Taking a Bite: Proteasomal Protein Processing

Nat Cell Biol. 2002 May;4(5):E113-6. doi: 10.1038/ncb0502-e113.


The proteasome is a hollow cylindrical protease that contains active sites concealed within its central cavity. Proteasomes usually completely degrade substrates into small peptides, but in a few cases, degradation can yield biologically active protein fragments. Examples of this are the transcription factors NF-kappa B, Spt23p and Mga2p, which are generated from precursors by proteasomal processing. How distinct protein domains are spared from degradation remains a matter of debate. Here, we discuss several models and suggest a novel mechanism for proteasomal processing.

MeSH terms

  • Animals
  • Cysteine Endopeptidases / metabolism*
  • Models, Biological
  • Multienzyme Complexes / metabolism*
  • NF-kappa B / metabolism*
  • Proteasome Endopeptidase Complex
  • Protein Structure, Tertiary
  • Transcription Factors / metabolism*
  • Ubiquitin / metabolism


  • Multienzyme Complexes
  • NF-kappa B
  • Transcription Factors
  • Ubiquitin
  • Cysteine Endopeptidases
  • Proteasome Endopeptidase Complex