Dataset Information

XL-MS and Native MS for CSN-CRL2 complexes

ABSTRACT: 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.

INSTRUMENT(S): Orbitrap Fusion, SYNAPT G2-Si, Q Exactive Plus

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Andy Lau

LAB HEAD: Argyris Politis

PROVIDER: PXD013018 | Pride | 2019-09-13

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	16_12_15_CS_COP9-mt-CRL2-nedd8_XL_1.raw	Raw
	16_12_15_CS_COP9-mt-CRL2-nedd8_XL_10.raw	Raw
	16_12_15_CS_COP9-mt-CRL2-nedd8_XL_11.raw	Raw
	16_12_15_CS_COP9-mt-CRL2-nedd8_XL_12.raw	Raw
	16_12_15_CS_COP9-mt-CRL2-nedd8_XL_13.raw	Raw

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Publications

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

Faull Sarah V SV Lau Andy M C AMC Martens Chloe C Ahdash Zainab Z Hansen Kjetil K Yebenes Hugo H Schmidt Carla C Beuron Fabienne F Cronin Nora B NB Morris Edward P EP Politis Argyris A

Nature communications 20190823 1

Cullin-Ring E3 Ligases (CRLs) regulate a multitude of cellular pathways through specific substrate receptors. The COP9 signalosome (CSN) deactivates CRLs by removing NEDD8 from activated Cullins. Here we present structures of the neddylated and deneddylated CSN-CRL2 complexes by combining single-particle cryo-electron microscopy (cryo-EM) with chemical cross-linking mass spectrometry (XL-MS). These structures suggest a conserved mechanism of CSN activation, consisting of conformational clamping ...[more]

PMID: 31444342

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Project description:The COP9 signalosome (CSN) is a conserved protein complex occurring in all eukaryotes. The mammalian CSN consists of eight subunits (CSN1 – CSN8) and possesses an intrinsic metalloprotease JAMM motif localised to CSN5. In addition, it is associated with kinases such as protein kinase CK2 and D and the ubiquitin (Ub) specific protease 15. It regulates cullin-RING Ub ligases (CRLs) that label proteins for proteolysis with poly-Ub chains in the Ub proteasome system (UPS). CRLs contain one of the scaffolding cullins 1 – 7, a RING domain protein e. g. Rbx1, and one of hundreds of substrate binding units such as F-box or BTB proteins that specifically target proteins for ubiquitination. The CSN forms functional supercomplexes with CRLs. It removes the Ub-like protein Nedd8 from cullins by its metalloprotease activity and thereby inactivates CRLs. On the other hand, it is essential for CRL function by protecting components and allowing reassembly of the complexes. As a regulator of the UPS the CSN is involved in cell cycle10, DNA repair and development. Overexpression of CSN subunits has been reported in tumour cells. Up to date nothing is known about CSN biogenesis and its regulation. Ten years ago we have observed that overexpression of selected CSN subunits caused a coordinated increase of all CSN subunits and a de novo biosynthesis of the entire complex. Here we show that overexpression of CSN1 mediates an increase of c-Myc which coordinates CSN subunit expression via microRNAs (miRNAs). miRNAs are evolutionarily conserved, endogenous, small, noncoding RNA molecules of about 22 nucleotides that function as posttranscriptional gene regulators. We found that inhibitors of let-7 family miRNAs or upregulation of c-Myc, which represses let-7 miRNAs, resulted in a coordinated increase of CSN subunits and de novo CSN biogenesis. Keywords: Gene expression analysis of human RNA samples using topic-defined PIQOR™ Ubiquitin-PS Microarrays. Two different platforms were used (these are two different microarray batches which are identical in terms of the spotted cDNAs, but differ in the position of some cDNAs) Gene expression analysis of Hela cells overexpressing either CSN2 or CSN1 was performed to study CSN biogenesis and its regulation. Curcumin, Nr. 8 (Curcumin analogon) and Piceatannol were used for the treatment of Hela cells since they inhibit the CSN associated kinases. The aim was to investigate the effect on the signalosome. For each treatment 50 µM Curcumin, Nr. 8 and Piceatannol were used.