Mechanism of phosphoribosyl-ubiquitination mediated by a single Legionella effector
Ubiquitination is a post-translational modification that regulates many cellular processes in eukaryotes 1 – 4 . The conventional ubiquitination cascade culminates in a covalent linkage between the C terminus of ubiquitin (Ub) and a target protein, usually on a lysine side chain 1 , 5 . Recent studi...
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Published in | Nature (London) Vol. 557; no. 7707; pp. 729 - 733 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
01.05.2018
Nature Publishing Group |
Subjects | |
Online Access | Get full text |
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Summary: | Ubiquitination is a post-translational modification that regulates many cellular processes in eukaryotes
1
–
4
. The conventional ubiquitination cascade culminates in a covalent linkage between the C terminus of ubiquitin (Ub) and a target protein, usually on a lysine side chain
1
,
5
. Recent studies of the
Legionella pneumophila
SidE family of effector proteins revealed a ubiquitination method in which a phosphoribosyl ubiquitin (PR-Ub) is conjugated to a serine residue on substrates via a phosphodiester bond
6
–
8
. Here we present the crystal structure of a fragment of the SidE family member SdeA that retains ubiquitination activity, and determine the mechanism of this unique post-translational modification. The structure reveals that the catalytic module contains two distinct functional units: a phosphodiesterase domain and a mono-ADP-ribosyltransferase domain. Biochemical analysis shows that the mono-ADP-ribosyltransferase domain-mediated conversion of Ub to ADP-ribosylated Ub (ADPR-Ub) and the phosphodiesterase domain-mediated ligation of PR-Ub to substrates are two independent activities of SdeA. Furthermore, we present two crystal structures of a homologous phosphodiesterase domain from the SidE family member SdeD
9
in complexes with Ub and ADPR-Ub. The structures suggest a mechanism for how SdeA processes ADPR-Ub to PR-Ub and AMP, and conjugates PR-Ub to a serine residue in substrates. Our study establishes the molecular mechanism of phosphoribosyl-linked ubiquitination and will enable future studies of this unusual type of ubiquitination in eukaryotes.
Crystal structures of the
Legionella
effectors SdeA and SdeD uncover the mechanism of a unique phosphoribosyl-ubiquitination reaction. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Correspondence and requests for materials should be addressed to Y.M. (ym253@cornell.edu). Leading Contact Co-first author |
ISSN: | 0028-0836 1476-4687 |
DOI: | 10.1038/s41586-018-0147-6 |