351
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Hara H, Wada T, Bakal C, Kozieradzki I, Suzuki S, Suzuki N, Nghiem M, Griffiths EK, Krawczyk C, Bauer B, D'Acquisto F, Ghosh S, Yeh WC, Baier G, Rottapel R, Penninger JM. The MAGUK family protein CARD11 is essential for lymphocyte activation. Immunity 2003; 18:763-75. [PMID: 12818158 DOI: 10.1016/s1074-7613(03)00148-1] [Citation(s) in RCA: 275] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Members of the MAGUK family proteins cluster receptors and intracellular signaling molecules at the neuronal synapse. We report that genetic inactivation of the MAGUK family protein CARD11/Carma1/Bimp3 results in a complete block in T and B cell immunity. CARD11 is essential for antigen receptor- and PKC-mediated proliferation and cytokine production in T and B cells due to a selective defect in JNK and NFkappaB activation. Moreover, B cell proliferation and JNK activation were impaired upon stimulation of TLR4 with lipopolysaccharide, indicating that CARD11 is involved in both the innate and adaptive immune systems. Our results show that the same family of molecules are critical regulators of neuronal synapses and immune receptor signaling.
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Affiliation(s)
- Hiromitsu Hara
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr Gasse 7, A-1030, Vienna, Austria
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352
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McDonald D, Wu L, Bohks SM, KewalRamani VN, Unutmaz D, Hope TJ. Recruitment of HIV and its receptors to dendritic cell-T cell junctions. Science 2003; 300:1295-7. [PMID: 12730499 DOI: 10.1126/science.1084238] [Citation(s) in RCA: 556] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Monocyte-derived dendritic cells (MDDCs) can efficiently bind and transfer HIV infectivity without themselves becoming infected. Using live-cell microscopy, we found that HIV was recruited to sites of cell contact in MDDCs. Analysis of conjugates between MDDCs and T cells revealed that, in the absence of antigen-specific signaling, the HIV receptors CD4, CCR5, and CXCR4 on the T cell were recruited to the interface while the MDDCs concentrated HIV to the same region. We propose that contact between dendritic cells and T cells facilitates transmission of HIV by locally concentrating virus, receptor, and coreceptor during the formation of an infectious synapse.
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Affiliation(s)
- David McDonald
- Department of Microbiology and Immunology, University of Illinois, Chicago, IL 60612, USA
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353
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Torres E, Rosen MK. Contingent phosphorylation/dephosphorylation provides a mechanism of molecular memory in WASP. Mol Cell 2003; 11:1215-27. [PMID: 12769846 DOI: 10.1016/s1097-2765(03)00139-4] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Cells can retain information about previous stimuli to produce distinct future responses. The biochemical mechanisms by which this is achieved are not well understood. The Wiskott-Aldrich syndrome protein (WASP) is an effector of the Rho-family GTPase Cdc42, whose activation leads to stimulation of the actin nucleating assembly, Arp2/3 complex. We demonstrate that efficient phosphorylation and dephosphorylation of WASP at Y291 are both contingent on binding to activated Cdc42. Y291 phosphorylation increases the basal activity of WASP toward Arp2/3 complex and enables WASP activation by new stimuli, SH2 domains of Src-family kinases. The requirement for contingency in both phosphorylation and dephosphorylation enables long-term storage of information by WASP following decay of GTPase signals. This biochemical circuitry allows WASP to respond to the levels and timing of GTPase and kinase signals. It provides mechanisms to specifically achieve transient or persistent actin remodeling, as well as long-lasting potentiation of actin-based responses to kinases.
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Affiliation(s)
- Eduardo Torres
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75205, USA
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354
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Fais S, Malorni W. Leukocyte uropod formation and membrane/cytoskeleton linkage in immune interactions. J Leukoc Biol 2003; 73:556-63. [PMID: 12714569 DOI: 10.1189/jlb.1102568] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The acquisition of a cell polarity is a crucial requirement for migration, activation, and apoptosis of leukocytes. The polarization of leukocytes involves the formation of two distinct poles: the leading edge--the attachment cell site to the substrate allowing directional movements of the cell--and on the opposite side, the uropod--mostly involved in cell-to-cell interaction and in a variety of leukocyte activities including activation and apoptosis. However, the uropod takes shape in neutrophils, monocytes, and natural killer cells, and the formation of this cell protrusion seems to exert an important role in immune interactions. In fact, the polarization sites of leukocytes are involved in a complex cross-talk between cells and extracellular matrix components, and a number of receptors and counter-receptors crowd in the contact sites to allow efficient cell-to-cell or cell-substrate interaction. The membrane/cytoskeleton interaction plays a crucial role in tuning these activities and in "predisposing" leukocytes to their function through the acquisition of a polarized phenotype. This review is focused on the mechanisms underlying the formation of the leukocyte uropod, the role of cytoskeleton in defining its structure and function, and the involvement of the uropod in the complex interplay between immune cells.
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Affiliation(s)
- Stefano Fais
- Laboratory of Immunology, Istituto Superiore di Sanità, Rome, Italy.
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355
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Turner M. The role of Vav proteins in B cell responses. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 512:29-34. [PMID: 12405184 DOI: 10.1007/978-1-4615-0757-4_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Affiliation(s)
- Martin Turner
- Laboratory of Lymphocyte Signaling and Development Molecular Immunology Programme, The Babraham Institute Cambridge, UK
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356
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Dustin ML. Regulation of T cell migration through formation of immunological synapses: the stop signal hypothesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 512:191-201. [PMID: 12405204 DOI: 10.1007/978-1-4615-0757-4_25] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Michael L Dustin
- Program in Molecular Pathogenesis and Department of Pathology, Skirball Institute of Molecular Medicine, New York University School of Medicine, NY 10016, USA
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357
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Romeo PH, Lemarchandel V, Tordjman R. Neuropilin-1 in the immune system. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 515:49-54. [PMID: 12613542 DOI: 10.1007/978-1-4615-0119-0_4] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The neuropilin-1 (NRP1) and neuropilin-2 (NRP2) receptors can bind the class 3 semaphorin subfamily and the heparin-binding forms of vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF). The functions of NRP1 and NRP2 have been extensively studied in neurons where they act in axon guidance and in endothelial cells where they promote angiogenesis and cell migration. In this chapter, we will present evidences indicating that neuropilin-1 is likely to mediate contacts between the dendritic cells and the T lymphocytes via homotypic interactions and is essential for the initiation of the primary immune response. These results emphasize the molecular similarities between the nervous and the immune systems and open new areas in the modulation of the immune response.
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Affiliation(s)
- Paul-Henri Romeo
- Institut Cochin, Département Hématologie, INSERM U567, CNRS UMR 8104, Maternité Port-Royal, 123 Boulevard de Port-Royal, 75014 Paris, France.
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358
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Abstract
The heparan sulphate proteoglycan agrin is expressed as several isoforms in various tissues. Agrin is best known as a crucial organizer of postsynaptic differentiation at the neuromuscular junction, but it has recently also been implicated in the formation of the immunological synapse, the organization of the cytoskeleton and the amelioration of function in diseased muscle. So the activities of agrin might be of broader significance than previously anticipated.
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Affiliation(s)
- Gabriela Bezakova
- Department of Pharmacology/Neurobiology, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
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359
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Si MS, Ji P, Tromberg BJ, Lee M, Kwok J, Ng SC, Imagawa DK. Farnesyltransferase inhibition: a novel method of immunomodulation. Int Immunopharmacol 2003; 3:475-83. [PMID: 12689653 DOI: 10.1016/s1567-5769(02)00278-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Farnesyltransferase inhibitors (FTIs) are anticancer compounds that inhibit Ras GTPases. Since Ras GTPases play key roles in T cell activation and function, we hypothesized that FTIs have immunomodulatory properties and are potential antirejection agents. An investigation was performed on a potent FTI to evaluate this hypothesis in the in vitro setting. The in vitro effects of the FTI A-228839 were evaluated. Lectin- or antigen presenting cell (APC)-induced lymphocyte proliferation in the presence of A-228839 was measured. The effects of A-228839 on 1E5 T cell polarity were assessed by microscopy. Intracellular calcium ([Ca(2+)](i)) kinetics of lectin-activated lymphocytes was monitored by flow cytometry. The effects of A-228839 on peripheral blood mononuclear cell (PBMC) cytokine production was assessed by a cytometric bead array method. Activation-induced apoptosis was measured with an annexin V staining assay.A-228839 inhibited lectin-induced proliferation (IC(50)=0.24+/-0.11 microM). The inhibitory effects of A-228839 on lectin induced lymphocyte proliferation were additive to those of CsA. A-228839 was more effective in inhibiting APC-induced T cell proliferation (IC(50)=0.10+/-0.09 microM). A-228839 significantly disrupted the polarized shape of 1E5 T cells at physiologic concentrations. A-228839 altered PBMC baseline [Ca(2+)](i) but did not affect [Ca(2+)](i) kinetics during lectin-induced lymphocyte activation. A-228839 inhibited lymphocyte Th1 cytokine production at submicromolar levels and promoted apoptosis in lectin-activated lymphocytes.A-228839 potently inhibits lymphocyte activation and function. Our results suggest that FTIs may represent a new class of clinically useful immunomodulatory agents. A-228839 has potent in vitro immunomodulatory properties that warrant in vivo evaluation as an antirejection agent.
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Affiliation(s)
- Ming-Sing Si
- Department of Surgery, UCI College of Medicine, University of California, Irvine, CA 92868, USA
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360
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Abstract
The distinct protein kinase C (PKC) multigene family (PKC gene module) is known to be the 'classic' intracellular receptor for mitogenic phorbol esters, and it is widely accepted in the scientific community that the 'PKC effect' is essential in activation, differentiation, adhesion and motility, as well as in cellular survival, of T cells. Nevertheless, the first concepts about PKC isotype heterogeneity of cellular localization and function emerged only recently, when the PKC-theta pathways were mapped to critical signaling networks that control T cell receptor (TCR)/CD3-dependent interleukin (IL)-2 production and proliferation in T lymphocytes. This review summarizes the current knowledge about T cell expressed PKC gene products, their known and/or suspected regulation and cellular effector pathways, as well as physiological functions in T lymphocytes (as determined by molecular cell biology and ongoing mouse genetic studies). Given PKCs integral role in T cell function but today's very fragmentary molecular understanding of directly PKC-mediated effector functions in transmembrane signaling, a 'molecular biosystematics' approach is suggested to resolve the isotype-selective functions of this PKC gene family. Such an approach has to be based not only on genomic/cytogenetic analysis to establish its genetic relationships but also on biochemical/cell biology and genetic studies to resolve its functional diversity and, ultimately, nonredundant roles in real T cell physiology.
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Affiliation(s)
- Gottfried Baier
- Institute of Medical Biology and Human Genetics, University of Innsbruck, Austria.
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361
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Saito T, Yamasaki S. Negative feedback of T cell activation through inhibitory adapters and costimulatory receptors. Immunol Rev 2003; 192:143-60. [PMID: 12670402 DOI: 10.1034/j.1600-065x.2003.00022.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Antigen recognition by the T cell receptor (TCR) complex induces the formation of a TCR signalosome by recruiting various signaling molecules, generating the recognition signals for T cell activation. The activation status and functional outcome are positively and negatively regulated by dynamic organization of the signalosome and by costimulation signals. We have studied the negative regulation of T cell activation, particularly through inhibitory adapters and costimulation receptors that are little expressed in resting cells but are induced upon T cell activation. We described Grb-associated binder 2 (Gab2) and cytotoxic T lymphocyte antigen-4 (CTLA-4) as a representative inhibitory adapter and a negative costimulation receptor, respectively, both of which exhibit negative feedback. Gab2 functions as a signal branch for activation vs. inhibition, as phosphorylation of either Src homology 2 (SH2) domain-containing leukocyte phosphoprotein of 76 kDa (SLP-76) or Gab2 by zeta-associated protein of 70 kDa (ZAP-70) determines the fate of the response. As a professional inhibitory receptor, CTLA-4 inhibits T cell response by competition of ligand binding with positive costimulator receptor CD28, and also induces inhibitory signaling. The trafficking and the cell surface expression of CTLA-4 are dynamically regulated and induced. CTLA-4 is accumulated in lysosomes and secreted to the T cell-APC contact site upon TCR stimulation. As T cell activation proceeds, these inhibitory adapters and costimulation receptors are induced and suppress/regulate the responses as negative feedback.
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Affiliation(s)
- Takashi Saito
- Department of Molecular Genetics, Graduate School of Medicine, Chiba University, Chiba, Japan.
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362
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Abstract
Members of the phosphoinositide-3 kinase (PI3K) family control several cellular responses including cell growth, survival, cytoskeletal remodeling and the trafficking of intracellular organelles in many different types of cell. In particular PI3K has important functions in the immune system. It has been difficult to evaluate the roles of distinct PI3Ks in cellular immune responses because no PI3K inhibitors are specific for individual family members and because most stimuli activate several PI3K enzymes. The development of gene-targeted mice now enables us to examine the physiological functions of individual PI3K enzymes in the immune system in vivo.
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Affiliation(s)
- Shigeo Koyasu
- Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo 160-8582, Japan.
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363
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Trautmann A, Revy P, Donnadieu E, Bismuth G. [Immunological synapses and neuronal synapses]. Med Sci (Paris) 2003; 19:429-36. [PMID: 12836215 DOI: 10.1051/medsci/2003194429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The interface between two cells from the immune system has recently been coined "immunological synapse". The authors review recent findings concerning the structure of the synapse formed between T lymphocytes and antigen-presenting cells. T cells can be part of different synapses, depending on the antigen-presenting cell (B cell hybridoma, proteo-lipid bilayer, macrophage, dendritic cell). The synapse formed with dendritic cells is discussed in more details. A comparison is made with the synapses from the nervous system. Several parallel questions are discussed: how receptors can be clustered, what is the influence of synapse functioning on the structure of the synapse. It is suggested that in both cases two modes of communication exist in parallel: direct cell-cell contacts and soluble mediators, neurotransmitters in one case, putative immunotransmitters in the other.
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Affiliation(s)
- Alain Trautmann
- Département de Biologie Cellulaire, Institut Cochin, Inserm U.567, Cnrs UMR 8104, 22, rue Méchain, 75014 Paris, France.
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364
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Dustin ML. Coordination of T cell activation and migration through formation of the immunological synapse. Ann N Y Acad Sci 2003; 987:51-9. [PMID: 12727623 DOI: 10.1111/j.1749-6632.2003.tb06032.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
T cell activation is based on interactions of T cell antigen receptors with MHC-peptide complexes in a specialized cell-cell junction between the T cell and antigen-presenting cell-the immunological synapse. The immunological synapse coordinates naïve T cell activation and migration by stopping T cell migration with antigen-presenting cells bearing appropriate major histocompatibility complex (MHC) peptide complexes. At the same time, the immunological synapse allows full T cell activation through sustained signaling over a period of several hours. The immunological synapse supports activation in the absence of continued T cell migration, which is required for T cell activation through serial encounters. Src and Syk family kinases are activated early in immunological synapse formation, but this signaling process returns to the basal level after 30 min; at the same time, the interactions between T cell receptors (TCRs) and MHC peptides are stabilized within the immunological synapse. The molecular pattern of the mature synapse in helper T cells is a self-stabilized structure that is correlated with cytokine production and proliferation. I propose that this molecular pattern and its specific biochemical constituents are necessary to amplify signals from the partially desensitized TCR.
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Affiliation(s)
- Michael L Dustin
- Program in Molecular Pathogenesis, Skirball Institute of Biomolecular Medicine and the Department of Pathology, New York University School of Medicine, New York, New York 10016, USA.
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365
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McCann FE, Vanherberghen B, Eleme K, Carlin LM, Newsam RJ, Goulding D, Davis DM. The size of the synaptic cleft and distinct distributions of filamentous actin, ezrin, CD43, and CD45 at activating and inhibitory human NK cell immune synapses. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:2862-70. [PMID: 12626536 DOI: 10.4049/jimmunol.170.6.2862] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In this study, we report the organization of cytoskeletal and large transmembrane proteins at the inhibitory and activating NK cell immunological or immune synapse (IS). Filamentous actin accumulates at the activating, but not the inhibitory, NK cell IS. However, surprisingly, ezrin and the associated protein CD43 are excluded from the inhibitory, but not the activating, NK cell IS. This distribution of ezrin and CD43 at the inhibitory NK cell IS is similar to that previously seen at the activating T cell IS. CD45 is also excluded from the inhibitory, but not activating, NK cell IS. In addition, electron microscopy reveals wide and narrow domains across the synaptic cleft. Target cell HLA-C, located by immunogold labeling, clusters where the synaptic cleft spans the size of HLA-C bound to the inhibitory killer Ig-like receptor. These data are consistent with assembly of the NK cell IS involving a combination of cytoskeletal-driven mechanisms and thermodynamics favoring the organization of receptor/ligand pairs according to the size of their extracellular domains.
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MESH Headings
- Actin Cytoskeleton/metabolism
- Actin Cytoskeleton/ultrastructure
- Actins/metabolism
- Actins/ultrastructure
- Antigens, CD
- Cell Communication/immunology
- Cell Line, Transformed
- Clone Cells
- Cytoskeletal Proteins
- Cytotoxicity, Immunologic
- HLA-C Antigens/metabolism
- Humans
- Intercellular Junctions/immunology
- Intercellular Junctions/metabolism
- Intercellular Junctions/ultrastructure
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Killer Cells, Natural/ultrastructure
- Leukocyte Common Antigens/biosynthesis
- Leukocyte Common Antigens/metabolism
- Leukocyte Common Antigens/ultrastructure
- Leukosialin
- Lymphocyte Activation/immunology
- Microscopy, Confocal
- Microscopy, Immunoelectron
- Phosphoproteins/biosynthesis
- Phosphoproteins/metabolism
- Phosphoproteins/ultrastructure
- Receptors, Immunologic/biosynthesis
- Receptors, KIR2DL1
- Sialoglycoproteins/biosynthesis
- Sialoglycoproteins/metabolism
- Sialoglycoproteins/ultrastructure
- Tumor Cells, Cultured
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Affiliation(s)
- Fiona E McCann
- Department of Biological Sciences, Imperial College, London, United Kingdom
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366
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Lyubchenko TA, Wurth GA, Zweifach A. The actin cytoskeleton and cytotoxic T lymphocytes: evidence for multiple roles that could affect granule exocytosis-dependent target cell killing. J Physiol 2003; 547:835-47. [PMID: 12576500 PMCID: PMC2342722 DOI: 10.1113/jphysiol.2002.033522] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
One important mechanism cytotoxic T lymphocytes (CTLs) use to kill virus-infected, transplanted or tumour targets is exocytosis of granules that contain cytotoxic agents such as perforin and granzymes. Granule exocytosis-dependent target cell killing is a complex process, involving initial T-cell receptor (TCR)-dependent signalling that includes Ca2+ influx and activation of protein kinase C, shape changes that serve to bind the CTL to the target and, finally, exocytosis of lytic granules at the site of contact with the target cell. Although there is reason to propose that multiple steps in the lytic process could involve the actin cytoskeleton of CTLs, few studies have examined this issue, and those that have do not allow the specific step(s) involved to be determined. We have used the potent membrane-permeant actin cytoskeleton-modifying drugs jasplakinolide and latrunculin A to investigate the actin dependence of defined processes that are expected to be important for granule exocytosis-dependent killing. Our results, obtained using TALL-104 human leukaemic CTLs as a model system, are consistent with the idea that a functional actin cytoskeleton is required for TCR/CD3-dependent signalling, for activation of store-dependent Ca2+ influx and for CTL shape changes. When cells were stimulated with solid-phase anti-CD3 antibodies, treatment with either jasplakinolide or latrunculin A abolished granule exocytosis. However, when cells were stimulated in a manner that bypasses TCR/CD3-dependent signalling, granule exocytosis was not significantly altered, suggesting that the actin cytoskeleton does not function as a barrier to exocytosis.
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Affiliation(s)
- Taras A Lyubchenko
- Department of Physiology and Biophysics, University of Colorado Health Sciences Center, 4200 E. 9th Avenue, Denver, CO 80262, USA
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367
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McHeyzer-Williams M, McHeyzer-Williams L, Panus J, Pogue-Caley R, Bikah G, Driver D, Eisenbraun M. Helper T-cell-regulated B-cell immunity. Microbes Infect 2003; 5:205-12. [PMID: 12681409 DOI: 10.1016/s1286-4579(03)00012-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Helper T-cell-regulated B-cell responses constitute a major component of the immune response to many pathogens. Spatially and temporally organized cognate intercellular communication within secondary lymphoid organs is the critical regulating event in this complex adaptive response to antigen. Here, we discuss what is known of these molecular exchanges and their cellular consequences in a serial synapsis model of adaptive immunity.
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368
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Anderson ME, Siahaan TJ. Targeting ICAM-1/LFA-1 interaction for controlling autoimmune diseases: designing peptide and small molecule inhibitors. Peptides 2003; 24:487-501. [PMID: 12732350 DOI: 10.1016/s0196-9781(03)00083-4] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This review describes the role of modulation of intracellular adhesion molecule-1 (ICAM-1)/leukocyte function-associated antigen-1 (LFA-1) interaction in controlling autoimmune diseases or inducing immunotolerance. ICAM-1/LFA-1 interaction is essential for T-cell activation as well as for migration of T-cells to target tissues. This interaction also functions, along with Signal-1, as a co-stimulatory signal (Signal-2) for T-cell activation, which is delivered by the T-cell receptors (TCR)-major histocompatibility complex (MHC)-peptide complex. Therefore, blocking ICAM-1/LFA-1 interaction can suppress T-cell activation in autoimmune diseases and organ transplantation. Many types of inhibitors (i.e. antibodies, peptides, small molecules) have been developed to block ICAM-1/LFA-1 interactions, and some of these molecules have reached clinical trials. Peptides derived from ICAM-1 and LFA-1 sequences have been shown to inhibit T-cell adhesion and activation. In addition, these inhibitors have been useful in elucidating the mechanism of ICAM-1/LFA-1 interaction. Besides binding to LFA-1, the ICAM-1 peptide can be internalized by LFA-1 receptors into the cytoplasmic domain of T-cells. Therefore, this ICAM-1 peptide can be utilized to selectively target toxic drugs to T-cells, thus avoiding harmful side effects. Finally, bi-functional inhibitory peptide (BPI), which is made by conjugating the antigenic peptide and an LFA-1 peptide, can alter the T-cell commitment from T-helper-1 (Th1) to T-helper-2 (Th2)-like cells, suggesting that this peptide may have a role in blocking the formation of the "immunological synapse."
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Affiliation(s)
- Meagan E Anderson
- Department of Pharmaceutical Chemistry, The University of Kansas, 2095 Constant Avenue, Lawrence, KS 66047, USA
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369
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Giurisato E, McIntosh DP, Tassi M, Gamberucci A, Benedetti A. T cell receptor can be recruited to a subset of plasma membrane rafts, independently of cell signaling and attendantly to raft clustering. J Biol Chem 2003; 278:6771-8. [PMID: 12499387 DOI: 10.1074/jbc.m210758200] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The constitutive/inducible association of the T cell receptor (TCR) with isolated detergent-resistant, lipid raft-derived membranes has been studied in Jurkat T lymphocytes. Membranes resistant to 1% Triton X-100 contained virtually no CD3epsilon, part of the TCR complex, irrespective of cell stimulation. On the other hand, membranes resistant either to a lower Triton X-100 concentration (i.e. 0.2%) or to the less hydrophobic detergent Brij 58 (1%) contained (i) a low CD3epsilon amount (approximate 2.7% of total) in resting cells and (ii) a several times higher amount of the TCR component, after T cell stimulation with either antigen-presenting cells or with phytohemagglutinin. It appeared that CD3/TCR was constitutively associated with and recruited to a raft-derived membrane subset because (i) all three membrane preparations contained a similar amount of the raft marker tyrosine kinase Lck but no detectable amounts of the conventional membrane markers, CD45 phosphatase and transferrin receptor; (ii) a larger amount of particulate membranes were resistant to solubilization with 0.2% Triton X-100 and Brij 58 than to solubilization with 1% Triton X-100; and (iii) higher cholesterol levels were present in membranes resistant to either the lower Triton X-100 concentration or to Brij 58, as compared with those resistant to 1% Triton X-100. The recruitment of CD3 to the raft-derived membrane subset appeared (i) to occur independently of cell signaling events, such as protein-tyrosine phosphorylation and Ca(2+) mobilization/influx, and (ii) to be associated with clustering of plasma membrane rafts induced by multiple cross-linking of either TCR or the raft component, ganglioside GM(1). We suggest that during T cell stimulation a lateral reorganization of rafts into polarized larger domains can determine the recruitment of TCR into these domains, which favors a polarization of the signaling cascade.
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Affiliation(s)
- Emanuele Giurisato
- Dipartimento di Fisiopatologia e Medicina Sperimentale, Università degli Studi di Siena, Viale Aldo Moro No. 1, 53100-Siena, Italy
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370
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Fanzo JC, Hu CM, Jang SY, Pernis AB. Regulation of lymphocyte apoptosis by interferon regulatory factor 4 (IRF-4). J Exp Med 2003; 197:303-14. [PMID: 12566414 PMCID: PMC2193834 DOI: 10.1084/jem.20020717] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
To ensure that homeostasis of the immune system is maintained, the sensitivity of lymphocytes to Fas-mediated apoptosis is differentially regulated during their activation. The molecular mechanisms that link the activation program of lymphocytes to changes in sensitivity to Fas-mediated apoptosis have, however, not been fully characterized. In these studies, we have investigated whether Fas-mediated apoptosis can be regulated by interferon regulatory factor 4 (IRF-4), a lymphoid-restricted member of the IRF family of transcription factors. IRF-4 expression is upregulated during lymphocyte activation and IRF-4-deficient mice have defects in both lymphocyte activation and homeostasis. Here, we show that stable expression of IRF-4 in a human lymphoid cell line that normally lacks IRF-4 leads to a significantly enhanced apoptotic response on Fas receptor engagement. A systematic examination of the downstream effectors of Fas signaling in IRF-4-transfected cells demonstrates an increased activation of caspase-8, as well as an increase in Fas receptor polarization. We demonstrate that IRF-4-deficient mice display defects in activation-induced cell death, as well as superantigen-induced deletion, and that these defects are accompanied by impairments in Fas receptor polarization. These data suggest that IRF-4, by modulating the efficiency of the Fas-mediated death signal, is a novel participant in the regulation of lymphoid cell apoptosis.
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Affiliation(s)
- Jessica C Fanzo
- Department of Molecular Medicine, Columbia University, New York, NY 10032, USA
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371
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Abstract
An effective inflammatory immune response first requires the recruitment of cells to the site of inflammation and then their appropriate activation and regulation. Chemokines are critical in this response since they are both chemotactic and immunoregulatory molecules. In this regard, the interaction between CCL5 and CCR5 may be critical in regulating T cell functions, by mediating their recruitment and polarization, activation, and differentiation. Various tyrosine phosphorylation signaling cascades can be engaged following chemokine receptor aggregation on T cells, including the Jak-Stat pathway, FAK activation, the MAP kinase pathway, PI3-kinase activation, and transactivation of the T cell receptor. This review will address specific aspects related to chemokine-T cell interactions and the molecular signaling mechanisms that influence T cell function in an inflammatory immune response.
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Affiliation(s)
- Mark M Wong
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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372
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Byers AM, Kemball CC, Andrews NP, Lukacher AE. Regulation of antiviral CD8+ T cells by inhibitory natural killer cell receptors. Microbes Infect 2003; 5:169-77. [PMID: 12650775 DOI: 10.1016/s1286-4579(02)00086-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recent evidence indicates that CD8(+) T cells express natural killer cell receptors that constrain the range and magnitude of their activities. For virus-specific CD8(+) T cells, upregulation of these receptors serves to control infection, while concurrently minimizing bystander pathology. Dysregulated expression of these receptors, however, may foster the establishment of persistent virus infection.
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Affiliation(s)
- Anthony M Byers
- Department of Pathology and Laboratory Medicine, Woodruff Memorial Research Building, Rm. 7307, Emory University School of Medicine, 1639 Pierce Drive, Atlanta, GA 30322, USA
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373
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Gupta N, DeFranco AL. Visualizing lipid raft dynamics and early signaling events during antigen receptor-mediated B-lymphocyte activation. Mol Biol Cell 2003; 14:432-44. [PMID: 12589045 PMCID: PMC149983 DOI: 10.1091/mbc.02-05-0078] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Recent biochemical evidence indicates that an early event in signal transduction by the B-cell antigen receptor (BCR) is its translocation to specialized membrane subdomains known as lipid rafts. We have taken a microscopic approach to image lipid rafts and early events associated with BCR signal transduction. Lipid rafts were visualized on primary splenic B lymphocytes from wild-type or anti-hen egg lysozyme BCR transgenic mice, and on a mature mouse B-cell line Bal 17 by using fluorescent conjugates of cholera toxin B subunit or a Lyn-based chimeric protein, which targets green fluorescent protein to the lipid raft compartment. Time-lapse imaging of B cells stimulated via the BCR with the antigen hen egg lysozyme, or surrogate for antigen anti-IgM, demonstrated that lipid rafts are highly dynamic entities, which move laterally on the surface of these cells and coalesce into large regions. These regions of aggregated lipid rafts colocalized with the BCR and tyrosine-phosphorylated proteins. Microscopic imaging of live B cells also revealed an inducible colocalization of lipid rafts with the tyrosine kinase Syk and the receptor tyrosine phosphatase CD45. These two proteins play indispensable roles in BCR-mediated signaling but are not detectable in biochemically purified lipid raft fractions. Strikingly, BCR stimulation also induced the formation of long, thread-like filopodial projections, similar to previously described structures called cytonemes. These B-cell cytonemes are rich in lipid rafts and actin filaments, suggesting that they might play a role in long-range communication and/or transportation of signaling molecules during an immune response. These results provide a window into the morphological and molecular organization of the B-cell membrane during the early phase of BCR signaling.
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Affiliation(s)
- Neetu Gupta
- Department of Microbiology and Immunology, G. W. Hooper Foundation, University of California, San Francisco, 94143, USA
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374
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Hedges JF, Cockrell D, Jackiw L, Meissner N, Jutila MA. Differential mRNA expression in circulating gammadelta T lymphocyte subsets defines unique tissue-specific functions. J Leukoc Biol 2003; 73:306-14. [PMID: 12554808 DOI: 10.1189/jlb.0902453] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
To elucidate the functions of circulating gammadelta T cells, in the absence of antigen stimulation, the differential gene expression of two circulating gammadelta T cell subsets was analyzed. The two subsets, with distinct trafficking phenotypes in young calves, were GD3.5(+), CD8(-), WC1(+) or GD3.5(-), CD2(+), WC1(-), and 90-100% CD8(+) and were sorted based on GD3.5 and gammadelta T cell receptor expression. Results from two different human arrays probed with cDNA from these gammadelta T cell subsets indicated that they have markedly different tissue-specific functions. The genes preferentially expressed by GD3.5(+) (CD8(-)) gammadelta T cells demonstrated that they were highly activated, proliferative, and inflammatory, whereas those expressed by GD3.5(-) (primarily CD8(+)) gammadelta T cells were involved in promoting quiescence, consistent with a role for gammadelta T cells as sentinel mucosal cells, and several were interferon-regulated genes. Gene expression and phenotypic assays indicated that CD8(+) gammadelta T cells were apoptotic, whereas CD8(-) gammadelta T cells were apoptosis-resistant. Differential expression of multiple genes was confirmed in both arrays: That of 14 genes was confirmed by quantitative reverse transcriptase-polymerase chain reaction and that of seven proteins was confirmed by flow cytometry. This novel, genomic analysis of circulating gammadelta T cell subsets, without confounding effects of the tissue microenvironment, offers new insight into the biology and development of neonatal gammadelta T cells.
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Affiliation(s)
- Jodi F Hedges
- Department of Veterinary Molecular Biology, Marsh Laboratory, Montana State University, 19th and Lincoln, Bozeman, MT 59717, USA
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375
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Hiltbold EM, Poloso NJ, Roche PA. MHC class II-peptide complexes and APC lipid rafts accumulate at the immunological synapse. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:1329-38. [PMID: 12538693 DOI: 10.4049/jimmunol.170.3.1329] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Activation of CD4(+) Th cells requires their cognate interaction with APCs bearing specific relevant MHC class II-peptide complexes. This cognate interaction culminates in the formation of an immunological synapse that contains the various proteins and lipids required for efficient T cell activation. We now show that APC lipid raft membrane microdomains contain specific class II-peptide complexes and serve as platforms that deliver these raft-associated class II molecules to the immunological synapse. APC rafts are required for T cell:APC conjugate formation and T cell activation at low densities of relevant class II-peptide complexes, a requirement that can be overcome at high class II-peptide density. Analysis of confocal microscopy images revealed that over time APC lipid rafts, raft-associated relevant class II-peptide complexes, and even immunologically irrelevant class II molecules accumulate at the immunological synapse. As the immunological synapse matures, relevant class II-peptide complexes are sorted to a central region of the interface, while irrelevant class II molecules are excluded from this site. We propose that T cell activation is facilitated by recruitment of MHC class II-peptide complexes to the immunological synapse by virtue of their constitutive association with lipid raft microdomains.
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Affiliation(s)
- Elizabeth M Hiltbold
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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376
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Fuller CL, Braciale VL, Samelson LE. All roads lead to actin: the intimate relationship between TCR signaling and the cytoskeleton. Immunol Rev 2003; 191:220-36. [PMID: 12614363 DOI: 10.1034/j.1600-065x.2003.00004.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Regardless of cell type, the regulation of the actin cytoskeleton is tightly linked to vital biological properties such as polarity, motility, cell-cell contact, exocytosis and proliferation. In the immune system, where rapid and efficient response to antigen-provoked stimuli is crucial, an overwhelming amount of data implicate the actin cytoskeleton and its regulators as central to immune function. Increasingly, the cytoskeleton is considered an essential amplification step in T cell receptor (TCR)-, costimulatory-, and integrin-mediated signaling. Advances in genetic manipulation and confocal imaging have led to a keener appreciation of the importance of TCR signal integration by the actin cytoskeleton. This review outlines recent advances in elucidating the regulation of T cell function through the actin cytoskeleton. We also examine intriguing parallels between the immune system and other models of cytoskeletal regulation.
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Affiliation(s)
- Claudette L Fuller
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892-4255, USA
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377
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Holleran BJ, Barbar E, Payet MD, Dupuis G. Differential recruitment of alpha2beta1 and alpha4beta1 integrins to lipid rafts in Jurkat T lymphocytes exposed to collagen type IV and fibronectin. J Leukoc Biol 2003; 73:243-52. [PMID: 12554801 DOI: 10.1189/jlb.0902439] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Collagen type IV (CnIV) and fibronectin (Fn) were used as ligands to study the distribution of alpha(2)beta(1) and alpha(4)beta(1) integrins in low-density, detergent-resistant microdomains (DRM) of Jurkat lymphocytes. CnIV-coated microspheres induced (optical trapping) the redistribution of GM(1)-associated fluorescence from the cell periphery to the area of contact. This was not observed in cells treated with beta-methyl cyclodextrin (MCD). Fn- or bovine serum albumin-coated microspheres did not modify the peripheral distribution of fluorescence. These observations were confirmed by confocal microscopy. Western blot analysis of cells exposed to surfaces coated with CnIV revealed that the alpha(2)-subunit was initially present at low levels in DRM, became strongly associated after 40 min, and returned to basal levels after 75 min. Fn induced a slight recruitment of the beta(1)-integrin alpha(4)-subunit in DRM after 5 and 10 min, followed by a return to basal levels. Neither CnIV nor Fn triggered significant changes in the distribution of the beta(1)-subunit in DRM. Fn- and CnIV-coated microspheres or surfaces coated with these ligands triggered a MCD-sensitive mobilization of Ca(2)(+). MCD did not alter the state of the Ca(2)(+) reserves. The differential distributions of the alpha(2)beta(1) and alpha(4)beta(1) integrins in DRM may provide one additional step in the regulation of outside-in signaling involving these integrins.
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Affiliation(s)
- Brian J Holleran
- Signal Transduction Laboratory, Graduate Program in Immunology, Clinical Research Center, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Quebec, Canada J1H 5N4
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378
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Abstract
Important progress has been made in our understanding of the cellular and molecular processes underlying autoimmune neuromuscular diseases that has led us to identify targets for rational therapeutic intervention. Although antigen-specific immunotherapy is not yet available, old and new immunomodulatory treatments, alone or in combination, provide effective immunotherapy for most autoimmune disorders. In parallel, the achievements of molecular medicine provide more specific yet largely experimental therapeutic tools that need to be tested in the human diseases. Here we review the principles and targets of immunotherapy for autoimmune neuromuscular disorders, address applications and practical guidelines, and give an outlook on future developments.
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379
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Samstag Y, Eibert SM, Klemke M, Wabnitz GH. Actin cytoskeletal dynamics in T lymphocyte activation and migration. J Leukoc Biol 2003; 73:30-48. [PMID: 12525560 DOI: 10.1189/jlb.0602272] [Citation(s) in RCA: 141] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Dynamic rearrangements of the actin cytoskeleton are crucial for the function of numerous cellular elements including T lymphocytes. They are required for migration of T lymphocytes through the body to scan for the presence of antigens, as well as for the formation and stabilization of the immunological synapse at the interface between antigen-presenting cells and T lymphocytes. Supramolecular activation clusters within the immunological synapse play an important role for the initiation of T cell responses and for the execution of T cell effector functions. In addition to the T cell receptor/CD3 induced actin nucleation via Wasp/Arp2/3-activation, signals through accessory receptors of the T cell (i.e., costimulation) regulate actin cytoskeletal dynamics. In this regard, the actin-binding proteins cofilin and L-plastin represent prominent candidates linking accessory receptor stimulation to the rearrangement of the actin cytoskeleton. Cofilin enhances actin polymerization via its actin-severing activity, and as a long-lasting effect, cofilin generates novel actin monomers through F-actin depolymerization. L-plastin stabilizes actin filament structures by means of its actin-bundling activity.
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Affiliation(s)
- Yvonne Samstag
- Institute for Immunology, Ruprecht-Karls-University, Im Neuenheimer Feld 305, D-69120 Heidelberg, Germany.
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380
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Abstract
Engagement of the T cell receptor leads to the accumulation of filamentous actin, which is necessary for the formation of the immunological synapse and subsequent T cell activation. In the December issue of Molecular Cell, Sasahara et al. provide new insights into the link between the T cell receptor and actin assembly in the immunological synapse, and reveal a critical regulatory role for PKC theta in this process.
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Affiliation(s)
- Margot Thome
- Institute of Biochemistry, University of Lausanne, Chemin des Boveresses 155, CH-1066, Epalinges, Switzerland
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381
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Sommers CL, Samelson LE, Love PE. LAT: a T lymphocyte adapter protein that couples the antigen receptor to downstream signaling pathways. Bioessays 2003; 26:61-7. [PMID: 14696041 DOI: 10.1002/bies.10384] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Adapter molecules in a variety of signal transduction systems link receptors to a limited number of commonly used downstream signaling pathways. During T-cell development and mature T-cell effector function, a multichain receptor (the pre-T-cell antigen receptor or the T-cell antigen receptor) activates several protein tyrosine kinases. Receptor and kinase activation is linked to distal signaling pathways (PLC-gamma1 activation, Ca2+ influx, PKC activation and Ras/Erk activation) via the adapter protein LAT (Linker for Activation of T cells). Structure/function studies of LAT including expression of selected LAT point mutations in vivo reveals that these multiple pathways are integrated at the level of the LAT adapter. These studies suggest that similar levels of control may be found in other systems where adapter molecules are known to have important functions.
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Affiliation(s)
- Connie L Sommers
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4255, USA.
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382
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Groysman M, Hornstein I, Alcover A, Katzav S. Vav1 and Ly-GDI two regulators of Rho GTPases, function cooperatively as signal transducers in T cell antigen receptor-induced pathways. J Biol Chem 2002; 277:50121-30. [PMID: 12386169 DOI: 10.1074/jbc.m204299200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Rho family GTPases are pivotal for T cell signaling; however, the regulation of these proteins is not fully known. One well studied regulator of Rho GTPases is Vav1; a hematopoietic cell-specific guanine nucleotide exchange factor critical for signaling in T cells, including stimulation of the nuclear factor of activated T cells (NFAT). Surprisingly, Vav1 associates with Ly-GDI, a hematopoietic cell-specific guanine nucleotide dissociation inhibitor of Rac. Here, we studied the functional significance of the interaction between Vav1 and Ly-GDI in T cells. Upon organization of the immunological synapse, both Ly-GDI and Vav1 relocalize to T cell extensions in contact with the antigen-presenting cell. Ly-GDI is phosphorylated on tyrosine residues following T cell receptor stimulation, and it associates with the Src homology 2 region of an adapter protein, Shc. In addition, the interaction between Ly-GDI and Vav1 requires tyrosine phosphorylation. Overexpression of Ly-GDI alone is inhibitory to NFAT stimulation and calcium mobilization. However, when co-expressed with Vav1, Ly-GDI enhances Vav1 induction of NFAT activation, phospholipase Cgamma phosphorylation, and calcium mobilization. Moreover, Ly-GDI does not alter the regulation of these phenomena when coexpressed with oncogenic Vav1. Since oncogenic Vav1 does not bind Ly-GDI, this suggests that the functional cooperativity of Ly-GDI and Vav1 is dependent upon their association. Thus, our data suggest that the interaction of Vav1 and Ly-GDI creates a fine tuning mechanism for the regulation of intracellular signaling pathways leading to NFAT stimulation.
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Affiliation(s)
- Maya Groysman
- Hubert H. Humphrey Center for Experimental Medicine and Cancer Research, Hebrew University-Hadassah Medical School, Jerusalem, Israel
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383
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Vicente-Manzanares M, Sancho D, Yáñez-Mó M, Sánchez-Madrid F. The leukocyte cytoskeleton in cell migration and immune interactions. INTERNATIONAL REVIEW OF CYTOLOGY 2002; 216:233-89. [PMID: 12049209 DOI: 10.1016/s0074-7696(02)16007-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Leukocyte migration is crucial during the development of the immune system and in the responses to infection, inflammation, and tumor rejection. The migratory behavior of leukocytes under physiological and pathological conditions as well as the extracellular cues and intracellular machinery that control and guide migration have been studied thoroughly. The cytoskeleton of leukocytes is extremely versatile, bearing characteristic features that enable these cells to migrate under conditions of flow through narrow spaces and onto target tissues. What makes the cytoskeleton machinery so extraordinary is not so much its molecular composition, but its flexibility which allows it to display a unique combination of responses to the extracellular medium and a rapid regulation of the architecture of its components. This review focuses on the cytoskeleton of the leukocyte. Its molecular components and the regulation of their assembly and organization are discussed. Furthermore, it highlights aspects of the regulation of the leukocyte cytoskeleton that confer flexibility to these cells in order to perform their specific tasks. Finally, different subcellular structures such as the immunological synapse, the uropod of migrating leukocytes, and the phagosome displayed by phagocytic cells are discussed in detail. The relationship of the leukocyte with its environment occurs through different kinds of receptors that interact with ligands that are soluble, fixed on the membrane of other cells, or immobilized on the extracellular matrix. The impact of receptor-ligand binding on the functional responses and the rearrangement of the cytoskeleton is also examined.
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Affiliation(s)
- Miguel Vicente-Manzanares
- Servicio de Inmunología, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Spain
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384
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Ehrlich LIR, Ebert PJR, Krummel MF, Weiss A, Davis MM. Dynamics of p56lck translocation to the T cell immunological synapse following agonist and antagonist stimulation. Immunity 2002; 17:809-22. [PMID: 12479826 DOI: 10.1016/s1074-7613(02)00481-8] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
To study the spatio/temporal recruitment of lck during immunological synapse formation, we utilize high-speed time-lapse microscopy to visualize green fluorescent protein (GFP) fusions of lck and CD3zeta following agonist or altered peptide ligand (APL) stimulation. The dynamics of lck and CD3zeta recruitment are comparable; however, lck becomes excluded to the periphery of mature synapses, while most CD3zeta is centrally localized, suggesting a limited time frame within which lck can efficiently phosphorylate CD3 molecules during synapse maturation. Exposure of T cells to specific APLs affects the efficiency of conjugate formation and lck accumulation. Most surprisingly, we find an intracellular pool of lck associated with recycling endosomes that translocates to mature synapses within 10 min of calcium flux. This bolus of lck may contribute to intermediate-late signal transduction.
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385
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Wetzel SA, McKeithan TW, Parker DC. Live-cell dynamics and the role of costimulation in immunological synapse formation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:6092-101. [PMID: 12444111 DOI: 10.4049/jimmunol.169.11.6092] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Using transfected fibroblasts expressing both wild-type I-E(k) and green fluorescent protein-tagged I-E(k) with covalently attached antigenic peptide, we have monitored movement of specific MHC:peptide complexes during CD4(+) T cell-APC interactions by live-cell video microscopy. Ag recognition occurs within 30 s of T cell-APC contact, as shown by a sharp increase in cytoplasmic calcium ion concentration. Within 1 min, small MHC:peptide clusters form in the contact zone that coalesce into an immunological synapse over 3-20 min. When T cells conjugated to APC move across the APC surface, they appear to drag the synapse with them. This system was used to examine the role of costimulation in the formation of the immunological synapse. Blocking CD80/CD28 or ICAM-1/LFA-1 interactions alters synapse morphology and reduces the area and density of accumulated complexes. These reductions correlate with reduced T cell proliferation, while CD69 and CD25 expression and TCR down-modulation remain unaffected. Thus, costimulation is essential for normal mature immunological synapse formation.
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Affiliation(s)
- Scott A Wetzel
- Department of Molecular Microbiology and Immunology, Oregon Health Sciences University, Portland 97239, USA
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386
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Hori Y, Raychaudhuri S, Chakraborty AK. Analysis of pattern formation and phase separation in the immunological synapse. J Chem Phys 2002. [DOI: 10.1063/1.1512642] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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387
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Costello PS, Gallagher M, Cantrell DA. Sustained and dynamic inositol lipid metabolism inside and outside the immunological synapse. Nat Immunol 2002; 3:1082-9. [PMID: 12389042 DOI: 10.1038/ni848] [Citation(s) in RCA: 176] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2002] [Accepted: 08/27/2002] [Indexed: 01/14/2023]
Abstract
T cell activation is triggered by several hours of contact with peptide-major histocompatibility (MHC) complexes on the surface of antigen-presenting cells (APCs). The nature and location of the sustained signal transduction pathways required for T cell activation are unknown. We show here that the production of phosphatidylinositol(3,4,5)triphosphate (PIP3) was dynamically sustained for hours as T cells responded to antigen. In addition, sustained elevation of PIP3 was essential for T cell proliferation. There was PIP3 accumulation in the T cell-APC contact zone and at the antipodal pole of the cell. The immune synapse is thus not the sole site of sustained signal transduction in activated T cells.
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Affiliation(s)
- Patrick S Costello
- Lymphocyte Activation Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
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388
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McCann FE, Suhling K, Carlin LM, Eleme K, Taner SB, Yanagi K, Vanherberghen B, French PMW, Davis DM. Imaging immune surveillance by T cells and NK cells. Immunol Rev 2002; 189:179-92. [PMID: 12445274 DOI: 10.1034/j.1600-065x.2002.18915.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
As T cells and natural killer (NK) cells survey the surface of other cells, cognate receptors and ligands are commonly organized into distinct micrometer-scale domains at the intercellular contact, creating an immune or immunological synapse (IS). We aim to address the still unanswered questions of how this organization of proteins aids immune surveillance and how these domains are biophysically constructed. Molecular mechanisms for the formation of the IS include a role for the cytoskeleton, segregation of proteins according to the size of their extracellular domains, and association of proteins with lipid rafts. Towards understanding the function of the IS, it is instructive to compare and contrast the supramolecular organization of proteins at the inhibitory and activating NK cell IS with that at the activating T cell IS. Finally, it is essential to develop new technologies for probing molecular recognition at cell surfaces. Imaging parameters other than fluorescence intensity, such as the lifetime of the fluorophore's excited state, could be used to report on protein environments.
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Affiliation(s)
- Fiona E McCann
- Department of Biological Sciences, Sir Alexander Fleming Building, Imperial College of Science, Technology and Medicine, London, UK
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389
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Das V, Nal B, Roumier A, Meas-Yedid V, Zimmer C, Olivo-Marin JC, Roux P, Ferrier P, Dautry-Varsat A, Alcover A. Membrane-cytoskeleton interactions during the formation of the immunological synapse and subsequent T-cell activation. Immunol Rev 2002; 189:123-35. [PMID: 12445270 DOI: 10.1034/j.1600-065x.2002.18911.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Upon antigen recognition, T cells undergo substantial membrane and cytoskeletal rearrangements that lead to the formation of the immunological synapse and are necessary for subsequent T-cell activation. However, little is known about how membrane and cytoskeletal molecules interact during these processes. Here we discuss the involvement of the membrane-microfilament linker ezrin. We propose that ezrin is a component of the cytoskeleton-mediated architecture of the immunological synapse that plays a role in T-cell receptor clustering, protein kinase C theta translocation and intracellular signaling.
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Affiliation(s)
- Vincent Das
- Unité de Biologie des Interactions Cellulaires, CNRS URA 1960, Paris, France
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390
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Sancho D, Vicente-Manzanares M, Mittelbrunn M, Montoya MC, Gordón-Alonso M, Serrador JM, Sánchez-Madrid F. Regulation of microtubule-organizing center orientation and actomyosin cytoskeleton rearrangement during immune interactions. Immunol Rev 2002; 189:84-97. [PMID: 12445267 DOI: 10.1034/j.1600-065x.2002.18908.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The reorganization of membrane, cytoskeletal and signaling molecules during immune interactions is critical for the generation of immune response. At the initiation of the T cell-antigen presenting cell (APC) interaction, antigen-independent weak adhesion forces allow the scanning of the APC surface by the T cell receptor for specific antigens. The stabilization of T cell-APC conjugates involves the segregation of membrane and intracellular signaling proteins, driven by reorganization of membrane microdomains and cytoskeletal changes. In early T cell-APC cognate interactions, the microtubular cytoskeleton undergoes drastic changes that lead to microtubule-organizing center (MTOC) reorientation to the vicinity of the cell-cell contact area. Recent data on the dynamics of MTOC redistribution and its influence in T cell-APC conjugate stabilization, together with the description of an increasing number of signaling molecules associated to this complex, underscore the key role of MTOC translocation in the T cell response. We focus on the mechanisms that control the early MTOC reorientation during T cell-APC interaction and the relevance of this process to T cell activation.
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Affiliation(s)
- David Sancho
- Servicio de Inmunología, Hospital de la Princesa, Universidad Autónoma de Madrid, Madrid, Spain
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391
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Garcia GG, Miller RA. Age-dependent defects in TCR-triggered cytoskeletal rearrangement in CD4+ T cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:5021-7. [PMID: 12391217 DOI: 10.4049/jimmunol.169.9.5021] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previous research has shown that many of the CD4 T cells from older mice do not form functional immune synapses after conjugation with peptide-pulsed APC. We now show that the defect lies at a very early stage in the cytoskeletal reorganization that precedes movement of protein kinases and their substrates to the TCR/APC interface. Antagonist peptides presented to T cells from young mice induce migration of talin (but not paxillin, vinculin, or F-actin) to the APC contact zone, but CD4 T cells from older donors typically fail to show the talin polarization response. A spreading assay in which contact with anti-CD3-coated slides induces CD4 T cells to assume a conical shape and develop lammelopodia also shows a decline with age in the proportion of T cells that can initiate cytoskeletal changes in response to this simplified stimulus. Finally, the transition from detergent-soluble to cytoskeletal forms of the p16, p21, and p23 isoforms of CD3zeta in response to CD3/CD4/CD28 cross-linking is much stronger in young than in old T cells. Thus, defects in cytoskeletal reorganization triggered by initial contact between TCR and peptide-bearing APC precede, and presumably contribute to, defective activation of protein kinase-mediated signals in the first few minutes of the activation cascade in T cells from aged mice.
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Affiliation(s)
- Gonzalo G Garcia
- Department of Pathology, School of Medicine, and Institute of Gerontology, University of Michigan, Ann Arbor 48109, USA
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392
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Abstract
A synapse is a stable adhesive junction between two cells across which information is relayed by directed secretion. The nervous system and immune system utilize these specialized cell surface contacts to directly convey and transduce highly controlled secretory signals between their constituent cell populations. Each of these synaptic types is built around a microdomain structure comprising central active zones of exocytosis and endocytosis encircled by adhesion domains. Surface molecules that may be incorporated into and around the active zones contribute to modulation of the functional state of the synapse.
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Affiliation(s)
- Michael L Dustin
- Program in Molecular Pathogenesis, Skirball Institute of Biomolecular Medicine, Department of Pathology, New York University School of Medicine, New York, NY 10016 USA.
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393
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Oviedo‐Orta E, Evans WH. Gap junctions and connexins: potential contributors to the immunological synapse. J Leukoc Biol 2002. [DOI: 10.1189/jlb.72.4.636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
| | - W. Howard Evans
- Department of Medical Biochemistry and Wales Heart Research Institute, University of Wales College of Medicine, Cardiff, United Kingdom
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394
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Abstract
The specificity of the adaptive immune response is, in part, dependent on the clonal expression of the mature T cell receptor (TCR) on T lymphocytes. One mechanism regulating the clonality of the TCR occurs at the level of TCR-beta gene rearrangements during lymphocyte development. Expression of a nascent TCR-beta chain together with pre-Talpha (pTalpha) and CD3 molecules to form the pre-TCR complex, represents a critical checkpoint in T cell differentiation known as beta-selection. Indeed, failure to generate a functionally rearranged TCR-beta chain at this stage of development results in apoptosis. Signals derived from the pre-TCR complex trigger a maturation program within developing thymocytes that includes: rescue from apoptosis; inhibition of further DNA recombination at the TCR-beta gene locus (allowing for the clonality of antigen receptor expression; allelic exclusion); and induction of proliferation and differentiation. The signaling mechanisms that control this developmental program remain largely undefined. Here, we discuss recent evidence investigating the molecular mechanisms that regulate thymocyte differentiation downstream of pre-TCR formation.
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Affiliation(s)
- Alison M Michie
- Department of Immunology and Bacteriology, Western Infirmary, University of Glasgow, Glasgow, Scotland, G11 6NT, UK
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395
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Burroughs NJ, Wülfing C. Differential segregation in a cell-cell contact interface: the dynamics of the immunological synapse. Biophys J 2002; 83:1784-96. [PMID: 12324401 PMCID: PMC1302272 DOI: 10.1016/s0006-3495(02)73944-1] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Receptor-ligand couples in the cell-cell contact interface between a T cell and an antigen-presenting cell form distinct geometric patterns and undergo spatial rearrangement within the contact interface. Spatial segregation of the antigen and adhesion receptors occurs within seconds of contact, central aggregation of the antigen receptor then occurring over 1-5 min. This structure, called the immunological synapse, is becoming a paradigm for localized signaling. However, the mechanisms driving its formation, in particular spatial segregation, are currently not understood. With a reaction diffusion model incorporating thermodynamics, elasticity, and reaction kinetics, we examine the hypothesis that differing bond lengths (extracellular domain size) is the driving force behind molecular segregation. We derive two key conditions necessary for segregation: a thermodynamic criterion on the effective bond elasticity and a requirement for the seeding/nucleation of domains. Domains have a minimum length scale and will only spontaneously coalesce/aggregate if the contact area is small or the membrane relaxation distance large. Otherwise, differential attachment of receptors to the cytoskeleton is required for central aggregation. Our analysis indicates that differential bond lengths have a significant effect on synapse dynamics, i.e., there is a significant contribution to the free energy of the interaction, suggesting that segregation by differential bond length is important in cell-cell contact interfaces and the immunological synapse.
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396
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Bunnell SC, Hong DI, Kardon JR, Yamazaki T, McGlade CJ, Barr VA, Samelson LE. T cell receptor ligation induces the formation of dynamically regulated signaling assemblies. J Cell Biol 2002; 158:1263-75. [PMID: 12356870 PMCID: PMC2173229 DOI: 10.1083/jcb.200203043] [Citation(s) in RCA: 499] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Tcell antigen receptor (TCR) ligation initiates tyrosine kinase activation, signaling complex assembly, and immune synapse formation. Here, we studied the kinetics and mechanics of signaling complex formation in live Jurkat leukemic T cells using signaling proteins fluorescently tagged with variants of enhanced GFP (EGFP). Within seconds of contacting coverslips coated with stimulatory antibodies, T cells developed small, dynamically regulated clusters which were enriched in the TCR, phosphotyrosine, ZAP-70, LAT, Grb2, Gads, and SLP-76, excluded the lipid raft marker enhanced yellow fluorescent protein-GPI, and were competent to induce calcium elevations. LAT, Grb2, and Gads were transiently associated with the TCR. Although ZAP-70-containing clusters persisted for more than 20 min, photobleaching studies revealed that ZAP-70 continuously dissociated from and returned to these complexes. Strikingly, SLP-76 translocated to a perinuclear structure after clustering with the TCR. Our results emphasize the dynamically changing composition of signaling complexes and indicate that these complexes can form within seconds of TCR engagement, in the absence of either lipid raft aggregation or the formation of a central TCR-rich cluster.
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Affiliation(s)
- Stephen C Bunnell
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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397
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Schrum AG, Turka LA. The proliferative capacity of individual naive CD4(+) T cells is amplified by prolonged T cell antigen receptor triggering. J Exp Med 2002; 196:793-803. [PMID: 12235212 PMCID: PMC2194051 DOI: 10.1084/jem.20020158] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Strong antigenic encounter by T cells rapidly induces immunological synapse formation and surface T cell receptor (TCR) downregulation. Although surface TCR expression can remain low for several days, T cells can still sustain antigenic signaling. It has been unclear whether prolonged antigenic signaling occurs in the absence of surface TCR replenishment, being maintained by a few "nondownregulatable" surface TCRs that might reside in a synaptosomal structure. Alternatively, the low surface TCR level induced by antigen might represent a dynamic state of expression involving continual surface TCR replenishment, reengagement by antigen, and ongoing downregulation. To resolve this issue, we studied in vivo-generated, dual-specificity primary naive CD4(+) T cells. On these cells, antigenic stimulus exclusively downregulated antigen-specific, but not antigen-nonspecific, TCRs. In addition to providing a means to track TCR engagement, this also allowed us to use the antigen nonspecific TCR to track TCR expression in isolation from TCR engagement by antigen. Surface TCR replenishment began within the first day of stimulation, and occurred synchronously with continuous antigen-specific TCR engagement and downregulation. Furthermore, by enhancing CD25 expression, extended signaling through surface-replenishing TCRs significantly amplified the number of daughter cells generated by naive CD4(+) T cells that had already committed to proliferate. This effect required TCR engagement and could not be substituted for by interleukin 2. These data demonstrate that TCR triggering and consumption can occur over an extended period of time, with a significant impact on the effector responses evoked from naive CD4(+) T cells.
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Affiliation(s)
- Adam G Schrum
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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398
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Tang W, Duke-Cohan JS. Human secreted attractin disrupts neurite formation in differentiating cortical neural cells in vitro. J Neuropathol Exp Neurol 2002; 61:767-77. [PMID: 12230323 DOI: 10.1093/jnen/61.9.767] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Mutations at the Atrn locus that encodes a transmembrane protein with a large ectodomain are responsible for a juvenile-onset neurodegeneration manifest as hypomyelination and cerebral vacuole development in several rodent species. In addition to a membrane isoform, the human Atm locus generates by alternative splicing a secreted form corresponding to the entire ectodomain that then circulates at high concentration in the periphery, released in part by activated T lymphocytes. We report here that the secreted form mRNA is downregulated throughout representative discrete regions of the human brain while membrane attractin mRNA is well represented, resulting in the apparent absence of secreted attractin protein in cerebrospinal fluid (CSF). Transcription of attractin secreted form mRNA is strongly downregulated upon differentiation of a human cortical neuron-derived cell line (HCN-1A) to a mature neuron phenotype in response to nerve growth factor. Recombinant secreted attractin disrupts neurite formation by differentiated HCN-1A cells, resulting in higher levels of branching with shorter processes. This effect is duplicated by anti-attractin and by human serum but not by human serum depleted of attractin or by CSF We propose that inappropriate expression of secreted attractin in the CNS blocks membrane attractin function and that its presence, either by leakage from the periphery, aberrant transcription, or release from inflammatory foci may affect neuron extracellular interactions leading to neurodegeneration in the human.
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Affiliation(s)
- Wen Tang
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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399
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Pradhan D, Morrow J. The spectrin-ankyrin skeleton controls CD45 surface display and interleukin-2 production. Immunity 2002; 17:303-15. [PMID: 12354383 DOI: 10.1016/s1074-7613(02)00396-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
With T cell receptor stimulation, intracellular pools of CD45 and spectrin move to the surface. These processes are coupled. In both peripheral lymphocytes and Jurkat T cells, betaI spectrin and ankyrin associate with CD45. In Jurkat T cells, betaI spectrin peptides suppress surface recruitment of CD45 and CD3 and abrogate T cell activation. Other glycoproteins such as CD43 are not altered by the spectrin peptides. Spectrin's effects are mediated by ankyrin, which binds directly to the cytoplasmic domain of CD45 (K(d) = 4.3 +/- 3.0 nM). These data reveal a novel and unexpected contribution of the spectrin-ankyrin skeleton to the control of T lymphocyte function.
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Affiliation(s)
- Deepti Pradhan
- Department of Pathology, Yale University, 310 Cedar Street, New Haven, CT 06510, USA
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400
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Orange JS, Ramesh N, Remold-O'Donnell E, Sasahara Y, Koopman L, Byrne M, Bonilla FA, Rosen FS, Geha RS, Strominger JL. Wiskott-Aldrich syndrome protein is required for NK cell cytotoxicity and colocalizes with actin to NK cell-activating immunologic synapses. Proc Natl Acad Sci U S A 2002; 99:11351-6. [PMID: 12177428 PMCID: PMC123260 DOI: 10.1073/pnas.162376099] [Citation(s) in RCA: 217] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Wiskott-Aldrich syndrome (WAS) is a primary immunodeficiency disorder caused by a mutation in WAS protein (WASp) that results in defective actin polymerization. Although the function of many hematopoietic cells requires WASp, the specific expression and function of this molecule in natural killer (NK) cells is unknown. Here, we report that WAS patients have increased percentages of peripheral blood NK cells and that fresh enriched NK cells from two patients with a WASp mutation have defective cytolytic function. In normal NK cells, WASp was expressed and localized to the activating immunologic synapse (IS) with filamentous actin (F-actin). Perforin also localized to the NK cell-activating IS but at a lesser frequency than F-actin and WASp. The accumulation of F-actin and WASp at the activating IS was decreased significantly in NK cells that had been treated with the inhibitor of actin polymerization, cytochalasin D. NK cells from WAS patients lacked expression of WASp and accumulated F-actin at the activating IS infrequently. Thus, WASp has an important function in NK cells. In patients with WASp mutations, the resulting NK cell defects are likely to contribute to their disease.
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Affiliation(s)
- Jordan S Orange
- Department of Molecular and Cellular Biology, 7 Divinity Avenue, Harvard University, Cambridge, MA 02138, USA.
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