Structural analysis of the CSN complex to understand its inhibition mechanism
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ABSTRACT:
INSTRUMENT(S):
ORGANISM(S): Homo Sapiens (human)
SUBMITTER: 
Clinton Yu
LAB HEAD: Dr. Lan Huang
PROVIDER: PXD063822 | Pride | 2025-11-22
REPOSITORIES: Pride
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Project description:We performed interaction and structural analyses to unravel the molecular mechanisms underlying CSN inhibition. Various methods including Cryo-EM, cross-linking mass spectrometry, quantitative mass spectrometry and biochemical assays have been employed to define inhibitor-induced interaction and structural changes of the CSN complex in vitro and in cells.
2025-11-20 | PXD063786 | Pride
Project description:The COP9 signalosome (CSN) is an evolutionarily conserved protein complex that functions as a deneddylase to inactivate Cullin-RING E3 ligases for controlling protein ubiquitination. CSN possesses structural flexibility that is important for its activation upon binding to a diverse array of CRLs. The canonical and non-canonical CSN complexes consist of 8 (CSN1-8) and 9 (CSN1-9) subunits, respectively. Although CSN9 is not essential for CSN assembly and function, it appears to be important in non-catalytic regulation of CRLs by CSN. Here we employed a combinatory cross-linking mass spectrometry (XL-MS) approach to generate the largest PPI maps of human CSN complexes, which significantly enhanced the precision of integrative structural modeling. The resulting integrative structures allowed us not only to elucidate architectures of both complexes, but also to assess CSN structural dynamics that was not described in the crystal structure. In addition, we have determined CSN9 docking sites and its impact on the CSN structure. While CSN9 binding did not induce global conformational changes, it triggered subunit local reorientations that may be associated with CSN9 involvement in CSN-mediated steric regulation of CRLs.
2020-02-04 | PXD014673 | Pride
Project description: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.
2019-09-13 | PXD013018 | Pride
Project description: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.
2019-09-13 | PXD013001 | Pride
Project description:Sequestosome1 (SQSTM1) is an autophagy receptor that mediates degradation of intracellular cargo, including protein aggregates, through multiple protein interactions. These interactions form the SQSTM1 protein network that are mediated by SQSTM1 functional interaction domains, which include LIR, PB1, UBA and KIR. Despite various attempts to unravel the complexity of the SQSTM1 protein network, our understanding of the relationship of various components in cellular physiology and disease states continues to evolve. To investigate the SQSTM1 protein interaction network, we performed proximity profile labeling by fusing TurboID with the human protein SQSTM1 (TurboID::SQSTM1). This chimeric protein displayed well-established SQSTM1 features including: production of SQSTM1 intracellular bodies, binding to known SQSTM1 interacting partners via defined functional SQSTM1 interacting domains and capture of novel SQSTM1 interactors. Strikingly, aggregated tau protein altered the protein interaction network of SQSTM1 to include many stress associated proteins. Overall, our work reveals the dynamic landscape of the SQSTM1 protein network and offers a resource to study SQSTM1 function in cellular physiology and disease state.
2024-08-06 | PXD047725 | Pride
Project description:The COP9 signalosome (CSN), an eight-subunit protein complex, is conserved in all higher eukaryotes. CSN intersects the ubiquitin-proteasome pathway, modulating signaling pathways controlling various aspects of development. We are using Drosophila as a model system to elucidate the function of this important complex. Transcriptome data was generated for four csn mutants, sampled at three developmental time points. Our results are highly reproducible, being confirmed using two different experimental setups that entail different microarrays and different controls. Our results indicate that the CSN acts as a transcriptional repressor during Drosophila development, resulting in achronic gene expression in the csn mutants. "Time shift" analysis with the publicly-available Drosophila transcriptome data indicates that genes repressed by the CSN are normally induced primarily during late embyogenesis, or during metamorphosis. These temporal shifts are likely due to the roles of the CSN in regulating transcription factors. A null mutation in CSN subunit 4, and hypomorphic mutations in csn5 lead to more severe defects than seen in the csn5null mutants strain, suggesting that CSN5 carries only some of the CSN function. Keywords: time course csn mutants
2007-04-12 | GSE7303 | GEO
Project description:The COP9 signalosome complex (CSN) is a crucial regulator of ubiquitin ligases. Defects in CSN result in embryonic impairment and death in higher eukaryotes, whereas the filamentous fungus Aspergillus nidulans survives without CSN, but is unable to complete sexual development. We investigated overall impact of CSN activity on A. nidulans cells by combined transcriptome, proteome and metabolome analysis. Absence of csn5/csnE affects transcription of at least 15 % of genes during development, including numerous oxidoreductases. csnE deletion leads to changes in the fungal proteome indicating impaired redox regulation and hypersensitivity to oxidative stress. CSN promotes the formation of asexual spores by regulating developmental hormones produced by PpoA and PpoC dioxygenases. We identify more than 100 metabolites, including orsellinic acid derivatives, accumulating preferentially in the csnE mutant. We also show that CSN is required to activate glucanases and other cell wall recycling enzymes during development. These findings suggest a dual role for CSN during development: it is required early for protection against oxidative stress and hormone regulation and is later essential for control of secondary metabolism and cell wall rearrangement.
2010-09-09 | GSE22442 | GEO
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)
2011-10-27 | GSE19085 | GEO
Project description:The COP9 signalosome (CSN) is a highly conserved complex consisting of eight subunits, which influences key developmental pathways through its regulation of protein stability and transcription. Mutations in each of the CSN subunits exhibits diverse pleiotropic phenotypes We used microarrays to compare gene expression of two CSN mutants with their corresponding wild types: a non-lethal csn5a-1 mutant, vs. columbia ecotype, and a lethal, csn8 mutant, vs. Wassilewskija ecotype
2020-07-28 | GSE108376 | GEO
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.
2011-10-26 | E-GEOD-19085 | biostudies-arrayexpress