Currently, we face a global antibiotic resistance crisis aggravated by the slow development of more effective and anti-resistance promoting therapeutical solutions. Protein phosphorylation (PP) has recently emerged as one of the major post-translational modification in bacteria, involved in the regulation of multiple physiological processes. In this MSCA individual fellowship application we aim to bridge the current gap in the field for prokaryotes by unravelling the unknown regulatory role of PP on proteins involved in nitrosative stress (NS) detoxification in the model bacterium E.coli. We propose to examine for the first time both global protein modifications (e.g. phosphoproteomics) under nitrogen species stress, as well as characterize PP in individual proteins involved in NS response. We will construct a network model that reflect the phosphoproteomic changes upon NS in E.coli, that may pave the way for the design of new bacterial targets. Understanding how bacteria respond to the chemical weapons of the human innate system is fundamental to develop efficient therapies. We will pioneer research on the mechanism and the regulation of nitric oxide detoxification proteins already identified as phosphorylated, by analyzing how this modification influences their stability and activity in vitro and in vivo. This project opens up new research paths on bacterial detoxification systems and signalling in general, addressing for the first time the role of PP in these processes. The proposal brings together transversal and scientific skills that will enable the researcher to lead the development of this emerging field and position herself as an expert in the area, and aims at establishing the importance of PP in NO microbial response, a novelty in this field.