Browse
Submit Data
Databases
API
Help

Dataset Information

10 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

USP7 counteracts SCFbetaTrCP- but not APCCdh1-mediated proteolysis of Claspin.

ABSTRACT: Claspin is an adaptor protein that facilitates the ataxia telangiectasia and Rad3-related (ATR)-mediated phosphorylation and activation of Chk1, a key effector kinase in the DNA damage response. Efficient termination of Chk1 signaling in mitosis and during checkpoint recovery requires SCF(betaTrCP)-dependent destruction of Claspin. Here, we identify the deubiquitylating enzyme ubiquitin-specific protease 7 (USP7) as a novel regulator of Claspin stability. Claspin and USP7 interact in vivo, and USP7 is required to maintain steady-state levels of Claspin. Furthermore, USP7-mediated deubiquitylation markedly prolongs the half-life of Claspin, which in turn increases the magnitude and duration of Chk1 phosphorylation in response to genotoxic stress. Finally, we find that in addition to the M phase-specific, SCF(betaTrCP)-mediated degradation, Claspin is destabilized by the anaphase-promoting complex (APC) and thus remains unstable in G1. Importantly, we demonstrate that USP7 specifically opposes the SCF(betaTrCP)- but not APC(Cdh1)-mediated degradation of Claspin. Thus, Claspin turnover is controlled by multiple ubiquitylation and deubiquitylation activities, which together provide a flexible means to regulate the ATR-Chk1 pathway.

SUBMITTER: Faustrup H

PROVIDER: S-EPMC2615094 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

USP7 counteracts the activation of the mitotic program

Project description:Chemical inhibitors of the deubiquitinase USP7 are currently being developed as anticancer agents, due to their capacity to activate P53. Regardless of this activity, USP7 inhibitors also generate DNA damage in a p53-independent manner. However, the mechanism of this genotoxicity remains unknown. Surprisingly, even if USP7 inhibitors stop DNA replication, this occurs concomitant to a premature activation of mitotic kinases such as CDK1, which impairs chromosome segregation and is toxic for mammalian cells. Mechanistically, we show that USP7 interacts with the phosphatase PP2A and regulates its function. Accordingly, USP7 or PP2A inhibition trigger similar changes on the phosphoproteome, with a particular bias towards mitotic targets. Supporting our model, the toxicity of USP7 inhibitors is alleviated by lowering CDK1 activity or by the chemical activation of PP2A. Our work sheds light into the mechanism of action of USP7 inhibitors and provides the first example of triggering premature mitotic entry through perturbation of ubiquitin signaling.

2021-03-09 | PXD016623 | Pride

Phosphorylation by Akt1 promotes cytoplasmic localization of Skp2 and impairs APCCdh1-mediated Skp2 destruction.

Project description:Deregulated Skp2 function promotes cell transformation, and this is consistent with observations of Skp2 overexpression in many human cancers. However, the mechanisms underlying elevated Skp2 expression are still unknown. Here we show that the serine/threonine protein kinase Akt1, but not Akt2, directly controls Skp2 stability by a mechanism that involves degradation by the APC-Cdh1 ubiquitin ligase complex. We show further that Akt1 phosphorylates Skp2 at Ser 72, which is required to disrupt the interaction between Cdh1 and Skp2. In addition, we show that Ser 72 is localized within a putative nuclear localization sequence and that phosphorylation of Ser 72 by Akt leads to cytoplasmic translocation of Skp2. This finding expands our knowledge of how specific signalling kinase cascades influence proteolysis governed by APC-Cdh1 complexes, and provides evidence that elevated Akt activity and cytoplasmic Skp2 expression may be causative for cancer progression.

| S-EPMC2910589 | biostudies-literature

Microbiota modulation counteracts Alzheimer's disease progression influencing neuronal proteolysis and gut hormones plasma levels.

Project description:Gut microbiota has a proven role in regulating multiple neuro-chemical pathways through the highly interconnected gut-brain axis. Oral bacteriotherapy thus has potential in the treatment of central nervous system-related pathologies, such as Alzheimer's disease (AD). Current AD treatments aim to prevent onset, delay progression and ameliorate symptoms. In this work, 3xTg-AD mice in the early stage of AD were treated with SLAB51 probiotic formulation, thereby affecting the composition of gut microbiota and its metabolites. This influenced plasma concentration of inflammatory cytokines and key metabolic hormones considered therapeutic targets in neurodegeneration. Treated mice showed partial restoration of two impaired neuronal proteolytic pathways (the ubiquitin proteasome system and autophagy). Their cognitive decline was decreased compared with controls, due to a reduction in brain damage and reduced accumulation of amyloid beta aggregates. Collectively, our results clearly prove that modulation of the microbiota induces positive effects on neuronal pathways that are able to slow down the progression of Alzheimer's disease.

| S-EPMC5445077 | biostudies-literature

Polycomb protein SCML2 associates with USP7 and counteracts histone H2A ubiquitination in the XY chromatin during male meiosis.

Project description:Polycomb group proteins mediate transcriptional silencing in diverse developmental processes. Sex chromosomes undergo chromosome-wide transcription silencing during male meiosis. Here we report that mouse SCML2 (Sex comb on midleg-like 2), an X chromosome-encoded polycomb protein, is specifically expressed in germ cells, including spermatogonia, spermatocytes, and round spermatids. SCML2 associates with phosphorylated H2AX and localizes to the XY body in spermatocytes. Loss of SCML2 in mice causes defective spermatogenesis, resulting in sharply reduced sperm production. SCML2 interacts with and recruits a deubiquitinase, USP7, to the XY body in spermatocytes. In the absence of SCML2, USP7 fails to accumulate on the XY body, whereas H2A monoubiquitination is dramatically augmented in the XY chromatin. Our results demonstrate that the SCML2/USP7 complex constitutes a novel molecular pathway in modulating the epigenetic state of sex chromosomes during male meiosis.

| S-EPMC4310598 | biostudies-literature

Molecular mechanism for USP7-mediated DNMT1 stabilization by acetylation.

Project description:DNMT1 is an important epigenetic regulator that plays a key role in the maintenance of DNA methylation. Here we determined the crystal structure of DNMT1 in complex with USP7 at 2.9?Å resolution. The interaction between the two proteins is primarily mediated by an acidic pocket in USP7 and Lysine residues within DNMT1's KG linker. This intermolecular interaction is required for USP7-mediated stabilization of DNMT1. Acetylation of the KG linker Lysine residues impair DNMT1-USP7 interaction and promote the degradation of DNMT1. Treatment with HDAC inhibitors results in an increase in acetylated DNMT1 and decreased total DNMT1 protein. This negative correlation is observed in differentiated neuronal cells and pancreatic cancer cells. Our studies reveal that USP7-mediated stabilization of DNMT1 is regulated by acetylation and provide a structural basis for the design of inhibitors, targeting the DNMT1-USP7 interaction surface for therapeutic applications.

| S-EPMC4432644 | biostudies-literature

IKK and NF-kappaB-mediated regulation of Claspin impacts on ATR checkpoint function.

Project description:In response to replication stress, Claspin mediates the phosphorylation and activation of Chk1 by ATR. Claspin is not only necessary for the propagation of the DNA-damage signal, but its destruction by the ubiquitin-proteosome pathway is required to allow the cell to continue the cell cycle allowing checkpoint recovery. Here, we demonstrate that both the NF-kappaB family of transcription factors and their upstream kinase IKK can regulate Claspin levels by controlling its mRNA expression. Furthermore, we show that c-Rel directly controls Claspin gene transcription. Disruption of IKK and specific NF-kappaB members impairs ATR-mediated checkpoint function following DNA damage. Importantly, hyperactivation of IKK results in a failure to inactivate Chk1 and impairs the recovery from the DNA checkpoint. These results uncover a novel function for IKK and NF-kappaB modulating the DNA-damage checkpoint response, allowing the cell to integrate different signalling pathways with the DNA-damage response.

| S-EPMC2944043 | biostudies-literature

HSV ICP0 recruits USP7 to modulate TLR-mediated innate response.

Project description:Pattern recognition receptors represent the first line of defense against invading pathogens. Herpes simplex virus (HSV) encodes multiple ligands detected by these receptors, yet persists in the majority of infected individuals indicating a breakdown in host defense against the virus. Here we identify a novel mechanism through which HSV immediate-early protein ICP0 inhibits TLR-dependent inflammatory response by blocking NF-kappaB and JNK activation downstream of TLR signal activation. This process depends on ICP0-mediated translocation of USP7 (HAUSP) from the nucleus to cytoplasm. We show that nuclear USP7 migrates to the cytoplasm in response to TLR engagement, a process that contributes to termination of TLR response. Cytoplasmic USP7 binds to and deubiquitinates TRAF6 and IKKgamma, thus terminating TLR-mediated NF-kappaB and JNK activation. These findings suggest that USP7 is part of a negative feedback loop regulating TLR signaling and that ICP0 exploits this physiologic process to attenuate innate response to HSV. ICP0 inhibition of the TLR response serves to uncouple the innate and adaptive immune response, thereby playing a key role in HSV pathogenesis and persistence.

| S-EPMC3401030 | biostudies-literature

TSPY1 suppresses USP7-mediated p53 function and promotes spermatogonial proliferation.

Project description:Testis-specific protein Y-linked 1 (TSPY1) is expressed predominantly in adult human spermatogonia and functions in the process of spermatogenesis; however, our understanding of the underlying mechanism is limited. Here we observed that TSPY1, as an interacting partner of TSPY-like 5 (TSPYL5), enhanced the competitive binding of TSPYL5 to ubiquitin-specific peptidase 7 (USP7) in conjunction with p53. This activity, together with its promotion of TSPYL5 expression by acting as a transcription factor, resulted in increased p53 ubiquitylation. Moreover, TSPY1 could decrease the p53 level by inducing the degradation of ubiquitinated USP7. We demonstrated that the promotion of p53 degradation by TSPY1 influenced the activity of p53 target molecules (CDK1, p21, and BAX) to expedite the G2/M phase transition and decrease cell apoptosis, accelerating cell proliferation. Taken together, the observations reveal the significance of TSPY1 as a suppressor of USP7-mediated p53 function in inhibiting p53-dependent cell proliferation arrest. By simulating TSPY1 function in Tspy1-deficient spermatogonia derived from mouse testes, we found that TSPY1 could promote spermatogonial proliferation by decreasing the Usp7-modulated p53 level. The findings suggest an additional mechanism underlying the regulation of spermatogonial p53 function, indicating the significance of TSPY1 in germline homeostasis maintenance and the potential of TSPY1 in regulating human spermatogonial proliferation via the USP7-mediated p53 signaling pathway.

| S-EPMC5945610 | biostudies-literature

Cellular contractility requires ubiquitin mediated proteolysis.

Project description:BACKGROUND:Cellular contractility, essential for cell movement and proliferation, is regulated by microtubules, RhoA and actomyosin. The RhoA dependent kinase ROCK ensures the phosphorylation of the regulatory Myosin II Light Chain (MLC) Ser19, thereby activating actomyosin contractions. Microtubules are upstream inhibitors of contractility and their depolymerization or depletion cause cells to contract by activating RhoA. How microtubule dynamics regulates RhoA remains, a major missing link in understanding contractility. PRINCIPAL FINDINGS:We observed that contractility is inhibited by microtubules not only, as previously reported, in adherent cells, but also in non-adhering interphase and mitotic cells. Strikingly we observed that contractility requires ubiquitin mediated proteolysis by a Cullin-RING ubiquitin ligase. Inhibition of proteolysis, ubiquitination and neddylation all led to complete cessation of contractility and considerably reduced MLC Ser19 phosphorylation. CONCLUSIONS:Our results imply that cells express a contractility inhibitor that is degraded by ubiquitin mediated proteolysis, either constitutively or in response to microtubule depolymerization. This degradation seems to depend on a Cullin-RING ubiquitin ligase and is required for cellular contractions.

| S-EPMC2705188 | biostudies-literature

RIT1 oncoproteins escape LZTR1-mediated proteolysis.

Project description:RIT1 oncoproteins have emerged as an etiologic factor in Noonan syndrome and cancer. Despite the resemblance of RIT1 to other members of the Ras small guanosine triphosphatases (GTPases), mutations affecting RIT1 are not found in the classic hotspots but rather in a region near the switch II domain of the protein. We used an isogenic germline knock-in mouse model to study the effects of RIT1 mutation at the organismal level, which resulted in a phenotype resembling Noonan syndrome. By mass spectrometry, we detected a RIT1 interactor, leucine zipper-like transcription regulator 1 (LZTR1), that acts as an adaptor for protein degradation. Pathogenic mutations affecting either RIT1 or LZTR1 resulted in incomplete degradation of RIT1. This led to RIT1 accumulation and dysregulated growth factor signaling responses. Our results highlight a mechanism of pathogenesis that relies on impaired protein degradation of the Ras GTPase RIT1.

| S-EPMC6986682 | 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