Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Cancer-testis antigen MAGE-C2 binds Rbx1 and inhibits ubiquitin ligase-mediated turnover of cyclin E.

ABSTRACT: Cancer-testis antigen MAGE-C2 is normally expressed in testis but aberrantly expressed in various kinds of tumors. Its functions in tumor cells are mostly unknown. Here, we show that MAGE-C2 binds directly to the RING domain protein Rbx1, and participates in Skp1-Cullin1-F box protein (SCF) complex. Furthermore, MAGE-C2 can inhibit the E3 ubiquitin ligase activity of SCF complex. Ablation of endogenous MAGE-C2 decreases the level of cyclin E and accelerates cyclin E turnover by inhibiting ubiquitin-mediated proteasome degradation. Overexpression of MAGE-C2 increases the level of cyclin E and promotes G1-S transition and cell proliferation, and the results are further confirmed by knockdown of MAGE-C2. Overall, the study indicates that MAGE-C2 is involved in SCF complex and increases the stability of cyclin E in tumor cells.

SUBMITTER: Hao J

PROVIDER: S-EPMC4747207 | biostudies-literature | 2015 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Cancer-testis antigen MAGE-C2 binds Rbx1 and inhibits ubiquitin ligase-mediated turnover of cyclin E.

Hao Jiaqing J Song Xiao X Wang Jingjing J Guo Chengli C Li Yan Y Li Bing B Zhang Yu Y Yin Yanhui Y

Oncotarget 20151201 39

Cancer-testis antigen MAGE-C2 is normally expressed in testis but aberrantly expressed in various kinds of tumors. Its functions in tumor cells are mostly unknown. Here, we show that MAGE-C2 binds directly to the RING domain protein Rbx1, and participates in Skp1-Cullin1-F box protein (SCF) complex. Furthermore, MAGE-C2 can inhibit the E3 ubiquitin ligase activity of SCF complex. Ablation of endogenous MAGE-C2 decreases the level of cyclin E and accelerates cyclin E turnover by inhibiting ubiqui ...[more]

PMID: 26540345

Similar Datasets

The glomuvenous malformation protein Glomulin binds Rbx1 and regulates cullin RING ligase-mediated turnover of Fbw7.

Project description:Fbw7, a substrate receptor for Cul1-RING-ligase (CRL1), facilitates the ubiquitination and degradation of several proteins, including Cyclin E and c-Myc. In spite of much effort, the mechanisms underlying Fbw7 regulation are mostly unknown. Here, we show that Glomulin (Glmn), a protein found mutated in the vascular disorder glomuvenous malformation (GVM), binds directly to the RING domain of Rbx1 and inhibits its E3 ubiquitin ligase activity. Loss of Glmn in a variety of cells, tissues, and GVM lesions results in decreased levels of Fbw7 and increased levels of Cyclin E and c-Myc. The increased turnover of Fbw7 is dependent on CRL and proteasome activity, indicating that Glmn modulates the E3 activity of CRL1(Fbw7). These data reveal an unexpected functional connection between Glmn and Rbx1 and demonstrate that defective regulation of Fbw7 levels contributes to GVM.

| S-EPMC3336104 | biostudies-literature

MicroRNA-874 Functions as a Tumor Suppressor by Targeting Cancer/Testis Antigen HCA587/MAGE-C2.

Project description:Cancer/testis antigen HCA587/MAGE-C2 has been considered as a tumor specific target for immunotherapy. It has been reported that HCA587/MAGE-C2 plays an active role in tumorigenesis by promoting the growth and survival of tumor cells. However, the regulation of HCA587/MAGE-C2 expression in cancer cells remains largely unknown. MicroRNAs (miRNAs), a large family of gene regulators, have been shown to negatively regulate the expression of important cancer-related genes and contribute to the initiation and development of cancers. In this study, we conducted searches of miRNAs that regulate HCA587/MAGE-C2 expression. We combined bioinformatics tools with biological validation assays to demonstrate that HCA587/MAGE-C2 is a direct target of microRNA-874 (miR-874). Furthermore, we investigated the expression levels of miR-874 in human hepatocellular carcinoma tissues and paired adjacent normal tissues by stem-loop reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The results revealed a significant downregulation of miR-874 expression in tumor tissues compared to adjacent normal tissues. Finally, we demonstrated that overexpression of miR-874, as well as HCA587/MAGE-C2 silencing, resulted in suppression of tumor cell proliferation and invasion. Moreover, the inhibition effects of miR-874 on cell proliferation and invasion were reversed by co-expression of HCA587/MAGE-C2 in A375 cells. Taken together, our data demonstrated that HCA587/MAGE-C2 is a direct target of miR-874, and miR-874 may function as a tumor suppressive miRNA, at least in part, by negatively regulating HCA587/MAGE-C2 expression in cancer cells.

| S-EPMC4829551 | biostudies-literature

Crystal Structure of the Cul2-Rbx1-EloBC-VHL Ubiquitin Ligase Complex.

Project description:Cullin RING E3 ubiquitin ligases (CRLs) function in the ubiquitin proteasome system to catalyze the transfer of ubiquitin from E2 conjugating enzymes to specific substrate proteins. CRLs are large dynamic complexes and attractive drug targets for the development of small-molecule inhibitors and chemical inducers of protein degradation. The atomic details of whole CRL assembly and interactions that dictate subunit specificity remain elusive. Here we present the crystal structure of a pentameric CRL2VHL complex, composed of Cul2, Rbx1, Elongin B, Elongin C, and pVHL. The structure traps a closed state of full-length Cul2 and a new pose of Rbx1 in a trajectory from closed to open conformation. We characterize hotspots and binding thermodynamics at the interface between Cul2 and pVHL-EloBC and identify mutations that contribute toward a selectivity switch for Cul2 versus Cul5 recognition. Our findings provide structural and biophysical insights into the whole Cul2 complex that could aid future drug targeting.

| S-EPMC5462531 | biostudies-literature

The C2 domain of the Rsp5 ubiquitin ligase binds membrane phosphoinositides and directs ubiquitination of endosomal cargo.

Project description:Ubiquitin ligases of the Nedd4 family regulate membrane protein trafficking by modifying both cargo proteins and the transport machinery with ubiquitin. Here, we investigate the role of the yeast Nedd4 homologue, Rsp5, in protein sorting into vesicles that bud into the multivesicular endosome (MVE) en route to the vacuole. A mutant lacking the Rsp5 C2 domain is unable to ubiquitinate or sort biosynthetic cargo into MVE vesicles, whereas endocytic cargo is ubiquitinated and sorted efficiently. The C2 domain binds specifically to phosphoinositides in vitro and is sufficient for localization to membranes in intact cells. Mutation of a lysine-rich patch on the surface of the C2 domain abolishes membrane interaction and disrupts sorting of biosynthetic cargo. Translational fusion of ubiquitin to a biosynthetic cargo protein alleviates the requirement for the C2 domain in its MVE sorting. These results demonstrate that the C2 domain specifies Rsp5-dependent ubiquitination of endosomal cargo and suggest that Rsp5 function is regulated by membrane phosphoinositides.

| S-EPMC2172079 | biostudies-literature

RBX1/ROC1-SCF E3 ubiquitin ligase is required for mouse embryogenesis and cancer cell survival.

Project description:RBX1 (also known as ROC1) is a RING subunit of SCF (Skp1, Cullins, F-box proteins) E3 ubiquitin ligases, required for SCF to direct a timely degradation of diverse substrates, thereby regulating numerous cellular processes under both physiological and pathological conditions. Previous studies have shown that RBX1 is essential for growth in yeast, Caenorhabditis elegans and Drosophila. The role of RBX1 in mouse development and in regulation of cancer cell survival was unknown. Our recent work demonstrated that RBX1 is an essential gene for mouse embryogenesis, and targeted disruption of RBX1 causes embryonic lethality at E7.5 due to hypoproliferation as a result of p27 accumulation. We also showed that RBX1 is overexpressed in a number of human cancers, and siRNA silencing of RBX1 caused cancer cell death as a result of sequential induction of G2-M arrest, senescence and apoptosis. These findings reveal a physiological role of RBX1 during mouse development and a pathological role for the survival of human cancer cells. Differential outcomes between normal (growth arrest) and cancer cells (cell death) upon RBX1 disruption/silencing suggest RBX1 as a valid anticancer target.Comments on:Tan M, Davis SW, Saunders TL, Zhu Y, Sun Y. RBX1/ROC1 disruption results in early embryonic lethality due to proliferation failure, partially rescued by simultaneous loss of p27. Proc Natl Acad Sci USA. 2009; 106:6203-6208Jia L, Soengas MS, Sun Y. ROC1/RBX1 E3 ubiquitin ligase silencing suppresses tumor cell growth via sequential induction of G2-M arrest, apoptosis, and senescence. Cancer Res. 2009; 69:4974-82.

| S-EPMC2732615 | biostudies-literature

Regulation of MAGE-A3/6 by the CRL4-DCAF12 ubiquitin ligase and nutrient availability.

Project description:Melanoma antigen genes (MAGEs) are emerging as important oncogenic drivers that are normally restricted to expression in male germ cells but are aberrantly expressed in cancers and promote tumorigenesis. Mechanistically, MAGEs function as substrate specifying subunits of E3 ubiquitin ligases. Thus, the activation of germline-specific genes in cancer can drive metabolic and signaling pathways through altered ubiquitination to promote tumorigenesis. However, the mechanisms regulating MAGE expression and activity are unclear. Here, we describe how the MAGE-A3/6 proteins that function as repressors of autophagy are downregulated in response to nutrient deprivation. Short-term cellular starvation promotes rapid MAGE-A3/6 degradation in a proteasome-dependent manner. Proteomic analysis reveals that degradation of MAGE-A3/6 is controlled by the CRL4-DCAF12 E3 ubiquitin ligase. Importantly, the degradation of MAGE-A3/6 by CRL4-DCAF12 is required for starvation-induced autophagy. These findings suggest that oncogenic MAGEs can be dynamically controlled in response to stress to allow cellular adaptation, autophagy regulation, and tumor growth and that CRL4-DCAF12 activity is responsive to nutrient status.

| S-EPMC6607007 | biostudies-literature

E4 ubiquitin ligase promotes mitofusin turnover and mitochondrial stress response.

Project description:Ubiquitin-dependent control of mitochondrial dynamics is important for protein quality and neuronal integrity. Mitofusins, mitochondrial fusion factors, can integrate cellular stress through their ubiquitylation, which is carried out by multiple E3 enzymes in response to many different stimuli. However, the molecular mechanisms that enable coordinated responses are largely unknown. Here we show that yeast Ufd2, a conserved ubiquitin chain-elongating E4 enzyme, is required for mitochondrial shape adjustments. Under various stresses, Ufd2 translocates to mitochondria and triggers mitofusin ubiquitylation. This elongates ubiquitin chains on mitofusin and promotes its proteasomal degradation, leading to mitochondrial fragmentation. Ufd2 and its human homologue UBE4B also target mitofusin mutants associated with Charcot-Marie-Tooth disease, a hereditary sensory and motor neuropathy characterized by progressive loss of the peripheral nerves. This underscores the pathophysiological importance of E4-mediated ubiquitylation in neurodegeneration. In summary, we identify E4-dependent mitochondrial stress adaptation by linking various metabolic processes to mitochondrial fusion and fission dynamics.

| S-EPMC10434984 | biostudies-literature

UBXD7 binds multiple ubiquitin ligases and implicates p97 in HIF1alpha turnover.

Project description:p97 is an ATP-dependent chaperone that plays an important role in endoplasmic reticulum-associated degradation but whose connections to turnover of soluble proteins remain sparse. Binding of p97 to substrates is mediated by cofactors that contain ubiquitin-binding domains. We employed "network proteomics" to show that p97 assembles with all of the 13 mammalian UBX-domain proteins. The UBX proteins that bind ubiquitin conjugates also interact with dozens of E3 ubiquitin ligases, only one of which had been previously linked to p97. In particular, UBXD7 links p97 to the ubiquitin ligase CUL2/VHL and its substrate hypoxia-inducible factor 1alpha (HIF1alpha). Depletion of p97 leads to accumulation of endogenous HIF1alpha and increased expression of a HIF1alpha target gene. The large number of ubiquitin ligases found associated with UBX proteins suggests that p97 plays a far broader role than previously anticipated in the global regulation of protein turnover.

| S-EPMC2614663 | biostudies-literature

T cell receptor interactions with human leukocyte antigen govern indirect peptide selectivity for the cancer testis antigen MAGE-A4.

Project description:T cell-mediated immunity is governed primarily by T cell receptor (TCR) recognition of peptide-human leukocyte antigen (pHLA) complexes and is essential for immunosurveillance and disease control. This interaction is generally stabilized by interactions between the HLA surface and TCR germline-encoded complementarity-determining region (CDR) loops 1 and 2, whereas peptide selectivity is guided by direct interactions with the TCR CDR3 loops. Here, we solved the structure of a newly identified TCR in complex with a clinically relevant peptide derived from the cancer testis antigen melanoma antigen-A4 (MAGE-A4). The TCR bound pHLA in a position shifted toward the peptide's N terminus. This enabled the TCR to achieve peptide selectivity via an indirect mechanism, whereby the TCR sensed the first residue of the peptide through HLA residue Trp-167, which acted as a tunable gateway. Amino acid substitutions at peptide position 1 predicted to alter the HLA Trp-167 side-chain conformation abrogated TCR binding, indicating that this indirect binding mechanism is essential for peptide recognition. These findings extend our understanding of the molecular rules that underpin antigen recognition by TCRs and have important implications for the development of TCR-based therapies.

| S-EPMC7450119 | biostudies-literature

The CDK12-inhibitor CR8 mediates Cyclin K degradation through the CUL4-RBX1-DDB1 E3 ubiquitin ligase

Project description:Small molecules have been identified that induce protein-protein interactions between a substrate and a ubiquitin ligase, resulting in targeted protein degradation. Such molecular glue compounds, unlike traditional enzyme inhibitors, act sub-stoichiometrically to catalyse rapid depletion of previously inaccessible targets. Molecular glue degraders have the potential for clinical efficacy, but have thus far only been discovered serendipitously. Through correlations between compound cytotoxicity and E3 ligase expression levels, we found that CR8, a cyclin-dependent kinase (CDK) inhibitor, acts as a molecular glue degrader. A surface-exposed pyridyl moiety of CR8 is sufficient to induce complex formation between CDK12-Cyclin K and DDB1, a component of CUL4 E3 ubiquitin ligase complexes, which presents Cyclin K for ubiquitination and degradation. Our results reveal that minor surface-exposed modifications confer gain-of-function glue properties to an inhibitor. We hypothesize that chemical alteration of surface-exposed moieties is a broad strategy to turn a target binder into a molecular glue.

2020-06-10 | PXD016188 | Pride

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data