Degradation of polyubiquitinated proteins by proteasomes

  • Proteasomes are multi-protein complexes located in the cytosol and nucleus.
  • The proteasomes consist of two major sub-complexes:
    • the catalytic particle (20 S particle) and
    • the regulatory particle (19 S particle)
  • The proteasomes recognize polyubiquitinated proteins with ubiquitin chains of at least 4 ubiquitin molecules and degrades them into small peptides, 3-22 residues long.
  • The ubiquitin molecules are recycled.