1
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Notti RQ, Yi F, Heissel S, Bush MW, Molina H, Molvi Z, Klebanoff CA, Walz T. The resting state of the human T-cell receptor-CD3 complex. bioRxiv 2024:2023.08.22.554360. [PMID: 37662363 PMCID: PMC10473723 DOI: 10.1101/2023.08.22.554360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
The T-cell receptor (TCR) is central to the ligand-dependent activation of T lymphocytes and as such orchestrates both adaptive and pathologic immune processes 1 . However, major questions remain regarding the structure and function of the human TCR 2-4 . Here, we present cryogenic electron microscopy structures for the unliganded human TCR-CD3 complex in a native-like lipid bilayer, revealing two related conformations that are distinct from its structure in detergent. These new "closed and compacted" conformations afford insights into the interactions between the TCR-CD3 and the membrane, including conserved surface patches that make extensive outer leaflet contact, and suggest novel conformational regulation by glycans. We show that the closed/compacted conformations, not the extended one previously reported in detergent 5-8 , represent the unliganded resting state for the TCR-CD3 in vivo , underscoring the importance of structural interrogation of membrane proteins in native-like environments. We use conformation-locking disulfide mutants to show that ectodomain opening is necessary for maximal ligand-dependent TCR-CD3 activation, demonstrating that TCR-intrinsic conformational change is necessary for full TCR-CD3 activation and opening numerous avenues for immunoreceptor engineering.
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2
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Acuto O. T-cell virtuosity in ''knowing thyself". Front Immunol 2024; 15:1343575. [PMID: 38415261 PMCID: PMC10896960 DOI: 10.3389/fimmu.2024.1343575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 01/17/2024] [Indexed: 02/29/2024] Open
Abstract
Major Histocompatibility Complex (MHC) I and II and the αβ T-cell antigen receptor (TCRαβ) govern fundamental traits of adaptive immunity. They form a membrane-borne ligand-receptor system weighing host proteome integrity to detect contamination by nonself proteins. MHC-I and -II exhibit the "MHC-fold", which is able to bind a large assortment of short peptides as proxies for self and nonself proteins. The ensuing varying surfaces are mandatory ligands for Ig-like TCRαβ highly mutable binding sites. Conserved molecular signatures guide TCRαβ ligand binding sites to focus on the MHC-fold (MHC-restriction) while leaving many opportunities for its most hypervariable determinants to contact the peptide. This riveting molecular strategy affords many options for binding energy compatible with specific recognition and signalling aimed to eradicated microbial pathogens and cancer cells. While the molecular foundations of αβ T-cell adaptive immunity are largely understood, uncertainty persists on how peptide-MHC binding induces the TCRαβ signals that instruct cell-fate decisions. Solving this mystery is another milestone for understanding αβ T-cells' self/nonself discrimination. Recent developments revealing the innermost links between TCRαβ structural dynamics and signalling modality should help dissipate this long-sought-after enigma.
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Affiliation(s)
- Oreste Acuto
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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3
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Tawbeh A, Raas Q, Tahri-Joutey M, Keime C, Kaiser R, Trompier D, Nasser B, Bellanger E, Dessard M, Hamon Y, Benani A, Di Cara F, Cunha Alves T, Berger J, Weinhofer I, Mandard S, Cherkaoui-Malki M, Andreoletti P, Gondcaille C, Savary S. Immune response of BV-2 microglial cells is impacted by peroxisomal beta-oxidation. Front Mol Neurosci 2023; 16:1299314. [PMID: 38164407 PMCID: PMC10757945 DOI: 10.3389/fnmol.2023.1299314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/23/2023] [Indexed: 01/03/2024] Open
Abstract
Microglia are crucial for brain homeostasis, and dysfunction of these cells is a key driver in most neurodegenerative diseases, including peroxisomal leukodystrophies. In X-linked adrenoleukodystrophy (X-ALD), a neuroinflammatory disorder, very long-chain fatty acid (VLCFA) accumulation due to impaired degradation within peroxisomes results in microglial defects, but the underlying mechanisms remain unclear. Using CRISPR/Cas9 gene editing of key genes in peroxisomal VLCFA breakdown (Abcd1, Abcd2, and Acox1), we recently established easily accessible microglial BV-2 cell models to study the impact of dysfunctional peroxisomal β-oxidation and revealed a disease-associated microglial-like signature in these cell lines. Transcriptomic analysis suggested consequences on the immune response. To clarify how impaired lipid degradation impacts the immune function of microglia, we here used RNA-sequencing and functional assays related to the immune response to compare wild-type and mutant BV-2 cell lines under basal conditions and upon pro-inflammatory lipopolysaccharide (LPS) activation. A majority of genes encoding proinflammatory cytokines, as well as genes involved in phagocytosis, antigen presentation, and co-stimulation of T lymphocytes, were found differentially overexpressed. The transcriptomic alterations were reflected by altered phagocytic capacity, inflammasome activation, increased release of inflammatory cytokines, including TNF, and upregulated response of T lymphocytes primed by mutant BV-2 cells presenting peptides. Together, the present study shows that peroxisomal β-oxidation defects resulting in lipid alterations, including VLCFA accumulation, directly reprogram the main cellular functions of microglia. The elucidation of this link between lipid metabolism and the immune response of microglia will help to better understand the pathogenesis of peroxisomal leukodystrophies.
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Affiliation(s)
- Ali Tawbeh
- Laboratoire Bio-PeroxIL EA7270, University of Bourgogne, Dijon, France
| | - Quentin Raas
- Laboratoire Bio-PeroxIL EA7270, University of Bourgogne, Dijon, France
| | - Mounia Tahri-Joutey
- Laboratoire Bio-PeroxIL EA7270, University of Bourgogne, Dijon, France
- Laboratory of Biochemistry, Neurosciences, Natural Resources and Environment, Faculty of Sciences and Techniques, University Hassan I, Settat, Morocco
| | - Céline Keime
- Plateforme GenomEast, IGBMC, CNRS UMR 7104, Inserm U1258, University of Strasbourg, Illkirch, France
| | - Romain Kaiser
- Plateforme GenomEast, IGBMC, CNRS UMR 7104, Inserm U1258, University of Strasbourg, Illkirch, France
| | - Doriane Trompier
- Laboratoire Bio-PeroxIL EA7270, University of Bourgogne, Dijon, France
| | - Boubker Nasser
- Laboratory of Biochemistry, Neurosciences, Natural Resources and Environment, Faculty of Sciences and Techniques, University Hassan I, Settat, Morocco
| | - Emma Bellanger
- Aix Marseille Univ, CNRS, INSERM, CIML, Marseille, France
| | - Marie Dessard
- Aix Marseille Univ, CNRS, INSERM, CIML, Marseille, France
| | - Yannick Hamon
- Aix Marseille Univ, CNRS, INSERM, CIML, Marseille, France
| | - Alexandre Benani
- Centre des Sciences du Goût et de l'Alimentation, CNRS, INRAE, Institut Agro, University of Bourgogne, Dijon, France
| | - Francesca Di Cara
- Department of Microbiology and Immunology, Dalhousie University, IWK Health Centre, Halifax, NS, Canada
| | - Tânia Cunha Alves
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Johannes Berger
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Isabelle Weinhofer
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Stéphane Mandard
- LipSTIC LabEx, University of Bourgogne, INSERM LNC UMR1231, Dijon, France
| | | | | | | | - Stéphane Savary
- Laboratoire Bio-PeroxIL EA7270, University of Bourgogne, Dijon, France
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4
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Chiu TY, Lo CH, Lin YH, Lai YD, Lin SS, Fang YT, Huang WS, Huang SY, Tsai PY, Yang FH, Chong WM, Wu YC, Tsai HC, Liu YW, Hsu CL, Liao JC, Wang WJ. INPP5E regulates CD3ζ enrichment at the immune synapse by phosphoinositide distribution control. Commun Biol 2023; 6:911. [PMID: 37670137 PMCID: PMC10480498 DOI: 10.1038/s42003-023-05269-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 08/22/2023] [Indexed: 09/07/2023] Open
Abstract
The immune synapse, a highly organized structure formed at the interface between T lymphocytes and antigen-presenting cells (APCs), is essential for T cell activation and the adaptive immune response. It has been shown that this interface shares similarities with the primary cilium, a sensory organelle in eukaryotic cells, although the roles of ciliary proteins on the immune synapse remain elusive. Here, we find that inositol polyphosphate-5-phosphatase E (INPP5E), a cilium-enriched protein responsible for regulating phosphoinositide localization, is enriched at the immune synapse in Jurkat T-cells during superantigen-mediated conjugation or antibody-mediated crosslinking of TCR complexes, and forms a complex with CD3ζ, ZAP-70, and Lck. Silencing INPP5E in Jurkat T-cells impairs the polarized distribution of CD3ζ at the immune synapse and correlates with a failure of PI(4,5)P2 clearance at the center of the synapse. Moreover, INPP5E silencing decreases proximal TCR signaling, including phosphorylation of CD3ζ and ZAP-70, and ultimately attenuates IL-2 secretion. Our results suggest that INPP5E is a new player in phosphoinositide manipulation at the synapse, controlling the TCR signaling cascade.
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Grants
- National Science and Technology Council, Taiwan, NSTC 110-2326-B-A49A-503-MY3, 111-2628-B-A49A-016, and 112-2628-B-A49-009-MY3
- National Health Research Institutes (NHRI-EX109-10610BC) National Taiwan University and Academia Sinica Innovative Joint Program (109L104303)
- National Science and Technology Council, Taiwan, NSTC 109-2628-B-010-016 Cancer Progression Research Center NYCU, from the Higher Education Sprout Project by MOE
- National Science and Technology Council, Taiwan, NSTC 107-2313-B-001-009 National Science and Technology Council, Taiwan, NSTC 108-2313-B-001-003 National Taiwan University and Academia Sinica Innovative Joint Program Grant (NTU-SINICA- 108L104303)
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Affiliation(s)
- Tzu-Yuan Chiu
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 106319, Taiwan
- The Scripps Research Institute, La Jolla, 92037, USA
| | - Chien-Hui Lo
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Yi-Hsuan Lin
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Yun-Di Lai
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Shan-Shan Lin
- Institute of Molecular Medicine, National Taiwan University, Taipei, 10002, Taiwan
| | - Ya-Tian Fang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 106319, Taiwan
| | - Wei-Syun Huang
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Shen-Yan Huang
- Institute of Microbiology and Immunology, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Pei-Yuan Tsai
- Institute of Microbiology and Immunology, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Fu-Hua Yang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 106319, Taiwan
| | - Weng Man Chong
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 106319, Taiwan
| | - Yi-Chieh Wu
- Graduate Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, 100233, Taiwan
| | - Hsing-Chen Tsai
- Graduate Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, 100233, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, 100233, Taiwan
| | - Ya-Wen Liu
- Institute of Molecular Medicine, National Taiwan University, Taipei, 10002, Taiwan
| | - Chia-Lin Hsu
- Institute of Microbiology and Immunology, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Jung-Chi Liao
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 106319, Taiwan.
- Syncell Inc., Taipei, 115202, Taiwan.
| | - Won-Jing Wang
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan.
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5
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Mezősi-Csaplár M, Szöőr Á, Vereb G. CD28 and 41BB Costimulatory Domains Alone or in Combination Differentially Influence Cell Surface Dynamics and Organization of Chimeric Antigen Receptors and Early Activation of CAR T Cells. Cancers (Basel) 2023; 15:3081. [PMID: 37370693 DOI: 10.3390/cancers15123081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Chimeric antigen receptor (CAR)-modified T cells brought a paradigm shift in the treatment of chemotherapy-resistant lymphomas. Conversely, clinical experience with CAR T cells targeting solid tumors has been disheartening, indicating the necessity of their molecular-level optimization. While incorporating CD28 or 41BB costimulatory domains into CARs in addition to the CD3z signaling domain improved the long-term efficacy of T cell products, their influence on early tumor engagement has yet to be elucidated. We studied the antigen-independent self-association and membrane diffusion kinetics of first- (.z), second- (CD28.z, 41BB.z), and third- (CD28.41BB.z) generation HER2-specific CARs in the resting T cell membrane using super-resolution AiryScan microscopy and fluorescence correlation spectroscopy, in correlation with RoseTTAFold-based structure prediction and assessment of oligomerization in native Western blot. While .z and CD28.z CARs formed large, high-density submicron clusters of dimers, 41BB-containing CARs formed higher oligomers that assembled into smaller but more numerous membrane clusters. The first-, second-, and third-generation CARs showed progressively increasing lateral diffusion as the distance of their CD3z domain from the membrane plane increased. Confocal microscopy analysis of immunological synapses showed that both small clusters of highly mobile CD28.41BB.z and large clusters of less mobile .z CAR induced more efficient CD3ζ and pLck phosphorylation than CD28.z or 41BB.z CARs of intermediate mobility. However, electric cell-substrate impedance sensing revealed that the CD28.41BB.z CAR performs worst in sequential short-term elimination of adherent tumor cells, while the .z CAR is superior to all others. We conclude that the molecular structure, membrane organization, and mobility of CARs are critical design parameters that can predict the development of an effective immune synapse. Therefore, they need to be taken into account alongside the long-term biological effects of costimulatory domains to achieve an optimal therapeutic effect.
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Affiliation(s)
- Marianna Mezősi-Csaplár
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Árpád Szöőr
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - György Vereb
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- ELKH-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Faculty of Pharmacy, University of Debrecen, 4032 Debrecen, Hungary
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6
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Thomas C, Tampé R. Structure and mechanism of immunoreceptors: New horizons in T cell and B cell receptor biology and beyond. Curr Opin Struct Biol 2023; 80:102570. [PMID: 36940642 DOI: 10.1016/j.sbi.2023.102570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 01/15/2023] [Accepted: 02/07/2023] [Indexed: 03/23/2023]
Abstract
Immunoreceptors, also named non-catalytic tyrosine-phosphorylated receptors, are a large class of leukocyte cell-surface proteins critically involved in innate and adaptive immune responses. Their most characteristic defining feature is a shared signal transduction machinery where binding events of cell surface-anchored ligands to the small extracellular receptor domains are translated into phosphorylation of conserved tyrosine-containing cytosolic sequence motifs initiating downstream signal transduction cascades. Despite their central importance to immunology, the molecular mechanism of how ligand binding activates the receptors and results in robust intracellular signaling has remained enigmatic. Recent breakthroughs in our understanding of the architecture and triggering mechanism of immunoreceptors come from cryogenic electron microscopy studies of the B cell and T cell antigen receptors.
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Affiliation(s)
- Christoph Thomas
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt/Main, Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt/Main, Germany.
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7
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Céspedes PF, Jainarayanan A, Fernández-Messina L, Valvo S, Saliba DG, Kurz E, Kvalvaag A, Chen L, Ganskow C, Colin-York H, Fritzsche M, Peng Y, Dong T, Johnson E, Siller-Farfán JA, Dushek O, Sezgin E, Peacock B, Law A, Aubert D, Engledow S, Attar M, Hester S, Fischer R, Sánchez-Madrid F, Dustin ML. T-cell trans-synaptic vesicles are distinct and carry greater effector content than constitutive extracellular vesicles. Nat Commun 2022; 13:3460. [PMID: 35710644 DOI: 10.1038/s41467-022-31160-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 06/07/2022] [Indexed: 12/19/2022] Open
Abstract
The immunological synapse is a molecular hub that facilitates the delivery of three activation signals, namely antigen, costimulation/corepression and cytokines, from antigen-presenting cells (APC) to T cells. T cells release a fourth class of signaling entities, trans-synaptic vesicles (tSV), to mediate bidirectional communication. Here we present bead-supported lipid bilayers (BSLB) as versatile synthetic APCs to capture, characterize and advance the understanding of tSV biogenesis. Specifically, the integration of juxtacrine signals, such as CD40 and antigen, results in the adaptive tailoring and release of tSV, which differ in size, yields and immune receptor cargo compared with steadily released extracellular vesicles (EVs). Focusing on CD40L+ tSV as model effectors, we show that PD-L1 trans-presentation together with TSG101, ADAM10 and CD81 are key in determining CD40L vesicular release. Lastly, we find greater RNA-binding protein and microRNA content in tSV compared with EVs, supporting the specialized role of tSV as intercellular messengers.
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8
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Ecker M, Schregle R, Kapoor-Kaushik N, Rossatti P, Betzler VM, Kempe D, Biro M, Ariotti N, Redpath GMI, Rossy J. SNX9-induced membrane tubulation regulates CD28 cluster stability and signalling. eLife 2022; 11:e67550. [PMID: 35050850 PMCID: PMC8786313 DOI: 10.7554/elife.67550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 01/12/2022] [Indexed: 12/12/2022] Open
Abstract
T cell activation requires engagement of a cognate antigen by the T cell receptor (TCR) and the co-stimulatory signal of CD28. Both TCR and CD28 aggregate into clusters at the plasma membrane of activated T cells. While the role of TCR clustering in T cell activation has been extensively investigated, little is known about how CD28 clustering contributes to CD28 signalling. Here, we report that upon CD28 triggering, the BAR-domain protein sorting nexin 9 (SNX9) is recruited to CD28 clusters at the immunological synapse. Using three-dimensional correlative light and electron microscopy, we show that SNX9 generates membrane tubulation out of CD28 clusters. Our data further reveal that CD28 clusters are in fact dynamic structures and that SNX9 regulates their stability as well as CD28 phosphorylation and the resulting production of the cytokine IL-2. In summary, our work suggests a model in which SNX9-mediated tubulation generates a membrane environment that promotes CD28 triggering and downstream signalling events.
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Affiliation(s)
- Manuela Ecker
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydneyAustralia
| | - Richard Schregle
- Biotechnology Institute Thurgau (BITg) at the University of KonstanzKreuzlingenSwitzerland
- Department of Biology, University of KonstanzKonstanzGermany
| | - Natasha Kapoor-Kaushik
- Electron Microscopy Unit, Mark Wainwright Analytical Centre, University of New South WalesSydneyAustralia
| | - Pascal Rossatti
- Biotechnology Institute Thurgau (BITg) at the University of KonstanzKreuzlingenSwitzerland
| | - Verena M Betzler
- Biotechnology Institute Thurgau (BITg) at the University of KonstanzKreuzlingenSwitzerland
| | - Daryan Kempe
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydneyAustralia
| | - Maté Biro
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydneyAustralia
| | - Nicholas Ariotti
- Electron Microscopy Unit, Mark Wainwright Analytical Centre, University of New South WalesSydneyAustralia
- Institute for Molecular Bioscience (IMB), University of QueenslandBrisbaneAustralia
| | - Gregory MI Redpath
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydneyAustralia
| | - Jeremie Rossy
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydneyAustralia
- Biotechnology Institute Thurgau (BITg) at the University of KonstanzKreuzlingenSwitzerland
- Department of Biology, University of KonstanzKonstanzGermany
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9
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Prakaash D, Cook GP, Acuto O, Kalli AC. Multi-scale simulations of the T cell receptor reveal its lipid interactions, dynamics and the arrangement of its cytoplasmic region. PLoS Comput Biol 2021; 17:e1009232. [PMID: 34280187 PMCID: PMC8321403 DOI: 10.1371/journal.pcbi.1009232] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 07/29/2021] [Accepted: 07/01/2021] [Indexed: 12/27/2022] Open
Abstract
The T cell receptor (TCR-CD3) initiates T cell activation by binding to peptides of Major Histocompatibility Complexes (pMHC). The TCR-CD3 topology is well understood but the arrangement and dynamics of its cytoplasmic tails remains unknown, limiting our grasp of the signalling mechanism. Here, we use molecular dynamics simulations and modelling to investigate the entire TCR-CD3 embedded in a model membrane. Our study demonstrates conformational changes in the extracellular and transmembrane domains, and the arrangement of the TCR-CD3 cytoplasmic tails. The cytoplasmic tails formed highly interlaced structures while some tyrosines within the immunoreceptor tyrosine-based activation motifs (ITAMs) penetrated the hydrophobic core of the membrane. Interactions between the cytoplasmic tails and phosphatidylinositol phosphate lipids in the inner membrane leaflet led to the formation of a distinct anionic lipid fingerprint around the TCR-CD3. These results increase our understanding of the TCR-CD3 dynamics and the importance of membrane lipids in regulating T cell activation.
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Affiliation(s)
- Dheeraj Prakaash
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Graham P. Cook
- Leeds Institute of Medical Research at St James’s, School of Medicine, University of Leeds, Leeds, United Kingdom
| | - Oreste Acuto
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Antreas C. Kalli
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
- * E-mail:
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10
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Lanz AL, Masi G, Porciello N, Cohnen A, Cipria D, Prakaash D, Bálint Š, Raggiaschi R, Galgano D, Cole DK, Lepore M, Dushek O, Dustin ML, Sansom MSP, Kalli AC, Acuto O. Allosteric activation of T cell antigen receptor signaling by quaternary structure relaxation. Cell Rep 2021; 36:109375. [PMID: 34260912 PMCID: PMC8293630 DOI: 10.1016/j.celrep.2021.109375] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 05/05/2021] [Accepted: 06/18/2021] [Indexed: 01/05/2023] Open
Abstract
The mechanism of T cell antigen receptor (TCR-CD3) signaling remains elusive. Here, we identify mutations in the transmembrane region of TCRβ or CD3ζ that augment peptide T cell antigen receptor (pMHC)-induced signaling not explicable by enhanced ligand binding, lateral diffusion, clustering, or co-receptor function. Using a biochemical assay and molecular dynamics simulation, we demonstrate that the gain-of-function mutations loosen the interaction between TCRαβ and CD3ζ. Similar to the activating mutations, pMHC binding reduces TCRαβ cohesion with CD3ζ. This event occurs prior to CD3ζ phosphorylation and at 0°C. Moreover, we demonstrate that soluble monovalent pMHC alone induces signaling and reduces TCRαβ cohesion with CD3ζ in membrane-bound or solubilised TCR-CD3. Our data provide compelling evidence that pMHC binding suffices to activate allosteric changes propagating from TCRαβ to the CD3 subunits, reconfiguring interchain transmembrane region interactions. These dynamic modifications could change the arrangement of TCR-CD3 boundary lipids to license CD3ζ phosphorylation and initiate signal propagation. Mutations in TCRβ and CD3ζ TMRs that reduce their interaction augment signaling pMHC and anti-CD3 binding to TCR-CD3 induce similar quaternary structure relaxation Soluble monovalent pMHC alone signals and reduces TCRαβ cohesion with CD3ζ Allosteric changes in TCR-CD3 dynamics instigate T cell activation
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Affiliation(s)
- Anna-Lisa Lanz
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Giulia Masi
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Nicla Porciello
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - André Cohnen
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Deborah Cipria
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Dheeraj Prakaash
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, UK
| | - Štefan Bálint
- Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK
| | - Roberto Raggiaschi
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Donatella Galgano
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - David K Cole
- Division Infection & Immunity, Cardiff University, Cardiff CF14 4XN, UK; Immunocore Ltd., Abingdon OX14 4RY, UK
| | | | - Omer Dushek
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Michael L Dustin
- Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
| | - Antreas C Kalli
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, UK; Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
| | - Oreste Acuto
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
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11
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Sadoun A, Biarnes-Pelicot M, Ghesquiere-Dierickx L, Wu A, Théodoly O, Limozin L, Hamon Y, Puech PH. Controlling T cells spreading, mechanics and activation by micropatterning. Sci Rep 2021; 11:6783. [PMID: 33762632 PMCID: PMC7991639 DOI: 10.1038/s41598-021-86133-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 03/02/2021] [Indexed: 01/31/2023] Open
Abstract
We designed a strategy, based on a careful examination of the activation capabilities of proteins and antibodies used as substrates for adhering T cells, coupled to protein microstamping to control at the same time the position, shape, spreading, mechanics and activation state of T cells. Once adhered on patterns, we examined the capacities of T cells to be activated with soluble anti CD3, in comparison to T cells adhered to a continuously decorated substrate with the same density of ligands. We show that, in our hand, adhering onto an anti CD45 antibody decorated surface was not affecting T cell calcium fluxes, even adhered on variable size micro-patterns. Aside, we analyzed the T cell mechanics, when spread on pattern or not, using Atomic Force Microscopy indentation. By expressing MEGF10 as a non immune adhesion receptor in T cells we measured the very same spreading area on PLL substrates and Young modulus than non modified cells, immobilized on anti CD45 antibodies, while retaining similar activation capabilities using soluble anti CD3 antibodies or through model APC contacts. We propose that our system is a way to test activation or anergy of T cells with defined adhesion and mechanical characteristics, and may allow to dissect fine details of these mechanisms since it allows to observe homogenized populations in standardized T cell activation assays.
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Affiliation(s)
- Anaïs Sadoun
- grid.5399.60000 0001 2176 4817Adhesion and Inflammation Lab (LAI), Aix Marseille University, LAI UM 61, 13288 Marseille, France ,grid.457381.cAdhesion and Inflammation Lab (LAI), Inserm, UMR_S 1067, 13288 Marseille, France ,grid.4444.00000 0001 2112 9282Adhesion and Inflammation Lab (LAI), CNRS, UMR 7333, 13288 Marseille, France ,grid.5399.60000 0001 2176 4817Centre d’Immunologie de Marseille Luminy (CIML), Aix-Marseille University, CNRS, Inserm, CIML Marseille, 13288 Marseille, France
| | - Martine Biarnes-Pelicot
- grid.5399.60000 0001 2176 4817Adhesion and Inflammation Lab (LAI), Aix Marseille University, LAI UM 61, 13288 Marseille, France ,grid.457381.cAdhesion and Inflammation Lab (LAI), Inserm, UMR_S 1067, 13288 Marseille, France ,grid.4444.00000 0001 2112 9282Adhesion and Inflammation Lab (LAI), CNRS, UMR 7333, 13288 Marseille, France
| | - Laura Ghesquiere-Dierickx
- grid.5399.60000 0001 2176 4817Adhesion and Inflammation Lab (LAI), Aix Marseille University, LAI UM 61, 13288 Marseille, France ,grid.457381.cAdhesion and Inflammation Lab (LAI), Inserm, UMR_S 1067, 13288 Marseille, France ,grid.4444.00000 0001 2112 9282Adhesion and Inflammation Lab (LAI), CNRS, UMR 7333, 13288 Marseille, France ,grid.7497.d0000 0004 0492 0584Present Address: Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Ambroise Wu
- grid.5399.60000 0001 2176 4817Centre d’Immunologie de Marseille Luminy (CIML), Aix-Marseille University, CNRS, Inserm, CIML Marseille, 13288 Marseille, France ,grid.8505.80000 0001 1010 5103Present Address: Department of Biophysics, University of Wrocław, Wrocław, Poland
| | - Olivier Théodoly
- grid.5399.60000 0001 2176 4817Adhesion and Inflammation Lab (LAI), Aix Marseille University, LAI UM 61, 13288 Marseille, France ,grid.457381.cAdhesion and Inflammation Lab (LAI), Inserm, UMR_S 1067, 13288 Marseille, France ,grid.4444.00000 0001 2112 9282Adhesion and Inflammation Lab (LAI), CNRS, UMR 7333, 13288 Marseille, France
| | - Laurent Limozin
- grid.5399.60000 0001 2176 4817Adhesion and Inflammation Lab (LAI), Aix Marseille University, LAI UM 61, 13288 Marseille, France ,grid.457381.cAdhesion and Inflammation Lab (LAI), Inserm, UMR_S 1067, 13288 Marseille, France ,grid.4444.00000 0001 2112 9282Adhesion and Inflammation Lab (LAI), CNRS, UMR 7333, 13288 Marseille, France
| | - Yannick Hamon
- grid.5399.60000 0001 2176 4817Centre d’Immunologie de Marseille Luminy (CIML), Aix-Marseille University, CNRS, Inserm, CIML Marseille, 13288 Marseille, France
| | - Pierre-Henri Puech
- grid.5399.60000 0001 2176 4817Adhesion and Inflammation Lab (LAI), Aix Marseille University, LAI UM 61, 13288 Marseille, France ,grid.457381.cAdhesion and Inflammation Lab (LAI), Inserm, UMR_S 1067, 13288 Marseille, France ,grid.4444.00000 0001 2112 9282Adhesion and Inflammation Lab (LAI), CNRS, UMR 7333, 13288 Marseille, France
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12
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Abstract
The plasma membrane (PM) spatiotemporal organization is one of the major factors controlling cell signaling and whole-cell homeostasis. The PM lipids, including cholesterol, determine the physicochemical properties of the membrane bilayer and thus play a crucial role in all membrane-dependent cellular processes. It is known that lipid content and distribution in the PM are not random, and their transversal and lateral organization is highly controlled. Mainly sphingolipid- and cholesterol-rich lipid nanodomains, historically referred to as rafts, are extremely dynamic “hot spots” of the PM controlling the function of many cell surface proteins and receptors. In the first part of this review, we will focus on the recent advances of PM investigation and the current PM concept. In the second part, we will discuss the importance of several classes of ABC transporters whose substrates are lipids for the PM organization and dynamics. Finally, we will briefly present the significance of lipid ABC transporters for immune responses.
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Affiliation(s)
- Ambroise Wu
- Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | | | - Stephane Savary
- Lab. Bio-PeroxIL EA7270, University of Bourgogne Franche-Comté, Dijon, France
| | - Yannick Hamon
- Aix Marseille University, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Tomasz Trombik
- Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
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13
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Xu C, Wan Z, Shaheen S, Wang J, Yang Z, Liu W. A PI(4,5)P2-derived "gasoline engine model" for the sustained B cell receptor activation. Immunol Rev 2020; 291:75-90. [PMID: 31402506 DOI: 10.1111/imr.12775] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 12/14/2022]
Abstract
To efficiently initiate activation responses against rare ligands in the microenvironment, lymphocytes employ sophisticated mechanisms involving signaling amplification. Recently, a signaling amplification mechanism initiated from phosphatidylinositol (PI) 4, 5-biphosphate [PI(4,5)P2] hydrolysis and synthesis for sustained B cell activation has been reported. Antigen and B cell receptor (BCR) recognition triggered the prompt reduction of PI(4,5)P2 density within the BCR microclusters, which led to the positive feedback for the synthesis of PI(4,5)P2 outside of the BCR microclusters. At single molecule level, the diffusion of PI(4,5)P2 was slow, allowing for the maintenance of a PI(4,5)P2 density gradient between the inside and outside of the BCR microclusters and the persistent supply of PI(4,5)P2 from outside to inside of the BCR microclusters. Here, we review studies that have contributed to uncovering the molecular mechanisms of PI(4,5)P2-derived signaling amplification model. Based on these studies, we proposed a "gasoline engine model" in which the activation of B cell signaling inside the microclusters is similar to the working principle of burning gasoline within the engine chamber of a gasoline engine. We also discuss the evidences showing the potential universality of this model and future prospects.
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Affiliation(s)
- Chenguang Xu
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Zhengpeng Wan
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Samina Shaheen
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Jing Wang
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Zhiyong Yang
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California
| | - Wanli Liu
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
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14
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Connolly A, Gagnon E. Electrostatic interactions: From immune receptor assembly to signaling. Immunol Rev 2019; 291:26-43. [DOI: 10.1111/imr.12769] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 04/30/2019] [Indexed: 12/21/2022]
Affiliation(s)
- Audrey Connolly
- Institut de Recherche en Immunologie et Cancérologie/Institute for Research in Immunology and Cancer Montréal Québec Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine Université de Montréal Montréal Québec Canada
| | - Etienne Gagnon
- Institut de Recherche en Immunologie et Cancérologie/Institute for Research in Immunology and Cancer Montréal Québec Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine Université de Montréal Montréal Québec Canada
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15
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Saveanu L, Zucchetti AE, Evnouchidou I, Ardouin L, Hivroz C. Is there a place and role for endocyticTCRsignaling? Immunol Rev 2019; 291:57-74. [DOI: 10.1111/imr.12764] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/02/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Loredana Saveanu
- National French Institute of Health and Medical Research (INSERM) 1149 Center of Research on Inflammation Paris France
- National French Center of Scientific Research (CNRS) ERL8252 Paris France
- Laboratory of Inflamex Excellency Faculty of Medicine Xavier Bichat Site Paris France
- Paris Diderot UniversitySorbonne Paris Cité Paris France
| | - Andres E. Zucchetti
- Institut Curie PSL Research UniversityINSERMU932 “Integrative analysis of T cell activation” team Paris France
| | - Irini Evnouchidou
- National French Institute of Health and Medical Research (INSERM) 1149 Center of Research on Inflammation Paris France
- National French Center of Scientific Research (CNRS) ERL8252 Paris France
- Laboratory of Inflamex Excellency Faculty of Medicine Xavier Bichat Site Paris France
- Paris Diderot UniversitySorbonne Paris Cité Paris France
- Inovarion Paris France
| | - Laurence Ardouin
- Institut Curie PSL Research UniversityINSERMU932 “Integrative analysis of T cell activation” team Paris France
| | - Claire Hivroz
- Institut Curie PSL Research UniversityINSERMU932 “Integrative analysis of T cell activation” team Paris France
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16
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Abstract
The primary cilium has gone from being a vestigial organelle to a crucial signaling hub of growing interest given the association between a group of human disorders, collectively known as ciliopathies, and defects in its structure or function. In recent years many ciliogenesis proteins have been observed at extraciliary sites in cells and likely perform cilium-independent functions ranging from regulation of the cytoskeleton to vesicular trafficking. Perhaps the most striking example is the non-ciliated T lymphocyte, in which components of the ciliary machinery are repurposed for the assembly and function of the immunological synapse even in the absence of a primary cilium. Furthermore, the specialization traits described at the immunological synapse are similar to those seen in the primary cilium. Here, we review common regulators and features shared by the immunological synapse and the primary cilium that document the remarkable homology between these structures.
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Affiliation(s)
- Chiara Cassioli
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | - Cosima T Baldari
- Department of Life Sciences, University of Siena, 53100 Siena, Italy.
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17
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Limozin L, Puech PH. Membrane Organization and Physical Regulation of Lymphocyte Antigen Receptors: A Biophysicist's Perspective. J Membr Biol 2019; 252:397-412. [PMID: 31352492 DOI: 10.1007/s00232-019-00085-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/18/2019] [Indexed: 12/19/2022]
Abstract
Receptors at the membrane of immune cells are the central players of innate and adaptative immunity, providing effective defence mechanisms against pathogens or cancer cells. Their function is intimately linked to their position at and within the membrane which provides accessibility, mobility as well as membrane proximal cytoskeleton anchoring, all of these elements playing important roles in the final function and links to cellular actions. Understanding how immune cells integrate the specific signals received at their membrane to take a decision remains an immense challenge and a very active field of fundamental and applied research. Recent progress in imaging and micromanipulation techniques have led to an unprecedented refinement in the description of molecular structures and supramolecular assemblies at the immune cell membrane, and provided a glimpse into their dynamics and regulation by force. Several key elements have been scrutinized such as the roles of relative sizes of molecules, lateral organisation, motion in the membrane of the receptors, but also physical cues such as forces, mediated by cellular substrates of different rigidities or applied by the cell itself, in conjunction with its partner cell. We review here these recent discoveries associated with a description of the biophysical methods used. While a conclusive picture integrating all of these components is still lacking, mainly due to the implication of diverse and different mechanisms and spatio-temporal scales involved, the amount of quantitative data available opens the way for physical modelling and numerical simulations and new avenues for experimental research.
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18
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Hawse WF, Cattley RT. T cells transduce T-cell receptor signal strength by generating different phosphatidylinositols. J Biol Chem 2019; 294:4793-4805. [PMID: 30692200 DOI: 10.1074/jbc.ra118.006524] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 01/14/2019] [Indexed: 12/26/2022] Open
Abstract
T-cell receptor (TCR) signaling strength is a dominant factor regulating T-cell differentiation, thymic development, and cytokine signaling. The molecular mechanisms by which TCR signal strength is transduced to downstream signaling networks remains ill-defined. Using computational modeling, biochemical assays, and imaging flow cytometry, we found here that TCR signal strength differentially generates phosphatidylinositol species. Weak TCR signals generated elevated phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and reduced phosphatidylinositol (3,4,5)-trisphosphate (PIP3) levels, whereas strong TCR signals reduced PI(4,5)P2 and elevated PIP3 levels. A proteomics screen revealed that focal adhesion kinase bound PI(4,5)P2, biochemical assays disclosed that focal adhesion kinase is preferentially activated by weak TCR signals and is required for optimal Treg induction, and further biochemical experiments revealed how TCR signaling strength regulates AKT activation. Low PIP3 levels generated by weak TCR signals were sufficient to activate phosphoinositide-dependent kinase-1 to phosphorylate AKT on Thr-308 but insufficient to activate mTOR complex 2 (mTORC2), whereas elevated PIP3 levels generated by a strong TCR signal were required to activate mTORC2 to phosphorylate Ser-473 on AKT. Our results provide support for a model that links TCR signaling to mTORC2 activation via phosphoinositide 3-kinase signaling. Together, the findings in this work establish that T cells measure TCR signal strength by generating different levels of phosphatidylinositol species that engage alternate signaling networks to control cell fate decisions.
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Affiliation(s)
- William F Hawse
- From the Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Richard T Cattley
- From the Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
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19
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Xia F, Qian CR, Xun Z, Hamon Y, Sartre AM, Formisano A, Mailfert S, Phelipot MC, Billaudeau C, Jaeger S, Nunès JA, Guo XJ, He HT. TCR and CD28 Concomitant Stimulation Elicits a Distinctive Calcium Response in Naive T Cells. Front Immunol 2018; 9:2864. [PMID: 30564247 PMCID: PMC6288997 DOI: 10.3389/fimmu.2018.02864] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 11/20/2018] [Indexed: 11/13/2022] Open
Abstract
T cell activation is initiated upon ligand engagement of the T cell receptor (TCR) and costimulatory receptors. The CD28 molecule acts as a major costimulatory receptor in promoting full activation of naive T cells. However, despite extensive studies, why naive T cell activation requires concurrent stimulation of both the TCR and costimulatory receptors remains poorly understood. Here, we explore this issue by analyzing calcium response as a key early signaling event to elicit T cell activation. Experiments using mouse naive CD4+ T cells showed that engagement of the TCR or CD28 with the respective cognate ligand was able to trigger a rise in fluctuating calcium mobilization levels, as shown by the frequency and average response magnitude of the reacting cells compared with basal levels occurred in unstimulated cells. The engagement of both TCR and CD28 enabled a further increase of these two metrics. However, such increases did not sufficiently explain the importance of the CD28 pathways to the functionally relevant calcium responses in T cell activation. Through the autocorrelation analysis of calcium time series data, we found that combined but not separate TCR and CD28 stimulation significantly prolonged the average decay time (τ) of the calcium signal amplitudes determined with the autocorrelation function, compared with its value in unstimulated cells. This increasement of decay time (τ) uniquely characterizes the fluctuating calcium response triggered by concurrent stimulation of TCR and CD28, as it could not be achieved with either stronger TCR stimuli or by co-engaging both TCR and LFA-1, and likely represents an important feature of competent early signaling to provoke efficient T cell activation. Our work has thus provided new insights into the interplay between the TCR and CD28 early signaling pathways critical to trigger naive T cell activation.
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Affiliation(s)
- Fan Xia
- Aix Marseille University, CNRS, INSERM, CIML, Marseille, France
| | - Cheng-Rui Qian
- Aix Marseille University, CNRS, INSERM, CIML, Marseille, France
| | - Zhou Xun
- School of Economics, Jiangxi University of Finance and Economics, Nanchang, China.,Aix Marseille University, AMSE and GREQAM, Marseille, France
| | - Yannick Hamon
- Aix Marseille University, CNRS, INSERM, CIML, Marseille, France
| | | | | | | | | | | | | | - Jacques A Nunès
- Aix Marseille University, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, Marseille, France.,Equipe Labellisée Fondation pour la Recherche Médicale, Centre de Recherche en Cancérologie de Marseille, Immunology and Cancer, Marseille, France
| | - Xiao-Jun Guo
- Aix Marseille University, CNRS, INSERM, CIML, Marseille, France
| | - Hai-Tao He
- Aix Marseille University, CNRS, INSERM, CIML, Marseille, France
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