β-arrestins are so-called hub proteins: they make complexes with many different partners, assembling functional complexes, and thereby fulfilling their biological function. The importance of this process in G protein-coupled receptor (GPCR) signalling has been fully demonstrated for many different receptors. For direct interactions, determining the interface regions, on β-arrestins and on the partners, is crucial for understanding the function of the complex. Indeed, this brings information on which proteins can interact simultaneously with β-arrestins, or, on the contrary, which partners are exclusive.We present here a method in two steps: protein–protein docking allows finding a limited number of peptides predicted to be involved in the interaction, and then experimental approaches that might be used for validating the prediction.