title: Temperature effect on inclusion body formation and stress response in the periplasm of Escherichia coli.
abstract: We previously characterized a defective-folding mutant of maltose-binding protein of Escherichia coli, MalE31, which formed periplasmic inclusion bodies. Here, we show that MalE31 aggregation does not affect bacterial growth at 30 degrees C but is lethal at 37 degrees C. Surprisingly, under mild heat shock conditions at 42 degrees C, inclusion bodies are degraded and bacterial growth is restored. One physiological consequence for the cells overproducing MalE31 was to induce an extracytoplasmic stress response by increasing the expression of the heat shock protease DegP via the CpxA/CpxR two-component signalling pathway. Furthermore, we show that the Cpx response is required to rescue the cells from the toxicity mediated by MalE31. Finally, expression of highly destabilized MalE variants that do not aggregate in the periplasm also induces the Cpx pathway, indicating that inclusion body formation is not necessary to activate this specific extracytoplasmic stress regulatory system.
authors.affiliation: Humboldt-Universität zu Berlin, Institut für Biologie/Bakterienphysiologie, Chausseestr. 117, D-10115 Berlin, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Hunke
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Betton
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018869:Heat-Shock Response; D002479:Inclusion Bodies / Q000502:physiology*; D019897:Periplasm / Q000378:metabolism*; D033902:Periplasmic Binding Proteins / Q000235:genetics / Q000378:metabolism*; D033903:Periplasmic Proteins / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; C461619:MalE protein, E coli; D033902:Periplasmic Binding Proteins; D033903:Periplasmic Proteins; C085504:CpxR protein, Bacteria; D011494:Protein Kinases; C490475:CpxA protein, E coli; C092472:CpxA protein, bacteria; C061682:DegP protease; D012697:Serine Endopeptidases