Innovita Research Foundation

I.R.F. / Aging news / General / 08062001

Proteasomes, Mitochondrial Function, and Cellular Senescence
Posted on: June 20, 2008

Proteasome plays fundamental roles in the removal of oxidized proteins and in the normal degradation of short-lived proteins. It has been known that the impairment in proteasome observed during the replicative senescence of human fibroblasts has significant effects on MAPK signaling, proliferation, life span, senescent phenotype, and protein oxidative status. These studies have demonstrated that proteasome inhibition and replicative senescence caused accumulation of intracellular protein carbonyl content.

So to answer more questions, scientists investigated the mechanisms by which proteasome dysfunction modulates protein oxidation during cellular senescence. And results indicate that proteasome inhibition during replicative senescence has significant effects on intra- and extracellular ROS production in vitro.

The data also show that ROS impaired the proteasome function, which is partially reversible by antioxidants. Increases in ROS after proteasome inhibition correlated with a significant negative effect on the activity of most mitochondrial electron transporters.

So it is proposed that failures in proteasome during cellular senescence lead to mitochondrial dysfunction, ROS production, and oxidative stress. Furthermore, it is likely that changes in proteasome dynamics could generate a prooxidative condition at the immediate extracellular microenvironment that could cause tissue injury during aging, in vivo.

Source: Torres CA, Perez VI.; Proteasome modulates mitochondrial function during cellular senescence.; Free Radic Biol Med. 2008 Feb 1;44(3):403-14. Epub 2007 Oct 10.
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