Structural basis for RING-Cys-Relay E3 ligase activity and its role in axon integrity

Mabbitt, P. D., Loreto, A., Déry, M.-A., Fletcher, A. J., Stanley, M., Pao, K.-C., Wood, N. T., Coleman, M. P. and Virdee, S. (2020) Structural basis for RING-Cys-Relay E3 ligase activity and its role in axon integrity. Nature Chemical Biology, 16(11), pp. 1227-1236. (doi: 10.1038/s41589-020-0598-6) (PMID:32747811) (PMCID:PMC7610530)

Abstract

MYCBP2 is a ubiquitin (Ub) E3 ligase (E3) that is essential for neurodevelopment and regulates axon maintenance. MYCBP2 transfers Ub to nonlysine substrates via a newly discovered RING-Cys-Relay (RCR) mechanism, where Ub is relayed from an upstream cysteine to a downstream substrate esterification site. The molecular bases for E2–E3 Ub transfer and Ub relay are unknown. Whether these activities are linked to the neural phenotypes is also unclear. We describe the crystal structure of a covalently trapped E2~Ub:MYCBP2 transfer intermediate revealing key structural rearrangements upon E2–E3 Ub transfer and Ub relay. Our data suggest that transfer to the dynamic upstream cysteine, whilst mitigating lysine activity, requires a closed-like E2~Ub conjugate with tempered reactivity, and Ub relay is facilitated by a helix–coil transition. Furthermore, neurodevelopmental defects and delayed injury-induced degeneration in RCR-defective knock-in mice suggest its requirement, and that of substrate esterification activity, for normal neural development and programmed axon degeneration.

• Item Type: Articles
• Additional Information: This work was funded by UK Medical Research Council (MC_UU_12016/8) and Biotechnology and Biological Sciences Research Council (BB/ P003982/1). A.L. was funded by a Sir Henry Wellcome Postdoctoral Fellowship from the Wellcome Trust (210904/Z/18/Z).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Fletcher, Dr Adam
• Authors: Mabbitt, P. D., Loreto, A., Déry, M.-A., Fletcher, A. J., Stanley, M., Pao, K.-C., Wood, N. T., Coleman, M. P., and Virdee, S.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity; College of Medical Veterinary and Life Sciences > School of Infection & Immunity > Centre for Virus Research
• Journal Name: Nature Chemical Biology
• Publisher: Nature Research
• ISSN: 1552-4450
• ISSN (Online): 1552-4469
• Published Online: 03 August 2020