1. Cullin-RING ligases employ geometrically optimized catalytic partners for substrate targeting.
- Author
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Li J, Purser N, Liwocha J, Scott DC, Byers HA, Steigenberger B, Hill S, Tripathi-Giesgen I, Hinkle T, Hansen FM, Prabu JR, Radhakrishnan SK, Kirkpatrick DS, Reichermeier KM, Schulman BA, and Kleiger G
- Subjects
- Humans, Ubiquitination, Ubiquitin metabolism, Polyubiquitin metabolism, Carrier Proteins metabolism, Ubiquitin-Protein Ligases genetics, Ubiquitin-Protein Ligases metabolism, Cullin Proteins genetics, Cullin Proteins metabolism
- Abstract
Cullin-RING ligases (CRLs) ubiquitylate specific substrates selected from other cellular proteins. Substrate discrimination and ubiquitin transferase activity were thought to be strictly separated. Substrates are recognized by substrate receptors, such as Fbox or BCbox proteins. Meanwhile, CRLs employ assorted ubiquitin-carrying enzymes (UCEs, which are a collection of E2 and ARIH-family E3s) specialized for either initial substrate ubiquitylation (priming) or forging poly-ubiquitin chains. We discovered specific human CRL-UCE pairings governing substrate priming. The results reveal pairing of CUL2-based CRLs and UBE2R-family UCEs in cells, essential for efficient PROTAC-induced neo-substrate degradation. Despite UBE2R2's intrinsic programming to catalyze poly-ubiquitylation, CUL2 employs this UCE for geometrically precise PROTAC-dependent ubiquitylation of a neo-substrate and for rapid priming of substrates recruited to diverse receptors. Cryo-EM structures illuminate how CUL2-based CRLs engage UBE2R2 to activate substrate ubiquitylation. Thus, pairing with a specific UCE overcomes E2 catalytic limitations to drive substrate ubiquitylation and targeted protein degradation., Competing Interests: Declaration of interests B.A.S. is a member of the scientific advisory boards of Interline Therapeutics and BioTheryX and co-inventor of intellectual property licensed to Cinsano. D.S.K. and K.M.R. were employees of Genentech/Roche at the time the work was completed. T.H. is currently an employee of Genentech/Roche. D.S.K. is an employee and shareholder of Orion Medicines. S.H. is currently an employee and shareholder of Amgen., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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