scholarly journals Dynamic equilibrium between calcineurin and kinase activities regulates the phosphorylation state and localization of the nuclear factor of activated T-cells

1997 ◽  
Vol 324 (2) ◽  
pp. 597-603 ◽  
Author(s):  
John E. SCOTT ◽  
Valerie A. RUFF ◽  
Karen L. LEACH
Keyword(s):  
T Cells ◽  
Nuclear Localization ◽  
T Cell Activation ◽  
Cell Activation ◽  
Kinase Inhibitors ◽  
Dynamic Equilibrium ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Phosphorylation State

The nuclear factor of activated T-cells (NFATp) is a phosphorylated transcription factor that resides in the cytoplasm of unactivated T-cells. T-cell activation results in the activation of the phosphatase calcineurin (CaN), which leads to the dephosphorylation and subsequent nuclear localization of NFATp. We have investigated the role of kinases in the phosphorylation state and subcellular localization of NFATp. The phosphorylation state and nuclear/cytoplasmic location of NFATp were determined in unstimulated murine HT-2 cells treated with a panel of kinase inhibitors. Two of the seven kinase inhibitors, staurosporine (St) and bisindolylmaleimide I (BI), resulted in the dephosphorylation and nuclear localization of NFATp. These St-induced effects were inhibited by pretreatment with FK506, indicating that CaN activity was required for the observed effects on NFATp. Treatment of cells with ionomycin resulted in NFATp dephosphorylation and nuclear localization. Removal of ionomycin from the cells resulted in the reappearance of phosphorylated NFATp in the cytosol. St and BI also inhibited the re-accumulation of NFATp in the cytoplasm and its re-phosphorylation after ionomycin removal. The re-accumulation of NFATp in the cytosol after ionomycin withdrawal was shown to be energy- and temperature-dependent. Taken together, these results suggest that in unstimulated cells NFATp is actively maintained in the cytoplasm by kinases acting in opposition to basal CaN activity.

scholarly journals The Ca2+ export pump PMCA clears near-membrane Ca2+ to facilitate store-operated Ca2+ entry and NFAT activation

2019 ◽  
Vol 12 (602) ◽  
pp. eaaw2627 ◽  
Author(s):  
Christina K. Go ◽  
Robert Hooper ◽  
Matthew R. Aronson ◽  
Bryant Schultz ◽  
Taha Cangoz ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Fate ◽  
T Cell Activation ◽  
Splice Variant ◽  
Cell Activation ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Plasma Membrane Calcium Atpase ◽  
Nfat Activation ◽  
Transcription Factor Nuclear Factor

Ca2+ signals, which facilitate pluripotent changes in cell fate, reflect the balance between cation entry and export. We found that overexpression of either isoform of the Ca2+-extruding plasma membrane calcium ATPase 4 (PMCA4) pump in Jurkat T cells unexpectedly increased activation of the Ca2+-dependent transcription factor nuclear factor of activated T cells (NFAT). Coexpression of the endoplasmic reticulum–resident Ca2+ sensor stromal interaction molecule 1 (STIM1) with the PMCA4b splice variant further enhanced NFAT activity; however, coexpression with PMCA4a depressed NFAT. No PMCA4 splice variant dependence in STIM1 association was observed, whereas partner of STIM1 (POST) preferentially associated with PMCA4b over PMCA4a, which enhanced, rather than inhibited, PMCA4 function. A comparison of global and near-membrane cytosolic Ca2+ abundances during store-operated Ca2+ entry revealed that PMCA4 markedly depressed near-membrane Ca2+ concentrations, particularly when PMCA4b was coexpressed with STIM1. PMCA4b closely associated with both POST and the store-operated Ca2+ channel Orai1. Furthermore, POST knockdown increased the near-membrane Ca2+ concentration, inhibiting the global cytosolic Ca2+ increase. These observations reveal an unexpected role for POST in coupling PMCA4 to Orai1 to promote Ca2+ entry during T cell activation through Ca2+ disinhibition.

scholarly journals p21ras and calcineurin synergize to regulate the nuclear factor of activated T cells.

1993 ◽  
Vol 178 (5) ◽  
pp. 1517-1522 ◽  
Author(s):  
M Woodrow ◽  
N A Clipstone ◽  
D Cantrell
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Protein Tyrosine Kinase ◽  
Cell Activation ◽  
Interleukin 2 ◽  
Cytosolic Calcium ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Guanine Nucleotide Binding Protein

In T lymphocytes, triggering of the T cell receptor (TCR) induces several signaling cascades which ultimately synergize to induce the activity of the nuclear factor of activated T cells (NFAT), a DNA binding complex critical to the inducibility and T cell specificity of the T cell growth factor interleukin 2. One immediate consequence of T cell activation via the TCR is an increase in cytosolic calcium. Calcium signals are important for NFAT induction, and recent studies have identified calcineurin, a calcium-calmodulin dependent serine-threonine phosphatase, as a prominent component of the calcium signaling pathway in T cells. A second important molecule in TCR signal transduction is the guanine nucleotide binding protein, p21ras, which is coupled to the TCR by a protein tyrosine kinase dependent mechanism. The experiments presented here show that expression by transfection of mutationally activated calcineurin or activated p21ras alone is insufficient for NFAT transactivation. However, coexpression of the activated calcineurin with activated p21ras could mimic TCR signals in NFAT induction. These data identify calcineurin and p21ras as cooperative partners in T cell activation.

scholarly journals Nuclear Factor of Activated T Cells c Is a Target of p38 Mitogen-Activated Protein Kinase in T Cells

2003 ◽  
Vol 23 (18) ◽  
pp. 6442-6454 ◽  
Author(s):  
Chia-Cheng Wu ◽  
Shu-Ching Hsu ◽  
Hsiu-ming Shih ◽  
Ming-Zong Lai
Keyword(s):  
T Cells ◽  
Protein Kinase ◽  
P38 Mapk ◽  
T Cell Activation ◽  
Cell Activation ◽  
Mitogen Activated Protein Kinase ◽  
Nuclear Factor ◽  
Creb Binding Protein ◽  
Activated T Cells ◽  
Mitogen Activated Protein

ABSTRACT p38 mitogen activated protein kinase (MAPK) is essential for T-cell activation. Here we demonstrated that nuclear factor of activated T cells (NFAT) is a direct target of p38 MAPK. Inhibition of p38 MAPK led to selective inactivation of NFAT in T cells. We further linked a strict requirement of p38 MAPK to activation of NFATc. A stimulatory effect of p38 MAPK on at least four other stages of NFATc activation was found. First, the p38 MAPK cascade activated the NFATc promoter and induced the transcription of NFATc mRNA. Second, p38 MAPK mildly increased the mRNA stability of NFATc. Third, p38 MAPK enhanced the translation of NFATc mRNA. Fourth, p38 MAPK promoted the interaction of NFATc with the coactivator CREB-binding protein. In contrast, p38 MAPK moderately enhanced the expulsion of NFATc from the nucleus in T cells. Therefore, p38 MAPK has opposite effects on different stages of NFATc activation. All together, the overall effect of p38 MAPK on NFATc in T cells is clear activation.

scholarly journals Annexin A5 is essential for PKCθ translocation during T-cell activation

2020 ◽  
Vol 295 (41) ◽  
pp. 14214-14221
Author(s):  
Zhaoqing Hu ◽  
Lin Li ◽  
Banghui Zhu ◽  
Yi Huang ◽  
Xinran Wang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Critical Role ◽  
Adaptive Immune System ◽  
Annexin A5 ◽  
Activated T Cells ◽  
Calcium Dependent

T-cell activation is a critical part of the adaptive immune system, enabling responses to foreign cells and external stimulus. In this process, T-cell antigen receptor (TCR) activation stimulates translocation of the downstream kinase PKCθ to the membrane, leading to NF-κB activation and thus transcription of relevant genes. However, the details of how PKCθ is recruited to the membrane remain enigmatic. It is known that annexin A5 (ANXA5), a calcium-dependent membrane-binding protein, has been reported to mediate PKCδ activation by interaction with PKCδ, a homologue of PKCθ, which implicates a potential role of ANXA5 involved in PKCθ signaling. Here we demonstrate that ANXA5 does play a critical role in the recruitment of PKCθ to the membrane during T-cell activation. ANXA5 knockout in Jurkat T cells substantially inhibited the membrane translocation of PKCθ upon TCR engagement and blocked the recruitment of CARMA1-BCL10-MALT1 signalosome, which provides a platform for the catalytic activation of IKKs and subsequent activation of canonical NF-κB signaling in activated T cells. As a result, NF-κB activation was impaired in ANXA5-KO T cells. T-cell activation was also suppressed by ANAX5 knockdown in primary T cells. These results demonstrated a novel role of ANXA5 in PKC translocation and PKC signaling during T-cell activation.

scholarly journals Reduction of Foxp3+Cells by Depletion with the PC61 mAb Induces Mortality in Resistant BALB/c Mice Infected withToxoplasma gondii

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Eda Patricia Tenorio ◽  
Jonadab Efraín Olguín ◽  
Jacquelina Fernández ◽  
Pablo Vieyra ◽  
Rafael Saavedra
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Toxoplasma Gondii ◽  
T Cell Activation ◽  
Cell Activation ◽  
Acute Infection ◽  
Infectious Agents ◽  
Facs Analysis ◽  
Activated T Cells

Regulatory T cells (Tregs) areCD4+Foxp3+cells that modulate autoimmune responses. Tregs have been shown to be also involved during the immune response against infectious agents. The aim of this work is to study the role of Tregs during the infection with the intracellular protozoanToxoplasma gondii. Resistant BALB/c mice were injected with 200 μg of anti-CD25 mAb (clone PC61) and 2 days later they were infected with 20 cysts of the ME49 strain ofT. gondii. We observed that depleted mice showed 50–60% mortality during the acute infection. When FACS analysis was carried out, we observed that although injection of PC61 mAb eliminated 50% of Tregs, infected-depleted mice showed a similar percentage of CD25+Foxp3−(activated T cells, Tact) to those observed in infected nondepleted animals, demonstrating that in our depletion/infection system, injection of PC61 mAb did not hamper T cell activation while percentage of Tregs was reduced by 75% 10 days post infection. We concluded that Tregs are essential during protection in the acute phase ofT. gondiiinfection.

scholarly journals Curcumin Suppresses T Cell Activation by Blocking Ca 2+ Mobilization and Nuclear Factor of Activated T Cells (NFAT) Activation

2012 ◽  
Vol 287 (13) ◽  
pp. 10200-10209 ◽  
Author(s):  
Christian Kliem ◽  
Anette Merling ◽  
Marco Giaisi ◽  
Rebecca Köhler ◽  
Peter H. Krammer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Nfat Activation

scholarly journals Annexin-1 modulates T-cell activation and differentiation

Blood ◽  
2006 ◽  
Vol 109 (3) ◽  
pp. 1095-1102 ◽  
Author(s):  
Fulvio D'Acquisto ◽  
Ahmed Merghani ◽  
Emilio Lecona ◽  
Guglielmo Rosignoli ◽  
Karim Raza ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Disease Onset ◽  
Etiologic Factor ◽  
Nuclear Factor ◽  
Th2 Response ◽  
Activated T Cells ◽  
Annexin 1

Abstract Annexin-1 is an anti-inflammatory protein that plays an important homeostatic role in innate immunity; however, its potential actions in the modulation of adaptive immunity have never been explored. Although inactive by itself, addition of annexin-1 to stimulated T cells augmented anti-CD3/CD28-mediated CD25 and CD69 expression and cell proliferation. This effect was paralleled by increased nuclear factor-κB (NF-κB), nuclear factor of activated T cells (NFATs), and activator protein-1 (AP-1) activation and preceded by a rapid T-cell receptor (TCR)–induced externalization of the annexin-1 receptor. Interestingly, differentiation of naive T cells in the presence of annexin-1 increased skewing in Th1 cells; in the collagen-induced arthritis model, treatment of mice with annexin-1 during the immunization phase exacerbated signs and symptoms at disease onset. Consistent with these findings, blood CD4+ cells from patients with rheumatoid arthritis showed a marked up-regulation of annexin-1 expression. Together these results demonstrate that annexin-1 is a molecular “tuner” of TCR signaling and suggest this protein might represent a new target for the development of drugs directed to pathologies where an unbalanced Th1/Th2 response or an aberrant activation of T cells is the major etiologic factor.

scholarly journals Effects of blocking helper T cell induction in vivo with anti-Ia antibodies. Possible role of I-A/E hybrid molecules as restriction elements.

1980 ◽  
Vol 152 (4) ◽  
pp. 996-1010 ◽  
Author(s):  
J Sprent
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Activated T Cells ◽  
Hybrid Molecules ◽  
T Cell Help

To examine the role of Ia antigens in controlling T cell activation in vivo, unprimed (CBA X B6)F1 (H-2k X H-2b) T cells were positively selected to sheep erythrocytes (SRC) for 5 d in irradiated F1 mice in the presence of large doses of anti-Iak antibody. With selection in the presence of broad-spectrum anti-Iak antibody (A.TH anti-A.TL antiserum), the activated T cells were markedly reduced in their capacity to collaborate with either B10.BR (I-Ak I-Bk I-Jk I-Ek I-Ck) (kkkkk) or B10.A(4R) (kbbbb) B cells but gave good helper responses with B10 (bbbbb) and (B10 X B10.BR)F1 B cells. Because there was no evidence for suppression, these findings were taken to imply that the anti-Iak antibody bound to Ia determinants on radioresistant macrophagelike cells of F1 host origin and blocked the activation of the IGk-restricted subgroup of F1 T cells but did not affect activation of the Iab-restricted T cell subgroup. Analogous experiments in which F1 T cells were selected to SRC in F1 mice in the presence of monoclonal anti-I-Ak antibody gave different results. In this situation, the reduction in T cell help for Iak-bearing B cells applied to B10.A(4R) B cells but not to B10.BR B cells. With selection of F1 T cells in B10.A(4R) mice, by contrast, anti-I-Ak antibody blocked T cell help for both B10.A(4R) and B10.BR B cells. These data suggested that genes telomeric to the I-A subregion were involved in controlling T cell activation and T-B collaboration. Because no evidence could be found that I-B through I-C determinants per se could act as restrictions elements, the working hypothesis for the data is that Iak-restricted T cells consist of two subgroups of cells: one subgroup is restricted by I-A-encoded molecules, whereas the other is restricted by I-A/E hybrid molecules encoded by two separated genes situated in the I-A and I-E subregions, respectively. The notion that A/E hybrid molecules serve as restriction elements is in line with the findings of other workers that these molecules can act as alloantigens and control responses to certain antigens under double Ir gene control.

UR-1505, a New Salicylate, Blocks T Cell Activation through Nuclear Factor of Activated T Cells

2007 ◽  
Vol 72 (2) ◽  
pp. 269-279 ◽  
Author(s):  
Juan Román ◽  
Alberto Fernández de Arriba ◽  
Sonia Barrón ◽  
Pedro Michelena ◽  
Marta Giral ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Nuclear Factor ◽  
Activated T Cells
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