scholarly journals Two independently regulated Ca2+ entry mechanisms coexist in Jurkat T cells during T cell receptor antigen activation

1993 ◽  
Vol 293 (2) ◽  
pp. 395-398 ◽  
Author(s):  
S C Chow ◽  
G E Kass ◽  
S Orrenius
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Antigen Receptor ◽  
Cell Receptor ◽  
Jurkat Cells ◽  
Receptor Complex ◽  
T Cell Antigen Receptor ◽  
Bivalent Cation ◽  
Cell Antigen Receptor ◽  
Cell Antigen

Receptor-mediated Ca2+ influx was studied in the human leukaemic T cell line, Jurkat. Stimulation of these cells through the T cell antigen-receptor complex with OKT3 (an antibody against the CD3 molecules of the T cell antigen-receptor complex), or inhibition of the endoplasmic reticular Ca(2+)-ATPase with thapsigargin, resulted in Ca2+ mobilization from intracellular stores and the activation of Ca2+ and Mn2+ entry. The rates of thapsigargin-induced Ca2+ and Mn2+ entry in Jurkat cells were 76% and 64% respectively of those observed after treatment of these cells with OKT3. The combined addition of thapsigargin plus OKT3 to Jurkat cells produced an enhanced effect on the sustained increase in the cytosolic free Ca2+ concentration that was greater than that obtained by addition of thapsigargin or OKT3 alone. The rates of Ca2+ and Mn2+ entry were increased to 119% and 112% respectively of the OKT3-induced rates. Taken together, these results suggest that the inositol 1,4,5-trisphosphate-sensitive Ca(2+)-pool-dependent bivalent cation entry only accounts for 57% and 52% respectively of the total OKT3-dependent Ca2+ and Mn2+ entry, and that the rest is mediated by second messenger(s). Thus two separate pathways coexist in regulating Ca2+ entry in Jurkat cells during activation mediated through the T cell receptor.

scholarly journals Lack of gene rearrangement and mRNA expression of the beta chain of the T cell receptor in spontaneous rat large granular lymphocyte leukemia lines.

1985 ◽  
Vol 161 (5) ◽  
pp. 1249-1254 ◽  
Author(s):  
C W Reynolds ◽  
M Bonyhadi ◽  
R B Herberman ◽  
H A Young ◽  
S M Hedrick
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Antigen Receptor ◽  
Cell Receptor ◽  
Large Granular Lymphocyte ◽  
Beta Chain ◽  
T Cell Antigen Receptor ◽  
Cell Antigen Receptor ◽  
Cell Antigen ◽  
Lgl Leukemia

Using the murine cDNA clone for the beta chain of the T cell antigen receptor, we have examined four highly cytotoxic rat large granular lymphocyte (LGL) leukemia lines for the expression of unique rearrangements and mRNA transcription of the genes coding for the T cell antigen receptor. In contrast to normal rat T cells and nine rat T cell lines, the LGL leukemia lines exhibited no detectable gene rearrangements in the beta chain locus after digestion of LGL DNA by four restriction enzymes. Northern blots containing RNA from these LGL tumor lines demonstrated a low level of aberrant or nonrearranged beta chain transcription (less than 10 copies per cell) but virtually no translatable 1.3 kilobase message. These results demonstrate that LGL leukemia lines which mediate both natural killer (NK) and antibody-dependent cell-mediated cytotoxicity (ADCC) activities do not express the beta chain of the T cell receptor. The nature of the NK cell receptor for antigen remains elusive.

scholarly journals Identification of Inhibitors of the Association of ZAP-70 with the T Cell Receptor by High-Throughput Screen

2016 ◽  
Vol 22 (3) ◽  
pp. 324-331 ◽  
Author(s):  
Patrick R. Visperas ◽  
Christopher G. Wilson ◽  
Jonathan A. Winger ◽  
Qingrong Yan ◽  
Kevin Lin ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Peptide Binding ◽  
Antigen Receptor ◽  
Cell Receptor ◽  
T Cell Antigen Receptor ◽  
Cell Antigen Receptor ◽  
Cell Antigen ◽  
Antigen Receptor Signaling ◽  
Fluorescence Polarization Assay

ZAP-70 is a critical molecule in the transduction of T cell antigen receptor signaling and the activation of T cells. Upon activation of the T cell antigen receptor, ZAP-70 is recruited to the intracellular ζ-chains of the T cell receptor, where ZAP-70 is activated and colocalized with its substrates. Inhibitors of ZAP-70 could potentially function as treatments for autoimmune diseases or organ transplantation. In this work, we present the design, optimization, and implementation of a screen for inhibitors that would disrupt the interaction between ZAP-70 and the T cell antigen receptor. The screen is based on a fluorescence polarization assay for peptide binding to ZAP-70.

scholarly journals Transmembrane signalling by the T cell antigen receptor. Perturbation of the T3-antigen receptor complex generates inositol phosphates and releases calcium ions from intracellular stores.

1985 ◽  
Vol 161 (3) ◽  
pp. 446-456 ◽  
Author(s):  
J B Imboden ◽  
J D Stobo
Keyword(s):  
T Cell ◽  
Calcium Ions ◽  
Inositol Phosphates ◽  
Inositol Trisphosphate ◽  
Antigen Receptor ◽  
Jurkat Cells ◽  
Receptor Complex ◽  
T Cell Antigen Receptor ◽  
Cell Antigen Receptor ◽  
Cell Antigen

Antibodies against the T3-antigen receptor complex can activate the human T cell line, Jurkat, to produce interleukin 2 (2-5). This activation is initiated by a receptor-mediated increase in the concentration of free cytoplasmic calcium ions [Ca2+]i (3, 4). In this communication, we investigate the mechanism by which the receptor complex increases [Ca2+ )i in Jurkat cells. The initial receptor-mediated change in [Ca2+]i can occur when extracellular Ca2+ is depleted by EGTA. Perturbation of the T cell antigen receptor, therefore, generates a signal which mobilizes Ca2+ from intracellular stores. As inositol trisphosphate appears to function as such a signal for certain hormone receptors, we measured the levels of inositol trisphosphate and of the other inositol phosphate compounds in Jurkat. Antibodies to either the antigen receptor heterodimer or T3 determinants result in marked elevations of all three inositol phosphates. These changes in inositol phosphates are not secondary to the receptor-mediated increases in [Ca2+]i as demonstrated by the inability of the Ca2+ ionophore, ionomycin, to affect the levels of any of these compounds. In concentrations between 0.1 and 1 microM, purified inositol trisphosphate releases Ca2+ from permeabilized Jurkat cells. Taken together, these data indicate that, during activation, perturbation of the T3-antigen receptor complex generates inositol trisphosphate. This compound functions as an intracellular signal to release Ca2+ from intracellular stores, leading to increases in [Ca2+]i.

The extracellular part of ζ is buried in the T cell antigen receptor complex

2008 ◽  
Vol 116 (2) ◽  
pp. 203-210 ◽  
Author(s):  
Susana Minguet ◽  
Mahima Swamy ◽  
Elaine P. Dopfer ◽  
Eva Dengler ◽  
Balbino Alarcón ◽  
...  
Keyword(s):  
T Cell ◽  
Antigen Receptor ◽  
Receptor Complex ◽  
T Cell Antigen Receptor ◽  
Cell Antigen Receptor ◽  
Cell Antigen

Susceptibility to cell death is a dominant phenotype: triggering of activation-driven T-cell death independent of the T-cell antigen receptor complex

1992 ◽  
Vol 12 (1) ◽  
pp. 379-385
Author(s):  
G Nickas ◽  
J Meyers ◽  
L D Hebshi ◽  
J D Ashwell ◽  
D P Gold ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Interleukin 2 ◽  
Antigen Receptor ◽  
Alternative Activation ◽  
Receptor Complex ◽  
T Cell Antigen Receptor ◽  
Cell Antigen Receptor ◽  
Cell Antigen

The failure of Thy-1 and Ly-6 to trigger interleukin-2 production in the absence of surface T-cell antigen receptor complex (TCR) expression has been interpreted to suggest that functional signalling via these phosphatidylinositol-linked alternative activation molecules is dependent on the TCR. We find, in contrast, that stimulation of T cells via Thy-1 or Ly-6 in the absence of TCR expression does trigger a biological response, the cell suicide process of activation-driven cell death. Activation-driven cell death is a process of physiological cell death that likely represents the mechanism of negative selection of T cells. The absence of the TCR further reveals that signalling leading to activation-driven cell death and to lymphokine production are distinct and dissociable. In turn, the ability of alternative activation molecules to function in the absence of the TCR raises another issue: why immature T cells, thymomas, and hybrids fail to undergo activation-driven cell death in response to stimulation via Thy-1 and Ly-6. One possibility is that these activation molecules on immature T cells are defective. Alternatively, susceptibility to activation-driven cell death may be developmentally regulated by TCR-independent factors. We have explored these possibilities with somatic cell hybrids between mature and immature T cells, in which Thy-1 and Ly-6 are contributed exclusively by the immature partner. The hybrid cells exhibit sensitivity to activation-driven cell death triggered via Thy-1 and Ly-6. Thus, the Thy-1 and Ly-6 molecules of the immature T cells can function in a permissive environment. Moreover, with regard to susceptibility to Thy-1 and Ly-6 molecules of the immature T cells can function in a permissive environment. Moreover, with regard to susceptibility to Thy-1 and Ly-6 triggering, the mature phenotype of sensitivity to cell death is genetically dominant.

scholarly journals A 275 basepair fragment at the 5' end of the interleukin 2 gene enhances expression from a heterologous promoter in response to signals from the T cell antigen receptor.

1987 ◽  
Vol 165 (2) ◽  
pp. 395-407 ◽  
Author(s):  
D B Durand ◽  
M R Bush ◽  
J G Morgan ◽  
A Weiss ◽  
G R Crabtree
Keyword(s):  
T Cell ◽  
Cell Line ◽  
Antigen Receptor ◽  
Calcium Ionophore ◽  
Jurkat Cells ◽  
T Cell Antigen Receptor ◽  
Linked Gene ◽  
Cell Antigen Receptor ◽  
Cell Antigen ◽  
Flanking Region

Using a transient transfection assay, we have defined the sequences required for the activation of the IL-2 gene in response to signals from the T cell antigen receptor. To do so we have transfected the human T cell line Jurkat with hybrid DNA constructs in which fragments from the IL-2 gene are linked to an indicator gene. The indicator gene product, as well as IL-2 production from the endogenous IL-2 gene were assayed after activation of the transfected Jurkat cells by various stimuli. We have demonstrated that a 275 bp fragment stretching from 52 to 326 bp upstream of the IL-2 gene transcription initiation site is required for expression of the linked indicator gene. This IL-2 gene fragment has several of the characteristics of a transcriptional enhancer element, in that it functions in both orientations and will enhance the expression from the promoter of an unrelated gene. Such enhancement occurred only after activation of Jurkat cells through the T cell antigen receptor. More specifically, this 275 bp fragment activated the expression of a linked gene after binding of a monoclonal antibody to the Jurkat T cell antigen receptor in the presence of PMA. In addition, calcium ionophore, which circumvents antigen receptor binding in T cell activation, induced the expression of the linked gene through this 275 bp sequence, in the presence of PMA. Finally, in a mutant Jurkat cell line lacking T3/antigen receptor complexes at the cell surface, no expression due to the IL-2 5' flanking region was seen after exposure to antibody to the T cell antigen receptor plus PMA or to PHA plus PMA. In contrast, calcium ionophore plus PMA did induce the expression of a linked gene through the IL-2 5' flanking region in the mutant Jurkat cell line. The responsiveness of the transfected hybrid genes containing the IL-2 regulatory region paralleled the expression of the endogenous IL-2 gene, as determined by IL-2 bioassays. We conclude that the 275 bp IL-2 sequence (-326 to -52 bp) is a target for the signal pathway originating at the T cell antigen receptor. Definition of this 275 bp target sequence should now permit the isolation of the molecules that bind to and activate the IL-2 gene.

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