Protection of cullin–RING E3 ligases by CSN–UBP12

Wu, June‐Tai; Chan, Y.; Chien, Ching‐Te

doi:10.1016/j.tcb.2006.05.001

Cited by 60 publications

(49 citation statements)

References 59 publications

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“…At the same time, CSN-mediated cullin derubylation is essential for in vivo organized E3 functions . In fact, CSN derubylation and its associated UBP12-mediated deubiquitination activities promote CRL E3 function by counteracting the instability of the E3 components caused by CRL autoubiquitination activity (He et al, 2005;Wee et al, 2005;Cope and Deshaies, 2006;Wu et al, 2006). Together, these findings demonstrate that cycles of rubylation/derubylation are essential for maintaining an optimal pool of active Cullin-RING ligases and explain the mechanism underlying substrate accumulation in csn mutants (Lykke-Andersen et al, 2003;Cope and Deshaies, 2006;Denti et al, 2006).…”

Section: Introductionmentioning

confidence: 93%

Role of the MPN Subunits in COP9 Signalosome Assembly and Activity, and Their Regulatory Interaction withArabidopsisCullin3-Based E3 Ligases

et al. 2007

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The COP9 signalosome (CSN) is an evolutionarily conserved multisubunit protein complex that regulates a variety of biological processes. Among its eight subunits, CSN5 and CSN6 contain a characteristic MPN (for Mpr1p and Pad1p Nterminal) domain and, in Arabidopsis thaliana, are each encoded by two genes: CSN5A, CSN5B and CSN6A, CSN6B, respectively. We characterized both MPN subunits using a series of single and double mutants within each gene family. Our results indicate that although CSN6A and CSN6B retain mostly redundant functions, CSN5A and CSN5B play unequal roles in the regulation of plant development. Complete depletion of either of the two MPN members results in CSN instability and the decay of various CSN components, along with the complete loss of CUL1, CUL3, and CUL4 derubylation. Furthermore, we demonstrate that CSN interacts with CUL3, in addition to CUL1 and CUL4, and that the lack of CSN activity differentially affects the stability of those three cullins. Interestingly, we also show that optimal CUL3 activity is required to maintain the cellular pool of CSN5, through a posttranscriptional mechanism. Our data suggest the existence of reciprocal regulation between CUL3 and CSN5 accumulation. This study thus completes the genetic analysis of all CSN subunits and confirms the structural interdependence between PCI and MPN subunits in functional CSN complex formation.

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Section: Introductionmentioning

confidence: 93%

Role of the MPN Subunits in COP9 Signalosome Assembly and Activity, and Their Regulatory Interaction withArabidopsisCullin3-Based E3 Ligases

et al. 2007

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“…The conjugated SUMO moiety can be removed by Sentrin-specific proteases (SENPs) that also process SUMO precursors (Mukhopadhyay and Dasso, 2007). The other Ubl, Nedd8, modifies and activates cullin family proteins that function as scaffold to organize cullin-RING Ub ligase (CRLs) complexes (Hori et al, 1999;Pan et al, 2004;Wu et al, 2006). The process of neddylation has also been shown to regulate several cellular proteins and among these are the tumor suppressor protein p53 (Xirodimas et al, 2004), the breast cancer-associated protein BCA3 (Gao et al, 2006) and ribosomal proteins (Xirodimas et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

DEN1 deneddylates non-cullin proteins in vivo

Chan

Yoon

et al. 2008

Journal of Cell Science

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The ubiquitin-like protein Nedd8/Rub1 covalently modifies and activates cullin ubiquitin ligases. However, the repertoire of Nedd8-modified proteins and the regulation of protein neddylation status are not clear. The cysteine protease DEN1/NEDP1 specifically processes the Nedd8 precursor and has been suggested to deconjugate Nedd8 from cullin proteins. By characterizing the Drosophila DEN1 protein and DEN1 null (DEN1null) mutants, we provide in vitro and in vivo evidence that DEN1, in addition to processing Nedd8, deneddylates many cellular proteins. Although purified DEN1 protein efficiently deneddylates the Nedd8-conjugated cullin proteins Cul1 and Cul3, neddylated Cul1 and Cul3 protein levels are not enhanced in DEN1null. Strikingly, many cellular proteins are highly neddylated in DEN1 mutants and are deneddylated by purified DEN1 protein. DEN1 deneddylation activity is distinct from that of the cullin-deneddylating CSN. Genetic analyses indicate that a balance between neddylation and deneddylation maintained by DEN1 is crucial for animal viability.

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“…Although some experiments indicate that neddylation may control the assembly of E3 complexes or the association of E3 ligases with E2 ubiquitin conjugating emzymes, it needs to be said that the precise role of neddylation for E3 function is at present not understood (Kawakami et al, 2001;Bornstein et al, 2006;Wu et al, 2006). NEDD8 is deconjugated from Cullins (deneddylation) through the activity of COP9 signalosome (CSN) subunit 5 (CSN5) (Schwechheimer et al, 2001;Cope et al, 2002;Chiba and Tanaka, 2004;Dohmann et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Characterization of theVIER F-BOX PROTEINEGenes fromArabidopsisReveals Their Importance for Plant Growth and Development

et al. 2007

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E3 ubiquitin ligases (E3s) target proteins for degradation by the 26S proteasome. In SKP1/CDC53/F-box protein–type E3s, substrate specificity is conferred by the interchangeable F-box protein subunit. The vast majority of the 694 F-box proteins encoded by the Arabidopsis thaliana genome remain to be understood. We characterize the VIER F-BOX PROTEINE (VFB; German for FOUR F-BOX PROTEINS) genes from Arabidopsis that belong to subfamily C of the Arabidopsis F-box protein superfamily. This subfamily also includes the F-box proteins TRANSPORT INHIBITOR RESPONSE1 (TIR1)/AUXIN SIGNALING F-BOX (AFB) proteins and EIN3 BINDING F-BOX proteins, which regulate auxin and ethylene responses, respectively. We show that loss of VFB function causes delayed plant growth and reduced lateral root formation. We find that the expression of a number of auxin-responsive genes and the activity of DR5:β-glucuronidase, a reporter for auxin reponse, are reduced in the vfb mutants. This finding correlates with an increase in the abundance of an AUXIN/INDOLE-3-ACETIC ACID repressor. However, we also find that auxin responses are not affected in the vfb mutants and that a representative VFB family member, VFB2, cannot functionally complement the tir1-1 mutant. We therefore exclude the possibility that VFBs are functional orthologs of TIR1/AFB proteins.

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Protection of cullin–RING E3 ligases by CSN–UBP12

Cited by 60 publications

References 59 publications

Role of the MPN Subunits in COP9 Signalosome Assembly and Activity, and Their Regulatory Interaction withArabidopsisCullin3-Based E3 Ligases

Role of the MPN Subunits in COP9 Signalosome Assembly and Activity, and Their Regulatory Interaction withArabidopsisCullin3-Based E3 Ligases

DEN1 deneddylates non-cullin proteins in vivo

Characterization of theVIER F-BOX PROTEINEGenes fromArabidopsisReveals Their Importance for Plant Growth and Development

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