Proteolysis of the phage lambda CII regulatory protein by FtsH (HflB) of Escherichia coli

Mol Microbiol. 1997 Jun;24(6):1303-10. doi: 10.1046/j.1365-2958.1997.4231796.x.


Rapid proteolysis plays an important role in regulation of gene expression. Proteolysis of the phage lambda CII transcriptional activator plays a key role in the lysis-lysogeny decision by phage lambda. Here we demonstrate that the E. coli ATP-dependent protease FtsH, the product of the host ftsH/hflB gene, is responsible for the rapid proteolysis of the CII protein. FtsH was found previously to degrade the heat-shock transcription factor sigma32. Proteolysis of sigma32 requires, in vivo, the presence of the DnaK-DnaJ-GrpE chaperone machine. Neither DnaK-DnaJ-GrpE nor GroEL-GroES chaperone machines are required for proteolysis of CII in vivo. Purified FtsH carries out specific ATP-dependent proteolysis of CII in vitro. The degradation of CII is at least 10-fold faster than that of sigma32. Electron microscopy revealed that purified FtsH forms ring-shaped structures with a diameter of 6-7 nm.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Dependent Proteases
  • Adenosine Triphosphatases / metabolism*
  • Adenosine Triphosphatases / ultrastructure
  • Bacterial Proteins / metabolism*
  • Bacterial Proteins / ultrastructure
  • Bacteriophage lambda*
  • Endopeptidases / metabolism
  • Escherichia coli / enzymology*
  • Escherichia coli / virology
  • Escherichia coli Proteins
  • Membrane Proteins / metabolism*
  • Membrane Proteins / ultrastructure
  • Transcription Factors / metabolism*
  • Viral Proteins


  • Bacterial Proteins
  • Escherichia coli Proteins
  • Membrane Proteins
  • Transcription Factors
  • Viral Proteins
  • cII protein, bacteriophage lambda
  • Endopeptidases
  • ATP-Dependent Proteases
  • FtsH protein, E coli
  • Adenosine Triphosphatases