Oxidative stress, aging and the proteasomal system

Oxygen free radicals and other oxidants are causingpotential danger for intracellular proteins during thelifetime of cells and organisms. Therefore, proteinoxidation is one of the natural consequences ofaerobic life. The degradation of non-functional,oxidized proteins is an essential part of theantioxidant defenses of cells. The major proteolyticsystem responsible for the removal of oxidizedcytosolic proteins is the proteasomal system. Thissystem consists of the 20S 'core' proteasome and amultitude of various regulators. It is known thatcertain components of this system are regulated duringoxidative stress and aging.One of the highlights of age-related changes ofcellular metabolism is the accumulation of oxidizedproteins. The question whether the accumulation ofoxidized proteins during aging is due to a malfunctionof the intracellular proteolytic machinery of the cellremains still unsolved. The information availableabout an age-related decline of the proteasomal systemis very contradictory. The current literature aboutthe proteasomal system, the regulation of this systemduring oxidative stress and the age-related changesare in the focus of this review.