A cut above: Bacterial deubiquitinases with ubiquitin clippase activity

Pathogenic or symbiotic bacteria residing inside eukaryotic cells often foil attempts to eliminate them by secreting deubiquitinases into the host. In this issue of Molecular Cell, Hermanns et al.¹ uncover an unexpected “clippase” activity in certain bacterial deubiquitinases, which cleaves substrate-linked ubiquitin within the ubiquitin C terminus, thereby inactivating it.