Abstract
Oxygen serves as an electron acceptor, enabling efficient production of ATP. However, oxygen can also be converted into toxic reactive oxygen species (ROS), such as superoxide and hydrogen peroxide (H2O2); ROS can damage a variety of cellular components, including proteins and unsaturated lipids. Detection of ROS (peroxides) is an important step in the oxidative stress response.
Peroxiredoxin (Prx) is a family of ubiquitous peroxidases found in species ranging from Escherichia coli to humans. In many cases, Prx can reduce H2O2 and/or alkylhydroperoxides at the expense of electrons from NADPH through the Trx-dependent redox system (Tpx activity). The catalytic cysteine (Cys) residue of Prx is directly oxidized by hydroperoxides. This oxidation event is followed by the formation of a disulfide bond linkage with a resolving Cys of the same molecule of Prx or with a resolving Cys of another Prx molecule (dimer formation). The disulfide bond can be reduced by Trx. We have suggested that, in addition to their function as peroxidases, Prx family proteins may serve as intrinsic receptors of H2O2 and possible other hydroperoxide. Additionally, Prx proteins may relay information about the presence of hydroperoxides to the independent target proteins of each Prx.
In this symposium, I will introduce our recent progress in both yeast and mammalian systems that underscores the role of Prx on hydroperoxide and the redox-dependent modulation of the Prx’s target proteins.
