E3 ligase substrate adaptor SPOP fine tunes the UPR of pancreatic beta cells
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1186973 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR31369046.fastq.gz | Fastqsanger.gz | |||
| SRR31369047.fastq.gz | Fastqsanger.gz | |||
| SRR31369048.fastq.gz | Fastqsanger.gz | |||
| SRR31369049.fastq.gz | Fastqsanger.gz |
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Project description:The Cullin-3 E3 ligase adaptor protein, SPOP, targets proteins for ubiquitination and proteasomal degradation. We previously established the β cell transcription factor (TF) and human diabetes gene PDX1 as an SPOP substrate, suggesting a functional role for SPOP in the β cell. Here, we generated a β cell specific Spop deletion mouse strain (SpopβKO) and found that Spop is necessary to prevent aberrant basal insulin secretion and for maintaining glucose- stimulated insulin secretion (GSIS) through impacts on glycolysis and glucose-stimulated calcium flux. Integration of proteomic, TF-regulatory gene network and biochemical analyses identified XBP1 as a functionally important SPOP substrate in pancreatic β cells. Further, loss of SPOP strengthened the IRE1α-XBP1 axis of unfolded protein response (UPR) signaling. ER stress promoted proteasomal degradation of SPOP, supporting a model whereby SPOP fine-tunes XBP1 activation during the UPR. These results position SPOP as a regulator of β cell function and proper UPR activation.
2024-12-02 | GSE282084 | GEO
Project description:The Cullin 3 E3 ligase adaptor protein, SPOP, targets proteins for ubiquitination and proteasomal degradation. We previously established the β cell transcription factor (TF) and human diabetes gene PDX1 as an SPOP substrate, suggesting a functional role for SPOP in the β cell. Here, we generated a β cell specific Spop deletion mouse strain (SpopβKO) and found that Spop is necessary to prevent aberrant basal insulin secretion and for maintaining glucose- stimulated insulin secretion (GSIS) through impacts on glycolysis and glucose-stimulated calcium flux. Integration of proteomic, TF-regulatory gene network and biochemical analyses identified XBP1 as a functionally important SPOP substrate in pancreatic β cells.Further, loss of SPOP strengthened the IRE1α-XBP1 axis of unfolded protein response (UPR) signaling. ER stress promoted proteasomal degradation of SPOP, supporting a model whereby SPOP fine-tunes XBP1 activation during the UPR. These results position SPOP as a regulatorof β cell function and proper UPR activation.
2024-11-12 | PXD052527 | Pride
Project description:NUP98-rearranged (NUP98-r) acute myeloid leukemia (AML) is associated with poor clinical outcomes and represents a major therapeutic challenge due to the lack of strategies for the direct elimination of NUP98-fusion oncoproteins. While targeted degradation of cancer-driving oncoproteins is an attractive strategy, the molecular mechanisms controlling NUP98 fusion oncoprotein stability are not known. Here, we used CRISPR/Cas9 screening to identify the E3 ligase SPOP as a direct regulator of NUP98 oncofusion stability and a novel tumor suppressor in NUP98-r AML. SPOP loss caused a selective increase of NUP98 fusion oncoprotein levels, and promoted leukemia cell proliferation. Leveraging this specificity, we show that induced proximity of SPOP and the NUP98::KDM5A fusion oncoprotein via a bioPROTAC approach induced full clearance of the fusion oncoprotein, and drove terminal differentiation and apoptosis of NUP98-r leukemia cells in vitro and in vivo. Altogether, our study identifies the SPOP E3 ligase as a direct regulator of NUP98 oncofusion stability and presents a blueprint for redirecting the ubiquitin proteasome system to selectively target cancer driving fusion oncoproteins.
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Project description:SPOP is a ubiquitin ligase adaptor frequently mutated in prostate cancer. It is involved in ubiquitination and degradation of substrate proteins. We examined the impact of wild-type and mutant SPOP on the transcriptional profile of prostate cancer cells. We cloned several naturally occurring (in human prostate cancer) SPOP mutants and expressed the corresponding constructs in prostate cancer cells. Our experimental conditions were: Human prostate cancer cells (LNCaP-Abl), transfected with control vector, SPOP-wt, and any of the following mutants: SPOP-F102C, SPOP-F133V, SPOP-F133L (2-4 biological replicates each). We analyzed their gene expression profiles for differences induced by SPOP-wt vs SPOP-mutant.
2014-10-10 | E-GEOD-59432 | biostudies-arrayexpress
Project description:The SPOP gene, which encodes an E3 ubiquitin ligase adaptor, is frequently mutated in a number of cancer types. However, the mechanisms by which SPOP functions as a tumor suppressor remain poorly understood. Here, we show that SPOP promotes senescence, an important tumor suppression mechanism, by targeting the SENP7 deSUMOylase for degradation. SPOP is upregulated during senescence. This correlates with ubiquitin-mediated degradation of SENP7, which promotes senescence by increasing HP1α sumoylation and the associated epigenetic gene silencing. Ectopic wild-type SPOP, but not its cancer-associated mutants, drives senescence. Conversely, SPOP knockdown overcomes senescence. These phenotypes correlate with ubiquitination and degradation of SENP7 and HP1α sumoylation, subcellular re-localization, and its associated gene silencing. Furthermore, SENP7 is expressed at higher levels in prostate tumor specimens with SPOP mutation (n = 13) compared to those with wild-type SPOP (n = 80). In summary, SPOP acts as a tumor suppressor by promoting senescence through degrading SENP7.
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Project description:H3K36me3 has been reported to associate with active gene expression, and SETD2 is the mainly methyltransferase for H3K36me3. We identified SPOP which is a CUL3 family protein as a E3 ligase for SETD2. Genome wide analysis by using ChIPSeq and RNASeq demonstrate that SPOP specificly eliminate H3K36me3 modification at target genes and resulted in alternative splicing of those target genes.
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Project description:Reactivation of fetal hemoglobin (HbF) production benefits patients with sickle cell disease and β-thalassemia. To identify new HbF regulators that might be amenable to pharmacologic control, we screened a protein domain-focused CRISPR-Cas9 library targeting chromatin regulators, including BTB domain-containing proteins. Speckle-type POZ protein (SPOP), a substrate adaptor of the CUL3 ubiquitin ligase complex, emerged as a novel HbF repressor. Depletion of SPOP or overexpression of a dominant negative version significantly raised fetal globin messenger RNA and protein levels with minimal detrimental effects on normal erythroid maturation, as determined by transcriptome and proteome analyses. SPOP controls HbF expression independently of the major transcriptional HbF repressors BCL11A and LRF. Finally, pharmacologic HbF inducers cooperate with SPOP depletion during HbF upregulation. Our study implicates SPOP and the CUL3 ubiquitin ligase system in controlling HbF production in human erythroid cells and may offer new therapeutic strategies for the treatment of β-hemoglobinopathies.
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Project description:SPOP is a ubiquitin ligase adaptor frequently mutated in prostate cancer. It is involved in ubiquitination and degradation of substrate proteins. We examined the impact of wild-type and mutant SPOP on the transcriptional profile of prostate cancer cells.
2014-10-10 | GSE59432 | GEO
Project description:Purpose: Little is known about the interplay of driver mutations that never co-occur within the same cancer cells. The latter scenario has been identified in prostate cancer where recurrent gene fusions involving the oncogenic ERG transcription factor and point mutations in the ubiquitin ligase adaptor SPOP are strictly mutually exclusive. We show that ERG and mutant SPOP – even though oncogenic on their own – are together synthetic sick. Description: RNA-Seq of lentiviral-transduced VCaP cells with stable knockdown of wild type SPOP (2 x hairpins) or stable overexpression of either wild-type or mutant SPOP (Y87C, F102C, W131G).
2020-12-05 | E-MTAB-7165 | biostudies-arrayexpress
Project description:The dysregulation of ubiquitin-mediated proteasomal degradation has emerged as an important mechanism of pathogenesis in several cancers. The speckle-type POZ protein (SPOP) functions as a substrate adaptor for the cullin3-RING ubiquitin ligase and controls the cellular persistence of a diverse array of protein substrates in hormone signalling, epigenetic control and cell cycle regulation, to name a few. Mutations in SPOP and the resulting dysregulation of this proteostatic pathway play causative roles in the pathogenesis of prostate and endometrial cancers, whereas overexpression and mislocalization are associated with kidney cancer. Understanding the molecular mechanism of the normal function of SPOP as well as the cause of SPOP-mediated oncogenesis is thus critical for eventual therapeutic targeting of SPOP and other related pathways. Here, we will review SPOP structure, function and the molecular mechanism of how this function is achieved. We will then review how mutations and protein mislocalization contribute to cancer pathogenesis and will provide a perspective on how SPOP may be targeted therapeutically.
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