The Priority Programme aims to catalyse a decisive transition towards a true and thorough understanding of redox signalling cascades in the coming years. For this Priority Programme we propose an assembly of scientists uniquely positioned and selected for the task at hand, because of their conceptual and/or technical leadership. Within the programme, expertise and technology will be exchanged and made available in a highly synergistic way aiming to cross the borders between disciplines and to identify common principles of thiol switching across different model organisms – ranging from bacteria, protozoa, yeast and plants to mammals. A well-balanced analysis of model systems shall enable the programme to define and to examine general redox signalling concepts of thiol switching, and at the same time, the rapid exchange and translation of results will speed up our understanding of thiol switching in the different model systems.