scholarly journals Identification of a Phospholipase C-γ1 (PLC-γ1) SH3 Domain-Binding Site in SLP-76 Required for T-Cell Receptor-Mediated Activation of PLC-γ1 and NFAT

2001 ◽  
Vol 21 (13) ◽  
pp. 4208-4218 ◽  
Author(s):  
Deborah Yablonski ◽  
Theresa Kadlecek ◽  
Arthur Weiss
Keyword(s):  
T Cell ◽  
Phospholipase C ◽  
T Cell Receptor ◽  
Function Analysis ◽  
Cell Receptor ◽  
Sh3 Domain ◽  
Functional Domain ◽  
Rich Region ◽  
Activated T Cells ◽  
Proline Rich Region

ABSTRACT SLP-76 is an adapter protein required for T-cell receptor (TCR) signaling. In particular, TCR-induced tyrosine phosphorylation and activation of phospholipase C-γ1 (PLC-γ1), and the resultant TCR-inducible gene expression, depend on SLP-76. Nonetheless, the mechanisms by which SLP-76 mediates PLC-γ1 activation are not well understood. We now demonstrate that SLP-76 directly interacts with the Src homology 3 (SH3) domain of PLC-γ1. Structure-function analysis of SLP-76 revealed that each of the previously defined protein-protein interaction domains can be individually deleted without completely disrupting SLP-76 function. Additional deletion mutations revealed a new, 67-amino-acid functional domain within the proline-rich region of SLP-76, which we have termed the P-1 domain. The P-1 domain mediates a constitutive interaction of SLP-76 with the SH3 domain of PLC-γ1 and is required for TCR-mediated activation of Erk, PLC-γ1, and NFAT (nuclear factor of activated T cells). The adjacent Gads-binding domain of SLP-76, also within the proline-rich region, mediates inducible recruitment of SLP-76 to a PLC-γ1-containing complex via the recruitment of both PLC-γ1 and Gads to another cell-type-specific adapter, LAT. Thus, TCR-induced activation of PLC-γ1 entails the binding of PLC-γ1 to both LAT and SLP-76, a finding that may underlie the requirement for both LAT and SLP-76 to mediate the optimal activation of PLC-γ1.

scholarly journals RasGRF2, a Guanosine Nucleotide Exchange Factor for Ras GTPases, Participates in T-Cell Signaling Responses

2007 ◽  
Vol 27 (23) ◽  
pp. 8127-8142 ◽  
Author(s):  
Sergio Ruiz ◽  
Eugenio Santos ◽  
Xosé R. Bustelo
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Signaling ◽  
Phospholipase C ◽  
T Cell Receptor ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
T Cell Signaling ◽  
Activated T Cells ◽  
Exchange Factor

ABSTRACT The Ras pathway is critical for the development and function of T lymphocytes. The stimulation of this GTPase in T cells occurs primarily through the Vav1- and phospholipase C-γ1-dependent activation of RasGRP1, a diacylglycerol-responsive Ras GDP/GTP exchange factor. Here, we show that a second exchange factor, RasGRF2, also participates in T-cell signaling. RasGRF2 is expressed in T cells, translocates to immune synapses, activates Ras, and stimulates the transcriptional factor NF-AT (nuclear factor of activated T cells) through Ras- and phospholipase C-γ1-dependent routes. T-cell receptor-, Vav1-, and Ca2+-elicited pathways synergize with RasGRF2 for NF-AT stimulation. The analysis of RasGRF2-deficient mice indicates that this protein is required for the induction of bona fide NF-AT targets such as the cytokines tumor necrosis factor alpha and interleukin 2, while it plays minor roles in Ras activation itself. The comparison of lymphocytes from Vav1 −/−, Rasgrf2 −/−, and Vav1 −/−; Rasgrf2 −/− mice demonstrates that the RasGRF2 pathway cooperates with the Vav1/RasGRP1 route in the blasting transformation and proliferation of mature T cells. These results identify RasGRF2 as an additional component of the signaling machinery involved in T-cell receptor- and NF-AT-mediated immune responses.

scholarly journals T cell receptor-dependent cell death of T cell hybridomas mediated by the CD30 cytoplasmic domain in association with tumor necrosis factor receptor-associated factors.

1996 ◽  
Vol 183 (2) ◽  
pp. 669-674 ◽  
Author(s):  
S Y Lee ◽  
C G Park ◽  
Y Choi
Keyword(s):  
Cell Death ◽  
T Cell ◽  
Tumor Necrosis Factor ◽  
T Cell Receptor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Receptor ◽  
Cell Receptor ◽  
Cytoplasmic Domain ◽  
Activated T Cells ◽  
Necrosis Factor

CD30 is a member of the tumor necrosis factor superfamily and a surface marker for Hodgkin's disease. Normal activated T cells and several virally transformed T or B cell lines also show CD30 expression. The interaction of CD30 with its ligand induces cell death or proliferation, depending on the cell type. In this report we characterize the signals mediated by the intracellular domain of CD30 and show that, in combination with signal(s) transduced by the T cell receptor, the multimerization of CD30 cytoplasmic domain induces Fas(CD95)-independent cell death in T cell hybridomas. Deletion analysis shows that the COOH-terminal 66 amino acids of CD30 are required to induce cell death. Using the yeast two-hybrid system, we have identified that the same region of CD30 interacts with tumor necrosis factor receptor-associated factor (TRAF)1 and TRAF2. These results indicate that TRAF1 and/or TRAF2 play an important role in cell death in addition to their previously identified roles in cell proliferation.

scholarly journals Fyn-Binding Protein (Fyb)/Slp-76–Associated Protein (Slap), Ena/Vasodilator-Stimulated Phosphoprotein (Vasp) Proteins and the Arp2/3 Complex Link T Cell Receptor (Tcr) Signaling to the Actin Cytoskeleton

2000 ◽  
Vol 149 (1) ◽  
pp. 181-194 ◽  
Author(s):  
Matthias Krause ◽  
Antonio S. Sechi ◽  
Marlies Konradt ◽  
David Monner ◽  
Frank B. Gertler ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Actin Cytoskeleton ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
T Cell Signaling ◽  
Tcr Signaling ◽  
Activated T Cells ◽  
Antigen Presenting ◽  
Syndrome Protein

T cell receptor (TCR)-driven activation of helper T cells induces a rapid polarization of their cytoskeleton towards bound antigen presenting cells (APCs). We have identified the Fyn- and SLP-76–associated protein Fyb/SLAP as a new ligand for Ena/ vasodilator-stimulated phosphoprotein (VASP) homology 1 (EVH1) domains. Upon TCR engagement, Fyb/SLAP localizes at the interface between T cells and anti-CD3–coated beads, where Evl, a member of the Ena/VASP family, Wiskott-Aldrich syndrome protein (WASP) and the Arp2/3 complex are also found. In addition, Fyb/SLAP is restricted to lamellipodia of spreading platelets. In activated T cells, Fyb/SLAP associates with Ena/VASP family proteins and is present within biochemical complexes containing WASP, Nck, and SLP-76. Inhibition of binding between Fyb/SLAP and Ena/VASP proteins or WASP and the Arp2/3 complex impairs TCR-dependent actin rearrangement, suggesting that these interactions play a key role in linking T cell signaling to remodeling of the actin cytoskeleton.

scholarly journals Crucial Role for Nuclear Factor of Activated T Cells in T Cell Receptor-mediated Regulation of Human Interleukin-17

2004 ◽  
Vol 279 (50) ◽  
pp. 52762-52771 ◽  
Author(s):  
Xikui K. Liu ◽  
Xin Lin ◽  
Sarah L. Gaffen
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Promoter Activity ◽  
Cell Receptor ◽  
Cross Linking ◽  
Supporting Evidence ◽  
Nuclear Factor ◽  
Tcr Signaling ◽  
Activated T Cells

The biological activities of the inflammatory cytokine interleukin (IL)-17 have been widely studied. However, comparatively little is known about how IL-17 expression is controlled. Here, we examined the basis for transcriptional regulation of the human IL-17 gene. IL-17 secretion was induced in peripheral blood mononuclear cells following anti-CD3 cross-linking to activate the T cell receptor (TCR), and costimulatory signaling through CD28 strongly enhanced CD3-induced IL-17 production. To definecis-acting elements important for IL-17 gene regulation, we cloned 1.25 kb of genomic sequence upstream of the transcriptional start site. This putative promoter was active in Jurkat T cells following CD3 and CD28 cross-linking, and its activity was inhibited by cyclosporin A and MAPK inhibitors. The promoter was also active in Hut102 T cells, which we have shown to secrete IL-17 constitutively. Overexpression of nuclear factor of activated T cells (NFAT) or Ras enhanced IL-17 promoter activity, and studies in Jurkat lines deficient in specific TCR signaling pathways provided supporting evidence for a role for NFAT. To delineate the IL-17 minimal promoter, we created a series of 5′ truncations and identified a region between -232 and -159 that was sufficient for inducible promoter activity. Interestingly, two NFAT sites were located within this region, which bound to NFATc1 and NFATc2 in nuclear extracts from Hut102 and Jurkat cells. Moreover, mutations of these sites dramatically reduced both specific DNA binding and reporter gene activity, and chromatin immunoprecipitation assays showed occupancy of NFAT at this regionin vivo. Together, these data show that NFAT is the crucial sensor of TCR signaling in the IL-17 promoter.

S.100. SAP Augments Proximal T Cell Receptor Signal Strength Necessary for Restimulation-induced Apoptosis of Activated T Cells

2009 ◽  
Vol 131 ◽  
pp. S160 ◽  
Author(s):  
Andrew Snow ◽  
Rebecca Marsh ◽  
Scott Krummey ◽  
Philip Roehrs ◽  
Kejian Zhang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Signal Strength ◽  
Cell Receptor ◽  
Activated T Cells ◽  
Receptor Signal ◽  
S 100 ◽  
Induced Apoptosis

scholarly journals Interleukin-21 Receptor Gene Induction in Human T Cells Is Mediated by T-Cell Receptor-Induced Sp1 Activity

2005 ◽  
Vol 25 (22) ◽  
pp. 9741-9752 ◽  
Author(s):  
Zheng Wu ◽  
Hyoung-Pyo Kim ◽  
Hai-Hui Xue ◽  
Hong Liu ◽  
Keji Zhao ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Promoter Activity ◽  
Receptor Gene ◽  
Cell Receptor ◽  
Small Interfering Rnas ◽  
Activated T Cells ◽  
Protein Levels ◽  
Interleukin 21

ABSTRACT Interleukin-21 (IL-21) plays important roles in regulating the immune response. IL-21 receptor (IL-21R) mRNA is expressed at a low level in human resting T cells but is rapidly induced by mitogenic stimulation. We now investigate the basis for IL21R gene regulation in T cells. We found that the −80 to −20 region critically regulates IL-21R promoter activity and corresponds to a major DNase I-hypersensitive site. Electrophoretic mobility shift assays, DNA affinity chromatography followed by mass spectrometry, and chromatin immunoprecipitation assays revealed that Sp1 binds to this region in vitro and in vivo. Moreover, mutation of the Sp1 motif markedly reduced IL-21R promoter activity, and Sp1 small interfering RNAs effectively diminished IL-21R expression in activated T cells. Interestingly, upon T-cell receptor (TCR) stimulation, T cells increased IL-21R expression and Sp1 protein levels while decreasing Sp1 phosphorylation. Moreover, phosphatase inhibitors that increased phosphorylation of Sp1 diminished IL-21R transcription. These data indicate that TCR-induced IL-21R expression is driven by TCR-mediated augmentation of Sp1 protein levels and may partly depend on the dephosphorylation of Sp1.

scholarly journals Vav1 Transduces T Cell Receptor Signals to the Activation of Phospholipase C-γ1 via Phosphoinositide 3-Kinase-dependent and -independent Pathways

2002 ◽  
Vol 195 (9) ◽  
pp. 1103-1114 ◽  
Author(s):  
Lucinda F. Reynolds ◽  
Lesley A. Smyth ◽  
Trisha Norton ◽  
Norman Freshney ◽  
Julian Downward ◽  
...  
Keyword(s):  
T Cell ◽  
Phospholipase C ◽  
T Cell Receptor ◽  
Genetic System ◽  
Cell Receptor ◽  
Calcium Flux ◽  
Double Positive ◽  
Signaling Complex ◽  
Tcr Signals ◽  
Phosphoinositide 3 Kinase

Vav1 is a signal transducing protein required for T cell receptor (TCR) signals that drive positive and negative selection in the thymus. Furthermore, Vav1-deficient thymocytes show greatly reduced TCR-induced intracellular calcium flux. Using a novel genetic system which allows the study of signaling in highly enriched populations of CD4+CD8+ double positive thymocytes, we have studied the mechanism by which Vav1 regulates TCR-induced calcium flux. We show that in Vav1-deficient double positive thymocytes, phosphorylation, and activation of phospholipase C-γ1 (PLCγ1) is defective. Furthermore, we demonstrate that Vav1 regulates PLCγ1 phosphorylation by at least two distinct pathways. First, in the absence of Vav1 the Tec-family kinases Itk and Tec are no longer activated, most likely as a result of a defect in phosphoinositide 3-kinase (PI3K) activation. Second, Vav1-deficient thymocytes show defective assembly of a signaling complex containing PLCγ1 and the adaptor molecule Src homology 2 domain–containing leukocyte phosphoprotein 76. We show that this latter function is independent of PI3K.

Defective Cytokine Expression but Adult-Type T-Cell Receptor, CD8, and p56lck Modulation in CD3− or CD2-Activated T Cells from Neonates

1995 ◽  
Vol 37 (1) ◽  
pp. 64-69 ◽  
Author(s):  
H Pirenne-Ansart ◽  
F Paillard ◽  
D De Groote ◽  
A Eljaafari ◽  
S Le Gac ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Cytokine Expression ◽  
Activated T Cells ◽  
Adult Type
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