20S proteasome from LMP7 knock out mice reveals altered proteolytic activities and cleavage site preferences

FEBS Lett. 1996 Mar 25;383(1-2):109-13. doi: 10.1016/0014-5793(96)00110-x.

Abstract

20S proteasomes of tissues from LMP7 knock out mice which show reduced MHC class I restricted antigen presentation were analyzed with regard to their subunit composition, peptide hydrolyzing activity and their ability to cleave a synthetic 25-mer polypeptide. LMP7 deficiency results in an enhanced incorporation of subunit MB1 and in a 2-3.8-fold increase in Vmax for the Suc-LLVY-MCA hydrolyzing activity. Since LMP7 deficiency also affects the cleavage site preference of 20S proteasomes the reduced MHC class I antigen presentation of LMP7 knock out mice is most likely due to an impairment in peptide generation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Chromatography, High Pressure Liquid
  • Cysteine Endopeptidases / chemistry*
  • Cysteine Endopeptidases / isolation & purification
  • Cysteine Endopeptidases / metabolism*
  • Electrophoresis, Gel, Two-Dimensional
  • Histocompatibility Antigens Class I / immunology
  • Immunoblotting
  • Kinetics
  • Liver / enzymology
  • Mice
  • Mice, Knockout
  • Molecular Sequence Data
  • Multienzyme Complexes / chemistry*
  • Multienzyme Complexes / isolation & purification
  • Multienzyme Complexes / metabolism*
  • Peptides / chemistry
  • Peptides / metabolism
  • Proteasome Endopeptidase Complex
  • Protein Conformation
  • Proteins / genetics
  • Proteins / physiology*
  • Spleen / enzymology
  • Thymus Gland / enzymology
  • Transfection

Substances

  • Histocompatibility Antigens Class I
  • Multienzyme Complexes
  • Peptides
  • Proteins
  • Cysteine Endopeptidases
  • LMP7 protein
  • Proteasome Endopeptidase Complex