Secretory Pathway Quality Control Operating in Golgi, Plasmalemmal, and Endosomal Systems

Traffic. 2002 Nov;3(11):771-80. doi: 10.1034/j.1600-0854.2002.31102.x.


Exportable proteins that have significant defects in nascent polypeptide folding or subunit assembly are frequently retained in the endoplasmic reticulum and subject to endoplasmic reticulum-associated degradation by the ubiquitin-proteasome system. In addition to this, however, there is growing evidence for post-endoplasmic reticulum quality control mechanisms in which mutant or non-native exportable proteins may undergo anterograde transport to the Golgi complex and post-Golgi compartments before intracellular disposal. In some instances, these proteins may undergo retrograde transport back to the endoplasmic reticulum with re-targeting to the endoplasmic reticulum-associated degradation pathway; in other typical cases, they are targeted into the endosomal system for degradation by vacuolar/lysosomal proteases. Such quality control targeting is likely to involve recognition of features more commonly expressed in mutant proteins, but may also be expressed by wild-type proteins, especially in cells with perturbation of local environments that are essential for normal protein trafficking and stability in the secretory pathway and at the cell surface.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Biological Transport
  • Carrier Proteins / metabolism
  • Cell Membrane / metabolism*
  • Endoplasmic Reticulum / metabolism*
  • Endosomes / metabolism*
  • Golgi Apparatus / metabolism*
  • Humans
  • Membrane Proteins / metabolism
  • Models, Biological
  • Protein Transport


  • Carrier Proteins
  • Membrane Proteins