RbfA and IF3 couple ribosome biogenesis and translation initiation to increase stress tolerance

• Published in: Nucleic acids research Vol. 48; no. 1; pp. 359 - 372
• Main Authors: Sharma, Indra Mani, Woodson, Sarah A
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 10.01.2020
• Subjects: Adaptation, Physiological - genetics; Anti-Bacterial Agents - pharmacology; Cold Temperature; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - metabolism; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Gene Expression Regulation, Bacterial; Organelle Biogenesis; Peptide Chain Initiation, Translational; Prokaryotic Initiation Factor-3 - genetics; Prokaryotic Initiation Factor-3 - metabolism; Protein Processing, Post-Translational; Ribosomal Proteins - genetics; Ribosomal Proteins - metabolism; Ribosomes - genetics; Ribosomes - metabolism; RNA and RNA-protein complexes; Stress, Physiological - genetics
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/gkz1065

Abstract Bacterial ribosome biogenesis and translation occur in the same cellular compartment. Therefore, a biochemical gate-keeping step is required to prevent error-prone immature ribosomes from engaging in protein synthesis. Here, we provide evidence for a previously unknown quality control mechanism in which the abundant ribosome assembly factor, RbfA, suppresses protein synthesis by immature Escherichia coli 30S subunits. After 30S maturation, RbfA is displaced by initiation factor 3 (IF3), which promotes translation initiation. Genetic interactions between RbfA and IF3 show that RbfA release by IF3 is important during logarithmic growth as well as during stress encountered during stationary phase, low nutrition, low temperature, and antibiotics. By gating the transition from 30S biogenesis to translation initiation, RbfA and IF3 maintain the fidelity of bacterial protein synthesis.