scholarly journals ERM-Dependent Assembly of T-Cell Receptor Signaling and Co-stimulatory Molecules on Microvilli Prior to Activation

2019 ◽  
Author(s):  
Shirsendu Ghosh ◽  
Vincenzo Di Bartolo ◽  
Liron Tubul ◽  
Eyal Shimoni ◽  
Elena Kartvelishvily ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Protein Tyrosine Kinase ◽  
Cell Receptor ◽  
Signaling Molecules ◽  
Dominant Negative ◽  
Actin Binding ◽  
Dependent Manner ◽  
Proximal Signaling

SummaryT-cell surfaces are covered with microvilli, actin-rich and flexible protrusions. We use super-resolution microscopy to show that ≥90% T-cell receptor (TCR) complex molecules TCRαβ and TCRζ, as well as the co-receptor CD4 and the co-stimulatory molecule CD2 reside on microvilli of human T cells. Furthermore, TCR proximal signaling molecules involved in the initial stages of the immune response, such as the protein tyrosine kinase Lck and the key adaptor molecule LAT, are also enriched on microvilli. Notably, phosphorylated proteins of the ERM (ezrin, radixin, moesin) family colocalize with these heterodimers as well as with actin filaments within the microvilli of resting T cells. This finding implies a role for one or more phosphorylated ERMs in linking the TCR complex to the actin cytoskeleton within microvilli. Indeed, expression of a dominant-negative ezrin fragment effectively redistributes TCR molecules over the whole T cell surface. Our results establish microvilli as key signaling hubs, in which the TCR complex and its proximal signaling molecules and adaptors are pre-assembled prior to activation in an ERM-dependent manner. The preformed positioning of these actin-binding TCR assemblies on individual microvilli can facilitate the local transmission of TCR signals seconds after TCR occupancy and impacts the slower subsequent events that lead to the assembly of immunological synapses.

scholarly journals Comparison of T Cell Receptor-Induced Proximal Signaling and Downstream Functions in Immortalized and Primary T Cells

PLoS ONE ◽  
2009 ◽  
Vol 4 (5) ◽  
pp. e5430 ◽  
Author(s):  
Rebekah R. Bartelt ◽  
Noemi Cruz-Orcutt ◽  
Michaela Collins ◽  
Jon C. D. Houtman
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Proximal Signaling

scholarly journals IL-15 in tumor microenvironment causes rejection of large established tumors by T cells in a noncognate T cell receptor-dependent manner

2013 ◽  
Vol 110 (20) ◽  
pp. 8158-8163 ◽  
Author(s):  
R. B. Liu ◽  
B. Engels ◽  
K. Schreiber ◽  
C. Ciszewski ◽  
A. Schietinger ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Microenvironment ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Dependent Manner

scholarly journals Combinatorial Effect of T-Cell Receptor Ligation and CD45 Isoform Expression on the Signaling Contribution of the Small GTPases Ras and Rap1

2000 ◽  
Vol 20 (23) ◽  
pp. 8740-8747 ◽  
Author(s):  
Jan Czyzyk ◽  
David Leitenberg ◽  
Tom Taylor ◽  
Kim Bottomly
Keyword(s):  
Signal Transduction ◽  
Molecular Weight ◽  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Small Gtpases ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Negative Mutant

ABSTRACT By using ligands with various affinities for the T-cell receptor (TCR) and by altering the contribution of the CD45 tyrosine phosphatase, the effects of the potency of TCR-induced signals on the function of small GTPases Ras and Rap1 were studied. T cells expressing low-molecular-weight CD45 isoforms (e.g., CD45RO) exhibited the strongest activation of the Ras-dependent Elk-1 transcription factor and the highest sensitivity to the inhibitory action of dominant negative mutant Ras compared to T cells expressing high-molecular-weight CD45 isoforms (ABC). Moreover, stimulation of CD45RO+, but not CD45ABC+, T cells with a high-affinity TCR ligand induced suboptimal Elk-1 activation compared with the stimulation induced by an intermediate-affinity TCR-ligand interaction. This observation suggested that the Ras-dependent signaling pathway is safeguarded in CD45RO+ expressors by a negative regulatory mechanism(s) which prohibits maximal activation of the Ras-dependent signaling events following high-avidity TCR-ligand engagement. Interestingly, the biochemical activity of another small GTPase, the Ras-like protein Rap1, which has been implicated in the functional suppression of Ras signaling, was inversely correlated with the extent of Elk-1 activation induced by different-affinity TCR ligands. Consistently, overexpression of putative Rap dominant negative mutant RapN17 or the physiologic inhibitor of Rap1, the Rap GTPase-activating protein RapGAP, augmented the Elk-1 response in CD45RO+ T cells. This is in contrast to the suppressive effect of RapN17 and RapGAP on CD45ABC+ T cells, underscoring the possibility that Rap1 can act as either a repressor or a potentiator of Ras effector signals, depending on CD45 isoform expression. These observations suggest that cells expressing distinct isoforms of CD45 employ different signal transduction schemes to optimize Ras-mediated signal transduction in activated T lymphocytes.

scholarly journals INF2 promotes the formation of detyrosinated microtubules necessary for centrosome reorientation in T cells

2012 ◽  
Vol 198 (6) ◽  
pp. 1025-1037 ◽  
Author(s):  
Laura Andrés-Delgado ◽  
Olga M. Antón ◽  
Francesca Bartolini ◽  
Ana Ruiz-Sáenz ◽  
Isabel Correas ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Immunological Synapse ◽  
Cell Receptor ◽  
Microtubule Stabilization ◽  
Rho Family Gtpases ◽  
Tubulin Subunit ◽  
Proximal Signaling ◽  
Signaling Components

T cell antigen receptor–proximal signaling components, Rho-family GTPases, and formin proteins DIA1 and FMNL1 have been implicated in centrosome reorientation to the immunological synapse of T lymphocytes. However, the role of these molecules in the reorientation process is not yet defined. Here we find that a subset of microtubules became rapidly stabilized and that their α-tubulin subunit posttranslationally detyrosinated after engagement of the T cell receptor. Formation of stabilized, detyrosinated microtubules required the formin INF2, which was also found to be essential for centrosome reorientation, but it occurred independently of T cell receptor–induced massive tyrosine phosphorylation. The FH2 domain, which was mapped as the INF2 region involved in centrosome repositioning, was able to mediate the formation of stable, detyrosinated microtubules and to restore centrosome translocation in DIA1-, FMNL1-, Rac1-, and Cdc42-deficient cells. Further experiments indicated that microtubule stabilization was required for centrosome polarization. Our work identifies INF2 and stable, detyrosinated microtubules as central players in centrosome reorientation in T cells.

scholarly journals Histone 3 Lysine 9 (H3K9) Methyltransferase Recruitment to the Interleukin-2 (IL-2) Promoter Is a Mechanism of Suppression of IL-2 Transcription by the Transforming Growth Factor-β-Smad Pathway

2011 ◽  
Vol 286 (41) ◽  
pp. 35456-35465 ◽  
Author(s):  
Yu Wakabayashi ◽  
Taiga Tamiya ◽  
Ichiro Takada ◽  
Tomohiro Fukaya ◽  
Yuki Sugiyama ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Histone Methylation ◽  
Methylation Status ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Proximal Region ◽  
Dependent Manner ◽  
H3k27 Trimethylation

Suppression of IL-2 βproduction from T cells is an important process for the immune regulation by TGF-β. However, the mechanism by which this suppression occurs remains to be established. Here, we demonstrate that Smad2 and Smad3, two major TGF-β-downstream transcription factors, are redundantly essential for TGF-β-mediated suppression of IL-2 production in CD4+ T cells using Smad2- and Smad3-deficient T cells. Both Smad2 and Smad3 were recruited into the proximal region of the IL-2 promoter in response to TGF-β. We then investigated the histone methylation status of the IL-2 promoter. Although both histone H3 lysine 9 (H3K9) and H3K27 trimethylation have been implicated in gene silencing, only H3K9 trimethylation was increased in the proximal region of the IL-2 promoter in a Smad2/3-dependent manner, whereas H3K27 trimethylation was not. The H3K9 methyltransferases Setdb1 and Suv39h1 bound to Smad3 and suppressed IL-2 promoter activity in collaboration with Smad3. Overexpression of Suv39h1 in 68-41 T cells strongly inhibited IL-2 production in response to T cell receptor stimulation irrespective of the presence or absence of TGF-β, whereas Setdb1 overexpression only slightly suppressed IL-2 production. Silencing of Suv39h1 by shRNA reverted the suppressive effect of TGF-β on IL-2 production. Furthermore, TGF-β induced Suv39h1 recruitment to the proximal region of the IL-2 promoter in wild type primary T cells; however, this was not observed in Smad2−/−Smad3+/− T cells. Thus, we propose that Smads recruit H3K9 methyltransferases Suv39h1 to the IL-2 promoter, thereby inducing suppressive histone methylation and inhibiting T cell receptor-mediated IL-2 transcription.

scholarly journals Constitutive tyrosine phosphorylation of the T-cell receptor (TCR) zeta subunit: regulation of TCR-associated protein tyrosine kinase activity by TCR zeta.

1993 ◽  
Vol 13 (9) ◽  
pp. 5771-5780 ◽  
Author(s):  
N S van Oers ◽  
W Tao ◽  
J D Watts ◽  
P Johnson ◽  
R Aebersold ◽  
...  
Keyword(s):  
T Cells ◽  
Lymph Node ◽  
T Cell ◽  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
T Cell Receptor ◽  
Protein Tyrosine Kinase ◽  
Cell Receptor ◽  
Total Cell ◽  
Zeta Chain

The T-cell receptor (TCR) zeta subunit is an important component of the TCR complex, involved in signal transduction events following TCR engagement. In this study, we showed that the TCR zeta chain is constitutively tyrosine phosphorylated to similar extents in thymocytes and lymph node T cells. Approximately 35% of the tyrosine-phosphorylated TCR zeta (phospho zeta) precipitated from total cell lysates appeared to be surface associated. Furthermore, constitutive phosphorylation of TCR zeta in T cells occurred independently of antigen stimulation and did not require CD4 or CD8 coreceptor expression. In lymph node T cells that constitutively express tyrosine-phosphorylated TCR zeta, there was a direct correlation between surface TCR-associated protein tyrosine kinase (PTK) activity and expression of phospho zeta. TCR stimulation of these cells resulted in an increase in PTK activity that coprecipitated with the surface TCR complex and a corresponding increase in the levels of phospho zeta. TCR ligations also contributed to the detection of several additional phosphoproteins that coprecipitated with surface TCR complexes, including a 72-kDa tyrosine-phosphorylated protein. The presence of TCR-associated PTK activity also correlated with the binding of a 72-kDa protein, which became tyrosine phosphorylated in vitro kinase assays, to tyrosine phosphorylated TCR zeta. The cytoplasmic region of the TCR zeta chain was synthesized, tyrosine phosphorylated, and conjugated to Sepharose beads. Only tyrosine-phosphorylated, not nonphosphorylated, TCR zeta beads were capable of immunoprecipitating the 72-kDa protein from total cell lysates. This 72-kDa protein is likely the murine equivalent of human PTK ZAP-70, which has been shown to associate specifically with phospho zeta. These results suggest that TCR-associated PTK activity is regulated, at least in part, by the tyrosine phosphorylation status of TCR zeta.

scholarly journals Human Immunodeficiency Virus Reactivation by Phorbol Esters or T-Cell Receptor Ligation Requires both PKCα and PKCθ

2005 ◽  
Vol 79 (15) ◽  
pp. 9821-9830 ◽  
Author(s):  
Sergey A. Trushin ◽  
Gary D. Bren ◽  
Susana Asin ◽  
Kevin N. Pennington ◽  
Carlos V. Paya ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Phorbol Esters ◽  
Cell Receptor ◽  
Therapeutic Drug ◽  
Dependent Manner ◽  
Pkc Isoforms ◽  
Immunodeficiency Virus

ABSTRACT Latently human immunodeficiency virus (HIV)-infected memory CD4+ T cells represent the major obstacle to eradicating HIV from infected patients. Antigens, T-cell receptor (TCR) ligation, and phorbol esters can reactivate HIV from latency in a protein kinase C (PKC)-dependent manner; however, it is unknown which specific PKC isoforms are required for this effect. We demonstrate that constitutively active (CA) forms of both PKCθ, PKCθA148E, and PKCα, PKCαA25E, induce HIV long terminal repeat (LTR)-dependent transcription in Jurkat and primary human CD4+ T cells and that both PKCθA148E and PKCαA25E cause HIV reactivation in J1.1 T cells. Suppression of both PKCα and PKCθ with short hairpinned (sh) RNA inhibited CD3/CD28-induced HIV LTR-dependent transcription and HIV reactivation in J1.1 T cells. Both prostratin and phorbol myristate 13-acetate induced HIV LTR-dependent transcription and HIV reactivation in J1.1 T cells that was blocked by shRNA against either PKCα or PKCθ. Since suppression of PKCα and PKCθ together has no greater inhibitory effect on HIV reactivation than inhibition of PKCα alone, our data confirm that PKCα and PKCθ act in sequence. The requirement for PKCα and PKCθ for prostratin-induced HIV reactivation and the ability of selective PKCα or PKCθ agonists to induce HIV transcription indicate that these PKC isoforms are important targets for therapeutic drug design.

Constitutive tyrosine phosphorylation of the T-cell receptor (TCR) zeta subunit: regulation of TCR-associated protein tyrosine kinase activity by TCR zeta

1993 ◽  
Vol 13 (9) ◽  
pp. 5771-5780
Author(s):  
N S van Oers ◽  
W Tao ◽  
J D Watts ◽  
P Johnson ◽  
R Aebersold ◽  
...  
Keyword(s):  
T Cells ◽  
Lymph Node ◽  
T Cell ◽  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
T Cell Receptor ◽  
Protein Tyrosine Kinase ◽  
Cell Receptor ◽  
Total Cell ◽  
Zeta Chain

The T-cell receptor (TCR) zeta subunit is an important component of the TCR complex, involved in signal transduction events following TCR engagement. In this study, we showed that the TCR zeta chain is constitutively tyrosine phosphorylated to similar extents in thymocytes and lymph node T cells. Approximately 35% of the tyrosine-phosphorylated TCR zeta (phospho zeta) precipitated from total cell lysates appeared to be surface associated. Furthermore, constitutive phosphorylation of TCR zeta in T cells occurred independently of antigen stimulation and did not require CD4 or CD8 coreceptor expression. In lymph node T cells that constitutively express tyrosine-phosphorylated TCR zeta, there was a direct correlation between surface TCR-associated protein tyrosine kinase (PTK) activity and expression of phospho zeta. TCR stimulation of these cells resulted in an increase in PTK activity that coprecipitated with the surface TCR complex and a corresponding increase in the levels of phospho zeta. TCR ligations also contributed to the detection of several additional phosphoproteins that coprecipitated with surface TCR complexes, including a 72-kDa tyrosine-phosphorylated protein. The presence of TCR-associated PTK activity also correlated with the binding of a 72-kDa protein, which became tyrosine phosphorylated in vitro kinase assays, to tyrosine phosphorylated TCR zeta. The cytoplasmic region of the TCR zeta chain was synthesized, tyrosine phosphorylated, and conjugated to Sepharose beads. Only tyrosine-phosphorylated, not nonphosphorylated, TCR zeta beads were capable of immunoprecipitating the 72-kDa protein from total cell lysates. This 72-kDa protein is likely the murine equivalent of human PTK ZAP-70, which has been shown to associate specifically with phospho zeta. These results suggest that TCR-associated PTK activity is regulated, at least in part, by the tyrosine phosphorylation status of TCR zeta.

scholarly journals T cell receptor specificity drives accumulation of a reparative population of regulatory T cells within acutely injured skeletal muscle

2019 ◽  
Vol 116 (52) ◽  
pp. 26727-26733 ◽  
Author(s):  
Jun Cho ◽  
Wilson Kuswanto ◽  
Christophe Benoist ◽  
Diane Mathis
Keyword(s):  
Skeletal Muscle ◽  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
T Cell Receptor ◽  
Muscle Regeneration ◽  
Cell Receptor ◽  
Dependent Manner ◽  
Chronic Injury ◽  
Hindlimb Muscle

Foxp3+CD4+regulatory T cells (Tregs) play important roles in controlling both homeostatic processes and immune responses at the tissue and organismal levels. For example, Tregs promote muscle regeneration in acute or chronic injury models by direct effects on local muscle progenitor cells, as well as on infiltrating inflammatory cells. Muscle Tregs have a transcriptome, a T cell receptor (TCR) repertoire, and effector capabilities distinct from those of classical, lymphoid-organ Tregs, but it has proven difficult to study the provenance and functions of these unique features due to the rarity of muscle Tregs and their fragility on isolation. Here, we attempted to sidestep these hindrances by generating, characterizing, and employing a line of mice carrying rearranged transgenes encoding the TCRα and TCRβ chains from a Treg clone rapidly and specifically expanded within acutely injured hindlimb muscle of young mice. Tregs displaying the transgene-encoded TCR preferentially accumulated in injured hindlimb muscle in a TCR-dependent manner both in the straight transgenic model and in adoptive-transfer systems; non-Treg CD4+T cells expressing the same TCR did not specifically localize in injured muscle. The definitive muscle-Treg transcriptome was not established until the transgenic Tregs inhabited muscle. When crossed onto themdxmodel of Duchenne muscular dystrophy, the muscle-Treg TCR transgenes drove enhanced accumulation of Tregs in hindlimb muscles and improved muscle regeneration. These findings invoke the possibility of harnessing muscle Tregs or their TCRs for treatment of skeletal muscle pathologies.

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