scholarly journals mDia1/3-dependent actin polymerization spatiotemporally controls LAT phosphorylation by Zap70 at the immune synapse

2020 ◽  
Vol 6 (1) ◽  
pp. eaay2432 ◽  
Author(s):  
D. Thumkeo ◽  
Y. Katsura ◽  
Y. Nishimura ◽  
P. Kanchanawong ◽  
K. Tohyama ◽  
...  
Keyword(s):  
Actin Polymerization ◽  
Transmembrane Protein ◽  
Three Dimensional ◽  
Cell Receptor ◽  
Filamentous Actin ◽  
Tcr Signaling ◽  
Immune Synapse ◽  
Physiological Importance ◽  
Resolution Imaging ◽  
Tcr Activation

The mechanism by which the cytosolic protein Zap70 physically interacts with and phosphorylates its substrate, the transmembrane protein LAT, upon T cell receptor (TCR) stimulation remains largely obscure. In this study, we found that the pharmacological inhibition of formins, a major class of actin nucleators, suppressed LAT phosphorylation by Zap70, despite TCR stimulation–dependent phosphorylation of Zap70 remaining intact. High-resolution imaging and three-dimensional image reconstruction revealed that localization of phosphorylated Zap70 to the immune synapse (IS) and subsequent LAT phosphorylation are critically dependent on formin-mediated actin polymerization. Using knockout mice, we identify mDia1 and mDia3, which are highly expressed in T cells and which localize to the IS upon TCR activation, as the critical formins mediating this process. Our findings therefore describe previously unsuspected roles for mDia1 and mDia3 in the spatiotemporal control of Zap70-dependent LAT phosphorylation at the IS through regulation of filamentous actin, and underscore their physiological importance in TCR signaling.

scholarly journals Formin-generated actomyosin arcs propel T cell receptor microcluster movement at the immune synapse

2016 ◽  
Vol 215 (3) ◽  
pp. 383-399 ◽  
Author(s):  
Sricharan Murugesan ◽  
Jinsung Hong ◽  
Jason Yi ◽  
Dong Li ◽  
Jordan R. Beach ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Immunological Synapse ◽  
Three Dimensional ◽  
Cell Receptor ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Tcr Signaling ◽  
Immune Synapse ◽  
Distal Edge

Actin assembly and inward flow in the plane of the immunological synapse (IS) drives the centralization of T cell receptor microclusters (TCR MCs) and the integrin leukocyte functional antigen 1 (LFA-1). Using structured-illumination microscopy (SIM), we show that actin arcs populating the medial, lamella-like region of the IS arise from linear actin filaments generated by one or more formins present at the IS distal edge. After traversing the outer, Arp2/3-generated, lamellipodia-like region of the IS, these linear filaments are organized by myosin II into antiparallel concentric arcs. Three-dimensional SIM shows that active LFA-1 often aligns with arcs, whereas TCR MCs commonly reside between arcs, and total internal reflection fluorescence SIM shows TCR MCs being swept inward by arcs. Consistently, disrupting actin arc formation via formin inhibition results in less centralized TCR MCs, missegregated integrin clusters, decreased T–B cell adhesion, and diminished TCR signaling. Together, our results define the origin, organization, and functional significance of a major actomyosin contractile structure at the IS that directly propels TCR MC transport.

scholarly journals Calcium influx through CRAC channels controls actin organization and dynamics at the immune synapse

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Catherine A Hartzell ◽  
Katarzyna I Jankowska ◽  
Janis K Burkhardt ◽  
Richard S Lewis
Keyword(s):  
Actin Polymerization ◽  
Calcium Influx ◽  
Cell Receptor ◽  
Feedback Loops ◽  
Tcr Signaling ◽  
Immune Synapse ◽  
Actin Organization ◽  
Crac Channels ◽  
Crac Channel ◽  
Antigen Presenting

T cell receptor (TCR) engagement opens Ca2+ release-activated Ca2+ (CRAC) channels and triggers formation of an immune synapse between T cells and antigen-presenting cells. At the synapse, actin reorganizes into a concentric lamellipod and lamella with retrograde actin flow that helps regulate the intensity and duration of TCR signaling. We find that Ca2+ influx is required to drive actin organization and dynamics at the synapse. Calcium acts by promoting actin depolymerization and localizing actin polymerization and the actin nucleation promotion factor WAVE2 to the periphery of the lamellipod while suppressing polymerization elsewhere. Ca2+-dependent retrograde actin flow corrals ER tubule extensions and STIM1/Orai1 complexes to the synapse center, creating a self-organizing process for CRAC channel localization. Our results demonstrate a new role for Ca2+ as a critical regulator of actin organization and dynamics at the synapse, and reveal potential feedback loops through which Ca2+ influx may modulate TCR signaling.

scholarly journals Ca2+/Calmodulin-Dependent Protein Kinase II Is a Modulator of CARMA1-Mediated NF-κB Activation

2006 ◽  
Vol 26 (14) ◽  
pp. 5497-5508 ◽  
Author(s):  
Kazuhiro Ishiguro ◽  
Todd Green ◽  
Joseph Rapley ◽  
Heather Wachtel ◽  
Cosmas Giallourakis ◽  
...  
Keyword(s):  
T Cell ◽  
Protein Kinase ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Receptor ◽  
Tcr Signaling ◽  
Dependent Protein Kinase ◽  
Immune Synapse ◽  
Protein Kinase Ii ◽  
Dependent Protein

ABSTRACT CARMA1 is a central regulator of NF-κB activation in lymphocytes. CARMA1 and Bcl10 functionally interact and control NF-κB signaling downstream of the T-cell receptor (TCR). Computational analysis of expression neighborhoods of CARMA1-Bcl10MALT 1 for enrichment in kinases identified calmodulin-dependent protein kinase II (CaMKII) as an important component of this pathway. Here we report that Ca2+/CaMKII is redistributed to the immune synapse following T-cell activation and that CaMKII is critical for NF-κB activation induced by TCR stimulation. Furthermore, CaMKII enhances CARMA1-induced NF-κB activation. Moreover, we have shown that CaMKII phosphorylates CARMA1 on Ser109 and that the phosphorylation facilitates the interaction between CARMA1 and Bcl10. These results provide a novel function for CaMKII in TCR signaling and CARMA1-induced NF-κB activation.

The costimulatory activity of Tim-3 requires Akt and MAPK signaling and its recruitment to the immune synapse

2021 ◽  
Vol 14 (687) ◽  
pp. eaba0717
Author(s):  
Shunsuke Kataoka ◽  
Priyanka Manandhar ◽  
Judong Lee ◽  
Creg J. Workman ◽  
Hridesh Banerjee ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Transmembrane Domain ◽  
Transmembrane Protein ◽  
Cell Receptor ◽  
Mapk Signaling ◽  
Inhibitory Protein ◽  
Immune Synapse

Expression of the transmembrane protein Tim-3 is increased on dysregulated T cells undergoing chronic activation, including during chronic infection and in solid tumors. Thus, Tim-3 is generally thought of as an inhibitory protein. We and others previously reported that under some circumstances, Tim-3 exerts paradoxical costimulatory activity in T cells (and other cells), including enhancement of the phosphorylation of ribosomal S6 protein. Here, we examined the upstream signaling pathways that control Tim-3–mediated increases in phosphorylated S6 in T cells. We also defined the localization of Tim-3 relative to the T cell immune synapse and its effects on downstream signaling. Recruitment of Tim-3 to the immune synapse was mediated exclusively by the transmembrane domain, replacement of which impaired the ability of Tim-3 to costimulate T cell receptor (TCR)–dependent S6 phosphorylation. Furthermore, enforced localization of the Tim-3 cytoplasmic domain to the immune synapse in a chimeric antigen receptor still enabled T cell activation. Together, our findings are consistent with a model whereby Tim-3 enhances TCR-proximal signaling under acute conditions.

scholarly journals Endoplasmic reticulum–associated degradation regulates mitochondrial dynamics in brown adipocytes

Science ◽  
2020 ◽  
Vol 368 (6486) ◽  
pp. 54-60 ◽  
Author(s):  
Zhangsen Zhou ◽  
Mauricio Torres ◽  
Haibo Sha ◽  
Christopher J. Halbrook ◽  
Françoise Van den Bergh ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Mitochondrial Dynamics ◽  
Three Dimensional ◽  
Sigma Receptor ◽  
High Resolution Imaging ◽  
Brown Adipocytes ◽  
Physiological Importance ◽  
Endoplasmic Reticulum Associated Degradation ◽  
Cold Sensitive ◽  
Resolution Imaging

The endoplasmic reticulum (ER) engages mitochondria at specialized ER domains known as mitochondria-associated membranes (MAMs). Here, we used three-dimensional high-resolution imaging to investigate the formation of pleomorphic “megamitochondria” with altered MAMs in brown adipocytes lacking the Sel1L-Hrd1 protein complex of ER-associated protein degradation (ERAD). Mice with ERAD deficiency in brown adipocytes were cold sensitive and exhibited mitochondrial dysfunction. ERAD deficiency affected ER-mitochondria contacts and mitochondrial dynamics, at least in part, by regulating the turnover of the MAM protein, sigma receptor 1 (SigmaR1). Thus, our study provides molecular insights into ER-mitochondrial cross-talk and expands our understanding of the physiological importance of Sel1L-Hrd1 ERAD.

scholarly journals Agent-Based Modeling of T Cell Receptor Cooperativity

2020 ◽  
Vol 21 (18) ◽  
pp. 6473
Author(s):  
Anastasios Siokis ◽  
Philippe A. Robert ◽  
Michael Meyer-Hermann
Keyword(s):  
T Cell ◽  
Synapse Formation ◽  
Immunological Synapse ◽  
Cell Receptor ◽  
Agent Based Model ◽  
Tcr Signaling ◽  
Immune Synapse ◽  
Agent Based ◽  
Affinity Modulation ◽  
Antigen Peptide

Immunological synapse (IS) formation is a key event during antigen recognition by T cells. Recent experimental evidence suggests that the affinity between T cell receptors (TCRs) and antigen is actively modulated during the early steps of TCR signaling. In this work, we used an agent-based model to study possible mechanisms for affinity modulation during IS formation. We show that, without any specific active mechanism, the observed affinity between receptors and ligands evolves over time and depends on the density of ligands of the antigen peptide presented by major histocompatibility complexes (pMHC) and TCR molecules. A comparison between the presence or absence of TCR–pMHC centrally directed flow due to F-actin coupling suggests that centripetal transport is a potential mechanism for affinity modulation. The model further suggests that the time point of affinity measurement during immune synapse formation is critical. Finally, a mathematical model of F-actin foci formation incorporated in the agent-based model shows that TCR affinity can potentially be actively modulated by positive/negative feedback of the F-actin foci on the TCR-pMHC association rate kon.

scholarly journals Condensation of the plasma membrane at the site of T lymphocyte activation

2005 ◽  
Vol 171 (1) ◽  
pp. 121-131 ◽  
Author(s):  
Katharina Gaus ◽  
Elena Chklovskaia ◽  
Barbara Fazekas de St. Groth ◽  
Wendy Jessup ◽  
Thomas Harder
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
Cell Activation ◽  
Transmembrane Protein ◽  
Lymphocyte Activation ◽  
Cell Receptor ◽  
Membrane Domains ◽  
Tcr Signaling

After activation, T lymphocytes restructure their cell surface to form membrane domains at T cell receptor (TCR)–signaling foci and immunological synapses (ISs). To address whether these rearrangements involve alteration in the structure of the plasma membrane bilayer, we used the fluorescent probe Laurdan to visualize its lipid order. We observed a condensation of the plasma membrane at TCR activation sites. The formation of ordered domains depends on the presence of the transmembrane protein linker for the activation of T cells and Src kinase activity. Moreover, these ordered domains are stabilized by the actin cytoskeleton. Membrane condensation occurs upon TCR stimulation alone but is prolonged by CD28 costimulation with TCR. In ISs, which are formed by conjugates of TCR transgenic T lymphocytes and cognate antigen-presenting cells, similar condensed membrane phases form first in central regions and later at the periphery of synapses. The formation of condensed membrane domains at T cell activation sites biophysically reflects membrane raft accumulation, which has potential implications for signaling at ISs.

scholarly journals T-Cell Receptor Activation Initiates Multiple Modes of Actin Polymerization within the Immune Synapse

2012 ◽  
Vol 102 (3) ◽  
pp. 349a
Author(s):  
Erdem Tabdanov ◽  
Alexander Gondarenko ◽  
Ryan Kerslake ◽  
James C. Hone ◽  
Lance C. Kam
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Actin Polymerization ◽  
Cell Receptor ◽  
Receptor Activation ◽  
Multiple Modes ◽  
Immune Synapse

scholarly journals Agent-Based Modeling of T Cell Receptor Cooperativity

2020 ◽  
Author(s):  
Anastasios Siokis ◽  
Philippe A. Robert ◽  
Michael Meyer-Hermann
Keyword(s):  
T Cell ◽  
Synapse Formation ◽  
Immunological Synapse ◽  
Cell Receptor ◽  
Agent Based Model ◽  
Tcr Signaling ◽  
Immune Synapse ◽  
Agent Based ◽  
Affinity Modulation ◽  
Antigen Peptide

AbstractImmunological synapse (IS) formation is a key event during antigen recognition by T cells. Recent experimental evidence suggests that the affinity between T cell receptors (TCRs) and antigen is actively modulated during the early steps of TCR signaling. In this work, we used an agent-based model to study possible mechanisms for affinity modulation during IS formation. We show that, without any specific active mechanism, the observed affinity between receptors and ligands evolves over time, and depends on the density of ligand pMHC (antigen peptide presented by major histocompatibility complexes) and TCR molecules. Comparison between the presence or absence of TCR-pMHC centrally directed flow due to F-actin coupling suggest centripetal transport is a potential mechanism for the affinity modulation. The model further suggests that the time point of affinity measurement during immune synapse formation is critical. Finally, a mathematical model of F-actin foci formation incorporated in the agent-based model, shows that TCR affinity can potentially be actively modulated by a positive/negative feedback of F-actin foci on the TCR-pMHC association rate kon.

scholarly journals Inhibition of T Cell Receptor Activation by Semi-Synthetic Sesquiterpene Lactone Derivatives and Molecular Modeling of Their Interaction with Glutathione and Tyrosine Kinase ZAP-70

Molecules ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 350 ◽  
Author(s):  
Andrei Khlebnikov ◽  
Igor Schepetkin ◽  
Anarkul Kishkentaeva ◽  
Zhanar Shaimerdenova ◽  
Gayane Atazhanova ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tyrosine Kinase ◽  
T Cell Receptor ◽  
Sesquiterpene Lactones ◽  
Cell Receptor ◽  
Receptor Activation ◽  
Tcr Signaling ◽  
Jurkat T Cells ◽  
Tcr Activation

A variety of natural compounds have been shown to modulate T cell receptor (TCR) activation, including natural sesquiterpene lactones (SLs). In the present studies, we evaluated the biological activity of 11 novel semi-synthetic SLs to determine their ability to modulate TCR activation. Of these compounds, α -epoxyarglabin, cytisinyl epoxyarglabin, 1 β ,10 α -epoxyargolide, and chloroacetate grosheimin inhibited anti-CD3-induced Ca2+ mobilization and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in Jurkat T cells. We also found that the active SLs depleted intracellular glutathione (GSH) in Jurkat T cells, supporting their reactivity towards thiol groups. Because the zeta-chain associated tyrosine kinase 70 kDa (ZAP-70) is essential for TCR signaling and contains a tandem SH2 region that is highly enriched with multiple cysteines, we performed molecular docking of natural SLs and their semi-synthetic derivatives into the ZAP-70 binding site. The docking showed that the distance between the carbon atom of the exocyclic methylene group and the sulfur atom in Cys39 of the ZAP-70 tandem SH2 module was 3.04–5.3 Å for active compounds. Furthermore, the natural SLs and their derivatives could be differentiated by their ability to react with the Cys39 SH-group. We suggest that natural and/or semi-synthetic SLs with an α -methylene- γ -lactone moiety can specifically target GSH and the kinase site of ZAP-70 and inhibit the initial phases of TCR activation.

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