Dissection of the carboxyl-terminal domain of the proteasomal subunit Rpn11 in maintenance of mitochondrial structure and function

Mol Biol Cell. 2008 Mar;19(3):1022-31. doi: 10.1091/mbc.e07-07-0717. Epub 2008 Jan 2.


We have previously demonstrated that the C-terminal part of Rpn11, a deubiquitinating enzyme in the lid of the proteasome, is essential for maintaining a correct cell cycle and normal mitochondrial morphology and function. The two roles are apparently unlinked as the mitochondrial role is mapped to the Carboxy-terminus, whereas the catalytic deubiquitinating activity is found within the N-terminal region. The mitochondrial defects are observed in rpn11-m1 (originally termed mpr1-1), a mutation that generates Rpn11 lacking the last 31 amino acids. No mitochondrial phenotypes are recorded for mutations in the MPN+/JAMM motif. In the present study, we investigated the participation of the last 31 amino acids of the Rpn11 protein by analysis of intragenic revertants and site-specific mutants. We identified a putative alpha-helix necessary for the maintenance of a correct cell cycle and determined that a very short region at the C-terminus of Rpn11 is essential for the maintenance of tubular mitochondrial morphology. Furthermore, we show that expression of the C-terminal part of Rpn11 is able to complement in trans all of the rpn11-m1 mitochondrial phenotypes. Finally, we investigate the mechanisms by which Rpn11 controls the mitochondrial shape and show that Rpn11 may regulate the mitochondrial fission and tubulation processes.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Endopeptidases / chemistry*
  • Endopeptidases / metabolism*
  • Green Fluorescent Proteins / metabolism
  • Mitochondria / metabolism*
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Oxygen Consumption
  • Phenotype
  • Proteasome Endopeptidase Complex / chemistry*
  • Proteasome Endopeptidase Complex / metabolism
  • Protein Binding
  • Protein Structure, Tertiary
  • Protein Subunits / chemistry*
  • Protein Subunits / metabolism*
  • Protein Transport
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Structure-Activity Relationship
  • Suppression, Genetic


  • Protein Subunits
  • RPN11 protein, S cerevisiae
  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • Green Fluorescent Proteins
  • Endopeptidases
  • Proteasome Endopeptidase Complex