scholarly journals A Role for Neutral Sphingomyelinase-mediated Ceramide Production in T Cell Receptor–induced Apoptosis and Mitogen-activated Protein Kinase–mediated Signal Transduction

1999 ◽  
Vol 189 (10) ◽  
pp. 1581-1589 ◽  
Author(s):  
Laura Tonnetti ◽  
Maria-Concetta Verí ◽  
Ezio Bonvini ◽  
Luciano D'Adamio
Keyword(s):  
T Cell ◽  
Protein Kinase ◽  
T Cell Receptor ◽  
Fumonisin B1 ◽  
Cell Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Tcr Signaling ◽  
Neutral Sphingomyelinase ◽  
Mitogen Activated Protein ◽  
Ceramide Production

Studying apoptosis induced by T cell receptor (TCR) cross-linking in the T cell hybridoma, 3DO, we found both neutral sphingomyelinase activation and production of ceramide upon receptor engagement. Pharmacological inhibition of ceramide production by the fungal toxin, fumonisin B1, impaired TCR-induced interleukin (IL)-2 production and programmed cell death. Addition of either exogenous ceramide or bacterial sphingomyelinase reconstituted both responses. Moreover, specific inactivation of neutral sphingomyelinase by antisense RNA inhibited IL-2 production and mitogen-activated protein kinase activation after TCR triggering. These results suggest that ceramide production by activation of neutral sphingomyelinase is an essential component of the TCR signaling machinery.

scholarly journals ASK1 Mediates Nur77 Expression in T-Cell Receptor Mediated Thymocyte Apoptosis

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 585
Author(s):  
Jianxin Huo ◽  
Shengli Xu ◽  
Kong-Peng Lam
Keyword(s):  
T Cell ◽  
Protein Kinase ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Signaling Cascades ◽  
Signaling Mechanism ◽  
Apoptotic Protein ◽  
Mitogen Activated Protein ◽  
Thymocyte Apoptosis

Apoptosis signal-regulating kinase 1 (ASK1) is a mitogen-activated protein kinase kinase kinase (MAPKKK) that activates downstream JNK and p38 mitogen-activated protein kinase (MAPK) to relay death signals into cells in response to various environmental stress. However, whether ASK1 plays a role in T cell receptor (TCR)-mediated apoptosis of thymocytes is unclear. Here, we show that ASK1 is activated upon TCR stimulation and plays an important role in TCR-mediated apoptosis of thymocytes by triggering downstream JNK and p38 signaling cascades. Mechanistically, ASK1-JNK/p38 signaling leads to the upregulation of neuron-derived clone 77 (Nur77), a critical pro-apoptotic protein involved in TCR-mediated apoptosis of thymocytes. Furthermore, we demonstrate that the activation of ASK1 is negatively modulated by Akt upon TCR stimulation. Thus, our results identify a previously unappreciated signaling mechanism involving ASK1 in TCR-mediated apoptosis of thymocytes.

scholarly journals Signal-Transducing Adaptor Molecules STAM1 and STAM2 Are Required for T-Cell Development and Survival

2002 ◽  
Vol 22 (24) ◽  
pp. 8648-8658 ◽  
Author(s):  
Mitsuhiro Yamada ◽  
Naoto Ishii ◽  
Hironobu Asao ◽  
Kazuko Murata ◽  
Chieko Kanazawa ◽  
...  
Keyword(s):  
T Cell ◽  
Protein Kinase ◽  
Double Mutant ◽  
T Cell Development ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Cell Development ◽  
Mitogen Activated Protein Kinase ◽  
Calcium Flux ◽  
Mitogen Activated Protein

ABSTRACT We previously reported that the STAM family members STAM1 and STAM2 are phosphorylated on tyrosine upon stimulation with cytokines through the γc-Jak3 signaling pathway, which is essential for T-cell development. Mice with targeted mutations in either STAM1 or STAM2 show no abnormality in T-cell development, and mice with double mutations for STAM1 and STAM2 are embryonically lethal; therefore, here we generated mice with T-cell-specific double mutations for STAM1 and STAM2 using the Cre/loxP system. These STAM1−/− STAM2−/− mice showed a significant reduction in thymocytes and a profound reduction in peripheral mature T cells. In proliferation assays, thymocytes derived from the double mutant mice showed a defective response to T-cell-receptor (TCR) stimulation by antibodies and/or cytokines, interleukin-2 (IL-2) and IL-7. However, signaling events downstream of receptors for IL-2 and IL-7, such as activations of STAT5, extracellular signal-regulated kinase (ERK), and protein kinase B (PKB)/Akt, and c-myc induction, were normal in the double mutant thymocytes. Upon TCR-mediated stimulation, prolonged activations of p38 mitogen-activated protein kinase and Jun N-terminal protein kinase were seen, but activations of ERK, PKB/Akt, and intracellular calcium flux were normal in the double mutant thymocytes. When the cell viability of cultured thymocytes was assessed, the double mutant thymocytes died more quickly than controls. These results demonstrate that the STAMs are indispensably involved in T-cell development and survival in the thymus through the prevention of apoptosis but are dispensable for the proximal signaling of TCR and cytokine receptors.

scholarly journals The Phosphotyrosine Phosphatase SHP-2 Participates in a Multimeric Signaling Complex and Regulates T Cell Receptor (TCR) coupling to the Ras/Mitogen-activated Protein Kinase (MAPK) Pathway in Jurkat T Cells

1998 ◽  
Vol 187 (9) ◽  
pp. 1417-1426 ◽  
Author(s):  
Julie A. Frearson ◽  
Denis R. Alexander
Keyword(s):  
T Cells ◽  
Protein Kinase ◽  
Tyrosine Phosphorylation ◽  
T Cell Receptor ◽  
Mapk Pathway ◽  
Cell Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Wild Type ◽  
Jurkat T Cells ◽  
Mitogen Activated Protein

Src homology 2 (SH2) domain–containing phosphotyrosine phosphatases (SHPs) are increasingly being shown to play critical roles in protein tyrosine kinase–mediated signaling pathways. The role of SHP-1 as a negative regulator of T cell receptor (TCR) signaling has been established. To further explore the function of the other member of this family, SHP-2, in TCR-mediated events, a catalytically inactive mutant SHP-2 was expressed under an inducible promoter in Jurkat T cells. Expression of the mutant phosphatase significantly inhibited TCR-induced activation of the extracellular-regulated kinase (ERK)-2 member of the mitogen-activated protein kinase (MAPK) family, but had no effect on TCR-ζ chain tyrosine phosphorylation or TCR-elicited Ca2+ transients. Inactive SHP-2 was targeted to membranes resulting in the selective increase in tyrosine phosphorylation of three membrane-associated candidate SHP-2 substrates of 110 kD, 55-60 kD, and 36 kD, respectively. Analysis of immunoprecipitates containing inactive SHP-2 also indicated that the 110-kD and 36-kD Grb-2–associated proteins were putative substrates for SHP-2. TCR-stimulation of Jurkat T cells expressing wild-type SHP-2 resulted in the formation of a multimeric cytosolic complex composed of SHP-2, Grb-2, phosphatidylinositol (PI) 3′-kinase, and p110. A significant proportion of this complex was shown to be membrane associated, presumably as a result of translocation from the cytosol. Catalytically inactive SHP-2, rather than the wild-type PTPase, was preferentially localized in complex with Grb-2 and the p85 subunit of PI 3′-kinase, suggesting that the dephosphorylating actions of SHP-2 may regulate the association of these signaling molecules to the p110 complex. Our results show that SHP-2 plays a critical role in linking the TCR to the Ras/MAPK pathway in Jurkat T cells, and also provide some insight into the molecular interactions of SHP-2 that form the basis of this signal transduction process.

scholarly journals Lck Regulates the Threshold of Activation in Primary T Cells, While both Lck and Fyn Contribute to the Magnitude of the Extracellular Signal-Related Kinase Response

2006 ◽  
Vol 26 (22) ◽  
pp. 8655-8665 ◽  
Author(s):  
Matthew Lovatt ◽  
Andrew Filby ◽  
Valentino Parravicini ◽  
Guy Werlen ◽  
Ed Palmer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Protein Kinase ◽  
Mapk Pathway ◽  
Cell Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Differentiation Potential ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Proximal Signaling

ABSTRACT The src family kinases p56lck (Lck) and p59fyn (Fyn) are the most proximal signaling molecules to be activated downstream of the T-cell receptor. Using an inducible transgenic model, we can regulate the expression of Lck in primary T cells and ask how the signaling cascade and differentiation potential are affected by the absence or the presence of reduced levels of Lck. We show that in naïve T cells, Lck controls the threshold of activation by preferentially regulating multiple signaling pathways that result in the mobilization of Ca2+ through activation of phospholipase C-gamma and protein kinase C as well as activation of the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) pathway. Fyn is also able to stimulate the ERK/MAPK pathway in primary T cells but has little influence on the mobilization of Ca2+. Only Lck efficiently stimulates production of diacylglycerol and therefore RasGRP1 recruitment to the plasma membrane and phosphorylation of Shc, suggesting that Fyn activates ERK via a different upstream signaling route. Finally, we show that signals through Lck are essential for the development of T-cell-effector potential, particularly for effective cytokine transcription.

scholarly journals Dissociation of Intracellular Signaling Pathways in Response to Partial Agonist Ligands of the T Cell Receptor

1998 ◽  
Vol 187 (10) ◽  
pp. 1699-1709 ◽  
Author(s):  
Luan A. Chau ◽  
Jeffrey A. Bluestone ◽  
Joaquín Madrenas
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Intracellular Signaling ◽  
Mapk Pathway ◽  
Partial Agonist ◽  
Cell Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Mapk Activation ◽  
Partial Agonists ◽  
Mitogen Activated Protein

The T cell receptor (TCR) is a versatile receptor able to generate different signals that result in distinct T cell responses. The pattern of early signals is determined by the TCR binding kinetics that control the ability of the ligand to coengage TCR and coreceptor. Coengagement of TCR and CD4 results in an agonist signaling pattern with complete tyrosine phosphorylation of TCR subunits, and recruitment and activation of ZAP-70. In contrast, TCR engagement without CD4 coengagement causes a partial agonist type of signaling, characterized by distinct phosphorylation of TCR subunits and recruitment but no activation of ZAP-70. The pathways triggered by partial agonist signaling are unknown. Here, we show that agonists cause association of active lck and active ZAP-70 with p120-GTPase–activating protein (p120-GAP). These associations follow engagement of CD4 or CD3, respectively. In contrast, partial agonists do not activate lck or ZAP-70, but induce association of p120-GAP with inactive ZAP-70. Despite these differences, both agonist and partial agonist signals activate the mitogen-activated protein kinase (MAPK) pathway. However, MAPK activation by partial agonists is transient, supporting a kinetic, CD4-dependent model for the mechanism of action of variant TCR ligands. Transient MAPK activation may explain some of the responses to TCR partial agonists and antagonists.

scholarly journals Structural Requirements of SLP-76 in Signaling via the High-Affinity Immunoglobulin E Receptor (FcεRI) in Mast Cells

2003 ◽  
Vol 23 (7) ◽  
pp. 2395-2406 ◽  
Author(s):  
Alexander Kettner ◽  
Vadim Pivniouk ◽  
Lalit Kumar ◽  
Hervé Falet ◽  
Jeng-Shin Lee ◽  
...  
Keyword(s):  
T Cell ◽  
Mast Cells ◽  
Immunoglobulin E ◽  
Critical Role ◽  
Cell Receptor ◽  
Sh2 Domain ◽  
Mitogen Activated Protein Kinase ◽  
Tcr Signaling ◽  
Binding Domains ◽  
Mitogen Activated Protein

ABSTRACT The adapter SLP-76 plays an essential role in FcεRI signaling, since SLP-76−/− bone marrow-derived mast cells (BMMC) fail to degranulate and release interleukin-6 (IL-6) following FcεRI ligation. To define the role of SLP-76 domains and motifs in FcεRI signaling, SLP-76−/− BMMC were retrovirally transduced with SLP-76 and SLP-76 mutants. The SLP-76 N-terminal and Gads binding domains, but not the SH2 domain, were critical for FcεRI-mediated degranulation and IL-6 secretion, whereas all three domains are essential for T-cell proliferation following T-cell receptor (TCR) ligation. Unexpectedly, the three tyrosine residues in SLP-76 critical for TCR signaling, Y112, Y128, and Y145, were not essential for IL-6 secretion, but were required for degranulation and mitogen-activated protein kinase activation. Furthermore, a Y112/128F SLP-76 mutant, but not a Y145F mutant, strongly reconstituted mast cell degranulation, suggesting a critical role for Y145 in FcεRI-mediated exocytosis. These results point to important differences in the function of SLP-76 between T cells and mast cells.

scholarly journals Ca2+/Calmodulin-Dependent Protein Kinase II Is a Modulator of CARMA1-Mediated NF-κB Activation

2006 ◽  
Vol 26 (14) ◽  
pp. 5497-5508 ◽  
Author(s):  
Kazuhiro Ishiguro ◽  
Todd Green ◽  
Joseph Rapley ◽  
Heather Wachtel ◽  
Cosmas Giallourakis ◽  
...  
Keyword(s):  
T Cell ◽  
Protein Kinase ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Receptor ◽  
Tcr Signaling ◽  
Dependent Protein Kinase ◽  
Immune Synapse ◽  
Protein Kinase Ii ◽  
Dependent Protein

ABSTRACT CARMA1 is a central regulator of NF-κB activation in lymphocytes. CARMA1 and Bcl10 functionally interact and control NF-κB signaling downstream of the T-cell receptor (TCR). Computational analysis of expression neighborhoods of CARMA1-Bcl10MALT 1 for enrichment in kinases identified calmodulin-dependent protein kinase II (CaMKII) as an important component of this pathway. Here we report that Ca2+/CaMKII is redistributed to the immune synapse following T-cell activation and that CaMKII is critical for NF-κB activation induced by TCR stimulation. Furthermore, CaMKII enhances CARMA1-induced NF-κB activation. Moreover, we have shown that CaMKII phosphorylates CARMA1 on Ser109 and that the phosphorylation facilitates the interaction between CARMA1 and Bcl10. These results provide a novel function for CaMKII in TCR signaling and CARMA1-induced NF-κB activation.

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