Escherichia coli FtsH is a membrane-bound, ATP-dependent protease which degrades the heat-shock transcription factor sigma 32

EMBO J. 1995 Jun 1;14(11):2551-60.


Escherichia coli FtsH is an essential integral membrane protein that has an AAA-type ATPase domain at its C-terminal cytoplasmic part, which is homologous to at least three ATPase subunits of the eukaryotic 26S proteasome. We report here that FtsH is involved in degradation of the heat-shock transcription factor sigma 32, a key element in the regulation of the E. coli heat-shock response. In the temperature-sensitive ftsH1 mutant, the amount of sigma 32 at a non-permissive temperature was higher than in the wild-type under certain conditions due to a reduced rate of degradation. In an in vitro system with purified components, FtsH catalyzed ATP-dependent degradation of biologically active histidine-tagged sigma 32. FtsH has a zinc-binding motif similar to the active site of zinc-metalloproteases. Protease activity of FtsH for histidine-tagged sigma 32 was stimulated by Zn2+ and strongly inhibited by the heavy metal chelating agent o-phenanthroline. We conclude that FtsH is a novel membrane-bound, ATP-dependent metalloprotease with activity for sigma 32. These findings indicate a new mechanism of gene regulation in E. coli.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Dependent Proteases
  • Adenosine Triphosphatases / chemistry
  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Binding Sites
  • Cations, Divalent / pharmacology
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial
  • Heat-Shock Proteins / metabolism*
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mutation
  • Nucleotides / metabolism
  • Protease Inhibitors / pharmacology
  • Sigma Factor / metabolism*
  • Substrate Specificity
  • Temperature
  • Transcription Factors / metabolism
  • Viral Proteins


  • Bacterial Proteins
  • Cations, Divalent
  • Escherichia coli Proteins
  • Heat-Shock Proteins
  • Membrane Proteins
  • Nucleotides
  • Protease Inhibitors
  • Sigma Factor
  • Transcription Factors
  • Viral Proteins
  • cII protein, bacteriophage lambda
  • heat-shock sigma factor 32
  • ATP-Dependent Proteases
  • FtsH protein, E coli
  • Adenosine Triphosphatases