摘要：SummaryUbiquitination is a major post-translational modification of ribosomal proteins. The role of ubiquitination in the regulation of ribosome functions is still being elucidated. However, the importance of ribosome deubiquitination remains unclear. Here, we show that the cycle of ubiquitination and deubiquitination of the 40S ribosome subunit eS7 is important for efficient translation. eS7 ubiquitination at lysine 83 is required for efficient protein translation. We identified Otu2 and Ubp3 as the deubiquitinating enzymes for eS7. Anotu2Δubp3Δ mutation caused a defect in protein synthesis. Ubp3 inhibited polyubiquitination of eS7 in polysomes to keep eS7 in a mono-ubiquitinated form, whereas Otu2 was specifically bound to the free 40S ribosome and promoted the dissociation of mRNAs from 40S ribosomes in the recycling step. Our results provide clues for understanding the molecular mechanism of the translation system via a ubiquitination-deubiquitination cycle.Graphical abstractDisplay OmittedHighlights•eS7 ubiquitination at lysine 83 is required for efficient protein translation•Ubp3 prevents eS7 from polyubiquitination in 80S ribosomes and polysomes•Otu2 deubiquitinates mono-ubiquitinated eS7 in the 40S ribosome•Otu2 facilitates dissociation of mRNAs from 40S ribosomes in ribosome recyclingBiological sciences; biochemistry; molecular biology
