Cell's Cleaning Mechanism Rebounds after Temporary Stress Episodes
Researchers at the Technion-Israel Institute of Technology have discovered that the proteasome - the "biological machine" that rids the body of damaged proteins - "takes a break" when cells are under harmful oxidative stress. Damaged proteins must be disposed of quickly, or they will accumulate and cause long-term damage. The findings are published this week in Cell Reports.
The team led by Prof. Michael Glickman, of the Technion Faculty of Biology, compares the phenomenon to a person caught in a sandstorm closing their eyes until the storm passes to avoid injury. They found that experiencing severe stress that may even lead to cell death, proteasomes can get back to work, as long as the stress is temporary.
Potential damage to cells comes from a long list of sources, including harmful oxidation that can arise as a side effect of the body’s natural energy production. Such free radicals (reactive oxidative species) attack the body – including the proteins that make up a large portion of human solid body mass.
Proteasomes remove damaged proteins by recycling them into new proteins. The paradox is that proteasomes themselves are made up of proteins, something that led the researchers to ask: how do proteasomes avoid oxidative stress damage?
“In our experiments, the proteasomes stop working for up to three hours during times of stress, with very minor deleterious effects,” said Prof. Glickman. “In this way, by shielding the protein-recycling mechanism, it reduces potential self-damage during an episode of oxidative stress, and in turn, protects the body from cumulative or unpredictable damage. After such a break, the proteasome can get back to cleaning up the oxidative stress left behind.”
The research was conducted as part of Nurit Livnat-Levanon’s doctoral thesis, in collaboration with Noa Reis, microbiologist and lab manager together with Prof Thorsten Hoppe their partner on a Deutsch-Israelische Projektkooperation (DIP) grant at the University of Cologne, Germany.