A functional screen for bacterial ubiquitin regulation identifies an unusual Pseudomonas aeruginosa E3 ligase.

A novel Pseudomonas aeruginosa E3 ligase, PUL-1, was identified and shown to regulate virulence in an animal infection model.

• Why it matters: Understanding bacterial effectors that manipulate host ubiquitination is crucial because these mechanisms are often unique and lack homology to eukaryotic proteins, complicating discovery and intervention.
• What they did: A workflow was developed to screen secreted bacterial effectors for ubiquitin regulatory activities, benchmarking against other pathogens, leading to the discovery of PUL-1, a cryptic E3 ligase with no known homologs.
• The result: PUL-1's ligase activity influences virulence in vivo, suggesting that identifying ubiquitin-targeted effectors can deepen insights into bacterial pathogenesis and host manipulation.