The extracytoplasmic adaptor protein CpxP is degraded with substrate by DegP

Daniel D. Isaac, Jerome S. Pinkner, Scott J. Hultgren, Thomas J. Silhavy

Research output: Contribution to journalArticlepeer-review

133 Scopus citations


In Escherichia coli, the CpxR/A two-component system senses various types of extracytoplasmic stresses and responds by activating the expression of genes encoding periplasmic protein folding and trafficking factors that clear such stresses to ensure the organism's survival. The cpxP gene encodes a small, stress-combative periplasmic protein and is the most strongly induced member of the Cpx regulon. We demonstrate that the Cpx stress response suppresses the toxicity associated with two misfolded proteins derived from the P pilus of uropathogenic E. coli and that mutations in either cpxP or the gene for the periplasmic protease DegP prevent suppression by preventing the degradation of these proteins. Strikingly, the presence of a periplasmic misfolded protein substrate significantly enhances the proteolysis of CpxP by DegP. Our data suggest that CpxP functions as a periplasmic adaptor protein that is required for the effective proteolysis of a subset of misfolded substrates by the DegP protease.

Original languageEnglish (US)
Pages (from-to)17775-17779
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number49
StatePublished - Dec 6 2005

All Science Journal Classification (ASJC) codes

  • General


  • Escherichia coli
  • Misfolded protein
  • Periplasm
  • Regulated proteolysis


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