scholarly journals The structure of the T cell antigen receptor genes in normal and malignant T cells

Blood ◽  
1986 ◽  
Vol 68 (2) ◽  
pp. 327-336
Author(s):  
MD Minden ◽  
TW Mak

In this review the genomic structure and the RNA transcripts of the alpha and beta chain of the T cell antigen receptor have been discussed. Studies of the structure of TcR beta in hematologic malignancies have revealed rearrangement in almost all of the T cell malignancies and a small proportion of non-T cell malignancies. In addition, clonal involvement of T cells in diseases such as Hodgkin's disease, angioimmunoblastic lymphadenopathy, and chronic T cell lymphocytosis have been observed. The study of the structure of the TcR beta gene is thus a useful tool for identifying clonal expansions of cells and in conjunction with studies of the immunoglobulin gene structure, and cell surface markers a useful tool for identifying cell lineage. At the present time the evaluation of the structure of the alpha chain genes has not been as fruitful. However, chromosome translocations involving the TcR alpha chain genes have been recognized and, in one case, this rearrangement has been in association with a known oncogene. With the isolation of more probes to the alpha chain region it should be possible to test its utility in identifying clonal populations and cell lineage. The recent isolation of the gamma gene of the T cell will also permit such studies. Preliminary results of studies carried out with a probe to the gamma chain gene of the T cell have paralleled results obtained with the TcR beta probe (unpublished observation).

Blood ◽  
1986 ◽  
Vol 68 (2) ◽  
pp. 327-336 ◽  
Author(s):  
MD Minden ◽  
TW Mak

Abstract In this review the genomic structure and the RNA transcripts of the alpha and beta chain of the T cell antigen receptor have been discussed. Studies of the structure of TcR beta in hematologic malignancies have revealed rearrangement in almost all of the T cell malignancies and a small proportion of non-T cell malignancies. In addition, clonal involvement of T cells in diseases such as Hodgkin's disease, angioimmunoblastic lymphadenopathy, and chronic T cell lymphocytosis have been observed. The study of the structure of the TcR beta gene is thus a useful tool for identifying clonal expansions of cells and in conjunction with studies of the immunoglobulin gene structure, and cell surface markers a useful tool for identifying cell lineage. At the present time the evaluation of the structure of the alpha chain genes has not been as fruitful. However, chromosome translocations involving the TcR alpha chain genes have been recognized and, in one case, this rearrangement has been in association with a known oncogene. With the isolation of more probes to the alpha chain region it should be possible to test its utility in identifying clonal populations and cell lineage. The recent isolation of the gamma gene of the T cell will also permit such studies. Preliminary results of studies carried out with a probe to the gamma chain gene of the T cell have paralleled results obtained with the TcR beta probe (unpublished observation).


2005 ◽  
Vol 25 (6) ◽  
pp. 2227-2241 ◽  
Author(s):  
Souad Rahmouni ◽  
Torkel Vang ◽  
Andres Alonso ◽  
Scott Williams ◽  
Marianne van Stipdonk ◽  
...  

ABSTRACT The Csk tyrosine kinase negatively regulates the Src family kinases Lck and Fyn in T cells. Engagement of the T-cell antigen receptor results in a removal of Csk from the lipid raft-associated transmembrane protein PAG/Cbp. Instead, Csk becomes associated with an ∼72-kDa tyrosine-phosphorylated protein, which we identify here as G3BP, a phosphoprotein reported to bind the SH3 domain of Ras GTPase-activating protein. G3BP reduced the ability of Csk to phosphorylate Lck at Y505 by decreasing the amount of Csk in lipid rafts. As a consequence, G3BP augmented T-cell activation as measured by interleukin-2 gene activation. Conversely, elimination of endogenous G3BP by RNA interference increased Lck Y505 phosphorylation and reduced TCR signaling. In antigen-specific T cells, endogenous G3BP moved into a intracellular location adjacent to the immune synapse, but deeper inside the cell, upon antigen recognition. Csk colocalization with G3BP occurred in this “parasynaptic” location. We conclude that G3BP is a new player in T-cell-antigen receptor signaling and acts to reduce the amount of Csk in the immune synapse.


1991 ◽  
Vol 88 (17) ◽  
pp. 7518-7522 ◽  
Author(s):  
H. Koseki ◽  
H. Asano ◽  
T. Inaba ◽  
N. Miyashita ◽  
K. Moriwaki ◽  
...  

1992 ◽  
Vol 12 (1) ◽  
pp. 379-385
Author(s):  
G Nickas ◽  
J Meyers ◽  
L D Hebshi ◽  
J D Ashwell ◽  
D P Gold ◽  
...  

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.


Blood ◽  
2003 ◽  
Vol 101 (9) ◽  
pp. 3534-3542 ◽  
Author(s):  
Mi-Ae Kang ◽  
Su-Young Yun ◽  
Jonghwa Won

Rosmarinic acid (RosA) is a hydroxylated compound frequently found in herbal plants and is mostly responsible for anti-inflammatory and antioxidative activity. Previously, we observed that RosA inhibited T-cell antigen receptor (TCR)– induced interleukin 2 (IL-2) expression and subsequent T-cell proliferation in vitro. In this study, we investigated in detail inhibitory mechanism of RosA on TCR signaling, which ultimately activates IL-2 promoter by activating transcription factors, such as nuclear factor of activated T cells (NF-AT) and activating protein-1 (AP-1). Interestingly, RosA inhibited NF-AT activation but not AP-1, suggesting that RosA inhibits Ca2+- dependent signaling pathways only. Signaling events upstream of NF-AT activation, such as the generation of inositol 1,4,5-triphosphate and Ca2+ mobilization, and tyrosine phosphorylation of phospholipase C-γ1 (PLC-γ1) were strongly inhibited by RosA. Tyrosine phosphorylation of PLC-γ1 is largely dependent on 3 kinds of protein tyrosine kinases (PTKs), ie, Lck, ZAP-70, and Itk. We found that RosA efficiently inhibited TCR-induced tyrosine phosphorylation and subsequent activation of Itk but did not inhibit Lck or ZAP-70. ZAP-70–dependent signaling pathways such as the tyrosine phosphorylation of LAT and SLP-76 and serine/threonine phosphorylation of mitogen-activated protein kinases (MAPKs) were intact in the presence of RosA, confirming that RosA suppresses TCR signaling in a ZAP-70–independent manner. Therefore, we conclude that RosA inhibits TCR signaling leading to Ca2+ mobilization and NF-AT activation by blocking membrane-proximal events, specifically, the tyrosine phosphorylation of inducible T cells kinase (Itk) and PLC-γ1.


1994 ◽  
Vol 180 (1) ◽  
pp. 401-406 ◽  
Author(s):  
M Izquierdo ◽  
S Bowden ◽  
D Cantrell

Triggering of the T cell antigen receptor (TCR) complex activates the serine/threonine kinase Raf-1 whose function is necessary for TCR induction of the interleukin 2 gene. Raf-1 has been identified as a candidate mitogen-activated protein (MAP) kinase kinase kinase (MKKK) and thus has the potential to couple the TCR to the activation of the MAP kinases such as ERK2. In the present study, the role of Raf-1 in ERK2 regulation of ERK2 in T cells has been explored. A constitutively active Raf-1 kinase, v-raf, or a dominant inhibitory Raf-1 mutant were expressed transiently from the pEF BOS vector in Jurkat cells and the effects of these Raf-1 mutants on a coexpressed ERK2 reporter was assessed. The action of the constitutively active Raf-1 was to stimulate the ERK2 kinase, whereas the dominant negative version of Raf-1 inhibited the ERK2 activation induced by triggering of the TCR. These data indicate a role for Raf-1 in the regulation of ERK2 in T cells.


2009 ◽  
Vol 10 (4) ◽  
pp. 375-384 ◽  
Author(s):  
Nicolas Fazilleau ◽  
Louise J McHeyzer-Williams ◽  
Hugh Rosen ◽  
Michael G McHeyzer-Williams

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