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Updated: May 27, 2026

In Vitro Analysis of E3 Ubiquitin Ligase Function
Published on: May 14, 2021
Conserved structural mechanisms for autoinhibition in IpaH ubiquitin ligases
Yang-Chieh Chou1, Alexander F A Keszei1, John R Rohde2
1Samuel Lunenfeld Research Institute, Toronto, Ontario M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
Abstract:
The IpaH family of novel E3 ligase (NEL) enzymes occur in a variety of pathogenic and commensal bacteria that interact with eukaryotic hosts. We demonstrate that the leucine-rich repeat (LRR) substrate recognition domains of different IpaH enzymes autoinhibit the enzymatic activity of the adjacent catalytic novel E3 ligase domain by two distinct but conserved structural mechanisms. Autoinhibition is required for the in vivo biological activity of two IpaH enzymes in a eukaryotic model system. Autoinhibition was retro-engineered into a constitutively active IpaH enzyme from Yersinia pestis by introduction of single site substitutions, thereby demonstrating the conservation of autoregulatory infrastructure across the IpaH enzyme family.
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