Tollervey lab paper featured in Nature Communications. Image Authors Winz, M.-L., Peil, L., Turowski, T.W., Rappsilber, J. and Tollervey, D. Summary The work reported here examined a housekeeping mechanism which removes faulty proteins as they form. This process is conserved in animals, plants and fungi and clears damaged proteins, preventing their accumulation in cells, tissues and organs. We used the model organism budding yeast to look at how proteins are produced. During this process, genetic information encoded in the DNA is first copied into a related molecule called RNA and then then used programme the synthesis of proteins. We concentrated on a part of this mechanism that removes proteins that have stalled when partially synthesised, thus clearing the way for further proteins to be produced. Specifically, we studied the yeast protein Hel2 and used UV light to identify where this protein touches RNAs that are in the processes of directing protein synthesis. When we removed the parts of Hel2 that directly contact the RNA, this prevented the destruction of faulty proteins, showing that these contacts are important for the mechanism. This work is important, because partly formed proteins are not only dysfunctional but may be toxic, for example when they form protein clumps such as those associated with Alzheimer’s or Parkinson’s diseases. Abstract Ribosome-associated quality control (RQC) pathways monitor and respond to ribosome stalling. Using in vivo UV-crosslinking and mass spectrometry, we identified a C‑terminal region in Hel2/Rqt1 as an RNA binding domain. Complementary crosslinking and sequencing data for Hel2 revealed binding to 18S rRNA and translated mRNAs. Hel2 preferentially bound mRNAs upstream and downstream of the stop codon. C-terminal truncation of Hel2 abolished the major 18S crosslink and polysome association, and altered mRNA binding. HEL2 deletion caused loss of RQC and, we report here, no-go decay (NGD), with comparable effects for Hel2 truncation including the RNA-binding site. Asc1 acts upstream of Hel2 in RQC and asc1∆ impaired Hel2 binding to 18S and mRNA. In conclusion: Hel2 is recruited or stabilized on translating 40S ribosomal subunits by interactions with 18S rRNA and Asc1. This 18S interaction is required for Hel2 function in RQC and NGD. Hel2 generally interacts with mRNA during translation termination. Related links Journal Link Tollervey Lab DOI This article was published on 2024-06-17
