Yeast 2-Cys peroxiredoxin Tsa1 protects cells from DNA damage-induced reactive oxygen species through peroxidase activity

Peroxiredoxins (Prxs) belong to a family of thiol-specific peroxidases that scavenge reactive oxygen species (ROS). Yeast Prx thiol-specific antioxidant (Tsa1) protects cells from oxidative stress and maintains genome stability. In this study, we investigated the role of Tsa1 in the response to DNA damage. We observed that Tsa1 among all five Prxs of yeast is the most responsive in cell viability and mutation rate assays. The Δtsa1 mutant is hypersensitive to DNA-damaging agents such as hydroxyurea, methyl methane sulfonate, and camptothecin. The Δtsa1 cells lead to reduced cell viability and cell growth after DNA damage. The Δtsa1-expressing wild-type Tsa1 rescues the sensitivity of Δtsa1 cells to DNA damage, but not in Δtsa1 cells carrying the active-site mutant Tsa1-C47S. We found that the level of ROS in Δtsa1 cells was increased more than in wild-type cells by DNA damage. Tsa1 completely restored the production of DNA damage-induced ROS in Δtsa1 cells, but not Tsa1-C47S. Finally, DNA damage-induced ROS resulted in a switch of Tsa1 from a low-molecular-weight to a high-molecular-weight complex. Taken together, these findings suggest that Tsa1 protects yeast cells from DNA damage by regulating the homeostasis of ROS through peroxidase activity.