Characterization of the role of COP9 signalosome in regulating cullin E3 ubiquitin ligase activity

Choo, Yin Yin; Boh, Boon Kim; Lou, Jessica Jie Wei; Eng, Jolane; Leck, Yee Chin; Anders, Benjamin; Smith, Peter G.; Hagen, Thilo

doi:10.1091/mbc.e11-03-0251

Cited by 18 publications

(18 citation statements)

References 47 publications

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“…Seven in absentia homologs 1 and 2 (SIAH 1 and 2) are RING finger E3 ubiquitin ligases that mediate ubiquitination and subsequent proteasomal degradation of target proteins [37]. CSN5 (COP9 subunit 5 or COP9S5) is a subunit of the large COP9 signalosome (CSN) which is responsible for the deneddylation and activation of Cullin RING E3 ubiquitin ligases that ubiquitinate target proteins for proteolysis [72]. Interaction of the MOR with these components of the ubiquitin/proteosome pathway was somewhat unexpected given the fact that the MOR is typically thought to be downregulated via lysosomal degradation [32].…”

Section: Discussionmentioning

confidence: 99%

MOR Is Not Enough: Identification of Novel mu-Opioid Receptor Interacting Proteins Using Traditional and Modified Membrane Yeast Two-Hybrid Screens

et al. 2013

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The mu-opioid receptor (MOR) is the G-protein coupled receptor primarily responsible for mediating the analgesic and rewarding properties of opioid agonist drugs such as morphine, fentanyl, and heroin. We have utilized a combination of traditional and modified membrane yeast two-hybrid screening methods to identify a cohort of novel MOR interacting proteins (MORIPs). The interaction between the MOR and a subset of MORIPs was validated in pulldown, co-immunoprecipitation, and co-localization studies using HEK293 cells stably expressing the MOR as well as rodent brain. Additionally, a subset of MORIPs was found capable of interaction with the delta and kappa opioid receptors, suggesting that they may represent general opioid receptor interacting proteins (ORIPS). Expression of several MORIPs was altered in specific mouse brain regions after chronic treatment with morphine, suggesting that these proteins may play a role in response to opioid agonist drugs. Based on the known function of these newly identified MORIPs, the interactions forming the MOR signalplex are hypothesized to be important for MOR signaling and intracellular trafficking. Understanding the molecular complexity of MOR/MORIP interactions provides a conceptual framework for defining the cellular mechanisms of MOR signaling in brain and may be critical for determining the physiological basis of opioid tolerance and addiction.

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Section: Discussionmentioning

confidence: 99%

MOR Is Not Enough: Identification of Novel mu-Opioid Receptor Interacting Proteins Using Traditional and Modified Membrane Yeast Two-Hybrid Screens

et al. 2013

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“…For example, the extent of CSN association with CUL4B approaches 40%, but is < 5% for CUL2 and CUL3 [36]. The neddylated cullin CTD-RING module is buried by the CSN in a manner that blocks the access of CDC34, thereby suppressing ubiquitin ligase activity (Fig 3A) [41].Second, and surprisingly, data from several studies, including the initial identification of the CSN as a CRL deneddylase [83], indicate that CSN subunits can associate avidly with neddylated CRLs [36,83,90]. Quantitative studies indicate that as much as 50% of cullins associated with CSN complexes retain neddylation, as determined with tagged CSN5 or CSN6 subunits in lysates generated in the presence of CSN inhibitor o-phenathroline to block post-lysis deneddylation [36,40].…”

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confidence: 99%

Building and remodelling Cullin–RING E3 ubiquitin ligases

2013

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Cullin-RING E3 ubiquitin ligases (CRLs) control a plethora of biological pathways through targeted ubiquitylation of signalling proteins. These modular assemblies use substrate receptor modules to recruit specific targets. Recent efforts have focused on understanding the mechanisms that control the activity state of CRLs through dynamic alterations in CRL architecture. Central to these processes are cycles of cullin neddylation and deneddylation, as well as exchange of substrate receptor modules to re-sculpt the CRL landscape, thereby responding to the cellular requirements to turn over distinct proteins in different contexts. This review is focused on how CRLs are dynamically controlled with an emphasis on how c ullin neddylation cycles are integrated with receptor exchange. Keywords: cullin; ubiquitin; Nedd8; COP9 signalosome; E3 ligase; CAND1 EMBO reports (2013) 14, 1050-1061 published online 15 November 2013; doi:10.1038/embor.2013 See the Glossary for abbreviations used in this article. IntroductionThe proteome is constantly remodelled to suit the needs of the cell, through both synthesis and turnover. Protein turnover is controlled through two main systems: the ubiquitin-proteasome system (UPS) and lysosomal degradation system, including autophagy. Although selective autophagy can provide a means by which to control the abundance of particular organelles and even single proteins, it is best understood as a means to control bulk turnover of cellular components [1]. Conversely, the UPS is a particularly versatile and highly regulated system [2] that allows selective turnover of individual regulatory proteins, even when they are incorporated into higher-order multiprotein assemblies. On the one hand, the entire population of a given protein targeted by the UPS might be subject to rapid tagging with ubiquitin and degradation by the proteasome. On the other hand, the UPS might control the degradation of only a small pool of a particular target protein, for example the population of a protein that has been phosphorylated by an upstream pathway. Thus, the UPS functions in space and time to sculpt the proteome and to control the abundance of active or inactive forms of signalling complexes and cellular machines. As illustrated in this Review, the UPS machinery that controls turnover of a wide swathe of the p roteome is itself dynamically regulated through many mechanisms.The tagging of proteins with particular types of ubiquitin chains serves to mark them for proteasomal degradation. This process occurs through an E1 (ubiquitin-activating enzyme)-E2 (ubiquitinconjugating enzyme)-E3 (ubiquitin ligase) cascade [3][4][5][6][7]. E3 plays a central role in substrate targeting by binding directly to the substrate and presenting target lysine residues to receive ubiquitin from the E2, in the case of RING E3s, or from a ubiquitin-charged cysteine residue in HECT and RBR E3s [6,[8][9][10]. Cullin-RING E3 ubiquitin ligases (CRLs), which were first discovered almost two decades ago [11][12][13], are a superfamily of RING E3...

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“…The CSN has an intrinsic metalloproteinase that removes the ubiquitin-like protein Nedd8 from cullins via a process known as deneddylation [11,12]. CSN-mediated deneddylation is purported to regulate the assembly and catalytic dynamics of various cullin-RING ubiquitin ligases (CRLs) [13][14][15], a large family of ubiquitin E3's that control the ubiquitination and degradation of many proteins. CSN subunit 8 (CSN8) is the smallest and the least conserved subunit of the CSN complex.…”

Section: Introductionmentioning

confidence: 99%

Hepatic Deficiency of COP9 Signalosome Subunit 8 Induces Ubiquitin-Proteasome System Impairment and Bim-Mediated Apoptosis in Murine Livers

Lei

et al. 2013

PLoS ONE

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The COP9 signalosome (CSN), an evolutionally highly conserved protein complex composed of 8 unique subunits (CSN1 through CSN8) in higher eukaryotes, is purported to modulate protein degradation mediated by the ubiquitin-proteasome system (UPS) but this has not been demonstrated in a critical mitotic parenchymal organ of vertebrates. Hepatocyte-specific knockout of the Cops8 gene (HS-Csn8KO) was shown to cause massive hepatocyte apoptosis and liver malfunction but the underlying mechanism remains unclear. Here, we report that Csn8/CSN exerts profound impacts on hepatic UPS function and is critical to the stability of the pro-apoptotic protein Bim. Significant decreases in CIS (cytokine-inducible Src homology 2 domain-containing protein), a Bim receptor of a cullin2-based ubiquitin ligase, were found to co-exist with a marked increase of Bim proteins. Csn8 deficiency also significantly decreased 19S proteasome subunit Rpt5 and markedly increased high molecular weight neddylated and ubiquitinated proteins. The use of a surrogate UPS substrate further reveals severe impairment of UPS-mediated proteolysis in HS-Csn8KO livers. Inclusion body-like materials were accumulated in Csn8 deficient hepatocytes. In addition to Bim, massive hepatocyte apoptosis in HS-Csn8KO livers is also associated with elevated expression of other members of the Bcl2 family, including pro-apoptotic Bax as well as anti-apoptotic Bcl2 and Bcl-XL. Increased interaction between Bcl2 and Bim, but not between Bcl2 and Bax, was detected. Hence, it is concluded that hepatic CSN8 deficiency impairs the UPS in the liver and the resultant Bim upregulation likely plays an important role in triggering hepatocyte apoptosis via sequestering Bcl2 away from Bax.

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Characterization of the role of COP9 signalosome in regulating cullin E3 ubiquitin ligase activity

Cited by 18 publications

References 47 publications

MOR Is Not Enough: Identification of Novel mu-Opioid Receptor Interacting Proteins Using Traditional and Modified Membrane Yeast Two-Hybrid Screens

MOR Is Not Enough: Identification of Novel mu-Opioid Receptor Interacting Proteins Using Traditional and Modified Membrane Yeast Two-Hybrid Screens

Building and remodelling Cullin–RING E3 ubiquitin ligases

Hepatic Deficiency of COP9 Signalosome Subunit 8 Induces Ubiquitin-Proteasome System Impairment and Bim-Mediated Apoptosis in Murine Livers

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