Essentiality of a non-RING element in priming donor ubiquitin for catalysis by a monomeric E3

Dou, H., Buetow, L., Sibbet, G.J., Cameron, K. and Huang, D.T. (2013) Essentiality of a non-RING element in priming donor ubiquitin for catalysis by a monomeric E3. Nature Structural and Molecular Biology, 20(8), pp. 982-986. (doi: 10.1038/nsmb.2621)

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Abstract

RING E3 ligases catalyze the transfer of ubiquitin (Ub) from E2 ubiquitin-conjugating enzyme thioesterified with Ub (E2~Ub) to substrate. For RING E3 dimers, the RING domain of one subunit and tail of the second cooperate to prime Ub, but how this is accomplished by monomeric RING E3s in the absence of a tail-like component is currently unknown. Here, we present a crystal structure of a monomeric RING E3, Tyr363-phosphorylated human CBL-B, bound to a stabilized Ub-linked E2, revealing a similar mechanism in activating E2~Ub. Both pTyr363 and the pTyr363-induced element interact directly with Ub's Ile36 surface, improving the catalytic efficiency of Ub transfer by ~200-fold. Hence, interactions outside the canonical RING domain are crucial for optimizing Ub transfer in both monomeric and dimeric RING E3s. We propose that an additional non-RING Ub-priming element may be a common RING E3 feature.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Huang, Professor Danny and Cameron, Mr Ken and Sibbet, Dr Gary and Dou, Miss Hao and Buetow, Dr Lori
Authors: Dou, H., Buetow, L., Sibbet, G.J., Cameron, K., and Huang, D.T.
College/School:College of Medical Veterinary and Life Sciences > School of Cancer Sciences
Journal Name:Nature Structural and Molecular Biology
Publisher:Nature Publishing Group
ISSN:1545-9993
ISSN (Online):1545-9985

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