Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

RanGTP aids anaphase entry through Ubr5-mediated protein turnover.

ABSTRACT: RanGTP is known to regulate the spindle assembly checkpoint (SAC), but the underlying molecular mechanism is unclear. BuGZ stabilizes SAC protein Bub3 through direct interaction and facilitates its mitotic function. Here we show that RanGTP promotes the turnover of BuGZ and Bub3 in metaphase, which in turn facilitates metaphase-to-anaphase transition. BuGZ and Bub3 interact with either importin-? or an E3 ubiquitin ligase, Ubr5. RanGTP promotes the dissociation of importin-? from BuGZ and Bub3 in metaphase. This results in increased binding of BuGZ and Bub3 to Ubr5, leading to ubiquitination and subsequent turnover of both proteins. We propose that elevated metaphase RanGTP levels use Ubr5 to couple overall chromosome congression to SAC silencing.

SUBMITTER: Jiang H

PROVIDER: S-EPMC4602037 | biostudies-literature | 2015 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

RanGTP aids anaphase entry through Ubr5-mediated protein turnover.

Jiang Hao H He Xiaonan X Feng Di D Zhu Xueliang X Zheng Yixian Y

The Journal of cell biology 20151005 1

RanGTP is known to regulate the spindle assembly checkpoint (SAC), but the underlying molecular mechanism is unclear. BuGZ stabilizes SAC protein Bub3 through direct interaction and facilitates its mitotic function. Here we show that RanGTP promotes the turnover of BuGZ and Bub3 in metaphase, which in turn facilitates metaphase-to-anaphase transition. BuGZ and Bub3 interact with either importin-β or an E3 ubiquitin ligase, Ubr5. RanGTP promotes the dissociation of importin-β from BuGZ and Bub3 i ...[more]

PMID: 26438829

Similar Datasets

C9orf72 protein quality control by UBR5-mediated heterotypic ubiquitin chains

Project description:Hexanucleotide repeat expansions within C9orf72 are a frequent cause of amyotrophic lateral sclerosis and frontotemporal dementia. Haploinsufficiency leading to reduced C9orf72 protein contributes to disease pathogenesis. C9orf72 binds SMCR8 to form a robust complex that regulates small GTPases, lysosomal integrity and autophagy. In contrast to this functional understanding, we know far less about assembly and turnover of the C9orf72-SMCR8 complex. Loss of either subunit causes the concurrent ablation of the respective partner. However, the molecular mechanism underlying this interdependence remains elusive. Here, we identify C9orf72 as substrate of branched ubiquitin chain-dependent protein quality control. We find that SMCR8 prevents C9orf72 from rapid degradation by the proteasome. Mass spectrometry and biochemical analyses reveal the E3 ligase UBR5 and the BAG6 chaperone complex as C9orf72 interacting proteins, which are components of the machinery that modifies proteins with K11/K48-linked heterotypic ubiquitin chains. Depletion of UBR5 results in reduced K11/K48 ubiquitination and increased C9orf72 when SMCR8 is absent. Our data provides novel insights into C9orf72 regulation with potential implication for strategies to antagonize C9orf72 loss during disease progression.

| S-SCDT-10_15252-EMBR_202255895 | biostudies-other

Protein phosphatase 2A (PP2A) promotes anaphase entry after DNA replication stress in budding yeast.

Project description:DNA replication stress activates the S-phase checkpoint that arrests the cell cycle, but it is poorly understood how cells recover from this arrest. Cyclin-dependent kinase (CDK) and protein phosphatase 2A (PP2A) are key cell cycle regulators, and Cdc55 is a regulatory subunit of PP2A in budding yeast. We found that yeast cells lacking functional PP2ACdc55 showed slow growth in the presence of hydroxyurea (HU), a DNA synthesis inhibitor, without obvious viability loss. Moreover, PP2A mutants exhibited delayed anaphase entry and sustained levels of anaphase inhibitor Pds1 after HU treatment. A DNA damage checkpoint Chk1 phosphorylates and stabilizes Pds1. We show that chk1Δ and mutation of the Chk1 phosphorylation sites in Pds1 largely restored efficient anaphase entry in PP2A mutants after HU treatment. In addition, deletion of SWE1, which encodes the inhibitory kinase for CDK or mutation of the Swe1 phosphorylation site in CDK (cdc28F19), also suppressed the anaphase entry delay in PP2A mutants after HU treatment. Our genetic data suggest that Swe1/CDK acts upstream of Pds1. Surprisingly, cdc55Δ showed significant suppression to the viability loss of S-phase checkpoint mutants during DNA synthesis block. Together, our results uncover a PP2A-Swe1-CDK-Chk1-Pds1 axis that promotes recovery from DNA replication stress.

| S-EPMC8694091 | biostudies-literature

Akt1 promotes stimuli-induced endothelial-barrier protection through FoxO-mediated tight-junction protein turnover.

Project description:Vascular permeability regulated by the vascular endothelial growth factor (VEGF) through endothelial-barrier junctions is essential for inflammation. Mechanisms regulating vascular permeability remain elusive. Although 'Akt' and 'Src' have been implicated in the endothelial-barrier regulation, it is puzzling how both agents that protect and disrupt the endothelial-barrier activate these kinases to reciprocally regulate vascular permeability. To delineate the role of Akt1 in endothelial-barrier regulation, we created endothelial-specific, tamoxifen-inducible Akt1 knockout mice and stable ShRNA-mediated Akt1 knockdown in human microvascular endothelial cells. Akt1 loss leads to decreased basal and angiopoietin1-induced endothelial-barrier resistance, and enhanced VEGF-induced endothelial-barrier breakdown. Endothelial Akt1 deficiency resulted in enhanced VEGF-induced vascular leakage in mice ears, which was rescued upon re-expression with Adeno-myrAkt1. Furthermore, co-treatment with angiopoietin1 reversed VEGF-induced vascular leakage in an Akt1-dependent manner. Mechanistically, our study revealed that while VEGF-induced short-term vascular permeability is independent of Akt1, its recovery is reliant on Akt1 and FoxO-mediated claudin expression. Pharmacological inhibition of FoxO transcription factors rescued the defective endothelial barrier due to Akt1 deficiency. Here we provide novel insights on the endothelial-barrier protective role of VEGF in the long term and the importance of Akt1-FoxO signaling on tight-junction stabilization and prevention of vascular leakage through claudin expression.

| S-EPMC5023469 | biostudies-literature

The Apc5 subunit of the anaphase-promoting complex/cyclosome interacts with poly(A) binding protein and represses internal ribosome entry site-mediated translation.

Project description:The anaphase-promoting complex/cyclosome (APC/C) is a multisubunit ubiquitin ligase that mediates the proteolysis of cell cycle proteins in mitosis and G(1). We used a yeast three-hybrid screen to identify proteins that interact with the internal ribosome entry site (IRES) of platelet-derived growth factor 2 mRNA. Surprisingly, this screen identified Apc5, although it does not harbor a classical RNA binding domain. We found that Apc5 binds the poly(A) binding protein (PABP), which directly binds the IRES element. PABP was found to enhance IRES-mediated translation, whereas Apc5 overexpression counteracted this effect. In addition to its association with the APC/C complex, Apc5 binds much heavier complexes and cosediments with the ribosomal fraction. In contrast to Apc3, which is associated only with the APC/C and remains intact during differentiation, Apc5 is degraded upon megakaryocytic differentiation in correlation with IRES activation. Expression of Apc5 in differentiated cells abolished IRES activation. This is the first report implying an additional role for an APC/C subunit, apart from its being part of the APC/C complex.

| S-EPMC387753 | biostudies-literature

MicroRNA-361-5p slows down gliomas development through regulating UBR5 to elevate ATMIN protein expression.

Project description:MicroRNA (miR)-361-5p has been studied to suppress gliomas development. Based on that, an insight into the regulatory mechanism of miR-361-5p in gliomas was supplemented from ubiquitin protein ligase E3 component N-recognin 5 (UBR5)-mediated ubiquitination of ataxia-telangiectasia mutated interactor (ATMIN). miR-361-5p, ATMIN, and UBR5 levels were clinically analyzed in gliomas tissues, which were further validated in gliomas cell lines. Loss/gain-of-function method was applied to determine the roles of miR-361-5p and UBR5 in gliomas, as to cell viability, migration, invasion, colony formation ability, and apoptosis in vitro and tumorigenesis in vivo. The relationship between miR-361-5p and UBR5 was verified and the interaction between UBR5 and ATMIN was explored. It was detected that reduced miR-361-5p and ATMIN and enhanced UBR5 levels showed in gliomas. Elevating miR-361-5p was repressive in gliomas progression. UBR5 was directly targeted by miR-361-5p. UBR5 can ubiquitinate ATMIN. miR-361-5p suppressed gliomas by regulating UBR5-mediated ubiquitination of ATMIN. Downregulating UBR5 impeded gliomas tumor growth in vivo. Upregulating miR-361-5p targets UBR5 to promote ATMIN protein expression, thus to recline the malignant phenotype of gliomas cells.

| S-EPMC8319180 | biostudies-literature

Cyclin A1 in Oocytes Prevents Chromosome Segregation And Anaphase Entry.

Project description:In several species, including Xenopus, mouse and human, two members of cyclin A family were identified. Cyclin A2, which is ubiquitously expressed in dividing cells and plays role in DNA replication, entry into mitosis and spindle assembly, and cyclin A1, whose function is less clear and which is expressed in spermatocytes, leukemia cells and in postmitotic multiciliated cells. Deletion of the gene showed that cyclin A1 is essential for male meiosis, but nonessential for female meiosis. Our results revealed, that the cyclin A1 is not only dispensable in oocytes, we show here that its expression is in fact undesirable in these cells. Our data demonstrate that the APC/C and proteasome in oocytes are unable to target sufficiently cyclin A1 before anaphase, which leads into anaphase arrest and direct inhibition of separase. The cyclin A1-induced cell cycle arrest is oocyte-specific and the presence of cyclin A1 in early embryos has no effect on cell cycle progression or chromosome division. Cyclin A1 is therefore not only an important cell cycle regulator with biased expression in germline, being essential for male and damaging for female meiosis, its persistent expression during anaphase in oocytes shows fundamental differences between APC/C function in oocytes and in early embryos.

| S-EPMC7198627 | biostudies-literature

Ciliary entry of the kinesin-2 motor KIF17 is regulated by importin-beta2 and RanGTP.

Project description:The biogenesis, maintenance and function of primary cilia are controlled through intraflagellar transport (IFT) driven by two kinesin-2 family members, the heterotrimeric KIF3A/KIF3B/KAP complex and the homodimeric KIF17 motor. How these motors and their cargoes gain access to the ciliary compartment is poorly understood. Here, we identify a ciliary localization signal (CLS) in the KIF17 tail domain that is necessary and sufficient for ciliary targeting. Similarities between the CLS and classic nuclear localization signals (NLSs) suggest that similar mechanisms regulate nuclear and ciliary import. We hypothesize that ciliary targeting of KIF17 is regulated by a ciliary-cytoplasmic gradient of the small GTPase Ran, with high levels of GTP-bound Ran (RanGTP) in the cilium. Consistent with this, cytoplasmic expression of GTP-locked Ran(G19V) disrupts the gradient and abolishes ciliary entry of KIF17. Furthermore, KIF17 interacts with the nuclear import protein importin-beta2 in a manner dependent on the CLS and inhibited by RanGTP. We propose that Ran has a global role in regulating cellular compartmentalization by controlling the shuttling of cytoplasmic proteins into nuclear and ciliary compartments.

| S-EPMC2896429 | biostudies-literature

Structural and numerical chromosome changes in colon cancer develop through telomere-mediated anaphase bridges, not through mitotic multipolarity.

Project description:Telomere dysfunction has been associated with chromosomal instability in colorectal carcinoma, but the consequences of telomere-dependent instability for chromosome integrity and clonal evolution have been little explored. We show here that abnormally short telomeres lead to a wide spectrum of mitotic disturbances in colorectal cancer cell lines, including anaphase bridging, whole-chromosome lagging, and mitotic multipolarity. These abnormalities were found in both the presence and absence of microsatellite instability. The mean telomere length varied extensively between cells from the same tumor, allowing the establishment of tumor cell subpopulations with highly different frequencies of mitotic disturbances. Anaphase bridging typically resulted in either inter-centromeric chromatin fragmentation or centromere detachment, leading to pericentromeric chromosome rearrangements and loss of whole chromosomes, respectively. There was a strong correlation between anaphase bridges and multipolar mitoses, and the induction of dicentric chromosomes by gamma irradiation and telomerase inhibition led to an elevated frequency of multipolar mitotic spindles, suggesting that multipolarity could result from polyploidization triggered by anaphase bridging. Chromatid segregation in multipolar mitoses was close to random, resulting in frequent nullisomies and nonviable daughter cells. In contrast, there was a high clonogenic survival among cells having gone through anaphase bridging in bipolar mitoses. Bridging of telomere-deficient chromosomes could thus be a major mutational mechanism in colorectal cancer, whereas mitotic multipolarity appears to be a secondary phenomenon that rarely, if ever, contributes to clonal evolution.

| S-EPMC556242 | biostudies-literature

Iron regulatory protein 2 turnover through a nonproteasomal pathway.

Project description:Iron regulatory protein 2 (IRP2) controls the synthesis of many proteins involved in iron metabolism, and the level of IRP2 itself is regulated by varying the rate of its degradation. The proteasome is known to mediate degradation, with specificity conferred by an iron-sensing E3 ligase. Most studies on the degradation of IRP2 have employed cells overexpressing IRP2 and also rendered iron deficient to further increase IRP2 levels. We utilized a sensitive, quantitative assay for IRP2, which allowed study of endogenous IRP2 degradation in HEK293A cells under more physiologic conditions. We found that under these conditions, the proteasome plays only a minor role in the degradation of IRP2, with almost all the IRP2 being degraded by a nonproteasomal pathway. This new pathway is calcium-dependent but is not mediated by calpain. Elevating the cellular level of IRP2 by inducing iron deficiency or by transfection causes the proteasomal pathway to account for the major fraction of IRP2 degradation. We conclude that under physiological, iron-sufficient conditions, the steady-state level of IRP2 in HEK293A cells is regulated by the nonproteasomal pathway.

| S-EPMC3129150 | biostudies-literature

CDK2 Inhibition Causes Anaphase Catastrophe in Lung Cancer through the Centrosomal Protein CP110.

Project description:Aneuploidy is frequently detected in human cancers and is implicated in carcinogenesis. Pharmacologic targeting of aneuploidy is an attractive therapeutic strategy, as this would preferentially eliminate malignant over normal cells. We previously discovered that CDK2 inhibition causes lung cancer cells with more than two centrosomes to undergo multipolar cell division leading to apoptosis, defined as anaphase catastrophe. Cells with activating KRAS mutations were especially sensitive to CDK2 inhibition. Mechanisms of CDK2-mediated anaphase catastrophe and how activated KRAS enhances this effect were investigated. Live-cell imaging provided direct evidence that following CDK2 inhibition, lung cancer cells develop multipolar anaphase and undergo multipolar cell division with the resulting progeny apoptotic. The siRNA-mediated repression of the CDK2 target and centrosome protein CP110 induced anaphase catastrophe of lung cancer cells. In contrast, CP110 overexpression antagonized CDK2 inhibitor-mediated anaphase catastrophe. Furthermore, activated KRAS mutations sensitized lung cancer cells to CDK2 inhibition by deregulating CP110 expression. Thus, CP110 is a critical mediator of CDK2 inhibition-driven anaphase catastrophe. Independent examination of murine and human paired normal-malignant lung tissues revealed marked upregulation of CP110 in malignant versus normal lung. Human lung cancers with KRAS mutations had significantly lower CP110 expression as compared with KRAS wild-type cancers. Thus, a direct link was found between CP110 and CDK2 inhibitor antineoplastic response. CP110 plays a mechanistic role in response of lung cancer cells to CDK2 inhibition, especially in the presence of activated KRAS mutations.

| S-EPMC4433598 | 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