Functions of Typical 2-Cys Peroxiredoxins in Yeast

Peroxiredoxins are ubiquitous proteins that are found from bacteria to humans. Until recently they were thought to solely act as antioxidants catalysing the reduction of peroxides through their associated thioredoxin peroxidase activity. However, recent work has begun to uncover hitherto unsuspected roles for one group of these proteins, the typical 2-Cys peroxiredoxins (2-Cys Prx). For example, typical 2-Cys Prxs have been found to have roles in the model organisms Schizosaccharomyces pombe and Saccharomyces cerevisiae in regulating signal transduction, in DNA damage responses and as molecular chaperones. There is increasing evidence that rm H2O2 is utilised as a signalling molecule to regulate a range of important cellular processes. As abundant and ubiquitous peroxidase enzymes the peroxidase activity of typical 2-Cys Prxs is important in the regulation of these functions. Significantly, studies in yeast suggest that the regulation of the thioredoxin peroxidase and chaperone activities of these multi-function enzymes is an important aspect of H2O2–mediated signal transduction and consequently have provided important insight into the roles of these proteins in higher eukaryotes