Copper‐induced oxidative stress in Saccharomyces cerevisiae targets enzymes of the glycolytic pathway

Abstract

Increased cellular levels of reactive oxygen species are known to arise during exposure of organisms to elevated metal concentrations, but the consequences for cells in the context of metal toxicity are poorly characterized. Using two-dimensional gel electrophoresis, combined with immunodetection of protein carbonyls, we report here that exposure of the yeast Saccharomyces cerevisiae to copper causes a marked increase in cellular protein carbonyl levels, indicative of oxidative protein damage. The response was time dependent, with total-protein oxidation peaking approximately 15 min after the onset of copper treatment. Moreover, this oxidative damage was not evenly distributed among the expressed proteins of the cell. Rather, in a similar manner to peroxide-induced oxidative stress, copperdependent protein carbonylation appeared to target glycolytic pathway and related enzymes, as well as heat shock proteins. Oxidative targeting of these and other enzymes was isoformspeci¢c and, in most cases, was also associated with a decline in the proteins' relative abundance. Our results are consistent with a model in which copper-induced oxidative stress disables the £ow of carbon through the preferred glycolytic pathway, and promotes the production of glucose-equivalents within the pentose phosphate pathway. Such re-routing of the metabolic £ux may serve as a rapid-response mechanism to help cells counter the damaging e¡ects of copper-induced oxidative stress. ß

Regulation of phosphoglucomutase 1 phosphorylation and activity by a signaling kinase

“…It has been shown earlier that cells respond to oxidative stress by directed oxidation and inactivation of glycolytic enzymes, leading to a metabolic reshuffling of glucose equivalents through the pentose phosphate pathway. It has been proposed that this metabolic shift could provide the necessary reducing power (NADPH 2 ) for antioxidant defense mechanism for the cells (Shanmuganathan et al, 2004). Considering that cancer cells are subjected to chronic oxidative stress and Pak1 activates PGM activity to the same extent as do thioredoxin and DTT, Pak1 could be heavily involved in helping cancer cells cope with oxidative insults in addition to mimicking a stress response in these cells.…”

Decoding Serological Response to Candida Cell Wall Immunome into Novel Diagnostic, Prognostic, and Therapeutic Candidates for Systemic Candidiasis by Proteomic and Bioinformatic Analyses

“…IgG antibody levels appeared to increase the risk of SC by no confounding factors and, through the immune response other than that directed against Pgk1p, Eno1p, Met6p, Gap1p, and Fba1p, stress-induced proteins (61)(62)(63)(64)(65). The correlation observed among circulating levels of antibodies against these stress-related proteins, also noted along the course of SC (36,66), may reflect the stressful environment resulting from the Candida invasive process (64,67).…”

Copper supplementation increases yeast life span under conditions requiring respiratory metabolism

“…Two genes responsive to high copper levels, CRS5 and CUP1-2, showed increased transcript levels in cells grown in YPG supplemented with copper, although levels were only approximately 2-fold higher than in cells grown in YPG. The concentration of copper used in this experiment (60 μM) was more than 100-fold below levels known to be toxic to yeast (Shanmuganathan et al, 2004). Expression levels of most genes, including genes involved in stress response and respiration, were unchanged.…”