Robust cullin-RING ligase function is established by a multiplicity of poly-ubiquitylation pathways
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ABSTRACT:
PROVIDER: PRJNA561505 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR10012256.fastq.gz | Fastqsanger.gz | |||
| SRR10012257.fastq.gz | Fastqsanger.gz | |||
| SRR10012258.fastq.gz | Fastqsanger.gz | |||
| SRR10012259.fastq.gz | Fastqsanger.gz | |||
| SRR10012260.fastq.gz | Fastqsanger.gz |
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Project description:The large family of SCF ubiquitin ligases catalyze ubiquitylation by bridging protein substrates and ubiquitin-modifying enzymes. S. cerevisiae SCFs employ a sole, essential enzyme, Cdc34, to build poly-ubiquitin chains required for degradation. However, humans have no less than six chain building enzymes associated with SCFs, including the long assumed to be essential Cdc34 orthologs, UBE2R1 and UBE2R2. Furthermore, uncertainty regarding the physiological concentrations of ubiquitin-modifying enzymes has hindered in vitro mechanistic work. Proteomics was used to estimate enzyme levels in cells, and ubiquitylation assays were employed to quantitatively compare enzyme activities. The results show that UBE2R2 alone has negligible ubiquitylation activity at physiological concentrations, and the ablation of UBE2R1/2 had no effect on the stability of SCF substrates in cells. A genome-wide CRISPR screen revealed that UBE2G1 buffers against the deletion of UBE2R1/2. UBE2G1 had robust in vitro activity with SCF, and UBE2G1 knockdown in cells lacking UBE2R1/2 resulted in stabilization of the SCF substrate p27 as well as the Cul3-RING ligase substrate NRF2. The results reveal the human SCF enzyme system is heavily buffered and suggest that SCF specificity is diversified by association with multiple enzyme partners.
2020-01-01 | GSE136175 | GEO
Project description:Ubiquitin ligation is typically executed by hallmark E3 catalytic domains. Two such domains, "cullin-RING" and "RBR", are individually found in several hundred E3 ligases in humans, and collaborate with E2 enzymes to catalyze ubiquitylation. However, the vertebrate-specific CUL9 complex with RBX1 (also called ROC1), of interest due to its tumor suppressive interaction with TP53, uniquely encompasses both cullin-RING and RBR domains. Here, cryo-EM, biochemistry, and cellular assays elucidate a 1.8 MDa hexameric CUL9-RBX1 assembly. Within one dimeric subcomplex, an E2-bound RBR domain is activated by neddylation of its own cullin domain and positioning from the adjacent CUL9-RBX1 in trans. Our data show CUL9 as unique amongst RBX1-bound cullins in dependence on the metazoan-specific UBE2F neddylation enzyme, while the RBR domain protects from deneddylation. Mono-ubiquitylation of TP53 relies on both CUL9's neddylated cullin and RBR domains achieving self-assembled and chimeric cullin-RING/RBR E3 ligase activity.
2024-04-23 | PXD047326 | Pride
Project description:Ubiquitin ligation is typically executed by hallmark E3 catalytic domains. Two such domains, "cullin-RING" and "RBR", are individually found in several hundred E3 ligases in humans, and collaborate with E2 enzymes to catalyze ubiquitylation. However, the vertebrate-specific CUL9 complex with RBX1 (also called ROC1), of interest due to its tumor suppressive interaction with TP53, uniquely encompasses both cullin-RING and RBR domains. Here, cryo-EM, biochemistry, and cellular assays elucidate a 1.8 MDa hexameric CUL9-RBX1 assembly. Within one dimeric subcomplex, an E2-bound RBR domain is activated by neddylation of its own cullin domain and positioning from the adjacent CUL9-RBX1 in trans. Our data show CUL9 as unique amongst RBX1-bound cullins in dependence on the metazoan-specific UBE2F neddylation enzyme, while the RBR domain protects it from deneddylation. Substrate ubiquitylation relies on both CUL9's neddylated cullin and RBR domains achieving self-assembled and chimeric cullin-RING/RBR E3 ligase activity.
2024-04-09 | PXD047229 | Pride
Project description:The cullin-RING ligases (CRLs) form the major family of E3 ubiquitin ligases. The prototypic CRLs in yeast, called SCF enzymes, employ a single E2 enzyme, Cdc34, to build poly-ubiquitin chains required for degradation. In contrast, six different human E2 and E3 enzyme activities, including Cdc34 orthologs UBE2R1 and UBE2R2, appear to mediate SCF-catalyzed substrate polyubiquitylation in vitro. The combinatorial interplay of these enzymes raises questions about genetic buffering of SCFs in human cells and challenges the dogma that E3s alone determine substrate specificity. To enable the quantitative comparisons of SCF-dependent ubiquitylation reactions with physiological enzyme concentrations, mass spectrometry was employed to estimate E2 and E3 levels in cells. In combination with UBE2R1/2, the E2 UBE2D3 and the E3 ARIH1 both promoted SCF-mediated polyubiquitylation in a substrate-specific fashion. Unexpectedly, UBE2R2 alone had negligible ubiquitylation activity at physiological concentrations and the ablation of UBE2R1/2 had no effect on the stability of SCF substrates in cells. A genome-wide CRISPR screen revealed that an additional E2 enzyme, UBE2G1, buffers against the loss of UBE2R1/2. UBE2G1 had robust in vitro chain extension activity with SCF, and UBE2G1 knockdown in cells lacking UBE2R1/2 resulted in stabilization of the SCF substrates p27 and CYCLIN E as well as the CUL2-RING ligase substrate HIF1α. The results demonstrate the human SCF enzyme system is diversified by association with multiple catalytic enzyme partners.
| S-EPMC6975927 | biostudies-literature
Project description:Ubiquitin and ubiquitin-like proteins (UBLs) are directed to targets by cascades of E1, E2, and E3 enzymes. The largest ubiquitin E3 subclass consists of cullin-RING ligases (CRLs), which contain one each of several cullins (CUL1, -2, -3, -4, or -5) and RING proteins (RBX1 or -2). CRLs are activated by ligation of the UBL NEDD8 to a conserved cullin lysine. How is cullin NEDD8ylation specificity established? Here we report that, like UBE2M (also known as UBC12), the previously uncharacterized E2 UBE2F is a NEDD8-conjugating enzyme in vitro and in vivo. Biochemical and structural analyses indicate how plasticity of hydrophobic E1-E2 interactions and E1 conformational flexibility allow one E1 to charge multiple E2s. The E2s have distinct functions, with UBE2M/RBX1 and UBE2F/RBX2 displaying different target cullin specificities. Together, these studies reveal the molecular basis for and functional importance of hierarchical expansion of the NEDD8 conjugation system in establishing selective CRL activation. Mol Cell 33:483-495, 2009. Keywords: Comparison of gene expression profiles Ube2m and Ube2f are E2 enzymes that direct protein modification by NEDD8. Here we explore the specific functions of Ube2f and Ube2m by comparing gene expression profiles following knockdown of their function in NIH 3T3 cells. We used microarrays to detail the global programme of gene expression changes following knockdown of Ube2m and Ube2f in NIH 3T3 cells. NIH 3T3 cells were transduced with retroviral constructs containing shRNA directed against Ube2m or Ube2f. Three replicates of each condition were analyzed.
2009-03-23 | E-GEOD-14088 | biostudies-arrayexpress
Project description:Ubiquitin and ubiquitin-like proteins (UBLs) are directed to targets by cascades of E1, E2, and E3 enzymes. The largest ubiquitin E3 subclass consists of cullin-RING ligases (CRLs), which contain one each of several cullins (CUL1, -2, -3, -4, or -5) and RING proteins (RBX1 or -2). CRLs are activated by ligation of the UBL NEDD8 to a conserved cullin lysine. How is cullin NEDD8ylation specificity established? Here we report that, like UBE2M (also known as UBC12), the previously uncharacterized E2 UBE2F is a NEDD8-conjugating enzyme in vitro and in vivo. Biochemical and structural analyses indicate how plasticity of hydrophobic E1-E2 interactions and E1 conformational flexibility allow one E1 to charge multiple E2s. The E2s have distinct functions, with UBE2M/RBX1 and UBE2F/RBX2 displaying different target cullin specificities. Together, these studies reveal the molecular basis for and functional importance of hierarchical expansion of the NEDD8 conjugation system in establishing selective CRL activation. Mol Cell 33:483-495, 2009. Keywords: Comparison of gene expression profiles
2009-03-24 | GSE14088 | GEO
Project description:The cullin-RING E3 ligase (CRL) network comprises over 300 unique complexes that switch from inactive to activated conformations upon site-specific cullin modification by the ubiquitin-like protein NEDD8. Assessing cellular repertoires of activated CRL complexes is critical for understanding eukaryotic regulation. However, probes surveying networks controlled by site-specific ubiquitin-like protein modifications are lacking. We report development of a synthetic antibody recognizing the active conformation of a NEDD8-linked cullin. We established a pipeline probing cellular networks of activated CUL1-, CUL2-, CUL3- and CUL4-containing CRLs, revealing the CRL complexes responding to stimuli. Profiling several cell types showed their baseline neddylated CRL repertoires vary, prime efficiency of targeted protein degradation, and are differentially rewired across distinct primary cell activation pathways. Thus, conformation-specific probes can permit nonenzymatic activity-based profiling across a system of numerous multiprotein complexes, which in the case of neddylated CRLs reveals widespread regulation and could facilitate development of degrader drugs.
2023-09-02 | PXD039649 | Pride
Project description:Intracellular pathogen infection leads to proteotoxic stress in host organisms. Previously we described a physiological program in the nematode C. elegans called the Intracellular Pathogen Response (IPR), which promotes resistance to proteotoxic stress and appears to be distinct from canonical proteostasis pathways. The IPR is controlled by PALS-22 and PALS-25, proteins of unknown biochemical function, which regulate expression of genes induced by natural intracellular pathogens. We previously showed that PALS-22 and PALS-25 regulate the mRNA expression of the predicted ubiquitin ligase component cullin cul-6, which promotes thermotolerance in pals-22 mutants. However, it was unclear whether CUL-6 acted alone, or together with other cullin-ring ubiquitin ligase components, which comprise a greatly expanded gene family in C. elegans. Here we use co-immunoprecipitation studies paired with genetic analysis to define the cullin-RING ligase components that act together with CUL-6 to promote thermotolerance. First, we identify a previously uncharacterized RING domain protein in the TRIM family we named RCS-1, which acts as a core component with CUL-6 to promote thermotolerance. Next, we show that the Skp-related proteins SKR-3, SKR-4 and SKR-5 act redundantly to promote thermotolerance with CUL-6. Finally, we screened F-box proteins that co-immunoprecipitate with CUL-6 and find that FBXA-158 and FBXA-75 promote thermotolerance. In summary, we have defined the three core components and two F-box adaptors of a cullin-RING ligase complex that promotes thermotolerance as part of the IPR in C. elegans, which adds to our understanding of how organisms cope with proteotoxic stress.
2020-02-07 | MSV000084936 | MassIVE
Project description:E3 ubiquitin ligases of the Cullin RING Ligase (CRL) family assemble into multiprotein complexes to diversify substrate adaptors and ensure selectivity in substrate engagement for degradation. Here we show a novel mechanism whereby mutations in substrate adaptors can drive neo-substrate degradation in cancer. KBTBD4 is a CRL3 substrate adaptor harbouring recurrent indel mutations in a subset of non-WNT/non-SHH medulloblastomas. We show that these mutations, arising in the substrate recognition domain of KBTBD4, promote the recruitment and ubiquitylation of the REST Corepressor (CoREST), which forms a complex to modulate chromatin accessibility and transcriptional programmes. We observe that this neomorphic activity of KBTBD4 mutants induces changes in epigenetic markers and significant alterations in transcription, diverting normal cellular programmes towards increased stemness. These results highlight mutation-driven neomorphic E3 ligase activity as a previously unrecognised mechanism in tumorigenesis, with implications for medulloblastoma pathogenesis and treatment.
2022-03-30 | GSE197240 | GEO
Project description:NEDD8 is a ubiquitin-like modifier most well-studied for its role in activating the largest family of ubiquitin E3 ligases, the cullin-RING ligases (CRLs). While many non-cullin neddylation substrates have been proposed over the years, validation of true NEDD8 targets has been challenging, as overexpression of exogenous NEDD8 can trigger NEDD8 conjugation through the ubiquitylation machinery. Here, we developed a deconjugation-resistant form of NEDD8 to stabilize the neddylated form of cullins and other non-cullin substrates. Using this strategy, we identified Ubc12, a NEDD8-specific E2 conjugating enzyme, as a substrate for auto-neddylation both in vitro and in cells. Furthermore, we identified SENP8/DEN1 as the protease that counteracts Ubc12 auto-neddylation, and observed aberrant neddylation of Ubc12 and other NEDD8 conjugation pathway components in engineered SENP8-deficient cells. Importantly, loss of SENP8 function contributes to reduced CRL activity, accumulation of CRL substrates, and defective cell cycle progression. Thus, our study highlights the importance of SENP8 in maintaining proper neddylation levels and CRL-dependent proteostasis, implicating this protease as a potential therapeutic target for inhibiting CRL activity.
2017-04-13 | MSV000080917 | MassIVE