Our group is interested in the understanding and manipulation of molecular interactions that govern the assembly of protein complexes. The focus is on scaffolding proteins that mediate non-covalent interactions in immune cells and other eukaryotic cells. NMR spectroscopy is used to solve the three-dimensional structure and to rationalize individual protein:ligand pairs. Complementary, phage display, peptide SPOT analysis and spectroscopic methods give valuable information on recognition codes and potential in vivointeractions. Spatial information is also used for the rational and semi-rational design of alternative scaffolds with novel binding properties. Adaptor domains also serve as baits in pulldown experiments. In combination with SILAC-MS and site-specific inhibition of protein interaction sites we are able to assess the relative importance of individual domains to the modular assembly of protein complexes. Furthermore, by extending our investigations to post-translationally modified adaptor domains, we aim to further de-convolute the complexity and dynamic regulation of certain signal transduction pathways in the cell. In this way our research has been led towards the functional investigation of MHC-peptide interactions and mRNA surveillance.