Ribosomal Hibernation-Associated Factors in Escherichia coli

Abstract

Bacteria convert active 70S ribosomes to inactive 100S ribosomes to survive under various stress conditions. This state, in which the ribosome loses its translational activity, is known as ribosomal hibernation. In gammaproteobacteria such as Escherichia coli, ribosome modulation factor and hibernation-promoting factor are involved in forming 100S ribosomes. The expression of ribosome modulation factor is regulated by (p)ppGpp (which is induced by amino acid starvation), cAMP-CRP (which is stimulated by reduced metabolic energy), and transcription factors involved in biofilm formation. This indicates that the formation of 100S ribosomes is an important strategy for bacterial survival under various stress conditions. In recent years, the structures of 100S ribosomes from various bacteria have been reported, enhancing our understanding of the 100S ribosome. Here, we present previous findings on the 100S ribosome and related proteins and describe the stress-response pathways involved in ribosomal hibernation.

In situ structure of a dimeric hibernating ribosome from a eukaryotic intracellular pathogen

“…Either mechanism prevents the dissociation of the small and large subunit, which is an essential prerequisite for mRNA loading and translation 1 . Moreover, ribosome dimerisation protects the ribosomes from degradation by RNases 4 .…”

Absence of Ribosome Modulation Factor Alters Growth and Competitive Fitness of Escherichia coli

“…Ribosome hibernation and inactivation are phenomena that occur in E. coli as a response to stress and low-nutrient conditions ( 1 – 6 ). Several roles for this have been proposed, including ribosome preservation and preparation of cells for the reinitiation of growth upon reinoculation into rich medium ( 6 , 25 , 31 , 35 ).…”

“…Ribosome hibernation and inactivation are phenomena that occur in E. coli as a response to stress and low-nutrient conditions ( 1 – 6 ). Several roles for this have been proposed, including ribosome preservation and preparation of cells for the reinitiation of growth upon reinoculation into rich medium ( 6 , 25 , 31 , 35 ). In E. coli , the dimerization of two 70S ribosomes requires the participation of RMF and HPF, while the binding of YfiA leads to inhibition of translation ( 6 ).…”

“…Several roles for this have been proposed, including ribosome preservation and preparation of cells for the reinitiation of growth upon reinoculation into rich medium ( 6 , 25 , 31 , 35 ). In E. coli , the dimerization of two 70S ribosomes requires the participation of RMF and HPF, while the binding of YfiA leads to inhibition of translation ( 6 ). While it has long been known that RMF is necessary for E. coli to create 100S ribosome particles ( 1 , 3 ), these 100S particles were traditionally thought to provide a means for the sequestration of ribosomes and to slow down translation by reducing the number of active 70S ribosomes ( 4 ).…”

“…Disturbances in the activity of this complex macromolecule can impair a cell’s ability to properly respond to changes in the environment. In Escherichia coli , one protein that is central to the regulation of ribosomal activity is the r ibosome m odulation f actor (RMF) ( 1 – 6 ). RMF primarily functions as the initiator, along with the h ibernation p romoting f actor (HPF), in the two-step process of binding two 70S ribosomes to form a 100S ribosome dimer ( 2 ).…”