Cells can respond to stalled ribosomes by sensing ribosome collisions and employing quality control pathways. How ribosome stalling is resolved without collisions, however, has remained elusive. Here, focusing on noncolliding stalling exhibited by decoding-defective ribosomes, we identified Fap1 as a stalling sensor triggering 18S nonfunctional rRNA decay via polyubiquitination of uS3. Ribosome profiling revealed an enrichment of Fap1 at the translation initiation site but also an association with elongating individual ribosomes. Cryo-EM structures of Fap1-bound ribosomes elucidated Fap1 probing the mRNA simultaneously at both the entry and exit channels suggesting an mRNA stasis sensing activity, and Fap1 sterically hinders the formation of canonical collided di-ribosomes. Our findings indicate that individual stalled ribosomes are the potential signal for ribosome dysfunction, leading to accelerated turnover of the ribosome itself.

• PMID: 36113412
• DOI full text
• PubMed

Reference Type

Journal Article | Research Support, N.I.H., Extramural | Research Support, Non-U.S. Gov't

Authors

Li S, Ikeuchi K, Kato M, Buschauer R, Sugiyama T, Adachi S, Kusano H, Natsume T, Berninghausen O, Matsuo Y, ... Show all

Primary Lit For

Additional Lit For

Review For