2015/01/01 by Peter Shen, Joseph Park, Yidan Qin +9 · 3 citations
Biochemistry, Genetics and Molecular Biology · #RNA Research and Splicing #RNA and protein synthesis mechanisms #RNA modifications and cancer
paper · doi:10.1126/science.1259724
openalex publication_date 2015/01/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
In Eukarya, stalled translation induces 40S dissociation and recruitment of the ribosome quality control complex (RQC) to the 60S subunit, which mediates nascent chain degradation. Here we report cryo-electron microscopy structures revealing that the RQC components Rqc2p (YPL009C/Tae2) and Ltn1p (YMR247C/Rkr1) bind to the 60S subunit at sites exposed after 40S dissociation, placing the Ltn1p RING (Really Interesting New Gene) domain near the exit channel and Rqc2p over the P-site transfer RNA (tRNA). We further demonstrate that Rqc2p recruits alanine- and threonine-charged tRNA to the A site and directs the elongation of nascent chains independently of mRNA or 40S subunits. Our work uncovers an unexpected mechanism of protein synthesis, in which a protein--not an mRNA--determines tRNA recruitment and the tagging of nascent chains with carboxy-terminal Ala and Thr extensions ("CAT tails").