A general strategy for discovery of inhibitors and activators of RING and U-box E3 ligases with ubiquitin variants

Gabrielsen, M. , Buetow, L., Nakasone, M. A., Ahmed, S. F., Sibbet, G. J., Smith, B. O. , Zhang, W., Sidhu, S. S. and Huang, D. T. (2017) A general strategy for discovery of inhibitors and activators of RING and U-box E3 ligases with ubiquitin variants. Molecular Cell, 68(2), 456-470.e10. (doi: 10.1016/j.molcel.2017.09.027) (PMID:29053960) (PMCID:PMC5655547)

Abstract

RING and U-box E3 ubiquitin ligases regulate diverse eukaryotic processes and have been implicated in numerous diseases, but targeting these enzymes remains a major challenge. We report the development of three ubiquitin variants (UbVs), each binding selectively to the RING or U-box domain of a distinct E3 ligase: monomeric UBE4B, phosphorylated active CBL, or dimeric XIAP. Structural and biochemical analyses revealed that UbVs specifically inhibited the activity of UBE4B or phosphorylated CBL by blocking the E2∼Ub binding site. Surprisingly, the UbV selective for dimeric XIAP formed a dimer to stimulate E3 activity by stabilizing the closed E2∼Ub conformation. We further verified the inhibitory and stimulatory functions of UbVs in cells. Our work provides a general strategy to inhibit or activate RING/U-box E3 ligases and provides a resource for the research community to modulate these enzymes.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Huang, Professor Danny and Gabrielsen, Dr Mads and Sibbet, Dr Gary and Smith, Dr Brian and Buetow, Dr Lori
• Authors: Gabrielsen, M., Buetow, L., Nakasone, M. A., Ahmed, S. F., Sibbet, G. J., Smith, B. O., Zhang, W., Sidhu, S. S., and Huang, D. T.
• College/School: College of Medical Veterinary and Life Sciences > School of Cancer Sciences; College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Molecular Cell
• Publisher: Elsevier
• ISSN: 1097-2765
• ISSN (Online): 1097-4164
• Published Online: 19 October 2017
• Copyright Holders: Copyright © 2017 The Authors
• First Published: First published in Molecular Cell 68(2):456-470.e10
• Publisher Policy: Reproduced under a Creative Commons License