title: The role of thiol oxidative stress response in heat-induced protein aggregate formation during thermotolerance in Bacillus subtilis.
abstract: Using Bacillus subtilis as a model organism, we investigated thermotolerance development by analysing cell survival and in vivo protein aggregate formation in severely heat-shocked cells primed by a mild heat shock. We observed an increased survival during severe heat stress, accompanied by a strong reduction of heat-induced cellular protein aggregates in cells lacking the ClpXP protease. We could demonstrate that the transcription factor Spx, a regulatory substrate of ClpXP, is critical for the prevention of protein aggregate formation because its regulon encodes redox chaperones, such as thioredoxin, required for protection against thiol-specific oxidative stress. Consequently B. subtilis cells grown in the absence of oxygen were more protected against severe heat shock and much less protein aggregates were detected compared to aerobically grown cells. The presented results indicate that in B. subtilis Spx and its regulon plays not only an important role for oxidative but also for heat stress response and thermotolerance development. In addition, our experiments suggest that the protection of misfolded proteins from thiol oxidation during heat shock can be critical for the prevention of cellular protein aggregation in vivo.
authors.affiliation: Institut für Biologie - Mikrobiologie, Freie Universität Berlin, D-14195, Berlin, Germany; Institut für Mikrobiologie, Leibniz Universität Hannover, D-30167, Hannover, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Runde
authors.forename: Noël
authors.initials: N
authors.lastname: Molière
authors.forename: Anja
authors.initials: A
authors.lastname: Heinz
authors.forename: Etienne
authors.initials: E
authors.lastname: Maisonneuve
authors.forename: Armgard
authors.initials: A
authors.lastname: Janczikowski
authors.forename: Alexander K W
authors.initials: AK
authors.lastname: Elsholz
authors.forename: Ulf
authors.initials: U
authors.lastname: Gerth
authors.forename: Michael
authors.initials: M
authors.lastname: Hecker
authors.forename: Kürşad
authors.initials: K
authors.lastname: Turgay
mesh_terms: D000222:Adaptation, Physiological; D000693:Anaerobiosis; D001412:Bacillus subtilis / Q000254:growth & development / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D018869:Heat-Shock Response; D006706:Homeostasis; D006358:Hot Temperature; D050296:Microbial Viability; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D020836:Protein Structure, Quaternary; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D013438:Sulfhydryl Compounds