scholarly journals CARMA1 Is Required for Akt-Mediated NF-κB Activation in T Cells

2006 ◽  
Vol 26 (6) ◽  
pp. 2327-2336 ◽  
Author(s):  
Preeti Narayan ◽  
Brittany Holt ◽  
Richard Tosti ◽  
Lawrence P. Kane

ABSTRACT Many details of the generic pathway for induction of NF-κB have been delineated, but it is still not clear how multiple, diverse receptor systems are able to converge on this evolutionarily conserved family of transcription factors. Recent studies have shown that the CARMA1, Bcl10, and MALT1 proteins are critical for coupling the common elements of the NF-κB pathway to the T-cell receptor (TCR) and CD28. We previously demonstrated a role for the serine/threonine kinase Akt in CD28-mediated NF-κB induction. Using a CARMA1-deficient T-cell line, we have now found that the CARMA complex is required for induction of NF-κB by Akt, in cooperation with protein kinase C activation. Furthermore, using a novel selective inhibitor of Akt, we confirm that Akt plays a modulatory role in NF-κB induction by the TCR and CD28. Finally, we provide evidence for a physical and functional interaction between Akt and CARMA and for Akt-dependent phosphorylation of Bcl10. Therefore, in T cells, Akt impinges upon NF-κB signaling through at least two separate mechanisms.

1987 ◽  
Vol 7 (12) ◽  
pp. 4472-4481
Author(s):  
C H June ◽  
J A Ledbetter ◽  
M M Gillespie ◽  
T Lindsten ◽  
C B Thompson

CD28 is a homodimeric glycoprotein expressed on the surface of a major subset of human T cells that has recently been identified as a member of the immunoglobulin supergene family. The binding of monoclonal antibodies to the CD28 antigen on purified T cells does not result in proliferation; however, previous studies have shown that the combination of CD28 stimulation and protein kinase C activation by phorbol myristate acetate (PMA) results in T-cell proliferation that is independent of both accessory cells and activation of the T-cell receptor-CD3 complex. In the present study, effects of stimulation by anti-CD28 on cell cycle progression and on the interleukin 2 (IL-2) and IL-2 receptor system have been investigated on primary cultures of purified peripheral-blood CD28+ T cells. There was no measurable effect on cell size or on DNA synthesis after stimulation of resting (G0) cells by CD28 alone. After 3 h of activation of T cells by PMA alone, a slight (8%) increase in cell volume occurred that did not progress to DNA synthesis. In contrast, T-cell stimulation by CD28 in combination with PMA resulted in a progressive increase in cell volume in approximately 100% of cells at 12 to 14 h after stimulation. Northern blot (RNA blot) analysis revealed that CD28 stimulation alone failed to cause expression of the alpha chain of the IL-2 receptor or of IL-2 mRNA, and in accord with previous studies, stimulation by PMA alone resulted in the accumulation of IL-2 receptor transcripts but no detectable IL-2 mRNA. In contrast, T-cell stimulation by the combination of CD28 and PMA resulted in the appearance of IL-2 transcripts and enhanced expression of IL-2 receptor mRNA. Functional studies revealed that the proliferation induced by CD28 and PMA stimulation was entirely resistant to cyclosporine, in contrast to T-cell activation induced by the CD3-T-cell receptor complex. Cyclosporine was found not to affect the accumulation of IL-2 mRNA after CD28 plus PMA stimulation, although there was no detectable IL-2 mRNA after stimulation by CD3 in the presence of the drug. Furthermore, stimulation by CD28 in combination with immobilized CD3 antibodies caused a striking enhancement of IL-2 mRNA expression that was, in part, resistant to the effects of cyclosporine. These studies indicate that the CD28 molecule synergizes with protein kinase C activation to induce IL-2 gene expression and demonstrate that stimulation by the CD28 pathway can cause vigorous T-cell proliferation even in the presence of cyclosporine and that cyclosporine does not prevent transcription of 16-2 mRNA, as has been suggested previously. Moreover, these findings suggest that a potential role for the CD28 molecule in vivo may be to augment IL-2 production after stimulation of the CD3-T-cell receptor molecular complex and thereby to amplify an antigen-specific immune response. Finally, these results provide further evidence that the CD28 molecule triggers T-cell proliferation in a manner that differs biochemically from CD3-T-cell receptor-induced proliferation.


1987 ◽  
Vol 7 (2) ◽  
pp. 650-656 ◽  
Author(s):  
J A Ledbetter ◽  
L E Gentry ◽  
C H June ◽  
P S Rabinovitch ◽  
A F Purchio

Stimulation of T cells or the Jurkat T-cell line with soluble antibodies to the CD3/T-cell receptor complex causes mobilization of cytoplasmic Ca2+, which is blocked by pertussis toxin but not by ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, and translocation of protein kinase C activity from the cytoplasm to the membrane. Such stimulation also causes phosphorylation of pp60c-src at an amino-terminal serine residue. These activities are consistent with induction of phosphatidylinositol metabolism after antibody binding. Anti-CD3 stimulation with antibody in solution, however, does not cause Jurkat cells to release interleukin 2 and blocks rather than induces proliferation of T cells. Induction of interleukin 2 production by Jurkat cells and proliferation by normal T cells requires anti-CD3 stimulation with antibody on a solid support, such as Sepharose beads or a plastic dish. Thus, we examined phosphorylation of pp60c-src after stimulation of Jurkat cells with anti-CD3 in solution or on solid phase. Both of these caused serine phosphorylation of pp60c-src that was indistinguishable even after 4 h of stimulation. These results indicate that the mode of anti-CD3 stimulation (in solution or on solid phase) controls a cellular function that modifies the consequences of signal transduction through phosphatidylinositol turnover.


2003 ◽  
Vol 14 (2) ◽  
pp. 349-360 ◽  
Author(s):  
Shi Niu ◽  
Haichun Xie ◽  
Eugene E. Marcantonio

Integrin receptor signals are costimulatory for mitogenesis with the T-cell receptor during T-cell activation. A subset of integrin receptors can link to the adapter protein Shc and provide a mitogenic stimulus. Using a combination of genetic and pharmacological approaches, we show herein that integrin signaling to Shc in T cells requires the receptor tyrosine phosphatase CD45, the Src family kinase member Lck, and protein kinase C. Our results suggest a model in which integrin-dependent serine phosphorylation of Lck is the critical step that determines the efficiency of Shc tyrosine phosphorylation in T cells. Serine phosphorylation of Lck is dependent on PKC and is also linked to CD45 dephosphorylation. Mutants of Lck that cannot be phosphorylated on the critical serine residues do not signal efficiently to Shc and have greatly reduced kinase activity. This signaling from integrins to Lck may be an important step in the costimulation with the T-cell receptor during lymphocyte activation.


1992 ◽  
Vol 12 (11) ◽  
pp. 5260-5267 ◽  
Author(s):  
K V Prasad ◽  
C E Rudd

The CD4 and CD8 antigens on T cells have been shown to associate with the Src family member p56lck and a GTP-binding protein, p32. The identification of receptor interactions with intracellular mediators is essential in the elucidation of downstream signals mediated by engagement of these receptor complexes. In this study, we report the detection of an additional 110-kDa polypeptide (p110) associated with the CD4-p56lck complex in human peripheral blood T lymphocytes and leukemic T-cell lines. p110 bound preferentially to CD4-p56lck as an assembled complex and poorly, if at all, to the individual components. p110 was recognized directly by an antiserum to the C-terminal region of the serine/threonine kinase Raf-1 and is related to a p110 polypeptide detected in anti-Raf-1 immunoprecipitates. Despite its association with the CD4-p56lck complex, p110 was found to be phosphorylated predominantly on serine residues. Furthermore, phorbol ester treatment of cells resulted in a transient increase in the detection of p110 associated with CD4-p56lck, concomitant with the modulation of CD4-p56lck from the cell surface. This Raf-1-related p110 is therefore likely to play a role in signals generated from the CD4-p56lck complex. p110 may serve as a bridge between the CD4-p56lck complex and the serine/threonine kinase pathways of T-cell activation.


Cell ◽  
1988 ◽  
Vol 55 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Viia E. Valge ◽  
Justin G.P. Wong ◽  
Barry M. Datlof ◽  
Anthony J. Sinskey ◽  
Anjana Rao

1997 ◽  
Vol 186 (8) ◽  
pp. 1277-1285 ◽  
Author(s):  
Marie Malissen ◽  
Pablo Pereira ◽  
David J. Gerber ◽  
Bernard Malissen ◽  
James P. DiSanto

We have investigated the role of common γ chain (γc)-signaling pathways for the development of T cell receptor for antigen (TCR)-γ/δ T cells. TCR-γ/δ–bearing cells were absent from the adult thymus, spleen, and skin of γc-deficient (γc−) mice, whereas small numbers of thymocytes expressing low levels of TCR-γ/δ were detected during fetal life. Recent reports have suggested that signaling via interleukin (IL)-7 plays a major role in facilitating TCR-γ/δ development through induction of V-J (variable-joining) rearrangements at the TCR-γ locus. In contrast, we detected clearly TCR-γ rearrangements in fetal thymi from γc− mice (which fail to signal in response to IL-7) and reduced TCR-γ rearrangements in adult γc thymi. No gross defects in TCR-δ or TCR-β rearrangements were observed in γc− mice of any age. Introduction of productively rearranged TCR Vγ1 or TCR Vγ1/Vδ6 transgenes onto mice bearing the γc mutation did not restore TCR-γ/δ development to normal levels suggesting that γc-dependent pathways provide additional signals to developing γ/δ T cells other than for the recombination process. Bcl-2 levels in transgenic thymocytes from γc− mice were dramatically reduced compared to γc+ transgenic littermates. We favor the concept that γc-dependent receptors are required for the maintenance of TCR-γ/δ cells and contribute to the completion of TCR-γ rearrangements primarily by promoting survival of cells committed to the TCR-γ/δ lineage.


1987 ◽  
Vol 7 (12) ◽  
pp. 4472-4481 ◽  
Author(s):  
C H June ◽  
J A Ledbetter ◽  
M M Gillespie ◽  
T Lindsten ◽  
C B Thompson

CD28 is a homodimeric glycoprotein expressed on the surface of a major subset of human T cells that has recently been identified as a member of the immunoglobulin supergene family. The binding of monoclonal antibodies to the CD28 antigen on purified T cells does not result in proliferation; however, previous studies have shown that the combination of CD28 stimulation and protein kinase C activation by phorbol myristate acetate (PMA) results in T-cell proliferation that is independent of both accessory cells and activation of the T-cell receptor-CD3 complex. In the present study, effects of stimulation by anti-CD28 on cell cycle progression and on the interleukin 2 (IL-2) and IL-2 receptor system have been investigated on primary cultures of purified peripheral-blood CD28+ T cells. There was no measurable effect on cell size or on DNA synthesis after stimulation of resting (G0) cells by CD28 alone. After 3 h of activation of T cells by PMA alone, a slight (8%) increase in cell volume occurred that did not progress to DNA synthesis. In contrast, T-cell stimulation by CD28 in combination with PMA resulted in a progressive increase in cell volume in approximately 100% of cells at 12 to 14 h after stimulation. Northern blot (RNA blot) analysis revealed that CD28 stimulation alone failed to cause expression of the alpha chain of the IL-2 receptor or of IL-2 mRNA, and in accord with previous studies, stimulation by PMA alone resulted in the accumulation of IL-2 receptor transcripts but no detectable IL-2 mRNA. In contrast, T-cell stimulation by the combination of CD28 and PMA resulted in the appearance of IL-2 transcripts and enhanced expression of IL-2 receptor mRNA. Functional studies revealed that the proliferation induced by CD28 and PMA stimulation was entirely resistant to cyclosporine, in contrast to T-cell activation induced by the CD3-T-cell receptor complex. Cyclosporine was found not to affect the accumulation of IL-2 mRNA after CD28 plus PMA stimulation, although there was no detectable IL-2 mRNA after stimulation by CD3 in the presence of the drug. Furthermore, stimulation by CD28 in combination with immobilized CD3 antibodies caused a striking enhancement of IL-2 mRNA expression that was, in part, resistant to the effects of cyclosporine. These studies indicate that the CD28 molecule synergizes with protein kinase C activation to induce IL-2 gene expression and demonstrate that stimulation by the CD28 pathway can cause vigorous T-cell proliferation even in the presence of cyclosporine and that cyclosporine does not prevent transcription of 16-2 mRNA, as has been suggested previously. Moreover, these findings suggest that a potential role for the CD28 molecule in vivo may be to augment IL-2 production after stimulation of the CD3-T-cell receptor molecular complex and thereby to amplify an antigen-specific immune response. Finally, these results provide further evidence that the CD28 molecule triggers T-cell proliferation in a manner that differs biochemically from CD3-T-cell receptor-induced proliferation.


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