title: A Novel SRP Recognition Sequence in the Homeostatic Control Region of Heat Shock Transcription Factor σ32.
abstract: Heat shock response (HSR) generally plays a major role in sustaining protein homeostasis. In Escherichia coli, the activity and amount of the dedicated transcription factor σ(32) transiently increase upon heat shock. The initial induction is followed by chaperone-mediated negative feedback to inactivate and degrade σ(32). Previous work reported that signal recognition particle (SRP)-dependent targeting of σ(32) to the membrane is essential for feedback control, though how SRP recognizes σ(32) remained unknown. Extensive photo- and disulfide cross-linking studies in vivo now reveal that the highly conserved regulatory region of σ(32) that lacks a consecutive hydrophobic stretch interacts with the signal peptide-binding site of Ffh (the protein subunit of SRP). Importantly, the σ(32)-Ffh interaction observed was significantly affected by mutations in this region that compromise the feedback regulation, but not by deleting the DnaK/DnaJ chaperones. Homeostatic regulation of HSR thus requires a novel type of SRP recognition mechanism.
authors.affiliation: Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Miyazaki
authors.affiliation: Faculty of Life Sciences, Kyoto Sangyo University, Kyoto 603-8555, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yura
authors.affiliation: Center for Sustainable Resource Science, RIKEN, Saitama 351-0198, Japan.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Center for Sustainable Resource Science, RIKEN, Saitama 351-0198, Japan.
authors.forename: Naoshi
authors.initials: N
authors.lastname: Dohmae
authors.affiliation: Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mori
authors.affiliation: Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Akiyama
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D004220:Disulfides / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D025461:Feedback, Physiological; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006706:Homeostasis / Q000235:genetics; D015151:Immunoblotting; D008958:Models, Molecular; D009154:Mutation; D011485:Protein Binding / Q000528:radiation effects; D000072417:Protein Domains; D012045:Regulatory Sequences, Nucleic Acid; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018271:Signal Recognition Particle / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D004220:Disulfides; C494635:DnaJ protein, E coli; D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C489352:HtpG protein, E coli; D012808:Sigma Factor; D018271:Signal Recognition Particle; C069774:heat-shock sigma factor 32; C063842:dnaK protein, E coli