RT Journal Article SR Electronic T1 Structural and kinetic analysis of the COP9-Signalosome activation and the cullin-RING ubiquitin ligase deneddylation cycle JF bioRxiv FD Cold Spring Harbor Laboratory SP 046367 DO 10.1101/046367 A1 Mosadeghi, Ruzbeh A1 Reichermeier, Kurt M. A1 Winkler, Martin A1 Schreiber, Anne A1 Reitsma, Justin M. A1 Zhang, Yaru A1 Stengel, Florian A1 Cao, Junyue A1 Kim, Minsoo A1 Sweredoski, Michael J. A1 Hess, Sonja A1 Leitner, Alexander A1 Aebersold, Ruedi A1 Peter, Matthias A1 Deshaies, Raymond J. A1 Enchev, Radoslav I. YR 2016 UL http://biorxiv.org/content/early/2016/03/30/046367.abstract AB The COP9-Signalosome (CSN) regulates cullin–RING ubiquitin ligase (CRL) activity and assembly by cleaving Nedd8 from cullins. Free CSN is autoinhibited, and it remains unclear how it becomes activated. We combine structural and kinetic analyses to identify mechanisms that contribute to CSN activation and Nedd8 deconjugation. Both CSN and neddylated substrate undergo large conformational changes upon binding, with important roles played by the N-terminal domains of Csn2 and Csn4 and the RING domain of Rbx1 in enabling formation of a high affinity, fully active complex. The RING domain is crucial for deneddylation, and works in part through conformational changes involving insert-2 of Csn6. Nedd8 deconjugation and re-engagement of the active site zinc by the autoinhibitory Csn5 glutamate-104 diminish affinity for Cul1/Rbx1 by ~100-fold, resulting in its rapid ejection from the active site. Together, these mechanisms enable a dynamic deneddylation-disassembly cycle that promotes rapid remodeling of the cellular CRL network.