@article {309,
	title = {Protein synthesis. Rqc2p and 60S ribosomal subunits mediate mRNA-independent elongation of nascent chains.},
	journal = {Science},
	volume = {347},
	number = {6217},
	year = {2015},
	month = {2015 Jan 2},
	pages = {75-8},
	abstract = {In Eukarya, stalled translation induces 40S\&nbsp;dissociation and recruitment of the ribosome quality control complex (RQC) to the 60S\&nbsp;subunit, which mediates nascent chain degradation. Here we report cryo{\textendash}electron microscopy structures revealing that the RQC components Rqc2p (YPL009C/Tae2) and Ltn1p (YMR247C/Rkr1) bind to the 60S\&nbsp;subunit at sites exposed after 40Sdissociation, 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\&nbsp;subunits. Our work uncovers an unexpected mechanism of protein synthesis, in which a protein{\textemdash}not an mRNA{\textemdash}determines tRNA recruitment and the tagging of nascent chains with carboxy-terminal Ala and Thr extensions ({\textquotedblleft}CAT tails{\textquotedblright}).},
	keywords = {Cryoelectron Microscopy, Nucleic Acid Conformation, Peptide Biosynthesis, Nucleic Acid-Independent, Protein Conformation, Ribosome Subunits, Large, Eukaryotic, RNA, Messenger, RNA, Transfer, Ala, RNA, Transfer, Thr, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Ubiquitin-Protein Ligases},
	issn = {1095-9203},
	doi = {10.1126/science.1259724},
	url = {http://www.sciencemag.org/content/347/6217/75.long},
	author = {Shen, Peter S and Park, Joseph and Qin, Yidan and Li, Xueming and Parsawar, Krishna and Larson, Matthew H and Cox, James and Cheng, Yifan and Lambowitz, Alan M and Weissman, Jonathan S and Brandman, Onn and Frost, Adam}
}
