Novel Insights into the Role of UBE3A in Regulating Apoptosis and Proliferation

The UBE3A gene codes for a protein with two known functions, a ubiquitin E3-ligase which catalyzes ubiquitin binding to substrate proteins and a steroid hormone receptor coactivator. UBE3A is most famous for its critical role in neuronal functioning. Lack of UBE3A protein expression leads to Angelman syndrome (AS), while its overexpression is associated with autism. In spite of extensive research, our understanding of UBE3A roles is still limited. We investigated the cellular and molecular effects of Ube3a deletion in mouse embryonic fibroblasts (MEFs) and Angelman syndrome (AS) mouse model hippocampi. Cell cultures of MEFs exhibited enhanced proliferation together with reduced apoptosis when Ube3a was deleted. These findings were supported by transcriptome and proteome analyses. Furthermore, transcriptome analyses revealed alterations in mitochondria-related genes. Moreover, an analysis of adult AS model mice hippocampi also found alterations in the expression of apoptosis- and proliferation-associated genes. Our findings emphasize the role UBE3A plays in regulating proliferation and apoptosis and sheds light into the possible effects UBE3A has on mitochondrial involvement in governing this balance.

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Critical Role of PDE4D in β2-Adrenoceptor-dependent cAMP Signaling in Mouse Embryonic Fibroblasts

Journal of Biological Chemistry ◽

10.1074/jbc.m803306200 ◽

2008 ◽

Vol 283 (33) ◽

pp. 22430-22442 ◽

Cited By ~ 36

Author(s):

Matthew D. Bruss ◽

Wito Richter ◽

Kathleen Horner ◽

S.-L. Catherine Jin ◽

Marco Conti

Keyword(s):

Critical Role ◽

Camp Signaling ◽

Mouse Embryonic Fibroblasts ◽

Embryonic Fibroblasts

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Angelman Syndrome

10.1093/med/9780199937837.003.0055 ◽

2017 ◽

Author(s):

Kristin W. Barañano

Keyword(s):

Angelman Syndrome ◽

Expressive Language ◽

Neurodevelopmental Disorder ◽

Synaptic Function ◽

Gait Disorder ◽

Ataxic Gait ◽

Synaptic Circuits ◽

Ubiquitin E3 Ligase ◽

Time Treatment

Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by maternal deficiency of the epigenetically imprinted gene UBE3A. It is characterized by severe developmental delay, an ataxic gait disorder, an apparent happy demeanor with frequent smiling or laughing, and severe expressive language impairments. Understanding the neurobiology of AS has focused on understanding how UBE3A is regulated by neuronal activity, as well as the targets of its ubiquitin E3 ligase activity. This has led to a model of the role of UBE3A in the regulation of experience-dependent sculpting of synaptic circuits. At this time, treatment is largely supportive, but efforts directed toward reversing the epigenetic silencing machinery may lead to improved synaptic function in AS patients.

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c-Cbl: An Important Regulator and a Target in Angiogenesis and Tumorigenesis

Cells ◽

10.3390/cells8050498 ◽

2019 ◽

Vol 8 (5) ◽

pp. 498 ◽

Cited By ~ 9

Author(s):

Chimera L. Lyle ◽

Mostafa Belghasem ◽

Vipul C. Chitalia

Keyword(s):

Therapeutic Potential ◽

Critical Role ◽

Modular Function ◽

Signaling Cascades ◽

Solid Organ ◽

Multifunctional Protein ◽

Ubiquitin E3 Ligase ◽

Important Regulator ◽

B Lineage

Casitas B lineage lymphoma (c-Cbl) is a multifunctional protein with a ubiquitin E3 ligase activity capable of degrading diverse sets of proteins. Although previous work had focused mainly on c-Cbl mutations in humans with hematological malignancies, recent emerging evidence suggests a critical role of c-Cbl in angiogenesis and human solid organ tumors. The combination of its unique structure, modular function, and ability to channelize cues from a rich network of signaling cascades, empowers c-Cbl to assume a central role in these disease models. This review consolidates the structural and functional insights based on recent studies that highlight c-Cbl as a target with tantalizing therapeutic potential in various models of angiogenesis and tumorigenesis.

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Loss of nuclear UBE3A activity is the predominant cause of Angelman syndrome in individuals carrying UBE3A missense mutations

Human Molecular Genetics ◽

10.1093/hmg/ddab050 ◽

2021 ◽

Author(s):

Stijn N V Bossuyt ◽

A Mattijs Punt ◽

Ilona J de Graaf ◽

Janny van den Burg ◽

Mark G Williams ◽

...

Keyword(s):

Catalytic Activity ◽

Angelman Syndrome ◽

Neurodevelopmental Disorder ◽

Critical Role ◽

Rapid Assessment ◽

Missense Mutations ◽

Catalytic Potential ◽

Ubiquitin Ligase Activity ◽

Ube3a Gene

Abstract Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by deletion (~75%) or mutation (~10%) of the UBE3A gene, which encodes a HECT type E3 ubiquitin protein ligase. Although the critical substrates of UBE3A are unknown, previous studies have suggested a critical role of nuclear UBE3A in AS pathophysiology. Here we investigated to what extent UBE3A missense mutations disrupt UBE3A subcellular localization as well as catalytic activity, stability and protein folding. Our functional screen of 31 UBE3A missense mutants revealed that UBE3A mislocalization is the predominant cause of UBE3A dysfunction, accounting for 55% of the UBE3A mutations tested. The second major cause (29%) is a loss of E3-ubiquitin ligase activity, as assessed in an E. coli in vivo ubiquitination assay. Mutations affecting catalytic activity are found not only in the catalytic HECT domain, but also in the N-terminal half of UBE3A, suggesting an important contribution of this N-terminal region to its catalytic potential. Together, our results show that loss of nuclear UBE3A E3 ligase activity is the predominant cause of UBE3A-linked Angelman syndrome. Moreover, our functional analysis screen allows rapid assessment of the pathogenicity of novel UBE3A missense variants which will be of particular importance when treatments for AS become available.

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Critical role of nitric oxide for proliferation and apoptosis of bone-marrow cells under septic conditions

Annals of Hematology ◽

10.1007/s002770050588 ◽

2000 ◽

Vol 79 (5) ◽

pp. 249-254 ◽

Cited By ~ 9

Author(s):

W. Barthlen ◽

C. Klemens ◽

S. Rogenhofer ◽

J. Stadler ◽

N. Unbehaun ◽

...

Keyword(s):

Nitric Oxide ◽

Bone Marrow ◽

Bone Marrow Cells ◽

Critical Role ◽

Proliferation And Apoptosis ◽

Marrow Cells

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Bioinformatics Analyses of the Transcriptome Reveal Ube3a-Dependent Effects on Mitochondrial-Related Pathways

International Journal of Molecular Sciences ◽

10.3390/ijms21114156 ◽

2020 ◽

Vol 21 (11) ◽

pp. 4156 ◽

Cited By ~ 1

Author(s):

Julia Panov ◽

Lilach Simchi ◽

Yonatan Feuermann ◽

Hanoch Kaphzan

Keyword(s):

Oxidative Stress ◽

Angelman Syndrome ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Learning Approaches ◽

Bioinformatics Analyses ◽

Ubiquitin E3 Ligase ◽

15Q Duplication ◽

Ube3a Gene ◽

Baseline State

The UBE3A gene encodes the ubiquitin E3-ligase protein, UBE3A, which is implicated in severe neurodevelopmental disorders. Lack of UBE3A expression results in Angelman syndrome, while UBE3A overexpression, due to genomic 15q duplication, results in autism. The cellular roles of UBE3A are not fully understood, yet a growing body of evidence indicates that these disorders involve mitochondrial dysfunction and increased oxidative stress. We utilized bioinformatics approaches to delineate the effects of murine Ube3a deletion on the expression of mitochondrial-related genes and pathways. For this, we generated an mRNA sequencing dataset from mouse embryonic fibroblasts (MEFs) in which both alleles of Ube3a gene were deleted and their wild-type controls. Since oxidative stress and mitochondrial dysregulation might not be exhibited in the resting baseline state, we also activated mitochondrial functioning in the cells of these two genotypes using TNFα application. Transcriptomes of the four groups of MEFs, Ube3a+/+ and Ube3a−/−, with or without the application of TNFα, were analyzed using various bioinformatics tools and machine learning approaches. Our results indicate that Ube3a deletion affects the gene expression profiles of mitochondrial-associated pathways. We further confirmed these results by analyzing other publicly available human transcriptome datasets of Angelman syndrome and 15q duplication syndrome.

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The SAM Domains of Anks Family Proteins Are Critically Involved in Modulating the Degradation of EphA Receptors

Molecular and Cellular Biology ◽

10.1128/mcb.01605-09 ◽

2010 ◽

Vol 30 (7) ◽

pp. 1582-1592 ◽

Cited By ~ 28

Author(s):

Jieun Kim ◽

Haeryung Lee ◽

Yujin Kim ◽

Sooyeon Yoo ◽

Eunjeong Park ◽

...

Keyword(s):

Potential Role ◽

Critical Role ◽

Dominant Negative ◽

Eph Receptors ◽

Wild Type ◽

Embryonic Fibroblasts ◽

Sam Domain ◽

Ligand Stimulation ◽

The Stability

ABSTRACT We recently reported that the phosphotyrosine-binding (PTB) domain of Anks family proteins binds to EphA8, thereby positively regulating EphA8-mediated signaling pathways. In the current study, we identified a potential role for the SAM domains of Anks family proteins in EphA signaling. We found that SAM domains of Anks family proteins directly bind to ubiquitin, suggesting that Anks proteins regulate the degradation of ubiquitinated EphA receptors. Consistent with the role of Cbl ubiquitin ligases in the degradation of Eph receptors, our results revealed that the ubiquitin ligase c-Cbl induced the ubiquitination and degradation of EphA8 upon ligand binding. Ubiquitinated EphA8 also bound to the SAM domains of Odin, a member of the Anks family proteins. More importantly, the overexpression of wild-type Odin protected EphA8 and EphA2 from undergoing degradation following ligand stimulation and promoted EphA-mediated inhibition of cell migration. In contrast, a SAM domain deletion mutant of Odin strongly impaired the function of endogenous Odin, suggesting that the mutant functions in a dominant-negative manner. An analysis of Odin-deficient primary embryonic fibroblasts indicated that Odin levels play a critical role in regulating the stability of EphA2 in response to ligand stimulation. Taken together, our studies suggest that the SAM domains of Anks family proteins play a pivotal role in enhancing the stability of EphA receptors by modulating the ubiquitination process.

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Optineurin mediates delivery of membrane from transferrin receptor-positive endosomes to autophagosomes

10.1101/2022.01.12.476135 ◽

2022 ◽

Author(s):

Megha Bansal ◽

Kapil Sirohi ◽

Shivranjani C Moharir ◽

Ghanshyam Swarup

Keyword(s):

Transferrin Receptor ◽

Control Mechanism ◽

Adaptor Protein ◽

Wild Type ◽

Autophagosome Formation ◽

Embryonic Fibroblasts ◽

Over Expression ◽

Ubiquitin Binding ◽

Quality Control Mechanism

Autophagy is a conserved quality control mechanism that removes damaged proteins, organelles and invading bacteria through lysosome-mediated degradation. During autophagy several organelles including endoplasmic reticulum, mitochondria, plasma membrane and endosomes contribute membrane for autophagosome formation. However, the mechanisms and proteins involved in membrane delivery to autophagosomes are not clear. Optineurin (OPTN), a cytoplasmic adaptor protein, is involved in promoting maturation of phagophores into autophagosomes; it is also involved in regulating endocytic trafficking and recycling of transferrin receptor (TFRC). Here, we have examined the role of optineurin in the delivery of membrane from TFRC-positive endosomes to autophagosomes. Only a small fraction of autophagosomes was positive for TFRC, indicating that TFRC-positive endosomes could contribute membrane to a subset of autophagosomes. The percentage of TFRC-positive autophagosomes was reduced in Optineurin knockout mouse embryonic fibroblasts (Optn-/-MEFs) in comparison with normal MEFs. Upon over-expression of optineurin, the percentage of TFRC-positive autophagosomes was increased in Optn-/- MEFs. Unlike wild-type optineurin, a disease-associated mutant, E478G, defective in ubiquitin binding, was not able to enhance formation of TFRC-positive autophagosomes in Optn-/- MEFs. TFRC degradation mediated by autophagy was decreased in optineurin deficient cells. Our results suggest that optineurin mediates delivery of TFRC and perhaps associated membrane from TFRC-positive endosomes to autophagosomes, and this may contribute to autophagosome formation.

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Ubiquitin E3 Ligase A20 Facilitates Processing Microbial Product in Nasal Epithelial Cells

Journal of Biological Chemistry ◽

10.1074/jbc.m112.392639 ◽

2012 ◽

Vol 287 (42) ◽

pp. 35318-35323 ◽

Cited By ~ 11

Author(s):

Yun-Fang An ◽

Tong-Li Li ◽

Xiao-Rui Geng ◽

Gui Yang ◽

Chang-Qing Zhao ◽

...

Keyword(s):

Epithelial Cells ◽

Critical Role ◽

E3 Ligase ◽

Allergic Diseases ◽

The Body ◽

Epithelial Cell Line ◽

Nasal Epithelial Cells ◽

Ubiquitin E3 Ligase ◽

Microbial Products

Microbial products play a role in the pathogenesis of allergic diseases; ubiquitin E3 ligase A20 (A20) is an important molecule in regulating inflammation in the body. The present study aims to elucidate the role of A20 in processing the absorbed microbial products in nasal epithelial cells. Human nasal mucosal specimens were collected from patients with or without chronic rhinitis and analyzed by immunohistochemistry. Human nasal epithelial cell line, RPMI2650 cell, was employed to assess the role of A20 in processing the absorbed staphylococcal enterotoxin B (SEB). The RPMI2650 cells absorbed SEB in the culture. The increase in A20 was observed in RPMI2650 cells in parallel to the absorption of SEB. A20 is a critical molecule in the degradation of SEB in the nasal epithelial cells by promoting the tethering of endosomes and lysosomes. A20 plays a critical role in processing of the absorbed SEB in nasal epithelial cells.

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