Ribosome-tethered molecular chaperones: the first line of defense against protein misfolding?

Curr Opin Microbiol. 2003 Apr;6(2):157-62. doi: 10.1016/s1369-5274(03)00030-4.


Folding of many cellular proteins is facilitated by molecular chaperones. Analysis of both prokaryotic and lower eukaryotic model systems has revealed the presence of ribosome-associated molecular chaperones, thought to be the first line of defense against protein aggregation as translating polypeptides emerge from the ribosome. However, structurally unrelated chaperones have evolved to carry out these functions in different microbes. In the yeast Saccharomyces cerevisiae, an unusual complex of Hsp70 and J-type chaperones associates with ribosome-bound nascent chains, whereas in Escherichia coli the ribosome-associated peptidyl-prolyl-cis-trans isomerase, trigger factor, plays a predominant role.

Publication types

  • Review

MeSH terms

  • Animals
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • HSP70 Heat-Shock Proteins / metabolism
  • Models, Biological
  • Molecular Chaperones / classification
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism*
  • Peptidylprolyl Isomerase / genetics
  • Peptidylprolyl Isomerase / metabolism
  • Protein Folding
  • Ribosomes / genetics
  • Ribosomes / metabolism*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*


  • Escherichia coli Proteins
  • HSP70 Heat-Shock Proteins
  • Molecular Chaperones
  • Saccharomyces cerevisiae Proteins
  • trigger factor, E coli
  • Peptidylprolyl Isomerase