title: CTT1 overexpression increases life span of calorie-restricted Saccharomyces cerevisiae deficient in Sod1.
abstract: Studies using different organisms revealed that reducing calorie intake, without malnutrition, known as calorie restriction (CR), increases life span, but its mechanism is still unkown. Using the yeast Saccharomyces cerevisiae as eukaryotic model, we observed that Cu, Zn-superoxide dismutase (Sod1p) is required to increase longevity, as well as to confer protection against lipid and protein oxidation under CR. Old cells of sod1 strain also presented a premature induction of apoptosis. However, when CTT1 (which codes for cytosolic catalase) was overexpressed, sod1 and WT strains showed similar survival rates. Furthermore, CTT1 overexpression decreased lipid peroxidation and delayed the induction of apoptotic process. Superoxide is rapidly converted to hydrogen peroxide by superoxide dismutase, but it also undergoes spontaneous dismutation albeit at a slower rate. However, the quantity of peroxide produced from superoxide in this way is two-fold higher. Peroxide degradation, catalyzed by catalase, is of vital importance, because in the presence of a reducer transition metal peroxide is reduced to the highly reactive hydroxyl radical, which reacts indiscriminately with most cellular constituents. These findings might explain why overexpression of catalase was able to overcome the deficiency of Sod1p, increasing life span in response to CR.
authors.affiliation: Department of Biochemistry, Institute of Chemistry, Federal University of Rio de Janeiro, Avenida Athos da Silveira Ramos 149, Bloco A, Lab 547, Rio de Janeiro, RJ, 21941-909, Brazil, rona.germana@gmail.com.
authors.forename: Germana
authors.initials: G
authors.lastname: Rona
authors.forename: Ricardo
authors.initials: R
authors.lastname: Herdeiro
authors.forename: Cristiane Juliano
authors.initials: CJ
authors.lastname: Mathias
authors.forename: Fernando Araripe
authors.initials: FA
authors.lastname: Torres
authors.forename: Marcos Dias
authors.initials: MD
authors.lastname: Pereira
authors.forename: Elis
authors.initials: E
authors.lastname: Eleutherio
mesh_terms: D000818:Animals; D031204:Caloric Restriction; D002374:Catalase / Q000235:genetics / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal / Q000235:genetics / Q000502:physiology; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation / Q000502:physiology; D008136:Longevity / Q000502:physiology*; D023421:Models, Animal; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*; D013482:Superoxide Dismutase / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D000072105:Superoxide Dismutase-1; D013481:Superoxides / Q000378:metabolism; D015854:Up-Regulation / Q000235:genetics / Q000502:physiology
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D013481:Superoxides; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1