Thiol-based H2O2 signalling in microbial systems

Cysteine residues, and in particular their thiolate groups, react not only with reactive oxygen species but also with electrophiles and with reactive nitrogen species. Thus, cysteine oxidation has often been linked to the toxic effects of some of these reactive molecules. However, thiol-based switches are common in protein sensors of antioxidant cascades, in both prokaryotic and eukaryotic organisms. We will describe here three redox sensors, the transcription factors OxyR, Yap1 and Pap1, which respond by disulfide bond formation to hydrogen peroxide stress, focusing specially on the differences among the three peroxide-sensing mechanisms.This work was supported by the Spanish Ministry of Science and Innovation (BFU2009-06933 and BFU2012-32045), PLAN E and FEDER, by the Spanish Program Consolider-Ingenio 2010 Grant CSD 2007-0020, and by SGR2009-195 from Generalitat de Catalunya (Spain) to E.H. E. H. is recipient of an ICREA Academia Award (Generalitat de Catalunya)