The Ribosome as a Platform for mRNA and Nascent Polypeptide Quality Control.

Accurate gene expression is a prerequisite for all cellular processes. Quality control machineries respond to errors during protein synthesis by refolding polypeptides or targeting them for degradation. As another layer of gene expression control, aberrant mRNAs can also be detected and eliminated by mRNA quality control systems while engaging the ribosome. In this review, I focus on recent studies on the cotranslational quality control mechanisms induced by abnormal translational elongation and termination, which result in the rapid degradation of aberrant polypeptides and mRNAs. Emerging evidence indicates that the ribosome has central roles in quality control processes, acting as a platform for discrimination during protein biogenesis and for initiation of downstream events that determine the fate of aberrant polypeptides and mRNAs.