Regulation of proteasome-mediated protein degradation during oxidative stress and aging.
Protein degradation is a physiological process required to maintain cellular functions. There are distinct proteolytic systems for different physiological tasks under changing environmental and pathophysiological conditions. The proteasome is responsible for the removal of oxidatively damaged proteins in the cytosol and nucleus. It has been demonstrated that proteasomal degradation increases due to mild oxidation, whereas at higher oxidant levels proteasomal degradation decreases. Moreover, the proteasome itself is affected by oxidative stress to varying degrees. The ATP-stimulated 26S proteasome is sensitive to oxidative stress, whereas the 20S form seems to be resistant. Non-degradable protein aggregates and cross-linked proteins are able to bind to the proteasome, which makes the degradation of other misfolded and damaged proteins less efficient. Consequently, inhibition of the proteasome has dramatic effects on cellular aging processes and cell viability. It seems likely that during oxidative stress cells are able to keep the nuclear protein pool free of damage, while cytosolic proteins may accumulate. This is because of the high proteasome content in the nucleus, which protects the nucleus from the formation and accumulation of non-degradable proteins. In this review we highlight the regulation of the proteasome during oxidative stress and aging.
Breusing
Nicolle
N
Institute of Biological Chemistry and Nutrition, University of Hohenheim, Garbenstrasse 28, D-70593 Stuttgart, Germany.
Grune
Tilman
T
D000375:Aging / Q000502:physiology*; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D006801:Humans; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism* / Q000502:physiology; D011506:Proteins / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism
D011506:Proteins; D017382:Reactive Oxygen Species; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease; C119011:26S proteasome non-ATPase regulatory subunit 13