TRIM 5α requires Ube2W to anchor Lys63‐linked ubiquitin chains and restrict reverse transcription

Fletcher, A. J., Christensen, D. E., Nelson, C., Tan, C. P., Schaller, T., Lehner, P. J., Sundquist, W. I. and Towers, G. J. (2015) TRIM 5α requires Ube2W to anchor Lys63‐linked ubiquitin chains and restrict reverse transcription. EMBO Journal, 34(15), pp. 2078-2095. (doi: 10.15252/embj.201490361) (PMID:26101372) (PMCID:PMC4551353)

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Abstract

TRIM5α is an antiviral, cytoplasmic, E3 ubiquitin (Ub) ligase that assembles on incoming retroviral capsids and induces their premature dissociation. It inhibits reverse transcription of the viral genome and can also synthesize unanchored polyubiquitin (polyUb) chains to stimulate innate immune responses. Here, we show that TRIM5α employs the E2 Ub-conjugating enzyme Ube2W to anchor the Lys63-linked polyUb chains in a process of TRIM5α auto-ubiquitination. Chain anchoring is initiated, in cells and in vitro, through Ube2W-catalyzed monoubiquitination of TRIM5α. This modification serves as a substrate for the elongation of anchored Lys63-linked polyUb chains, catalyzed by the heterodimeric E2 enzyme Ube2N/Ube2V2. Ube2W targets multiple TRIM5α internal lysines with Ub especially lysines 45 and 50, rather than modifying the N-terminal amino group, which is instead αN-acetylated in cells. E2 depletion or Ub mutation inhibits TRIM5α ubiquitination in cells and restores restricted viral reverse transcription, but not infection. Our data indicate that the stepwise formation of anchored Lys63-linked polyUb is a critical early step in the TRIM5α restriction mechanism and identify the E2 Ub-conjugating cofactors involved.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Fletcher, Dr Adam
Authors: Fletcher, A. J., Christensen, D. E., Nelson, C., Tan, C. P., Schaller, T., Lehner, P. J., Sundquist, W. I., and Towers, G. J.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
Journal Name:EMBO Journal
Publisher:EMBO Press
ISSN:0261-4189
ISSN (Online):1460-2075
Copyright Holders:Copyright © 2015 The Authors
First Published:First published in EMBO journal 34(15):2078-2095
Publisher Policy:Reproduced under a Creative Commons Licence

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