Fig. 4.
Disassembly of the 26S proteasome during oxidative stress. The components of the ubiquitin-26S proteasome system are highly sensitive to oxidative stress-induced inactivation. In response to oxidative stress, ECM29 facilitates the disassembly of the 26S proteasome, allowing for the unbound 20S proteasome to preferentially degrade oxidized proteins. 20S proteasomes may also bind to PA28 (11S) regulators to increase the efficiency of oxidized protein degradation. HSP70 acts as a holdase by binding the 19S regulatory unit until recovery from stress and is necessary for the reassembly of the 26S proteasome some 3–5 hours after an oxidative insult.
