 Phosphorylation is a common post-translational modification that can regulate protein function by altering its ability to interact with other proteins. In this study, researchers used a Phosphomimetic Peptid Display Library to identify phosphocytes that modulate interactions between proteins. They discovered 248 phosphocytes that affect the binding of two proteins involved in cell division, clathrin, and HURP. Further structural analysis revealed that the phosphocytes are important for the stability of the clathrin HURP complex, which is necessary for proper cell division. This study provides insight into how phosphorylation can regulate protein-protein interactions and thus control cellular processes. This article was authored by Johanna Klisch, Dmitriya Hrystoferova-Gavanska, Leandro Simonetti, and others.