The Hao-Fountain syndrome protein USP7 regulates neuronal connectivity in the brain via a novel p53-independent ubiquitin signaling pathway
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ABSTRACT:
PROVIDER: PRJNA1181528 | ENA |
REPOSITORIES: ENA
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Project description:Precise control of protein ubiquitination is essential for brain development, and hence, disruption of ubiquitin signaling networks can lead to neurological disorders. Mutations of the deubiquitinase USP7 cause the Hao-Fountain syndrome (HAFOUS), characterized by developmental delay, intellectual disability, autism, and aggressive behavior. These neurological and behavioral manifestations indicate important unknown roles of USP7 specificially in the nervous system. Here, we report that conditional deletion of USP7 in excitatory neurons in the mouse forebrain triggers diverse phenotypes including growth delay, sensorimotor deficits, learning and memory impairment, and aggressive behavior, resembling clinical features of HAFOUS. USP7 deletion induces neuronal apoptosis in a manner dependent of the tumor suppressor p53. However, most behavioral abnormalities in USP7 conditional mice persist despite p53 loss. Strikingly, USP7 deletion in the brain perturbs the synaptic proteome and dendritic spine morphogenesis independently of p53. Integrated proteomics and subsequent ubiquitin biochemical analysis identify the RNA splicing factor Ppil4 as a novel neuronal substrate of USP7. Consistent with the role of Ppil4 in RNA splicing, loss of USP7 disrupts splicing program of synaptic genes in the cerebral cortex. Improtantly, knockdown of Ppil4 in cortical neurons impairs dendritic spine morphogenesis, phenocopying the effect of USP7 loss on dendritic spines. These findings reveal a novel USP7-Ppil4 ubiquitin signaling link that regulates neuronal connectivity in the developing brain, with implications for our understanding of the pathogenesis of HAFOUS and other neurodevelopmental disorders.
2025-02-25 | GSE280944 | GEO
Project description:Individuals with genetic elimination of MLKL exhibit an increased susceptibility to neurodegenerative diseases like Alzheimer’s disease (AD). However, the specific mechanism behind this relationship is not yet fully understood. Here, we initially observed significant compromise in autophagy in the brains of MLKL knockout (KO) mice, as evidenced by the down-regulation of autophagy-initiation proteins Beclin1 and ULK1. To elucidate the mechanism by which MLKL, primarily a cytosolic protein, regulates the protein levels of Beclin1 and ULK1, we performed a proteomic screening of MLKL-association proteins and identified UBA52 as the binding partner under physiological conditions. Loss of MLKL induces a decrease in ubiquitin levels by preventing UBA52 from producing ubiquitin and the C-terminal ribosomal protein L40. Furthermore, we demonstrated that in the brain, the deubiquitinase (DUB) USP7 mediates the processing of UBA52, which is regulated by MLKL. Knock down (KD) of USP7 or UBA52 showed similar effects on autophagy and ubiquitin levels as MLKL KD/KO. Moreover, our results indicated that the reduction of Beclin1 and ULK1 upon MLKL loss is attributed to a decrease in their lysine 63 (K63)-linked polyubiquitination. Additionally, single-nucleus RNA sequencing revealed that the loss of MLKL resulted in the disruption of multiple neurodegenerative disease-related pathways, including those associated with AD. These results were consistent with the observation of cognitive impairment in MLKL KO mice and exacerbation of AD pathologies in an AD mouse model with MLKL deletion. Taken together, our findings demonstrate that MLKL-USP7-UBA52 signaling is required for autophagy in brain through maintaining ubiquitin homeostasis, and highlight the contribution of MLKL loss-induced ubiquitin deficits to the development of neurodegeneration. Thus, the maintenance of adequate levels of ubiquitin may provide a novel perspective to protect individuals from multiple neurodegenerative diseases through regulating autophagy.
2025-01-29 | GSE270139 | GEO
Project description:The AAA+ ATPase VCP regulates the extraction of SUMO and/or ubiquitin modified factors from chromatin. We previously showed that active DNA synthesis is associated with a SUMO-high and ubiquitin-low environment that is maintained by the deubiquitylase USP7. Here we unveil a functional cooperation between USP7 and VCP in the control of DNA replication conserved from Caenorhabditis elegans to mammals. The function of VCP during DNA replication is mediated by its cofactor FAF1, which facilitates the extraction of SUMOylated proteins that accumulate on chromatin upon USP7 inhibition. Supporting this cooperative role, the inactivation of the orthologues of USP7 and FAF1 is synthetic lethal in C. elegans, and USP7 and FAF1 inhibitors display synergistic toxicity. Together, these results reveal a coordinated activity of USP7 and VCPFAF1 in limiting SUMOylation at active replication forks and promoting the extraction and degradation of ubiquitylated proteins.
2021-09-12 | PXD018623 | Pride
Project description:Hundreds of DNA replication forks functioning simultaneously are essential for timely DNA duplication, but the organization of replication forks are poorly understood in mammalian cells. Here, we developed a replication-enriched in situ HiC (Repli-HiC) method to capture chromatin contacts located adjacent to replication forks and found two types of fountain-like chromatin contacts at thousands of loci. Interactions within fountain-spanning regions are confirmed by q3C-seq analysis of different stages of S phase cells.
2024-03-04 | GSE230613 | GEO
Project description:Ubiquitin Specific Peptidase 7 (USP7) is a deubiquitinase of several important regulatory proteins, and important regulator of TGFb pathway. To investigate their role in cell signaling, we analyzed global mRNA levels in HEK293T cells that were knocked down with shRNAs against USP7 and non-targeting control (CTRL).
2020-10-18 | GSE139094 | GEO
Project description:Epstein-Barr virus (EBV) is a ubiquitous human ɣ-herpesvirus implicated in various malignancies, including Burkitt’s lymphoma and gastric carcinomas. In most EBV-associated cancers, the viral genome is maintained as an extrachromosomal episome by the EBV nuclear antigen-1 (EBNA1). EBNA1 is considered to be a highly stable protein that interacts with the ubiquitin-specific protease 7 (USP7), but the precise role of USP7 in controlling EBNA1 stability and function is not fully understood. Here, we show that pharmacological inhibitors and small interfering RNA (siRNA) targeting USP7 reduce EBNA1 protein levels. The USP7 inhibitor GNE6776 altered EBNA1 protein interactions, including disrupting its ability to bind to USP7. GNE6776 also inhibited EBNA1 binding to EBV oriP DNA and reduced viral episome copy number. GNE6776 selectively inhibited EBV+ gastric and lymphoid cell proliferation in cell culture and slowed EBV+ tumor growth in mouse xenograft models. Transcriptomic studies revealed that USP7 inhibition differentially affected EBV+ cancer cells compared to EBV- cells with a significant effect on chromosome segregation and mitotic cell division pathways. Our findings indicate that USP7 inhibition perturbs EBNA1 stability and function and can be exploited to target EBV+ cancer cells selectively.
2025-01-31 | GSE284839 | GEO
Project description:Ubiquitin Specific Protease 7 (USP7), also named as herpesvirus-associated ubiquitin-specific protease (HAUSP), is one of the most abundant deubiquitinase and plays multifaceted roles in many cellular functions, including the protein homeostasis, DNA repair, gene transcription, and oncogenic pathways. To investigate the role of USP7 in p53-deficient lung cancer cells, the CRISPR/Cas9-mediated gene editing was employed to inactivate the USP7 locus in H1299 cells. The alterations of transcriptional enhancers and gene expression were analyzed by H3K27ac ChIP-seq and RNA-seq, respectively, in wildtype and USP7-KO H1299 lung cancer cells.
2021-09-16 | GSE172506 | GEO