Aging and dietary restriction effects on ubiquitination, sumoylation, and the proteasome in the heart

Dietary restriction (DR), in the absence of malnutrition, is the only intervention known to reliably increase average and maximal lifespan in a variety of organisms including mammals. Because the effects of DR on the heart are poorly understood, in the present study we examined the effects of DR on the ubiquitin-proteasome pathway (UPP) in the heart. In these studies we observed that DR significantly reduced age-related impairments in proteasome-mediated protein degradation, and reduced age-related increases in ubiquitinated, oxidized, and surnoylated protein in the heart. Interestingly, DR did not significantly increase the expression of 20S proteasome subunits or the proteasome maturation factor (POMP-1). These data demonstrate for the first time the effects ofaging and DR on proteasome biorgenesis and surnoylation in the heart. Cumulatively, our data indicate that DR has many beneficial effects towards and suggests that a preservation of the UPP may be a potential mechanism by which the UPP in the heart, DR mediates beneficial effects on the cardiovascular system. (c) 2008 Elsevier Ireland Ltd. All rights reserved.