Protein folding and quality control in the endoplasmic reticulum

Curr Opin Cell Biol. 2004 Aug;16(4):343-9. doi: 10.1016/


The endoplasmic reticulum (ER) is a highly versatile protein factory that is equipped with chaperones and folding enzymes essential for protein folding. ER quality control guided by these chaperones is essential for life. Whereas correctly folded proteins are exported from the ER, misfolded proteins are retained and selectively degraded. At least two main chaperone classes, BiP and calnexin/calreticulin, are active in ER quality control. Folding factors usually are found in complexes. Recent work emphasises more than ever that chaperones act in concert with co-factors and with each other.

Publication types

  • Review

MeSH terms

  • Animals
  • Calnexin / metabolism
  • Calreticulin / metabolism
  • Endoplasmic Reticulum / metabolism*
  • Endoplasmic Reticulum Chaperone BiP
  • Heat-Shock Proteins / metabolism
  • Humans
  • Lectins / metabolism
  • Models, Biological
  • Molecular Chaperones / metabolism
  • Protein Folding*
  • Protein Processing, Post-Translational


  • Calreticulin
  • Endoplasmic Reticulum Chaperone BiP
  • Heat-Shock Proteins
  • Lectins
  • Molecular Chaperones
  • Calnexin