Satpal Virdee is a program leader in protein ubiquitylation at the MRC Protein Phosphorylation and Ubiquitylation Unit at the University of Dundee. He is interested in studying E3 ligases at the biochemical, structural and cellular level. His lab recently developed probe technologies that enable parallel profiling of the activity state of potentially hundreds of E3 ligases (activity-based protein profiling). This technology allows one to not only address which E3 ligases are switched on and off during fundamental cellular processes, but to identify those that belong to undiscovered classes with medical importance.