteins; Ribosomes; Translation; Translation elongation; Ubiquitin-protein ligase; Ubiquitination
• DOI: 10.1101/2022.03.21.485216

How cells monitor the status of translating ribosomes is a major question in gene regulation. Elongating ribosomes frequently stall during mRNA translation, resulting in context-dependent activation of quality control pathways. However, surveillance mechanisms that specifically respond to stalled ribosomes with an elongation factor occupying the GTPase center have not been identified. By employing ternatin-4, an allosteric elongation factor-1α (eEF1A) inhibitor, we unveil an E3 ligase network that triggers ubiquitination and degradation of eEF1A on stalled ribosomes. A CRISPRi screen revealed two E3 ligases of unknown function, RNF14 and RNF25, which are both essential for ternatin-induced eEF1A degradation. Based on quantitative proteomics analysis, we find that RNF14 and RNF25 promote ubiquitination of eEF1A and a discrete set of ribosomal proteins. By forming a complex with RNF14, the ribosome collision sensor GCN1 plays an essential role in eEF1A degradation. Our findings illuminate a translation elongation checkpoint that monitors the ribosomal GTPase center. Competing Interest Statement The University of California, San Francisco has filed a provisional patent application related to this study; J.T., H.Y.W., and K.O. are listed as inventors.