scholarly journals Gene transcription in differentiating immature T cell receptor(neg) thymocytes resembles antigen-activated mature T cells.

1993 ◽  
Vol 178 (4) ◽  
pp. 1139-1149 ◽  
Author(s):  
J C Zúñiga-Pflücker ◽  
H L Schwartz ◽  
M J Lenardo
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Intercellular Adhesion Molecule ◽  
Brdu Incorporation ◽  
Nuclear Factor ◽  
Nf Kappa B ◽  
Activated T Cells ◽  
Heat Stable Antigen

Early in ontogeny thymocytes have a surface marker phenotype that resembles activated mature T cells but they lack expression of the T cell receptor (TCR) complex. We have made preparations of day 14/15 triple negative fetal thymocytes that exhibit the activated T lymphocyte markers CD25, intercellular adhesion molecule 1, Ly-6A/E, CD44, and heat stable antigen and are rapidly proliferating as evidenced by flow cytometric examination of BrdU incorporation. We found that binding activities of the gene regulators nuclear factor (NF)-kappa B, the NF-kappa B p50 homodimer complex, nuclear factor of activated T cells (NF-AT), oct-1, oct-2, activator protein 1 (AP-1), and serum response factor (SRF), are all present in these early thymocytes. Whereas the octamer factors and SRF persist during ontogeny, NF-kappa B, NF-AT, and AP-1 decrease and are undetectable in the adult thymus. Transfection of disaggregated thymocytes by electroporation or intact thymic lobes by gold-particle bombardment revealed that reporter constructs for NF-kappa B, NF-AT, AP-1, octamer factors and, to a small extent, the TCR-alpha enhancer were active in early thymocyte development. We rigorously eliminated the possibility that these transcriptional events were due to minor populations of TCR+ cells by showing that these reporter constructs were also active in recombinase activating gene (RAG)-/- thymocytes that are incapable of completing TCR gene rearrangement, and predominantly contain cells that have an activated phenotype. Thus, transcriptional events that are usually triggered by antigen stimulation in mature T cells take place early in thymic ontogeny in the absence of the TCR. Our analysis suggests that there are striking regulatory similarities but also important differences between the activation processes that take place in antigen-stimulated mature T cells and thymic progenitor cells.

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.

scholarly journals Hierarchy of signaling thresholds downstream of the T cell receptor and the Tec kinase ITK

2021 ◽  
Vol 118 (35) ◽  
pp. e2025825118
Author(s):  
Michael P. Gallagher ◽  
James M. Conley ◽  
Pranitha Vangala ◽  
Manuel Garber ◽  
Andrea Reboldi ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Signal Strength ◽  
Cell Receptor ◽  
Early Gene ◽  
Sequencing Analysis ◽  
Nuclear Factor ◽  
Activated T Cells

The strength of peptide:MHC interactions with the T cell receptor (TCR) is correlated with the time to first cell division, the relative scale of the effector cell response, and the graded expression of activation-associated proteins like IRF4. To regulate T cell activation programming, the TCR and the TCR proximal interleukin-2–inducible T cell kinase (ITK) simultaneously trigger many biochemically separate signaling cascades. T cells lacking ITK exhibit selective impairments in effector T cell responses after activation, but under the strongest signaling conditions, ITK activity is dispensable. To gain insight into whether TCR signal strength and ITK activity tune observed graded gene expression through the unequal activation of distinct signaling pathways, we examined Erk1/2 phosphorylation or nuclear factor of activated T cells (NFAT) and nuclear factor (NF)-κB translocation in naïve OT-I CD8+ cell nuclei. We observed the consistent digital activation of NFAT1 and Erk1/2, but NF-κB displayed dynamic, graded activation in response to variation in TCR signal strength, tunable by treatment with an ITK inhibitor. Inhibitor-treated cells showed the dampened induction of AP-1 factors Fos and Fosb, NF-κB response gene transcripts, and survival factor Il2 transcripts. ATAC sequencing analysis also revealed that genomic regions most sensitive to ITK inhibition were enriched for NF-κB and AP-1 motifs. Specific inhibition of NF-κB during peptide stimulation tuned the expression of early gene products like c-Fos. Together, these data indicate a key role for ITK in orchestrating the optimal activation of separate TCR downstream pathways, specifically aiding NF-κB activation. More broadly, we revealed a mechanism by which variations in TCR signal strength can produce patterns of graded gene expression in activated T cells.

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.

PKCθ-regulated signalling in health and disease

2014 ◽  
Vol 42 (6) ◽  
pp. 1484-1489 ◽  
Author(s):  
Pulak R. Nath ◽  
Noah Isakov
Keyword(s):  
Signal Transduction ◽  
T Cells ◽  
T Cell ◽  
Immunological Synapse ◽  
Cell Types ◽  
Cell Receptor ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Health And Disease

Protein kinase Cθ (PKCθ) is a key enzyme in T-lymphocytes where it plays an important role in signal transduction downstream of the activated T-cell receptor (TCR) and the CD28 co-stimulatory receptor. Antigenic stimulation of T-cells triggers PKCθ translocation to the centre of the immunological synapse (IS) at the contact site between antigen-specific T-cells and antigen-presenting cells (APCs). The IS-residing PKCθ phosphorylates and activates effector molecules that transduce signals into distinct subcellular compartments and activate the transcription factors, nuclear factor κB (NF-κB), nuclear factor of activated T-cells (NFAT) and activating protein 1 (AP-1), which are essential for the induction of T-cell-mediated responses. Besides its major biological role in T-cells, PKCθ is expressed in several additional cell types and is involved in a variety of distinct physiological and pathological phenomena. For example, PKCθ is expressed at high levels in platelets where it regulates signal transduction from distinct surface receptors, and is required for optimal platelet activation and aggregation, as well as haemostasis. In addition, PKCθ is involved in physiological processes regulating insulin resistance and susceptibility to obesity, and is expressed at high levels in gastrointestinal stromal tumours (GISTs), although the functional importance of PKCθ in these processes and cell types is not fully clear. The present article briefly reviews selected topics relevant to the biological roles of PKCθ in health and disease.

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 A Transcription Function for the T Cell–Specific Adapter (Tsad) Protein in T Cells

2001 ◽  
Vol 193 (12) ◽  
pp. 1425-1430 ◽  
Author(s):  
Francesc Marti ◽  
Nicholas H. Post ◽  
Elena Chan ◽  
Philip D. King
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nuclear Import ◽  
Regulatory Protein ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Sh2 Domain ◽  
Nuclear Factor ◽  
Transcription Activator ◽  
Activated T Cells

T cell–specific adapter (TSAd) protein is an Src homology 2 (SH2) domain–containing adapter molecule implicated in T cell receptor for antigen (TCR)-mediated interleukin 2 (IL-2) secretion in T cells. Here, we demonstrate that a substantial fraction of TSAd is found in the T cell nucleus. Nuclear import of TSAd is an active process that depends on TSAd SH2 domain recognition of a phosphotyrosine-containing ligand. Importantly, we show that TSAd can act as a potent transcriptional activator in T cells. Furthermore, the TSAd SH2 domain appears to be essential for this transcription-activating function independent of its role in nuclear import. Biochemical analyses suggest that a single TSAd SH2 domain ligand of 95–100 kD may be involved in these processes. Consistent with a role as a transcription activator, cotransfection of TSAd with an IL-2 promoter–reporter gene construct results in a considerable upregulation of IL-2 promoter activity. Further, we show that this augmentation requires a functional TSAd SH2 domain. However, TSAd does not appear to modulate the activity of the major recognized IL-2 gene transcription factors, nuclear factor κB (NF-κB), nuclear factor of activated T cells (NFAT), or activator protein 1 (AP-1). These findings point to the function of TSAd as a novel transcription-regulatory protein in T cells and illustrate the importance of the TSAd SH2 domain in this role.

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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