Protein interactions fulfil a critical role in a cell and their dysregulation contributes to human disease. We will apply an unique technology “toolbox” comprising MAPPIT, PPI-iMixPro and VIROTRAP, combined with state-of-the-art bioinformatics approaches, to gain new insights into the (patho)fysiological roles of selected protein interactions. In addition, we will use nanobodies as intrabodies to disturb protein interactions in cellulo.