Mutational analysis of subunit iβ2 (MECL-1) demonstrates conservation of cleavage specificity between yeast and mammalian proteasomes

Ulrike Salzmann, Sylvie Kral, Beate Braun, Sybille Standera, Marion Schmidt, Peter M. Kloetzel, Alice Sijts

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25 Scopus citations


Proteasomes are the major protein-degrading complexes in the cytosol and regulate many cellular processes. To examine the functional importance of the MC14/MECL-1 proteasome active site subunits, cell lines expressing a catalytically inactive form of MECL-1 were established. Whereas mutant MECL-1 was readily incorporated into cytosolic proteasomes, replacing the constitutive MC14 subunit, removal of the prosequence was incomplete indicating that its processing required autocatalytic cleavage. Functional analyses showed that the absence of the MC14/MECL-1 active sites abrogated proteasomal trypsin-like activity, but did not affect other catalytic activities. Our data demonstrate a conservation of cleavage specificity between mammalian and yeast proteasomes. Copyright (C) 1999 Federation of European Biochemical Societies.

Original languageEnglish (US)
Pages (from-to)11-15
Number of pages5
JournalFEBS Letters
Issue number1-2
StatePublished - Jul 2 1999



  • 20S proteasome
  • Autocatalytic processing
  • Interferon γ-inducible subunit
  • MECL-1 T1A
  • Peptide hydrolysis

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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