Nitro-Oleic Acid-Mediated Nitroalkylation Modulates the Antioxidant Function of Cytosolic Peroxiredoxin Tsa1 during Heat Stress in Saccharomyces cerevisiae Aranda Caño, Lorena López Jaramillo, Francisco Javier This research was funded by ERDF grants co-financed by the Spanish Ministry of Economy and Competitiveness (Project PGC2018-096405-B-I00), the Junta de Andalucia (group BIO286), the I+D+I project within the framework Programme of FEDER Andalucia 2014-2020 (Reference 1380901), the grants for I+D+I projects, on a competitive basis, within the scope of the Andalusian plan for research, development and innovation (Junta de Andalucia, PAIDI 2020, Reference: PY20_01002), and the funding for the recruitment of researchers under Action 9 and 10 of the Research Support Plan of the University of Jaen (2019-2020, R.02/10/2020; 2020-2021, R.01/01/2022). Heat stress is one of the abiotic stresses that leads to oxidative stress. To protect themselves, yeast cells activate the antioxidant response, in which cytosolic peroxiredoxin Tsa1 plays an important role in hydrogen peroxide removal. Concomitantly, the activation of the heat shock response (HSR) is also triggered. Nitro-fatty acids are signaling molecules generated by the interaction of reactive nitrogen species with unsaturated fatty acids. These molecules have been detected in animals and plants. They exert their signaling function mainly through a post-translational modification called nitroalkylation. In addition, these molecules are closely related to the induction of the HSR. In this work, the endogenous presence of nitro-oleic acid (NO2-OA) in Saccharomyces cerevisiae is identified for the first time by LC-MS/MS. Both hydrogen peroxide levels and Tsa1 activity increased after heat stress with no change in protein content. The nitroalkylation of recombinant Tsa1 with NO2-OA was also observed. It is important to point out that cysteine 47 (peroxidatic) and cysteine 171 (resolving) are the main residues responsible for protein activity. Moreover, the in vivo nitroalkylation of Tsa1 peroxidatic cysteine disappeared during heat stress as the hydrogen peroxide generated in this situation caused the rupture of the NO2-OA binding to the protein and, thus, restored Tsa1 activity. Finally, the amino acid targets susceptible to nitroalkylation and the modulatory effect of this PTM on the enzymatic activity of Tsa1 are also shown in vitro and in vivo. This mechanism of response was faster than that involving the induction of genes and the synthesis of new proteins and could be considered as a key element in the fine-tuning regulation of defence mechanisms against oxidative stress in yeast. 2022-06-14T07:53:37Z 2022-06-14T07:53:37Z 2022-05-14 info:eu-repo/semantics/article Aranda-Caño, L... [et al.]. Nitro-Oleic Acid-Mediated Nitroalkylation Modulates the Antioxidant Function of Cytosolic Peroxiredoxin Tsa1 during Heat Stress in Saccharomyces cerevisiae. Antioxidants 2022, 11, 972. [https://doi.org/10.3390/antiox11050972] http://hdl.handle.net/10481/75470 10.3390/antiox11050972 eng http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España MDPI