Structural basis of Cullin-2 RING E3 ligase regulation by the COP9 signalosome

Cullin-Ring E3 Ligases (CRLs) regulate a multitude of cellular pathways through specific substrate receptors. The COP9 signalosome (CSN) deactivates CRLs by removing NEDD8 (N8) from activated Cullins. The structure of stable CSN-CRL can be used to understand this mechanism of regulation. Here we pre...

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Published in:bioRxiv
Main Authors: Faull, Sarah V, Lau, Andy, Martens, Chloe, Ahdash, Zainab, Yebenes, Hugo, Schmidt, Carla, Beuron, Fabienne, Cronin, Nora B, Morris, Edward P, Politis, Argyris
Format: Paper
Language:English
Published: Cold Spring Harbor Cold Spring Harbor Laboratory Press 29.11.2018
Cold Spring Harbor Laboratory
Edition:1.1
Subjects:
Biochemistry
Cullin
Electron microscopy
Mass spectroscopy
Ubiquitin-protein ligase
ISSN:2692-8205, 2692-8205
Online Access:Get full text
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Summary:Cullin-Ring E3 Ligases (CRLs) regulate a multitude of cellular pathways through specific substrate receptors. The COP9 signalosome (CSN) deactivates CRLs by removing NEDD8 (N8) from activated Cullins. The structure of stable CSN-CRL can be used to understand this mechanism of regulation. Here we present the first structures of the neddylated and deneddylated CSN-CRL2 complexes by combining single particle cryo-electron microscopy (cryo-EM) with chemical cross-linking mass spectrometry (MS). These structures reveal a conserved mechanism of CSN activation, consisting of conformational clamping of the CRL2 substrate by CSN2/CSN4, release of the catalytic CSN5/CSN6 heterodimer and finally activation of the CSN5 deneddylation machinery. Using hydrogen deuterium exchange-MS we show that CRL2 binding and conformational activation of CSN5/CSN6 occur in a neddylation-independent manner. The presence of NEDD8 is required to activate the CSN5 active site. Overall, by synergising cryo-EM with MS, we identified novel sensory regions of the CSN that mediate its stepwise activation mechanism and provide a framework for better understanding the regulatory mechanism of other Cullin family members.
Bibliography:SourceType-Working Papers-1
ObjectType-Working Paper/Pre-Print-1
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ISSN:2692-8205
2692-8205
DOI:10.1101/483024