Is there an alternative to the proteasome in cytosolic protein degradation?
While it is clear that the proteasome is the major player in degradative proteolysis in the nucleus and cytosol, there is a lack of complete agreement on whether there are alternative proteolytic pathways or activities responsible for a significant degradation of cytosolic/nuclear substrates. Particularly relevant is the case of the aminopeptidase TPPII (tripeptidyl peptidase II), which has been suggested to be able to perform some of the proteasome functions. However, the current evidence seems to support only a limited role for these cytosolic alternatives. On the other hand, there is evidence of an alternative, autophagy, a pathway involving the delivery of cytosolic substrates to the lysosome for degradation.
Antón
Luis C
LC
CBMSO (Centro de Biología Molecular 'Severo Ochoa'), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain. lanton@cbm.uam.es
Villasevil
Eugenia M
EM
D000626:Aminopeptidases; D000941:Antigens / Q000378:metabolism; D001343:Autophagy / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000737:chemistry* / Q000378:metabolism; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D005805:Genes, MHC Class I; D006801:Humans; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D061988:Proteasome Inhibitors; D011506:Proteins / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000378:metabolism
D000941:Antigens; D061988:Proteasome Inhibitors; D011506:Proteins; D000626:Aminopeptidases; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C048001:tripeptidyl-peptidase 2; D012697:Serine Endopeptidases; D046988:Proteasome Endopeptidase Complex