Ribosome regulation, inhibition, and quality control mechanisms

PROJECT SUMMARY Ribosomes are the complex, cellular machinery responsible for promoting mRNA-directed translation of the genetic code to produce all proteins in every living organism. The ribosome must select correct tRNAs to decode the mRNA, facilitate peptide bond formation, and then move the tRNAs through its three functionally distinct tRNA binding sites in a dynamic and exquisitely orchestrated manner. We study the regulation, inhibition, and quality control mechanisms of the ribosome using integrated biochemistry and structural biology approaches. In this proposal, we extend our novel insights into the regulation of the ribosome by studying three themes. The first theme focuses on understanding translation fidelity events including miscoding, quality control, and processivity errors including mRNA frameshifting caused by tRNAs lacking posttranscriptional modifications and complex mRNAs. The second theme focuses on understaffing ribosome rescue, an event that occurs when ribosomes stall primarily because of defective mRNAs. And finally, the third theme focuses on the role of diverse bacterial ribonucleases including toxins and newly identified ribonucleases that inhibit translation to cause growth inhibition of ribosome hibernation. We will accomplish these questions using biochemistry and structural biology approaches to determine the mechanistic basis for which ribosomes are regulated.