scholarly journals Human T-Cell Lymphotropic Virus Type 1 p12I Expression Increases Cytoplasmic Calcium To Enhance the Activation of Nuclear Factor of Activated T Cells

2002 ◽  
Vol 76 (20) ◽  
pp. 10374-10382 ◽  
Author(s):  
Wei Ding ◽  
Björn Albrecht ◽  
Robert E. Kelley ◽  
Natarajan Muthusamy ◽  
Seung-Jae Kim ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Calcium Release ◽  
Nuclear Factor ◽  
Cytoplasmic Calcium ◽  
Activated T Cells ◽  
Human T Cell ◽  
Nfat Activation

ABSTRACT Human T-cell lymphotropic virus type 1 (HTLV-1) establishes persistent infection and is associated with lymphoproliferative or neurodegenerative diseases. As a complex retrovirus, HTLV-1 contains typical structural and enzymatic genes, as well as regulatory and accessory genes encoded in the pX region. The early events necessary for HTLV-1 to establish infection in lymphocytes, its primary target cells, remain unresolved. Recent studies have demonstrated the importance of regulatory and accessory gene products in determining this virus-host interaction. Among these, pX open reading frame I, which encodes two proteins, p12I and p27I, is required for establishing persistent infection in vivo and for infection in quiescent primary lymphocytes. In addition, p12I localizes in the endoplasmic reticulum (ER) and cis-Golgi apparatus and associates with a calcium binding protein, calreticulin. We recently reported that p12I expression induces the calcium-responsive T-cell transcription factor, nuclear factor of activated T cells (NFAT), in the presence of phorbol ester activation. Based on these studies, we hypothesize that p12I may modulate calcium release from the ER. Here, we report that p12I expression increases basal cytoplasmic calcium and concurrently diminishes calcium available for release from the ER stores. Overexpression of calreticulin, a calcium buffer protein, blocked p12I-mediated NFAT activation independently of its ability to bind p12I. Chemical inhibition studies using inhibitors of inositol 1,4,5-triphosphate receptor and calcium release-activated calcium channels suggest that inositol 1,4,5-triphosphate receptor in the ER membrane and calcium release-activated calcium channels in the plasma membrane contribute to p12I-mediated NFAT activation. Collectively, our results are the first to demonstrate the role of p12I in elevating cytoplasmic calcium, an antecedent to T-cell activation, and further support the important role of this accessory protein in the early events of HTLV-1 infection.

Nuclear factor of activated T cells and YY1 combine to repress IL-5 expression in a human T-cell line

1999 ◽  
Vol 104 (4) ◽  
pp. 820-827 ◽  
Author(s):  
Gretchen T.F. Schwenger ◽  
Régis Fournier ◽  
Leanne M. Hall ◽  
Colin J. Sanderson ◽  
Viatcheslav A. Mordvinov
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Line ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Human T Cell ◽  
Human T Cell Line

scholarly journals Inhibition of T-Cell Receptor Signal Transduction and Viral Expression by the Linker for Activation of T Cells-Interacting p12I Protein of Human T-Cell Leukemia/Lymphoma Virus Type 1

2007 ◽  
Vol 81 (17) ◽  
pp. 9088-9099 ◽  
Author(s):  
Risaku Fukumoto ◽  
Miroslav Dundr ◽  
Christophe Nicot ◽  
Anthony Adams ◽  
Valerio W. Valeri ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Virus Type ◽  
Calcium Release ◽  
Cell Receptor ◽  
Cell Leukemia ◽  
Viral Expression ◽  
Human T Cell

ABSTRACT The p12I protein of human T-cell leukemia/lymphoma virus type 1 (HTLV-1) is a small oncoprotein that increases calcium release following protein kinase C activation by phorbol myristate acetate, and importantly, this effect is linker for activation of T cells (LAT) independent. Here, we demonstrate that p12I inhibits the phosphorylation of LAT, Vav, and phospholipase C-γ1 and decreases NFAT (nuclear factor of activated T cells) activation upon engagement of the T-cell receptor (TCR) with anti-CD3 antibody. Furthermore, we demonstrate that p12I localizes to membrane lipid rafts and, upon engagement of the TCR, relocalizes to the interface between T cells and antigen-presenting cells, defined as the immunological synapse. A p12I knockout molecular clone of HTLV-1 expresses more virus upon antigen stimulation than the isogenic wild type, suggesting that, by decreasing T-cell responsiveness, p12I curtails viral expression. Thus, p12I has contrasting effects on TCR signaling: it down-regulates TCR in a LAT-dependent manner on one hand, and on the other, it increases calcium release in a LAT-independent manner. The negative regulation of T-cell activation by p12I may have evolved to minimize immune recognition of infected CD4+ T cells, to impair the function of infected cytotoxic CD8+ T cells, and to favor viral persistence in the infected host.

scholarly journals DC-SIGN Mediates Cell-Free Infection and Transmission of Human T-Cell Lymphotropic Virus Type 1 by Dendritic Cells

2009 ◽  
Vol 83 (21) ◽  
pp. 10908-10921 ◽  
Author(s):  
Pooja Jain ◽  
Sharrón L. Manuel ◽  
Zafar K. Khan ◽  
Jaya Ahuja ◽  
Kevin Quann ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
B Cell ◽  
Cell Lines ◽  
Glut 1 ◽  
Viral Binding ◽  
Human T Cell

ABSTRACT Despite the susceptibility of dendritic cells (DCs) to human T-cell lymphotropic virus type 1 (HTLV-1) infection and the defined role of these cells in disease pathogenesis, the mechanisms of viral binding to DCs have not been fully delineated. Recently, a glucose transporter, GLUT-1, heparan sulfate proteoglycans (HSPGs), and neuropilin-1 (NRP-1) were demonstrated to facilitate HTLV-1 entry into T cells. DCs express their own array of antigen receptors, the most important being the DC-specific intercellular adhesion molecule-3 (ICAM-3)-grabbing nonintegrin (DC-SIGN) with respect to retrovirus binding. Consequently, the role of DC-SIGN and other HTLV-1 attachment factors was analyzed in viral binding, transmission, and productive infection using monocyte-derived DCs (MDDCs), blood myeloid DCs, and B-cell lines expressing DC-SIGN. The relative expression of DC-SIGN, GLUT-1, HSPGs, and NRP-1 first was examined on both DCs and B-cell lines. Although the inhibition of these molecules reduced viral binding, HTLV-1 transmission from DCs to T cells was mediated primarily by DC-SIGN. DC-SIGN also was shown to play a role in the infection of MDDCs as well as model B-cell lines. The HTLV-1 infection of MDDCs also was achieved in blood myeloid DCs following the enhancement of virus-induced interleukin-4 production and subsequent DC-SIGN expression in this cell population. This study represents the first comprehensive analysis of potential HTLV-1 receptors on DCs and strongly suggests that DC-SIGN plays a critical role in HTLV-1 binding, transmission, and infection, thereby providing an attractive target for the development of antiretroviral therapeutics and microbicides.

scholarly journals Activation of Nuclear Factor of Activated T Cells by Human T-Lymphotropic Virus Type 1 Accessory Protein p12I

2002 ◽  
Vol 76 (7) ◽  
pp. 3493-3501 ◽  
Author(s):  
Björn Albrecht ◽  
Celine D. D'Souza ◽  
Wei Ding ◽  
Susheela Tridandapani ◽  
K. Mark Coggeshall ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Persistent Infection ◽  
Lymphocyte Activation ◽  
Accessory Protein ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
T Lymphotropic Virus ◽  
Calcium Dependent

ABSTRACT Human T-lymphotropic virus type 1 (HTLV-1) is the agent of an aggressive malignancy of CD4+ T lymphocytes, called adult T-cell lymphoma/leukemia, and is associated with numerous immune-mediated diseases. To establish infection, HTLV-1 must activate targeted T cells during early stages of infection. We recently demonstrated that the HTLV-1 accessory protein p12I is critical for persistent infection in vivo and for viral infectivity in quiescent primary lymphocytes, suggesting a role for p12I in lymphocyte activation. To test whether p12I modulates signaling pathways required for T-lymphocyte activation, we examined AP-1-, NF-κB-, and nuclear factor of activated T cells (NFAT)-driven reporter gene activity in p12I-expressing Jurkat T cells compared to vector-transfected control cells. HTLV-1 p12I specifically induced NFAT-mediated transcription approximately 20-fold in synergy with the Ras/mitogen-activated protein kinase pathway, but did not influence AP-1- or NF-κB-dependent gene expression. Inhibition of calcium-dependent signals by cyclosporin A, BAPTA-AM [glycine, N,N′-1,2-ethanediylbis(oxy-2,1-phenylene)-bis-N-2-(acetyloxy)methoxy-2-oxoethyl]-[bis(acetyloxy)methyl ester], and a dominant negative mutant of NFAT2 abolished the p12I-mediated activation of NFAT-dependent transcription. In contrast, inhibition of phospholipase C-γ and LAT (linker for activation of T cells) did not affect p12I-induced NFAT activity. Importantly, p12I functionally substituted for thapsigargin, which selectively depletes intracellular calcium stores. Our data are the first to demonstrate a role for HTLV-1 p12I in calcium-dependent activation of NFAT-mediated transcription in lymphoid cells. We propose a novel mechanism by which HTLV-1, a virus associated with lymphoproliferative disease, dysregulates common T-cell activation pathways critical for the virus to establish persistent infection.

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

miR-9 enhances the transactivation of nuclear factor of activated T cells by targeting KPNB1 and DYRK1B

2015 ◽  
Vol 308 (9) ◽  
pp. C720-C728 ◽  
Author(s):  
Yan Zeng ◽  
Yuna Wang ◽  
Zhiqin Wu ◽  
Kang Kang ◽  
Xiao Peng ◽  
...  
Keyword(s):  
T Cells ◽  
Signaling Pathway ◽  
Nuclear Translocation ◽  
Fast Response ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Cell Functions ◽  
Human T Cell ◽  
Nfat Activation ◽  
Subsequent Activation

The fast response to stimuli and subsequent activation of the nuclear factor of activated T cells (NFAT) signaling pathway play an essential role in human T cell functions. MicroRNAs (miRNAs) are increasingly implicated in regulation of numerous biological and pathological processes. In this study we demonstrate a novel function of miRNA-9 (miR-9) in regulation of the NFAT signaling pathway. Upon PMA-ionomycin stimulation, miR-9 was markedly increased, consistent with NFAT activation. Overexpression of miR-9 significantly enhanced NFAT activity and accelerated NFAT dephosphorylation and its nuclear translocation in response to PMA-ionomycin. Karyopherin-β1 (KPNB1, a nucleocytoplasmic transporter) and dual-specificity tyrosine phosphorylation-regulated kinase 1B (DYRK1B) were identified as direct targets of miR-9. Functionally, miR-9 promoted IL-2 production in stimulated human lymphocyte Jurkat T cells. Collectively, our data reveal a novel role for miR-9 in regulation of the NFAT pathway by targeting KPNB1 and DYRK1B.

scholarly journals Signals from OX40 regulate nuclear factor of activated T cells c1 and T cell helper 2 lineage commitment

2006 ◽  
Vol 103 (10) ◽  
pp. 3740-3745 ◽  
Author(s):  
T. So ◽  
J. Song ◽  
K. Sugie ◽  
A. Altman ◽  
M. Croft
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lineage Commitment ◽  
Nuclear Factor ◽  
Activated T Cells
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