Carnitine supplementation has protective and detrimental effects in Saccharomyces cerevisiae that are genetically mediated
Abstract
l-Carnitine plays a well-documented role in eukaryotic energy homeostasis by acting as a shuttling molecule for activated acyl residues across intracellular membranes. This activity, supported by carnitine acyl-transferases and transporters, is referred to as the carnitine shuttle. However, several pleiotropic and often beneficial effects of carnitine in humans have been reported that appear to be unrelated to shuttling activity, but little conclusive evidence regarding molecular mechanisms exists. We have recently demonstrated a role of carnitine, independent of the carnitine shuttle, in yeast stress protection. Here, we show that carnitine specifically protects against oxidative stress caused by H2O2 and the superoxide-generating agent menadione. Surprisingly, carnitine has a detrimental effect on survival when combined with thiol-modifying agents. Central elements of the oxidative stress response, specifically the transcription factors Yap1p and Skn7p, are shown to be required for carnitine's protective effect, but several downstream effectors are dispensable. A DNA microarray-based analysis identifies Cyc3p, a cytochrome c heme lyase, as being important for carnitine's impact during oxidative stress. These findings establish a direct genetic link to a carnitine-related phenotype that is independent of the shuttle system and suggests that Saccharomyces cerevisiae should provide a useful model for further elucidation of carnitine's physiological roles. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd.
Description
Keywords
carnitine, cytochrome 3 heme lyase, cytochrome c, diamide, hydrogen peroxide, menadione, reactive oxygen metabolite, transcription factor, transcription factor Skn7p, transcription factor Yap1, unclassified drug, article, cell damage, cell function, cell protection, concentration (parameters), controlled study, culture medium, DNA microarray, enrichment culture, gene expression, genetic analysis, genetic linkage, liquid culture, microarray analysis, nonhuman, oxidative stress, phenotype, protein function, redox stress, Saccharomyces cerevisiae, supplementation, Antioxidants, Carnitine, DNA-Binding Proteins, Hydrogen Peroxide, Lyases, Microbial Viability, Oxidants, Oxidative Stress, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Stress, Physiological, Transcription Factors, Vitamin B Complex, Vitamin K 3, Eukaryota, Saccharomyces cerevisiae
Citation
FEMS Yeast Research
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