Final Report Summary - ITRANS (Ion Transport at atomic level) Living cells are dependent on their membranes for protection, nutrients uptake, waste disposal and energy conservation. Of these processes, ion transport plays a central role in establishing and maintaining the difference of the transmembrene potential, allows osmotic balance and cell motility.In the project ITrans (Ion Transport at atomic level) we set to understand how transport takes place in proteins involved in the cellular respiration. We focused on one of the key players in cellular energy transduction processes: the respiratory Complex I (NADH:ubiquinone oxidoreductase). This complex nanomachine plays a central role in ion transport and energy transduction in humans and bacteria and has been in the focus of large discoveries in the bioenergetics field. Despite all the information already available on the structure and function of this molecular machine, a big debate still holds on the details of its mechanism of action and regulation. In the ITrans project we aimed contributing to decipher the mechanism of ion transport of Complex I at atomic level and to unravel how the regulation and control of ion transport is performed. We tackle these objectives using a multidisciplinary approach. The combination of experimental techniques, like Nuclear Magnetic Resonance (NMR) spectroscopy, that allow us to look at proteins at atomic level with bioinformatics and molecular modelling methodologies that provide us crucial information on the identification of ion pathways and mechanistic roles of the different sections of the proteins, permitted us to gain information on the mechanics of this truly complex protein system. Besides the biological understanding of how a crucial cellular system works, ITrans also aimed at establishing a novel methodology to study membrane proteins at atomic level. This approach is expected to play an important role in the study of membrane proteins at atomic level. During the implementation phase of the project, we established a new methodology to follow ion transport at atomic level, trained new students on the methodologies and actively interacted with the scientific communities. In parallel, the ITrans project allowed the creation of new collaborations between European research partners (e.g. researchers, research EU Infrastructures) leading to an exchange of know-how and permitting a truly career integration of the project fellow.