Browse
Submit Data
Databases
API
Help

Dataset Information

19 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Interaction of p53 with the CCT complex promotes protein folding and wild-type p53 activity.

ABSTRACT: p53 is a transcription factor that mediates tumor suppressor responses. Correct folding of the p53 protein is essential for these activities, and point mutations that induce conformational instability of p53 are frequently found in cancers. These mutant p53s not only lose wild-type activity but can also acquire the ability to promote invasion and metastasis. We show that folding of wild-type p53 is promoted by an interaction with the chaperonin CCT. Depletion of this chaperone in cells results in the accumulation of misfolded p53, leading to a reduction in p53-dependent gene expression. Intriguingly, p53 proteins mutated to prevent the interaction with CCT show conformational instability and acquire an ability to promote invasion and random motility that is similar to the activity of tumor-derived p53 mutants. Our data therefore suggest that both growth suppression and cell invasion may be differentially regulated functions of wild-type p53.

SUBMITTER: Trinidad AG

PROVIDER: S-EPMC3699784 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Mechanistic insights into protein folding by the eukaryotic chaperonin complex CCT.

Project description:The cytosolic chaperonin CCT is indispensable to eukaryotic life, folding the cytoskeletal proteins actin and tubulin along with an estimated 10% of the remaining proteome. However, it also participates in human diseases such as cancer and viral infections, rendering it valuable as a potential therapeutic target. CCT consists of two stacked rings, each comprised of eight homologous but distinct subunits, that assists the folding of a remarkable substrate clientele that exhibits both broad diversity and specificity. Much of the work in recent years has been aimed at understanding the mechanisms of CCT substrate recognition and folding. These studies have revealed new binding sites and mechanisms by which CCT uses its distinctive subunit arrangement to fold structurally unrelated substrates. Here, we review recent structural insights into CCT-substrate interactions and place them into the broader context of CCT function and its implications for human health.

| S-EPMC9704529 | biostudies-literature

The noncoding RNAs SNORD50A and SNORD50B-mediated TRIM21-GMPS interaction promotes the growth of p53 wild-type breast cancers by degrading p53.

Project description:Small nucleolar RNA SNORD50A and SNORD50B (SNORD50A/B) has been reported to be recurrently deleted and function as a putative tumor suppressor in different types of cancer by binding to and suppressing the activity of the KRAS oncoproteins. Its deletion correlates with poorer patient survival. However, in this study, we surprisingly found that SNORD50A/B loss predicted a better survival in breast cancer patients carrying wild-type p53. Functional studies showed that SNORD50A/B deletion strongly inhibited the proliferation, migration, invasion and tumorigenic potential, and induced cell cycle arrest and apoptosis in p53 wild-type breast cancer cells, while exerted the opposite effects in p53 mutated breast cancer cells. This was also supported by ectopically expressing SNORD50A/B in both p53 wild-type and mutated breast cancer cells. Mechanistically, SNORD50A/B clearly enhances the interaction between E3 ubiquitin ligase TRIM21 and its substrate GMPS by forming a complex among them, thereby promoting GMPS ubiquitination and its subsequent cytoplasmic sequestration. SNORD50A/B deletion in p53 wild-type breast cancer cells will release GMPS and induce the translocation of GMPS into the nucleus, where GMPS can recruit USP7 and form a complex with p53, thereby decreasing p53 ubiquitination, stabilizing p53 proteins, and inhibiting malignant phenotypes of cancer cells. Altogether, the present study first reports that SNORD50A/B plays an oncogenic role in p53 wild-type breast cancers by mediating TRIM21-GMPS interaction.

| S-EPMC8329294 | biostudies-literature

Chaperoning of mutant p53 protein by wild-type p53 protein causes hypoxic tumor regression.

Project description:Mutant (Mt) p53 abrogates tumor suppression functions of wild-type (WT) p53 through mutant-specific, gain-of-function effects, and patients bearing Mt p53 are chemoresistant. The dominant negative effect of p53 mutants results from their aggregation propensity which causes co-aggregation of WT p53. We explored the mechanism of p53 inactivation in hypoxia and hypothesized whether WT p53 could rescue Mt p53 in hypoxic tumors. WT p53 exists in mutant conformation in hypoxic core of MCF-7 solid tumors, and its conformation is oxygen-dependent. Under simulated hypoxia in cells, WT p53 undergoes conformational change in acquiring mutant conformation. An in vivo chaperone assay shows that WT p53 functions as a molecular chaperone in rescuing conformational and structural p53 mutants in cancer cells both at the transcription and proteome levels. WT p53 chaperone therapy is further shown to cause significant regression of tumor xenografts through reconversion of the mutant phenotype to wild-type p53. The chaperone function of WT p53 is directly linked to the induction of apoptosis in both cancer cells and tumor xenografts. As oncogenic p53 mutants are linked to chemoresistance in hypoxic tumors, p53 chaperone therapy will introduce new dimensions to existing cancer therapeutics. We propose that in cancer cells, WT p53 chaperoning may either exist as a cellular event to potentially reverse the dominant negative effect of its oncogenic mutants or to stabilize yet unidentified factors.

| S-EPMC3268447 | biostudies-literature

Structural basis of plp2-mediated cytoskeletal protein folding by TRiC/CCT.

Project description:The cytoskeletal proteins tubulin and actin are the obligate substrates of TCP-1 ring complex/Chaperonin containing TCP-1 (TRiC/CCT), and their folding involves co-chaperone. Through cryo-electron microscopy analysis, we present a more complete picture of TRiC-assisted tubulin/actin folding along TRiC adenosine triphosphatase cycle, under the coordination of co-chaperone plp2. In the open S1/S2 states, plp2 and tubulin/actin engaged within opposite TRiC chambers. Notably, we captured an unprecedented TRiC-plp2-tubulin complex in the closed S3 state, engaged with a folded full-length β-tubulin and loaded with a guanosine triphosphate, and a plp2 occupying opposite rings. Another closed S4 state revealed an actin in the intermediate folding state and a plp2. Accompanying TRiC ring closure, plp2 translocation could coordinate substrate translocation on the CCT6 hemisphere, facilitating substrate stabilization and folding. Our findings reveal the folding mechanism of the major cytoskeletal proteins tubulin/actin under the coordination of the biogenesis machinery TRiC and plp2 and extend our understanding of the links between cytoskeletal proteostasis and related human diseases.

| S-EPMC10017041 | biostudies-literature

Binding induced folding in p53-MDM2 complex.

Project description:The MDM2 N-terminal domain can bind to the transactivation domain of p53 and downregulate its ability to activate transcription. It was found that binding with p53 stabilizes the MDM2 N-terminal domain. Thus the coupling between binding and folding is essential in the normal functional interactions between p53 and MDM2. We have performed explicit-solvent molecular dynamics simulations (MD) for both bound MDM2(N) and apo-MDM2 to study the interdependence of binding and folding in the p53-MDM2 complex. Kinetic analysis of high-temperature MD simulations shows that both bound MDM2(N) and apo-MDM2 unfold via a two-state process. Both kinetics and free energy landscape analyses indicate that bound MDM2 unfolds in the order of p53 unbinding, tertiary unfolding, and finally secondary structure unfolding. Our data show that the unfolding pathways are different between bound MDM2(N) and apo-MDM2: the unfolding order of unstable helices and tertiary contacts is reversed. Transition state analysis shows that the transition state of bound MDM2 is more nativelike and more heterogeneous than that of apo-MDM2. The predicted Phi-values suggest that the stable helices are more nativelike than other regions in both bound MDM2(N) and apo-MDM2. Within the stable helices, helix II in bound MDM2 is more nativelike than that in apo-MDM2. However, helix I and IV in bound MDM2 are less nativelike than those in apo-MDM2.

| S-EPMC2528056 | biostudies-literature

CCT complex restricts neuropathogenic protein aggregation via autophagy.

Project description:Aberrant protein aggregation is controlled by various chaperones, including CCT (chaperonin containing TCP-1)/TCP-1/TRiC. Mutated CCT4/5 subunits cause sensory neuropathy and CCT5 expression is decreased in Alzheimer's disease. Here, we show that CCT integrity is essential for autophagosome degradation in cells or Drosophila and this phenomenon is orchestrated by the actin cytoskeleton. When autophagic flux is reduced by compromise of individual CCT subunits, various disease-relevant autophagy substrates accumulate and aggregate. The aggregation of proteins like mutant huntingtin, ATXN3 or p62 after CCT2/5/7 depletion is predominantly autophagy dependent, and does not further increase with CCT knockdown in autophagy-defective cells/organisms, implying surprisingly that the effect of loss-of-CCT activity on mutant ATXN3 or huntingtin oligomerization/aggregation is primarily a consequence of autophagy inhibition rather than loss of physiological anti-aggregation activity for these proteins. Thus, our findings reveal an essential partnership between two key components of the proteostasis network and implicate autophagy defects in diseases with compromised CCT complex activity.

| S-EPMC5155164 | biostudies-literature

Interaction with the CCT chaperonin complex limits APOBEC3A cytidine deaminase cytotoxicity.

Project description:The APOBEC3 cytidine deaminases are implicated as the cause of a prevalent somatic mutation pattern found in cancer genomes. The APOBEC3 enzymes act as viral restriction factors by mutating viral genomes. Mutation of the cellular genome is presumed to be an off-target activity of the enzymes, although the regulatory measures for APOBEC3 expression and activity remain undefined. It is therefore difficult to predict circumstances that enable APOBEC3 interaction with cellular DNA that leads to mutagenesis. The APOBEC3A (A3A) enzyme is the most potent deaminase of the family. Using proteomics, we evaluate protein interactors of A3A to identify potential regulators. We find that A3A interacts with the chaperonin-containing TCP-1 (CCT) complex, a cellular machine that assists in protein folding and function. Importantly, depletion of CCT results in A3A-induced DNA damage and cytotoxicity. Evaluation of cancer genomes demonstrates an enrichment of A3A mutational signatures in cancers with silencing mutations in CCT subunit genes. Together, these data suggest that the CCT complex interacts with A3A, and that disruption of CCT function results in increased A3A mutational activity.

| S-EPMC8419680 | biostudies-literature

Programmed cell death protein 5 interacts with the cytosolic chaperonin containing tailless complex polypeptide 1 (CCT) to regulate β-tubulin folding.

Project description:Programmed cell death protein 5 (PDCD5) has been proposed to act as a pro-apoptotic factor and tumor suppressor. However, the mechanisms underlying its apoptotic function are largely unknown. A proteomics search for binding partners of phosducin-like protein, a co-chaperone for the cytosolic chaperonin containing tailless complex polypeptide 1 (CCT), revealed a robust interaction between PDCD5 and CCT. PDCD5 formed a complex with CCT and β-tubulin, a key CCT-folding substrate, and specifically inhibited β-tubulin folding. Cryo-electron microscopy studies of the PDCD5·CCT complex suggested a possible mechanism of inhibition of β-tubulin folding. PDCD5 bound the apical domain of the CCTβ subunit, projecting above the folding cavity without entering it. Like PDCD5, β-tubulin also interacts with the CCTβ apical domain, but a second site is found at the sensor loop deep within the folding cavity. These orientations of PDCD5 and β-tubulin suggest that PDCD5 sterically interferes with β-tubulin binding to the CCTβ apical domain and inhibits β-tubulin folding. Given the importance of tubulins in cell division and proliferation, PDCD5 might exert its apoptotic function at least in part through inhibition of β-tubulin folding.

| S-EPMC3924310 | biostudies-literature

Loss of wild-type p53 promotes mutant p53-driven metastasis through acquisition of survival and tumor-initiating properties.

Project description:Missense-type mutant p53 plays a tumor-promoting role through gain-of-function (GOF) mechanism. In addition, the loss of wild-type TP53 through loss of heterozygosity (LOH) is widely found in cancer cells. However, malignant progression induced by cooperation of TP53 GOF mutation and LOH remains poorly understood. Here, we show that mouse intestinal tumors carrying Trp53 GOF mutation with LOH (AKTPM/LOH) are enriched in metastatic lesions when heterozygous Trp53 mutant cells (AKTP+/M) are transplanted. We show that Trp53 LOH is required for dormant cell survival and clonal expansion of cancer cells. Moreover, AKTPM/LOH cells show an increased in vivo tumor-initiating ability compared with AKTPNull and AKTP+/M cells. RNAseq analyses reveal that inflammatory and growth factor/MAPK pathways are specifically activated in AKTPM/LOH cells, while the stem cell signature is upregulated in both AKTPM/LOH and AKTPNull cells. These results indicate that TP53/Trp53 LOH promotes TP53/Trp53 GOF mutation-driven metastasis through the activation of distinct pathway combination.

| S-EPMC7214469 | biostudies-literature

Activity-Directed Synthesis of Inhibitors of the p53/hDM2 Protein-Protein Interaction.

Project description:Protein-protein interactions (PPIs) provide a rich source of potential targets for drug discovery and biomedical science research. However, the identification of structural-diverse starting points for discovery of PPI inhibitors remains a significant challenge. Activity-directed synthesis (ADS), a function-driven discovery approach, was harnessed in the discovery of the p53/hDM2 PPI. Over two rounds of ADS, 346 microscale reactions were performed, with prioritisation on the basis of the activity of the resulting product mixtures. Four distinct and novel series of PPI inhibitors were discovered that, through biophysical characterisation, were shown to have promising ligand efficiencies. It was thus shown that ADS can facilitate ligand discovery for a target that does not have a defined small-molecule binding site, and can provide distinctive starting points for the discovery of PPI inhibitors.

| S-EPMC7496268 | biostudies-literature

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