scholarly journals STIM2 targets Orai1/STIM1 to the AKAP79 signaling complex and confers coupling of Ca2+entry with NFAT1 activation

2020 ◽  
Vol 117 (28) ◽  
pp. 16638-16648 ◽  
Author(s):  
Ga-Yeon Son ◽  
Krishna Prasad Subedi ◽  
Hwei Ling Ong ◽  
Lucile Noyer ◽  
Hassan Saadi ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Unique Role ◽  
Signaling Complex ◽  
Contact Sites ◽  
Channel Function

The Orai1 channel is regulated by stromal interaction molecules STIM1 and STIM2 within endoplasmic reticulum (ER)-plasma membrane (PM) contact sites. Ca2+signals generated by Orai1 activate Ca2+-dependent gene expression. When compared with STIM1, STIM2 is a weak activator of Orai1, but it has been suggested to have a unique role in nuclear factor of activated T cells 1 (NFAT1) activation triggered by Orai1-mediated Ca2+entry. In this study, we examined the contribution of STIM2 in NFAT1 activation. We report that STIM2 recruitment of Orai1/STIM1 to ER-PM junctions in response to depletion of ER-Ca2+promotes assembly of the channel with AKAP79 to form a signaling complex that couples Orai1 channel function to the activation of NFAT1. Knockdown of STIM2 expression had relatively little effect on Orai1/STIM1 clustering or local and global [Ca2+]iincreases but significantly attenuated NFAT1 activation and assembly of Orai1 with AKAP79. STIM1ΔK, which lacks the PIP2-binding polybasic domain, was recruited to ER-PM junctions following ER-Ca2+depletion by binding to Orai1 and caused local and global [Ca2+]iincreases comparable to those induced by STIM1 activation of Orai1. However, in contrast to STIM1, STIM1ΔK induced less NFAT1 activation and attenuated the association of Orai1 with STIM2 and AKAP79. Orai1-AKAP79 interaction and NFAT1 activation were recovered by coexpressing STIM2 with STIM1ΔK. Replacing the PIP2-binding domain of STIM1 with that of STIM2 eliminated the requirement of STIM2 for NFAT1 activation. Together, these data demonstrate an important role for STIM2 in coupling Orai1-mediated Ca2+influx to NFAT1 activation.

scholarly journals A potential role for nuclear factor of activated T-cells in receptor tyrosine kinase and G-protein-coupled receptor agonist-induced cell proliferation

2002 ◽  
Vol 368 (1) ◽  
pp. 183-190 ◽  
Author(s):  
Chandrahasa R. YELLATURU ◽  
Salil K. GHOSH ◽  
R.K. RAO ◽  
Lisa K. JENNINGS ◽  
Aviv HASSID ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Dna Synthesis ◽  
G Protein ◽  
Receptor Tyrosine Kinase ◽  
Binding Activity ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Dna Binding Activity ◽  
G Protein Coupled

We have studied the role of nuclear factor of activated T-cells (NFAT) transcription factors in the induction of vascular smooth muscle cell (VSMC) growth by platelet-derived growth factor-BB (PDGF-BB) and thrombin, the receptor tyrosine kinase (RTK) and G-protein-coupled receptor (GPCR) agonists, respectively. NFATc1 but not NFATc2 or NFATc3 was translocated from the cytoplasm to the nucleus upon treatment of VSMCs with PDGF-BB or thrombin. Translocation of NFATc1 was followed by an increase in NFAT—DNA binding activity and NFAT-dependent reporter gene expression. Cyclosporin A (CsA), a potent and specific inhibitor of calcineurin, a calcium/calmodulin-dependent serine phosphatase involved in the dephosphorylation and activation of NFATs, blocked NFAT—DNA binding activity and NFAT-dependent reporter gene expression induced by PDGF-BB and thrombin. CsA also completely inhibited PDGF-BB- and thrombin-induced VSMC growth, as measured by DNA synthesis and cell number. In addition, forced expression of the NFAT-competing peptide VIVIT for calcineurin binding significantly attenuated the DNA synthesis induced by PDGF-BB and thrombin in VSMCs. Together, these findings for the first time demonstrate a role for NFATs in RTK and GPCR agonist-induced growth in VSMCs.

scholarly journals Antisense-mediated loss of calcium homoeostasis endoplasmic reticulum protein (CHERP; ERPROT213-21) impairs Ca2+ mobilization, nuclear factor of activated T-cells (NFAT) activation and cell proliferation in Jurkat T-lymphocytes

2003 ◽  
Vol 373 (1) ◽  
pp. 133-143 ◽  
Author(s):  
Flavia A. O'ROURKE ◽  
Janice M. LaPLANTE ◽  
Maurice B. FEINSTEIN
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
T Cells ◽  
Endoplasmic Reticulum ◽  
T Lymphocytes ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Endoplasmic Reticulum Protein ◽  
Hel Cells ◽  
Er Membrane

We recently discovered a novel gene on chromosome 19p13.1 and its product, an integral endoplasmic reticulum (ER) membrane protein, termed CHERP (calcium homoeostasis endoplasmic reticulum protein). A monoclonal antibody against its C-terminal domain inhibits Ins(1,4,5)P3-induced Ca2+ release from ER membrane vesicles of many cell types, and an antisense-mediated knockdown of CHERP in human erythroleukemia (HEL) cells greatly impaired Ca2+ mobilization by thrombin. In the present paper, we explore further CHERP's function in Jurkat T-lymphocytes. Confocal laser immunofluorescence microscopy showed that CHERP was co-localized with the Ins(1,4,5)P3 receptor throughout the cytoplasmic and perinuclear region, as previously found in HEL cells. Transfection of Jurkat cells with a lacI-regulated mammalian expression vector containing CHERP antisense cDNA caused a knockdown of CHERP and impaired the rise of cytoplasmic Ca2+ (measured by fura-2 acetoxymethyl ester fluorescence) caused by phytohaemagglutinin (PHA) and thrombin. A 50% fall of CHERP decreased the PHA-induced rise of the cytoplasmic free Ca2+ concentration ([Ca2+]i), but Ca2+ influx was unaffected. Greater depletion of CHERP (>70%) did not affect the concentration of Ins(1,4,5)P3 receptors, but diminished the rise of [Ca2+]i in response to PHA to ≤30% of that in control cells, decreased Ca2+ influx and slowed the initial rate of [Ca2+]i rise caused by thapsigargin, an inhibitor of the sarcoplasmic/endoplasmic-reticulum Ca2+-ATPase, suggesting there was also some deficit in ER Ca2+ stores. In CHERP-depleted cells the Ca2+-dependent activation and translocation of the key transcription factor NFAT (nuclear factor of activated T-cells) from cytoplasm to nucleus was suppressed. Furthermore, cell proliferation was greatly slowed (as in HEL cells) along with a 60% decrease in cyclin D1, a key regulator of progression through the G1 phase of the cell cycle. These findings provide further evidence that CHERP is an important component of the ER Ca2+-mobilizing system in cells, and its loss impairs Ca2+-dependent biochemical pathways and progression through the cell cycle.

scholarly journals Vascular Endothelial Growth Factor Activates Nuclear Factor of Activated T Cells in Human Endothelial Cells: a Role for Tissue Factor Gene Expression

1999 ◽  
Vol 19 (3) ◽  
pp. 2032-2043 ◽  
Author(s):  
Angel Luis Armesilla ◽  
Elisa Lorenzo ◽  
Pablo Gómez del Arco ◽  
Sara Martínez-Martínez ◽  
Arantzazu Alfranca ◽  
...  
Keyword(s):  
Gene Expression ◽  
Vascular Endothelial Growth Factor ◽  
T Cells ◽  
Endothelial Cells ◽  
Growth Factor ◽  
Vascular Endothelial ◽  
Nuclear Factor ◽  
Promoter Activation ◽  
Activated T Cells ◽  
Endothelial Growth Factor

ABSTRACT Vascular endothelial growth factor (VEGF) is a potent angiogenic inducer that stimulates the expression of tissue factor (TF), the major cellular initiator of blood coagulation. Here we show that signaling triggered by VEGF induced DNA-binding and transcriptional activities of nuclear factor of activated T cells (NFAT) and AP-1 in human umbilical vein endothelial cells (HUVECs). VEGF also induced TF mRNA expression and gene promoter activation by a cyclosporin A (CsA)-sensitive mechanism. As in lymphoid cells, NFAT was dephosphorylated and translocated to the nucleus upon activation of HUVECs, and these processes were blocked by CsA. NFAT was involved in the VEGF-mediated TF promoter activation as evidenced by cotransfection experiments with a dominant negative version of NFAT and site-directed mutagenesis of a newly identified NFAT site within the TF promoter that overlaps with a previously identified κB-like site. Strikingly, this site bound exclusively NFAT not only from nuclear extracts of HUVECs activated by VEGF, a stimulus that failed to induce NF-κB-binding activity, but also from extracts of cells activated with phorbol esters and calcium ionophore, a combination of stimuli that triggered the simultaneous activation of NFAT and NF-κB. These results implicate NFAT in the regulation of endothelial genes by physiological means and shed light on the mechanisms that switch on the gene expression program induced by VEGF and those regulating TF gene expression.

scholarly journals Nuclear Factor of Activated T Cells and Cytokines Gene Expression of the T Cells in AIDS Patients with Immune Reconstitution Inflammatory Syndrome during Highly Active Antiretroviral Therapy

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Jia Sun ◽  
Heling Chen ◽  
Yirui Xie ◽  
Junwei Su ◽  
Ying Huang ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Immune Reconstitution Inflammatory Syndrome ◽  
Highly Active Antiretroviral Therapy ◽  
Immune Reconstitution ◽  
High Expression ◽  
Nuclear Factor ◽  
Aids Patients ◽  
Activated T Cells ◽  
Inflammatory Syndrome

Background. The etiology of immune reconstitution inflammatory syndrome (IRIS) in AIDS patients after the initiation of HAART remains unknown. Several researches indicated that the development of IRIS is associated with the production and variation of cytokines, whose gene expression are closely related to the Ca2+/CN-nuclear factor of activated T cells (NFAT) pathway.Methods. We studied the expression of NFAT isoforms and their major target cytokines genes in peripheral blood CD3+T cells of subjects through fluorescence quantitative PCR and explored the expression changes of these genes before and after HAART.Results. After the initiation of HARRT, NFAT1, IL-6, and IL-8 gene expression showed a reversal trend in the CD3+T cells of the IRIS group and changed from low expression before HARRT to high expression after HARRT. In particular, the relative gene expression of NFAT1 was markedly higher compared with the other three isoforms. The IRIS group also showed higher NFAT4, NFAT2, NFAT1, IL-1β, IL-10, IL-2, IL-18, and TNF-αgene expression than the non-IRIS group.Conclusion. This study suggested that high expression levels of IL-2, IL-6, IL-8, TNF-α, IL-1β, IL-10, IL-12, and IL-18 can predict the risk of IRIS. The increased expression of NFAT1 and NFAT4 may promote the expression of cytokines, such as IL-6, IL-8, and TNF-α, which may promote the occurrence of IRIS.

scholarly journals Hierarchy of signaling thresholds downstream of the T cell receptor and the Tec kinase ITK

2021 ◽  
Vol 118 (35) ◽  
pp. e2025825118
Author(s):  
Michael P. Gallagher ◽  
James M. Conley ◽  
Pranitha Vangala ◽  
Manuel Garber ◽  
Andrea Reboldi ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Signal Strength ◽  
Cell Receptor ◽  
Early Gene ◽  
Sequencing Analysis ◽  
Nuclear Factor ◽  
Activated T Cells

The strength of peptide:MHC interactions with the T cell receptor (TCR) is correlated with the time to first cell division, the relative scale of the effector cell response, and the graded expression of activation-associated proteins like IRF4. To regulate T cell activation programming, the TCR and the TCR proximal interleukin-2–inducible T cell kinase (ITK) simultaneously trigger many biochemically separate signaling cascades. T cells lacking ITK exhibit selective impairments in effector T cell responses after activation, but under the strongest signaling conditions, ITK activity is dispensable. To gain insight into whether TCR signal strength and ITK activity tune observed graded gene expression through the unequal activation of distinct signaling pathways, we examined Erk1/2 phosphorylation or nuclear factor of activated T cells (NFAT) and nuclear factor (NF)-κB translocation in naïve OT-I CD8+ cell nuclei. We observed the consistent digital activation of NFAT1 and Erk1/2, but NF-κB displayed dynamic, graded activation in response to variation in TCR signal strength, tunable by treatment with an ITK inhibitor. Inhibitor-treated cells showed the dampened induction of AP-1 factors Fos and Fosb, NF-κB response gene transcripts, and survival factor Il2 transcripts. ATAC sequencing analysis also revealed that genomic regions most sensitive to ITK inhibition were enriched for NF-κB and AP-1 motifs. Specific inhibition of NF-κB during peptide stimulation tuned the expression of early gene products like c-Fos. Together, these data indicate a key role for ITK in orchestrating the optimal activation of separate TCR downstream pathways, specifically aiding NF-κB activation. More broadly, we revealed a mechanism by which variations in TCR signal strength can produce patterns of graded gene expression in activated T cells.

scholarly journals Junctophilin-4, a component of the endoplasmic reticulum–plasma membrane junctions, regulates Ca2+ dynamics in T cells

2016 ◽  
Vol 113 (10) ◽  
pp. 2762-2767 ◽  
Author(s):  
Jin Seok Woo ◽  
Sonal Srikanth ◽  
Miyuki Nishi ◽  
Peipei Ping ◽  
Hiroshi Takeshima ◽  
...  
Keyword(s):  
T Cells ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Genetic Manipulation ◽  
Erk Signaling ◽  
Excitable Cells ◽  
Activated T Cells ◽  
Activation Markers ◽  
Extracellular Signaling ◽  
Store Depletion

Orai1 and stromal interaction molecule 1 (STIM1) mediate store-operated Ca2+ entry (SOCE) in immune cells. STIM1, an endoplasmic reticulum (ER) Ca2+ sensor, detects store depletion and interacts with plasma membrane (PM)-resident Orai1 channels at the ER–PM junctions. However, the molecular composition of these junctions in T cells remains poorly understood. Here, we show that junctophilin-4 (JP4), a member of junctional proteins in excitable cells, is expressed in T cells and localized at the ER–PM junctions to regulate Ca2+ signaling. Silencing or genetic manipulation of JP4 decreased ER Ca2+ content and SOCE in T cells, impaired activation of the nuclear factor of activated T cells (NFAT) and extracellular signaling-related kinase (ERK) signaling pathways, and diminished expression of activation markers and cytokines. Mechanistically, JP4 directly interacted with STIM1 via its cytoplasmic domain and facilitated its recruitment into the junctions. Accordingly, expression of this cytoplasmic fragment of JP4 inhibited SOCE. Furthermore, JP4 also formed a complex with junctate, a Ca2+-sensing ER-resident protein, previously shown to mediate STIM1 recruitment into the junctions. We propose that the junctate–JP4 complex located at the junctions cooperatively interacts with STIM1 to maintain ER Ca2+ homeostasis and mediate SOCE in T cells.

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