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 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 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 Searching for immunotherapeutic targets in oncology during immune synapse formation

2021 ◽  
Vol 67 (3) ◽  
pp. 344-349
Author(s):  
Tatiana Nehaeva ◽  
Artem Karpov ◽  
Nino Pipia
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Synapse Formation ◽  
Immunological Synapse ◽  
Cell Receptor ◽  
Ligand Molecule ◽  
Receptor Ligands ◽  
Immune Synapse ◽  
Central Cluster ◽  
Antigen Presenting

Immunological synapse (IS) is a high-specialized connection between a T-lymphocyte and an antigen-presenting cell (APC), consisting of a cluster of T-cell receptors (TCR) surrounded by a ring of adhesion molecules. It has now been shown that formation of immune synapses is an active and dynamic mechanism that allows T cells to discriminate between potential antigenic ligands. At the first stage T-cell receptor ligands are involved in the external ring of the forming synapse. The movement of these complexes into the central cluster depends on the kinetics of T-cell receptor-ligand molecule interaction. Thus, the formation of a stable central cluster in the immunological synapse is a determining event for T-cell proliferation. The application of effective ways to influence on the IS by introduction into practice of new antitumor drugs and immunological synapse modulators allows to take a new look at the possibilities of tumor immunotherapy.

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.

scholarly journals Retrograde And Anterograde Transport Of LAT-Vesicles During The Immunological Synapse Formation: Defining The Finely-Tuned Mechanism

2020 ◽  
Author(s):  
Juan José Saez ◽  
Stéphanie Dogniaux ◽  
Massiullah Shafaq-Zadah ◽  
Ludger Johannes ◽  
Claire Hivroz ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Synapse Formation ◽  
Immunological Synapse ◽  
Retrograde Transport ◽  
Anterograde Transport ◽  
Immune Synapse ◽  
Cellular Context ◽  
Intracellular Compartments

ABSTRACTLAT is an important player of the signaling cascade induced by TCR activation. This adapter molecule is present at the plasma membrane of T lymphocytes and more abundantly in intracellular compartments. Upon T-cell activation the intracellular pool of LAT is recruited to the immune synapse (IS). We previously described two pathways controlling LAT trafficking: retrograde transport from endosomes to the TGN, and anterograde traffic from the Golgi to the IS. We address the specific role of 4 proteins, the GTPase Rab6, the t-SNARE syntaxin-16, the v-SNARE VAMP7 and the golgin GMAP210, in each pathway. Using different methods (endocytosis and Golgi trap assays, confocal and TIRF microscopy, TCR-signalosome pull down) we show that syntaxin-16 is regulating the retrograde transport of LAT whereas VAMP7 is regulating the anterograde transport. Moreover, GMAP210 and Rab6, known to contribute in both pathways, are in our cellular context specifically and respectively involved in anterograde and retrograde transport of LAT. Altogether, our data describe how retrograde and anterograde pathways coordinate LAT enrichment at the IS and point the Golgi as a central hub for the polarized recruitment of LAT to the IS. The role that this finely-tuned transport of signaling molecules plays in T-cell activation is discussed.

scholarly journals Developing T cells form an immunological synapse for passage through the β-selection checkpoint

2021 ◽  
Vol 220 (3) ◽  
Author(s):  
Amr H. Allam ◽  
Mirren Charnley ◽  
Kim Pham ◽  
Sarah M. Russell
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immunological Synapse ◽  
T Cell Development ◽  
Cell Receptor ◽  
Tcr Signaling ◽  
Cxcr4 Signaling ◽  
Thymic Stromal Cell

The β-selection checkpoint of T cell development tests whether the cell has recombined its genomic DNA to produce a functional T cell receptor β (TCRβ). Passage through the β-selection checkpoint requires the nascent TCRβ protein to mediate signaling through a pre-TCR complex. In this study, we show that developing T cells at the β-selection checkpoint establish an immunological synapse in in vitro and in situ, resembling that of the mature T cell. The immunological synapse is dependent on two key signaling pathways known to be critical for the transition beyond the β-selection checkpoint, Notch and CXCR4 signaling. In vitro and in situ analyses indicate that the immunological synapse promotes passage through the β-selection checkpoint. Collectively, these data indicate that developing T cells regulate pre-TCR signaling through the formation of an immunological synapse. This signaling platform integrates cues from Notch, CXCR4, and MHC on the thymic stromal cell to allow transition beyond the β-selection checkpoint.

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