scholarly journals MALT1 cleaves the E3 ubiquitin ligase HOIL-1 in activated T cells, generating a dominant negative inhibitor of LUBAC-induced NF-κB signaling

FEBS Journal ◽  
2015 ◽  
Vol 283 (3) ◽  
pp. 403-412 ◽  
Author(s):  
Lynn Elton ◽  
Isabelle Carpentier ◽  
Jens Staal ◽  
Yasmine Driege ◽  
Mira Haegman ◽  
...  
Keyword(s):  
T Cells ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Dominant Negative ◽  
Activated T Cells ◽  
Dominant Negative Inhibitor

scholarly journals The E3 ubiquitin ligase Cul4b promotes CD4+ T cell expansion by aiding the repair of damaged DNA

PLoS Biology ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. e3001041
Author(s):  
Asif A. Dar ◽  
Keisuke Sawada ◽  
Joseph M. Dybas ◽  
Emily K. Moser ◽  
Emma L. Lewis ◽  
...  
Keyword(s):  
Dna Damage ◽  
T Cells ◽  
T Cell ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Cell Receptor ◽  
Rapid Expansion ◽  
Activated T Cells ◽  
Pathogen Invasion ◽  
Damaged Dna

The capacity for T cells to become activated and clonally expand during pathogen invasion is pivotal for protective immunity. Our understanding of how T cell receptor (TCR) signaling prepares cells for this rapid expansion remains limited. Here we provide evidence that the E3 ubiquitin ligase Cullin-4b (Cul4b) regulates this process. The abundance of total and neddylated Cul4b increased following TCR stimulation. Disruption of Cul4b resulted in impaired proliferation and survival of activated T cells. Additionally, Cul4b-deficient CD4+ T cells accumulated DNA damage. In T cells, Cul4b preferentially associated with the substrate receptor DCAF1, and Cul4b and DCAF1 were found to interact with proteins that promote the sensing or repair of damaged DNA. While Cul4b-deficient CD4+ T cells showed evidence of DNA damage sensing, downstream phosphorylation of SMC1A did not occur. These findings reveal an essential role for Cul4b in promoting the repair of damaged DNA to allow survival and expansion of activated T cells.

scholarly journals Requirement for Transcription Factor NFAT in Interleukin-2 Expression

1999 ◽  
Vol 19 (3) ◽  
pp. 2300-2307 ◽  
Author(s):  
Chi-Wing Chow ◽  
Mercedes Rincón ◽  
Roger J. Davis
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Transcription Factor ◽  
Nuclear Translocation ◽  
Interleukin 2 ◽  
Inhibitory Effect ◽  
Dominant Negative ◽  
Activated T Cells ◽  
Nfat Activation ◽  
Nfat Transcription Factor

ABSTRACT The nuclear factor of activated T cells (NFAT) transcription factor is implicated in expression of the cytokine interleukin-2 (IL-2). Binding sites for NFAT are located in the IL-2 promoter. Furthermore, pharmacological studies demonstrate that the drug cyclosporin A inhibits both NFAT activation and IL-2 expression. However, targeted disruption of the NFAT1 and NFAT2 genes in mice does not cause decreased IL-2 secretion. The role of NFAT in IL-2 gene expression is therefore unclear. Here we report the construction of a dominant-negative NFAT mutant (dnNFAT) that selectively inhibits NFAT-mediated gene expression. The inhibitory effect of dnNFAT is mediated by suppression of activation-induced nuclear translocation of NFAT. Expression of dnNFAT in cultured T cells caused inhibition of IL-2 promoter activity and decreased expression of IL-2 protein. Similarly, expression of dnNFAT in transgenic mice also caused decreased IL-2 gene expression. These data demonstrate that NFAT is a critical component of the signaling pathway that regulates IL-2 expression.

scholarly journals Cbl-b, a RING-type E3 Ubiquitin Ligase, Targets Phosphatidylinositol 3-Kinase for Ubiquitination in T Cells

2000 ◽  
Vol 276 (7) ◽  
pp. 4872-4878 ◽  
Author(s):  
Deyu Fang ◽  
Hong-Ying Wang ◽  
Nan Fang ◽  
Yoav Altman ◽  
Chris Elly ◽  
...  
Keyword(s):  
T Cells ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Phosphatidylinositol 3 Kinase ◽  
Ring Type ◽  
Phosphatidylinositol 3

scholarly journals The E3 Ubiquitin Ligase Cbl-b Regulates Expansion but Not Functional Activity of Self-Reactive CD4 T Cells

2009 ◽  
Vol 183 (8) ◽  
pp. 4975-4983 ◽  
Author(s):  
Marie-Clare St. Rose ◽  
Harry Z. Qui ◽  
Suman Bandyopadhyay ◽  
Marianne A. Mihalyo ◽  
Adam T. Hagymasi ◽  
...  
Keyword(s):  
T Cells ◽  
Ubiquitin Ligase ◽  
Functional Activity ◽  
Cd4 T Cells ◽  
E3 Ubiquitin Ligase

scholarly journals Mice Lacking the Calcineurin Inhibitor Rcan2 Have an Isolated Defect of Osteoblast Function

Endocrinology ◽  
2012 ◽  
Vol 153 (7) ◽  
pp. 3537-3548 ◽  
Author(s):  
J. H. Duncan Bassett ◽  
John G. Logan ◽  
Alan Boyde ◽  
Moira S. Cheung ◽  
Holly Evans ◽  
...  
Keyword(s):  
T Cells ◽  
Bone Development ◽  
Skeletal Development ◽  
Dominant Negative ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Osteoblast Function ◽  
And Function

Calcineurin-nuclear factor of activated T cells signaling controls the differentiation and function of osteoclasts and osteoblasts, and regulator of calcineurin-2 (Rcan2) is a physiological inhibitor of this pathway. Rcan2 expression is regulated by T3, which also has a central role in skeletal development and bone turnover. To investigate the role of Rcan2 in bone development and maintenance, we characterized Rcan2−/− mice and determined its skeletal expression in T3 receptor (TR) knockout and thyroid-manipulated mice. Rcan2−/− mice had normal linear growth but displayed delayed intramembranous ossification, impaired cortical bone formation, and reduced bone mineral accrual during development as well as increased mineralization of adult bone. These abnormalities resulted from an isolated defect in osteoblast function and are similar to skeletal phenotypes of mice lacking the type 2 deiodinase thyroid hormone activating enzyme or with dominant-negative mutations of TRα, the predominant TR isoform in bone. Rcan2 mRNA was expressed in primary osteoclasts and osteoblasts, and its expression in bone was differentially regulated in TRα and TRβ knockout and thyroid-manipulated mice. However, in primary osteoblast cultures, T3 treatment did not affect Rcan2 mRNA expression or nuclear factor of activated T cells c1 expression and phosphorylation. Overall, these studies establish that Rcan2 regulates osteoblast function and its expression in bone is regulated by thyroid status in vivo.

Regulation of nuclear factor of activated T cells by phosphotyrosyl-specific phosphatase activity: a positive effect on HIV-1 long terminal repeat–driven transcription and a possible implication of SHP-1

Blood ◽  
2001 ◽  
Vol 97 (8) ◽  
pp. 2390-2400 ◽  
Author(s):  
Jean-François Fortin ◽  
Benoit Barbeau ◽  
Gilles A. Robichaud ◽  
Marie-Ève Paré ◽  
Anne-Marie Lemieux ◽  
...  
Keyword(s):  
T Cells ◽  
Long Terminal Repeat ◽  
Nuclear Translocation ◽  
Interleukin 2 ◽  
Dominant Negative ◽  
Terminal Repeat ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Nfat Activation ◽  
Hiv 1

Abstract Although protein tyrosine phosphatase (PTP) inhibitors used in combination with other stimuli can induce interleukin 2 (IL-2) production in T cells, a direct implication of nuclear factor of activated T cells (NFAT) has not yet been demonstrated. This study reports that exposure of leukemic T cells and human peripheral blood mononuclear cells to bis-peroxovanadium (bpV) PTP inhibitors markedly induce activation and nuclear translocation of NFAT. NFAT activation by bpV was inhibited by the immunosuppressive drugs FK506 and cyclosporin A, as well as by a specific peptide inhibitor of NFAT activation. Mobility shift assays showed specific induction of the NFAT1 member by bpV molecules. The bpV-mediated NFAT activation was observed to be important for the up-regulation of the human immunodeficiency virus 1 (HIV-1) long terminal repeat (LTR) and the IL-2 promoter; NFAT1 was demonstrated to be particularly important in bpV-dependent positive action on HIV-1 LTR transcription. The active participation of p56lck, ZAP-70, p21ras, and calcium in the bpV-mediated signaling cascade leading to NFAT activation was confirmed, using deficient cell lines and dominant-negative mutants. Finally, overexpression of wild-type SHP-1 resulted in a greatly diminished activation of NFAT by bpV, suggesting an involvement of SHP-1 in the regulation of NFAT activation. These data were confirmed by constitutive NFAT translocation observed in Jurkat cells stably expressing a dominant-negative version of SHP-1. The study proposes that PTP activity attenuates constitutive kinase activities that otherwise would lead to constant NFAT activation and that this activation is participating in HIV-1 LTR stimulation by PTP inhibition.

scholarly journals The E3 Ubiquitin Ligase Cbl-b Limits Nascent Th9 Differentiation

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2222-2222
Author(s):  
Isabelle Cornez ◽  
Sowmya Parampalli Yajnanarayana ◽  
Natascha Hermann-Kleiter ◽  
Stefan Ulrich Schmidt ◽  
Peter Brossart ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ubiquitin Ligase ◽  
Cd4 T Cells ◽  
Lung Inflammation ◽  
E3 Ubiquitin Ligase ◽  
Th9 Cells ◽  
Deficient Mice ◽  
Th9 Cell

Abstract Introduction: Th9 cells are critical mediators of allergy and anti-cancer immunity. The E3 ubiquitin ligase Cbl-b modulates T cell activation via regulation of the T cell receptor (TCR) activation threshold as well as by inducing TGF-β sensitivity, which is a critical differentiation factor for Th9 differentiation. Even though some evidence shows that Cbl-b impairs Th9 differentiation by targeting IL-4 dependent STAT6 activation, a complete suppression of Th9 differentiation in the absence of both STAT6 and Cbl-b is not achieved, implying the involvement of additional mechanisms. In this study, we evaluate the role of Cbl-b in early stages of TGF-β dependent Th9 differentiation. Methods: Th9 cells were generated from WT and cblb-deficient naïve CD4+ T cells. After maximum 3 days in presence of IL-4, TGF-β and anti-IFN-γ antibodies, differentiation was determined by the quantification of cytokines, mainly IL-9, and that of the two required transcription factors for Th9 differentiation, namely IRF4 and PU.1. Microarray assay revealed gene candidates that were further validated by mRNA and protein expression analysis. The functional role of Cbl-b was tested in a Th9-mediated murine lung allergy model, in which mice were challenged by intratracheal injections of house dust mite (HDM) extracts. Results: cblb-deficient naïve T cells more efficiently differentiate into Th9 cells after 3 days in culture, express in parallel PU.1 more intensively compared to WT Th9 cells, while retaining similar expression levels of IRF4, another important Th9 differentiation factor. Increased IL-9 level is not based on cblb -deficient T cell hyperproliferation, as we show an increased IL-9 production per cell by using combination of CFSE with intracellular IL-9 staining. Microarray analysis revealed that RUNX1, a known transcriptional modulator of PU.1, is more rapidly down-regulated in cblb-deficient Th9 cells compared to WT Th9 cells. Accordingly, knocking down RUNX1 by siRNA in naïve CD4+ T cells and subsequently differentiating them into Th9 cells, also induces higher IL-9 expression at the mRNA and protein levels in RUNX1-depleted Th9 cells compared to control scrambled siRNA-nucleofected Th9 cells. In the HDM murine allergy model, cblb-deficient mice have a higher lung inflammation as mirrored by increased eosinophils in the BAL and in the lungs, as well as by increased IgE production in the blood. These are also paralleled by an increased IL-9 expression level in the lungs of the allergic cblb -deficient mice. Conclusions: Cbl-b critically limits Th9 differentiation and may thus be a potential target to modify Th9 cell generation in allergy or cancer. Future studies will validate the molecular link that exists between Cbl-b and the RUNX1-dependent IL-9 expression as well as the in vivo significance of increased Th9 cell differentiation in cblb-deficient animal models of lung inflammation and cancer. Disclosures No relevant conflicts of interest to declare.

scholarly journals Arkadia Activates Smad3/Smad4-Dependent Transcription by Triggering Signal-Induced SnoN Degradation

2007 ◽  
Vol 27 (17) ◽  
pp. 6068-6083 ◽  
Author(s):  
Laurence Levy ◽  
Michael Howell ◽  
Debipriya Das ◽  
Sean Harkin ◽  
Vasso Episkopou ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Transforming Growth Factor ◽  
E3 Ubiquitin Ligase ◽  
Cancer Cell Line ◽  
Transforming Growth Factor Β ◽  
Dominant Negative ◽  
Luciferase Reporter ◽  
Dominant Negative Mutant ◽  
Esophageal Cancer Cell ◽  
Esophageal Cancer Cell Line

ABSTRACT E3 ubiquitin ligases play important roles in regulating transforming growth factor β (TGF-β)/Smad signaling. Screening of an E3 ubiquitin ligase small interfering RNA library, using TGF-β induction of a Smad3/Smad4-dependent luciferase reporter as a readout, revealed that Arkadia is an E3 ubiquitin ligase that is absolutely required for this TGF-β response. Knockdown of Arkadia or overexpression of a dominant-negative mutant completely abolishes transcription from Smad3/Smad4-dependent reporters, but not from Smad1/Smad4-dependent reporters or from reporters driven by Smad2/Smad4/FoxH1 complexes. We show that Arkadia specifically activates transcription via Smad3/Smad4 binding sites by inducing degradation of the transcriptional repressor SnoN. Arkadia is essential for TGF-β-induced SnoN degradation, but it has little effect on SnoN levels in the absence of signal. Arkadia interacts with SnoN and induces its ubiquitination irrespective of TGF-β/Activin signaling, but SnoN is efficiently degraded only when it forms a complex with both Arkadia and phosphorylated Smad2 or Smad3. Finally, we describe an esophageal cancer cell line (SEG-1) that we show has lost Arkadia expression and is deficient for SnoN degradation. Reintroduction of wild-type Arkadia restores TGF-β-induced Smad3/Smad4-dependent transcription and SnoN degradation in these cells, raising the possibility that loss of Arkadia function may be relevant in cancer.

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