Prokaryotic proteasomes: nanocompartments of degradation.
Proteasomes are self-compartmentalized energy-dependent proteolytic machines found in Archaea, Actinobacteria species of bacteria and eukaryotes. Proteasomes consist of two separate protein complexes, the core particle that hydrolyzes peptide bonds and an AAA+ ATPase domain responsible for the binding, unfolding and translocation of protein substrates into the core particle for degradation. Similarly to eukaryotes, proteasomes play a central role in protein degradation and can be essential in Archaea. Core particles associate with and utilize a variety of ATPase complexes to carry out protein degradation in Archaea. In actinobacterial species, such as Mycobacterium tuberculosis, proteasome-mediated degradation is associated with pathogenesis and does not appear to be essential. Interestingly, both actinobacterial species and Archaea use small proteins to covalently modify proteins, prokaryotic ubiquitin-like proteins (Pup) in Actinobacteria and ubiquitin-like small archaeal modifier proteins (SAMP) in Archaea. These modifications may play a role in proteasome targeting similar to the ubiquitin-proteasome system in eukaryotes.
Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Md., USA.
Matthew A
MA
Humbard
Julie A
JA
Maupin-Furlow
D039903:Actinobacteria / Q000378:metabolism*; D001105:Archaea / Q000378:metabolism*; D019843:Archaeal Proteins / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D059748:Proteolysis
D019843:Archaeal Proteins; D001426:Bacterial Proteins; D046988:Proteasome Endopeptidase Complex