Enolase in the RNA degradosome plays a crucial role in the rapid decay of glucose transporter mRNA in the response to phosphosugar stress in Escherichia coli.
The ptsG mRNA encoding the major glucose transporter is rapidly degraded in an RNase E-dependent manner in response to the accumulation of glucose 6-P or fructose 6-P when the glycolytic pathway is blocked at its early steps in Escherichia coli. RNase E, a major endonuclease, is associated with polynucleotide phosphorylase (PNPase), RhlB helicase and a glycolytic enzyme, enolase, which bind to its C-terminal scaffold region to form a multienzyme complex called the RNA degradosome. The role of enolase within the RNase E-based degradosome in RNA decay has been totally mysterious. In this article, we demonstrate that the removal of the scaffold region of RNase E suppresses the rapid degradation of ptsG mRNA in response to the metabolic stress without affecting the expression of ptsG mRNA under normal conditions. We also demonstrate that the depletion of enolase but not the disruption of pnp or rhlB eliminates the rapid degradation of ptsG mRNA. Taken together, we conclude that enolase within the degradosome plays a crucial role in the regulation of ptsG mRNA stability in response to a metabolic stress. This is the first instance in which a physiological role for enolase in the RNA degradosome has been demonstrated. In addition, we show that PNPase and RhlB within the degradosome cooperate to eliminate short degradation intermediates of ptsG mRNA.
Morita
Teppei
T
Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, Japan.
Kawamoto
Hiroshi
H
Mizota
Taisei
T
Inada
Toshifumi
T
Aiba
Hiroji
H
D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005947:Glucose / Q000378:metabolism; D009097:Multienzyme Complexes; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics* / Q000378:metabolism*; D010751:Phosphopyruvate Hydratase / Q000378:metabolism*; D011117:Polyribonucleotide Nucleotidyltransferase / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020365:RNA Helicases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D013403:Sugar Phosphates / Q000378:metabolism
D029968:Escherichia coli Proteins; D009097:Multienzyme Complexes; D012333:RNA, Messenger; D013403:Sugar Phosphates; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C031629:phosphoenolpyruvate-glucose phosphotransferase; D011117:Polyribonucleotide Nucleotidyltransferase; D020365:RNA Helicases; D010751:Phosphopyruvate Hydratase; D005947:Glucose