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bioRxiv · 10.1101/2022.03.21.485216

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

Oltion, K.·Carelli, J. D.·Yang, T.·See, S. K.·Wang, H.-Y.·Kampmann, M.·Taunton, J.
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Abstract

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-1 (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.

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Oltion, K., Carelli, J. D., Yang, T., See, S. K., Wang, H.-Y., Kampmann, M., Taunton, J.. 2022-03-22. An E3 ligase network engages GCN1 to promote elongation factor-1α degradation on stalled ribosomes. https://doi.org/10.1101/2022.03.21.485216

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