An inhibitor of the chymotrypsin-like activity of the proteasome (PSI) induces similar morphological changes in various cell lines

Folia Histochem Cytobiol. 1997;35(4):211-4.


Different established cell lines (SK-v human keratinocytes, B16F10 mouse melanoma, Muntjac fibroblasts, 3T3 mouse fibroblasts, CLV human fibroblasts) as well as primary cultures of mouse fibroblasts and giant cells were treated with N-benzyloxycarbonyl-Ile-Glu(O-t-butyl)-Ala-leucinal (proteasome inhibitor, PSI), a specific inhibitor of the chymotrypsin-like activity of the proteasome. PSI induced well characterized morphological changes in all cell lines studied, including vacuolization and accumulation of perinuclear aggregates, as detected by amido black staining. Together with previous reports on HeLa cells, the present findings support the hypothesis that ubiquitin- and proteasome-dependent proteolysis does not occur randomly in the entire cell, but it is concentrated in a well defined perinuclear region, the proteolytic center.

MeSH terms

  • Animals
  • Cell Line
  • Cell Nucleus / drug effects
  • Cell Nucleus / ultrastructure
  • Chymotrypsin / antagonists & inhibitors*
  • Cysteine Endopeptidases / drug effects*
  • Histocytochemistry
  • Humans
  • Mice
  • Multienzyme Complexes / drug effects*
  • Organelles / drug effects*
  • Organelles / ultrastructure*
  • Proteasome Endopeptidase Complex
  • Sprains and Strains
  • Tumor Cells, Cultured
  • Vacuoles / drug effects
  • Vacuoles / ultrastructure


  • Multienzyme Complexes
  • Chymotrypsin
  • Cysteine Endopeptidases
  • Proteasome Endopeptidase Complex