A temperature-dependent switch from chaperone to protease in a widely conserved heat shock protein

Cell. 1999 Apr 30;97(3):339-47. doi: 10.1016/s0092-8674(00)80743-6.

Abstract

Misfolding or unfolding of polypeptides can occur as a consequence of environmental stress and spontaneous mutation. The abundance of general chaperones and proteases suggests that cells distinguish between proteins that can be refolded and "hopeless" cases fated to enter the proteolytic pathway. The mechanisms controlling this key metabolic decision are not well understood. We show here that the widely conserved heat shock protein DegP (HtrA) has both general molecular chaperone and proteolytic activities. The chaperone function dominates at low temperatures, while the proteolytic activity is present at elevated temperatures. These results show that a single cellular factor can switch between two key pathways, controlling protein stability and turnover. Implications of this finding for intracellular protein metabolism are discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amylases / chemistry
  • Amylases / metabolism
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Chaperonins / metabolism*
  • DNA Primers
  • Endopeptidases / metabolism*
  • Escherichia coli / chemistry
  • Escherichia coli / enzymology*
  • Escherichia coli / genetics
  • Escherichia coli Proteins*
  • Gene Deletion
  • Gene Expression Regulation, Bacterial
  • Gene Expression Regulation, Enzymologic
  • Heat-Shock Proteins*
  • In Vitro Techniques
  • Lac Operon
  • Mutation / physiology
  • Periplasmic Proteins*
  • Protein Disulfide-Isomerases / genetics
  • Protein Folding
  • Serine Endopeptidases / chemistry
  • Serine Endopeptidases / genetics
  • Serine Endopeptidases / metabolism*
  • Substrate Specificity
  • Temperature
  • Transcription, Genetic / physiology
  • alpha-Amylases / metabolism

Substances

  • Bacterial Proteins
  • DNA Primers
  • Escherichia coli Proteins
  • Heat-Shock Proteins
  • Periplasmic Proteins
  • Amylases
  • MalS protein, E coli
  • alpha-Amylases
  • Endopeptidases
  • DegP protease
  • Serine Endopeptidases
  • Chaperonins
  • Protein Disulfide-Isomerases