Bussiere, Cyril; Hashem, Yaser; Arora, Sucheta; Frank, Joachim; Johnson, Arlen W.
Integrity of the P-site is probed during maturation of the 60S ribosomal subunit
JOURNAL OF CELL BIOLOGY, 197:747-759, JUN 11 2012

Eukaryotic ribosomes are preassembled in the nucleus and mature in the cytoplasm. Release of the antiassociation factor Tif6 by the translocase-like guanosine triphosphatase Efl1 is a critical late maturation step. In this paper, we show that a loop of Rpl10 that embraces the P-site transfer ribonucleic acid was required for release of Tif6, 90 angstrom away. Mutations in this P-site loop blocked 60S maturation but were suppressed by mutations in Tif6 or Efl1. Molecular dynamics simulations of the mutant Efl1 proteins suggest that they promote a conformation change in Efl1 equivalent to changes that elongation factor G and eEF2 undergo during translocation. These results identify molecular signaling from the P-site to Tif6 via Efl1, suggesting that the integrity of the P-site is interrogated during maturation. We propose that Efl1 promotes a functional check of the integrity of the 60S subunit before its first round of translation.

DOI:10.1083/jcb.201112131

Find full text with Google Scholar.