Structure and assembly pathway of the ribosome quality control complex.
Bottom Line: During ribosome-associated quality control, stalled ribosomes are split into subunits and the 60S-housed nascent polypeptides are poly-ubiquitinated by Listerin.Structural and mutational analyses showed that ribosome-bound NEMF recruits and stabilizes Listerin's N-terminal domain, while Listerin's C-terminal RWD domain directly contacts the ribosome to position the adjacent ligase domain near the nascent polypeptide exit tunnel.Thus, highly specific nascent chain targeting by Listerin is imparted by the avidity gained from a multivalent network of context-specific individually weak interactions, highlighting a new principle of client recognition during protein quality control.
Affiliation: MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.Show MeSH
Related in: MedlinePlus
Mentions: The combined data set containing 117,461 particles was processed through RELION (Scheres, 2012). After initial 3D refinement, movie processing was performed to adjust for drift and radiation damage (Bai et al., 2013), resulting in an initial map that showed extraribosomal density we provisionally assigned to Listerin and NEMF. These particles were then subjected to further 3D classification with a mask around the presumed Listerin and NEMF densities to enrich for their occupancy. The enriched class, containing 63,826 particles, was refined (Table 1) to produce our final map of a 60S-RNC in complex with Listerin and NEMF (Figure 3). Gold standard FSC curve analysis indicated an overall resolution of 3.6 Å (Figure S3C). The ribosome displayed the highest resolution, while local resolution for the associated factors decreased relative to the core of the ribosome (Figure S3D).
Affiliation: MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.