scholarly journals The ADAP/SKAP55 Signaling Module Regulates T-Cell Receptor-Mediated Integrin Activation through Plasma Membrane Targeting of Rap1

2006 ◽  
Vol 26 (19) ◽  
pp. 7130-7144 ◽  
Author(s):  
Stefanie Kliche ◽  
Dennis Breitling ◽  
Mauro Togni ◽  
Rico Pusch ◽  
Katja Heuer ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Small Gtpase ◽  
Membrane Targeting ◽  
Adapter Proteins ◽  
Integrin Activation ◽  
Raft Fraction ◽  
Inside Out

ABSTRACT Adhesion of T cells after stimulation of the T-cell receptor (TCR) is mediated via signaling processes that have collectively been termed inside-out signaling. The molecular basis for inside-out signaling is not yet completely understood. Here, we show that a signaling module comprising the cytosolic adapter proteins ADAP and SKAP55 is involved in TCR-mediated inside-out signaling and, moreover, that the interaction between ADAP and SKAP55 is mandatory for integrin activation. Disruption of the ADAP/SKAP55 module leads to displacement of the small GTPase Rap1 from the plasma membrane without influencing its GTPase activity. These findings suggest that the ADAP/SKAP55 complex serves to recruit activated Rap1 to the plasma membrane. In line with this hypothesis is the finding that membrane targeting of the ADAP/SKAP55 module induces T-cell adhesion in the absence of TCR-mediated stimuli. However, it appears as if the ADAP/SKAP55 module can exert its signaling function outside of the classical raft fraction of the cell membrane.

scholarly journals RIAM Links the ADAP/SKAP-55 Signaling Module to Rap1, Facilitating T-Cell-Receptor-Mediated Integrin Activation

2007 ◽  
Vol 27 (11) ◽  
pp. 4070-4081 ◽  
Author(s):  
Gaël Ménasché ◽  
Stefanie Kliche ◽  
Emily J. H. Chen ◽  
Theresia E. B. Stradal ◽  
Burkhart Schraven ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Small Gtpase ◽  
Adapter Proteins ◽  
Adapter Protein ◽  
Integrin Activation ◽  
Tcr Signaling ◽  
Antigen Presenting

ABSTRACT One outcome of T-cell receptor (TCR) signaling is increased affinity and avidity of integrins for their ligands. This occurs through a process known as inside-out signaling, which has been shown to require several molecular components including the adapter proteins ADAP (adhesion and degranulation-promoting adapter protein) and SKAP-55 (55-kDa src kinase-associated phosphoprotein) and the small GTPase Rap1. Herein, we provide evidence linking ADAP and SKAP-55 to RIAM, a recently described adapter protein that binds selectively to active Rap1. We identified RIAM as a key component linking the ADAP/SKAP-55 module to the small GTPase Rap1, facilitating TCR-mediated integrin activation. We show that RIAM constitutively interacts with SKAP-55 in both a heterologous transfection system and primary T cells and map the region essential for this interaction. Additionally, we find that the SKAP-55/RIAM complex is essential both for TCR-mediated adhesion and for efficient conjugate formation between T cells and antigen-presenting cells. Mechanistic studies revealed that the ADAP/SKAP-55 module relocalized RIAM and Rap1 to the plasma membrane following TCR activation to facilitate integrin activation. These results describe for the first time a link between ADAP/SKAP-55 and the Rap1/RIAM complex and provide a potential new mechanism for TCR-mediated integrin activation.

scholarly journals Cdc42 Couples T Cell Receptor Endocytosis to GRAF1-Mediated Tubular Invaginations of the Plasma Membrane

Cells ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1388 ◽  
Author(s):  
Rossatti ◽  
Ziegler ◽  
Schregle ◽  
Betzler ◽  
Ecker ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Cell Activation ◽  
Adaptor Protein ◽  
Cell Receptor ◽  
Small Gtpase ◽  
Endocytic Pathway ◽  
Bar Domain ◽  
Endocytic Vesicles

: T cell activation is immediately followed by internalization of the T cell receptor (TCR). TCR endocytosis is required for T cell activation, but the mechanisms supporting removal of TCR from the cell surface remain incompletely understood. Here we report that TCR endocytosis is linked to the clathrin-independent carrier (CLIC) and GPI-enriched endocytic compartments (GEEC) endocytic pathway. We show that unlike the canonical clathrin cargo transferrin or the adaptor protein Lat, internalized TCR accumulates in tubules shaped by the small GTPase Cdc42 and the Bin/amphiphysin/Rvs (BAR) domain containing protein GRAF1 in T cells. Preventing GRAF1-positive tubules to mature into endocytic vesicles by expressing a constitutively active Cdc42 impairs the endocytosis of TCR, while having no consequence on the uptake of transferrin. Together, our data reveal a link between TCR internalization and the CLIC/GEEC endocytic route supported by Cdc42 and GRAF1.

scholarly journals Dual Fatty Acylation of p59Fyn Is Required for Association with the T Cell Receptor ζ Chain through Phosphotyrosine–Src Homology Domain-2 Interactions

1999 ◽  
Vol 145 (2) ◽  
pp. 377-389 ◽  
Author(s):  
Woutervan't Hof ◽  
Marilyn D. Resh
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Insoluble Fraction ◽  
Sh2 Domain ◽  
Sh2 Domains ◽  
Fatty Acylation ◽  
Src Homology ◽  
Activation Motif

The first 10 residues within the Src homology domain (SH)–4 domain of the Src family kinase Fyn are required for binding to the immune receptor tyrosine-based activation motif (ITAM) of T cell receptor (TCR) subunits. Recently, mutation of glycine 2, cysteine 3, and lysines 7 and 9 was shown to block binding of Fyn to TCR ζ chain ITAMs, prompting the designation of these residues as an ITAM recognition motif (Gauen, L.K.T., M.E. Linder, and A.S. Shaw. 1996. J. Cell Biol. 133:1007–1015). Here we show that these residues do not mediate direct interactions with TCR ITAMs, but rather are required for efficient myristoylation and palmitoylation of Fyn. Specifically, coexpression of a K7,9A-Fyn mutant with N-myristoyltransferase restored myristoylation, membrane binding, and association with the cytoplasmic tail of TCR ζ fused to CD8. Conversely, treatment of cells with 2-hydroxymyristate, a myristoylation inhibitor, blocked association of wild-type Fyn with ζ. The Fyn NH2 terminus was necessary but not sufficient for interaction with ζ and both Fyn kinase and SH2 domains were required, directing phosphorylation of ζ ITAM tyrosines and binding to ζ ITAM phosphotyrosines. Fyn/ζ interaction was sensitive to octylglucoside and filipin, agents that disrupt membrane rafts. Moreover, a plasma membrane bound, farnesylated Fyn construct, G2A,C3S-FynKRas, was not enriched in the detergent insoluble fraction and did not associate with ζ. We conclude that the Fyn SH4 domain provides the signals for fatty acylation and specific plasma membrane localization, stabilizing the interactions between the Fyn SH2 domain and phosphotyrosines in TCR ζ chain ITAMs.

scholarly journals The gamma and epsilon subunits of the CD3 complex inhibit pre-Golgi degradation of newly synthesized T cell antigen receptors.

1990 ◽  
Vol 110 (4) ◽  
pp. 973-986 ◽  
Author(s):  
T Wileman ◽  
G R Carson ◽  
M Concino ◽  
A Ahmed ◽  
C Terhorst
Keyword(s):  
T Cells ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
T Cell ◽  
T Cell Receptor ◽  
Intracellular Transport ◽  
Cell Receptor ◽  
Dna Transfection ◽  
Antigen Receptors ◽  
Intracellular Degradation

The T cell receptor for antigen (TCR) is composed of six different transmembrane proteins. T cells carefully control the intracellular transport of the receptor and allow only complete receptors to reach the plasma membrane. In an attempt to understand how T cells regulate this process, we used c-DNA transfection and subunit-specific antibodies to follow the intracellular transport of five subunits (alpha beta gamma delta epsilon) of the receptor. In particular, we assessed the intracellular stability of each chain. Our results showed that the chains were markedly different in their susceptibility to intracellular degradation. TCR alpha and beta and CD3 delta were degraded rapidly, whereas CD3 gamma and epsilon were stable. An analysis of the N-linked oligosaccharides of the glycoprotein subunits suggested that the chains were unable to reach the medial Golgi during the metabolic chase. This was supported by immunofluorescence micrographs that showed both the stable CD3 gamma and unstable CD3 delta chain localized in the endoplasmic reticulum. To study the effects of subunit associations on intracellular transport we used cotransfection to reconstitute precise combinations of subunits. Associations between stable and unstable subunits expressed in the same cell led to the formation of stable complexes. These complexes were retained in or close to the endoplasmic reticulum. The results suggested that the intracellular transport of the T cell receptor could be regulated by two mechanisms. The TCR alpha and beta and CD3 delta subunits were degraded rapidly and as a consequence failed to reach the plasma membrane. CD3 gamma or epsilon were stable but were retained inside the cell. The results also demonstrated that there was an interplay between the two pathways such that the CD3 gamma and epsilon subunits were able to protect labile chains from rapid intracellular degradation. In this way, they could seed subunit assembly in or close to the endoplasmic reticulum and allow a stable receptor to form before its transport to the plasma membrane.

scholarly journals The T Cell Receptor Resides in Ordered Plasma Membrane Nanodomains that Aggregate Upon T Cell Activation

2015 ◽  
Vol 108 (2) ◽  
pp. 98a
Author(s):  
Ingela Parmryd ◽  
Astrid Riehl ◽  
Jelena Dinic ◽  
Jeremy Adler
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Receptor

scholarly journals ZAP-70 Association with T Cell Receptor ζ (TCRζ): Fluorescence Imaging of Dynamic Changes upon Cellular Stimulation

1998 ◽  
Vol 143 (3) ◽  
pp. 613-624 ◽  
Author(s):  
Joanne Sloan-Lancaster ◽  
John Presley ◽  
Jan Ellenberg ◽  
Tetsuo Yamazaki ◽  
Jennifer Lippincott-Schwartz ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
Tyrosine Kinase ◽  
T Cell Receptor ◽  
Protein Tyrosine Kinase ◽  
Specific Interaction ◽  
Active Form ◽  
Lymphocyte Activation ◽  
Cell Receptor ◽  
Protein Tyrosine

The nonreceptor protein tyrosine kinase ZAP-70 is a critical enzyme required for successful T lymphocyte activation. After antigenic stimulation, ZAP-70 rapidly associates with T cell receptor (TCR) subunits. The kinetics of its translocation to the cell surface, the properties of its specific interaction with the TCRζ chain expressed as a chimeric protein (TTζ and Tζζ), and its mobility in different intracellular compartments were studied in individual live HeLa cells, using ZAP-70 and Tζζ fused to green fluorescent protein (ZAP-70 GFP and Tζζ–GFP, respectively). Time-lapse imaging using confocal microscopy indicated that the activation-induced redistribution of ZAP-70 to the plasma membrane, after a delayed onset, is of long duration. The presence of the TCRζ chain is critical for the redistribution, which is enhanced when an active form of the protein tyrosine kinase Lck is coexpressed. Binding specificity to TTζ was indicated using mutant ZAP-70 GFPs and a truncated ζ chimera. Photobleaching techniques revealed that ZAP-70 GFP has decreased mobility at the plasma membrane, in contrast to its rapid mobility in the cytosol and nucleus. Tζζ– GFP is relatively immobile, while peripherally located ZAP-70 in stimulated cells is less mobile than cytosolic ZAP-70 in unstimulated cells, a phenotype confirmed by determining the respective diffusion constants. Examination of the specific molecular association of signaling proteins using these approaches has provided new insights into the TCRζ–ZAP-70 interaction and will be a powerful tool for continuing studies of lymphocyte activation.

scholarly journals Genome-wide CRISPR screen identifies FAM49B as a key regulator of actin dynamics and T cell activation

2018 ◽  
Vol 115 (17) ◽  
pp. E4051-E4060 ◽  
Author(s):  
Wanjing Shang ◽  
Yong Jiang ◽  
Michael Boettcher ◽  
Kang Ding ◽  
Marianne Mollenauer ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Cell Activation ◽  
Active Form ◽  
Cell Receptor ◽  
Small Gtpase ◽  
Genome Wide ◽  
A Genome ◽  
Crispr Screen

Despite decades of research, mechanisms controlling T cell activation remain only partially understood, which hampers T cell-based immune cancer therapies. Here, we performed a genome-wide CRISPR screen to search for genes that regulate T cell activation. Our screen confirmed many of the known regulators in proximal T cell receptor signaling and, importantly, also uncovered a previously uncharacterized regulator, FAM49B (family with sequence similarity 49 member B). FAM49B deficiency led to hyperactivation of Jurkat T cells following T cell receptor stimulation, as indicated by enhancement of CD69 induction, PAK phosphorylation, and actin assembly. FAM49B directly interacted with the active form of the small GTPase Rac, and genetic disruption of the FAM49B–Rac interaction compromised FAM49B function. Thus, FAM49B inhibits T cell activation by repressing Rac activity and modulating cytoskeleton reorganization.

scholarly journals Spatiotemporal Regulation of Signaling: Focus on T Cell Activation and the Immunological Synapse

2020 ◽  
Vol 21 (9) ◽  
pp. 3283
Author(s):  
Esther Garcia ◽  
Shehab Ismail
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
T Cell ◽  
T Cell Receptor ◽  
T Cell Activation ◽  
Cell Activation ◽  
Immunological Synapse ◽  
Cell Receptor ◽  
Signaling Network ◽  
Spatiotemporal Regulation

In a signaling network, not only the functions of molecules are important but when (temporal) and where (spatial) those functions are exerted and orchestrated is what defines the signaling output. To temporally and spatially modulate signaling events, cells generate specialized functional domains with variable lifetime and size that concentrate signaling molecules, enhancing their transduction potential. The plasma membrane is a key in this regulation, as it constitutes a primary signaling hub that integrates signals within and across the membrane. Here, we examine some of the mechanisms that cells exhibit to spatiotemporally regulate signal transduction, focusing on the early events of T cell activation from triggering of T cell receptor to formation and maturation of the immunological synapse.

INTEGRATION OF T CELL RECEPTOR–DEPENDENT SIGNALING PATHWAYS BY ADAPTER PROTEINS

1999 ◽  
Vol 17 (1) ◽  
pp. 89-108 ◽  
Author(s):  
James L. Clements ◽  
Nancy J. Boerth ◽  
Jong Ran Lee ◽  
Gary A. Koretzky
Keyword(s):  
T Cell ◽  
Signaling Pathways ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Adapter Proteins

scholarly journals T Cell Receptor (TCR) Interacting Molecule (TRIM), A Novel Disulfide-linked Dimer Associated with the TCR–CD3–ζ Complex, Recruits Intracellular Signaling Proteins to the Plasma Membrane

1998 ◽  
Vol 188 (3) ◽  
pp. 561-575 ◽  
Author(s):  
Eddy Bruyns ◽  
Anne Marie-Cardine ◽  
Henning Kirchgessner ◽  
Karin Sagolla ◽  
Andrej Shevchenko ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Amino Acid ◽  
T Cell ◽  
T Cell Receptor ◽  
Intracellular Signaling ◽  
Adaptor Protein ◽  
Cell Receptor ◽  
Sh2 Domain ◽  
Pi3 Kinase ◽  
Signaling Proteins

The molecular mechanisms regulating recruitment of intracellular signaling proteins like growth factor receptor–bound protein 2 (Grb2), phospholipase Cγ1, or phosphatidylinositol 3-kinase (PI3-kinase) to the plasma membrane after stimulation of the T cell receptor (TCR)– CD3–ζ complex are not very well understood. We describe here purification, tandem mass spectrometry sequencing, molecular cloning, and biochemical characterization of a novel transmembrane adaptor protein which associates and comodulates with the TCR–CD3–ζ complex in human T lymphocytes and T cell lines. This protein was termed T cell receptor interacting molecule (TRIM). TRIM is a disulfide-linked homodimer which is comprised of a short extracellular domain of 8 amino acids, a 19–amino acid transmembrane region, and a 159–amino acid cytoplasmic tail. In its intracellular domain, TRIM contains several tyrosine-based signaling motifs that could be involved in SH2 domain–mediated protein–protein interactions. Indeed, after T cell activation, TRIM becomes rapidly phosphorylated on tyrosine residues and then associates with the 85-kD regulatory subunit of PI3-kinase via an YxxM motif. Thus, TRIM represents a TCR-associated transmembrane adaptor protein which is likely involved in targeting of intracellular signaling proteins to the plasma membrane after triggering of the TCR.

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