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Bauer B, Wotapek T, Zöller T, Rutkowski E, Steinle A. The Activating C-type Lectin-like Receptor NKp65 Signals through a Hemi-immunoreceptor Tyrosine-based Activation Motif (hemITAM) and Spleen Tyrosine Kinase (Syk). J Biol Chem 2017; 292:3213-3223. [PMID: 28082678 DOI: 10.1074/jbc.m116.759977] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 01/11/2017] [Indexed: 11/06/2022] Open
Abstract
NKp65 is an activating human C-type lectin-like receptor (CTLR) triggering cellular cytotoxicity and cytokine secretion upon high-affinity interaction with the cognate CTLR keratinocyte-associated C-type lectin (KACL) selectively expressed by human keratinocytes. Previously, we demonstrated that NKp65-mediated cellular cytotoxicity depends on tyrosine 7, located in a cytoplasmic sequence motif of NKp65 resembling a hemi-immunoreceptor tyrosine-based activation motif (hemITAM). HemITAMs have been reported for a few activating myeloid-specific CTLRs, including Dectin-1 and CLEC-2, and consist of a single tyrosine signaling unit preceded by a triacidic motif. Upon receptor engagement, the hemITAM undergoes phosphotyrosinylation and specifically recruits spleen tyrosine kinase (Syk), initiating cellular activation. In this study, we addressed the functionality of the putative hemITAM of NKp65. We show that NKp65 forms homodimers and is phosphorylated at the hemITAM-embedded tyrosine 7 upon engagement by antibodies or KACL homodimers. HemITAM phosphotyrosinylation initiates a signaling pathway involving and depending on Syk, leading to cellular activation and natural killer (NK) cell degranulation. However, although NKp65 utilizes Syk for NK cell activation, a physical association of Syk with the NKp65 hemITAM could not be detected, unlike shown previously for the hemITAM of myeloid CTLR. Failure of NKp65 to recruit Syk is not due to an alteration of the triacidic motif, which rather affects the efficiency of hemITAM phosphotyrosinylation. In summary, NKp65 utilizes a hemITAM-like motif for cellular activation that requires Syk, although Syk appears not to be recruited to NKp65.
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Affiliation(s)
- Björn Bauer
- Institute for Molecular Medicine, Goethe University, 60590 Frankfurt am Main, Germany
| | - Tanja Wotapek
- Institute for Molecular Medicine, Goethe University, 60590 Frankfurt am Main, Germany
| | - Tobias Zöller
- Institute for Molecular Medicine, Goethe University, 60590 Frankfurt am Main, Germany
| | - Emilia Rutkowski
- Institute for Molecular Medicine, Goethe University, 60590 Frankfurt am Main, Germany
| | - Alexander Steinle
- Institute for Molecular Medicine, Goethe University, 60590 Frankfurt am Main, Germany.
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202
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Santos AM, Huo J, Hatherley D, Chirifu M, Davis SJ. A Protein Expression Toolkit for Studying Signaling in T Cells. Methods Mol Biol 2017; 1584:451-472. [PMID: 28255719 DOI: 10.1007/978-1-4939-6881-7_28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Innate and adaptive cellular immunity is dependent on interactions of cell surface receptors that initiate signaling, resulting in the formation of the immunological synapse and targeted delivery of effector functions. There has been considerable interest over the past 30 years in methods for isolating the extracellular regions of these receptors and components of the cytoplasmic signaling networks. This chapter describes our current protein expression toolkit used for structural studies of signaling proteins and the functional reconstitution of model cell surfaces, which comprises both bacterial and mammalian cell-based protein expression methodologies.
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Affiliation(s)
- Ana Mafalda Santos
- Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Headington, Oxford, OX3 9DS, UK
| | - Jiandong Huo
- Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Headington, Oxford, OX3 9DS, UK
| | - Deborah Hatherley
- Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Headington, Oxford, OX3 9DS, UK
| | - Mami Chirifu
- Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Simon J Davis
- Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Headington, Oxford, OX3 9DS, UK.
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203
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Abstract
Adoptive T-cell therapies have shown exceptional promise in the treatment of cancer, especially B-cell malignancies. Two distinct strategies have been used to redirect the activity of ex vivo engineered T cells. In one case, the well-known ability of the T-cell receptor (TCR) to recognize a specific peptide bound to a major histocompatibility complex molecule has been exploited by introducing a TCR against a cancer-associated peptide/human leukocyte antigen complex. In the other strategy, synthetic constructs called chimeric antigen receptors (CARs) that contain antibody variable domains (single-chain fragments variable) and signaling domains have been introduced into T cells. Whereas many reviews have described these two approaches, this review focuses on a few recent advances of significant interest. The early success of CARs has been followed by questions about optimal configurations of these synthetic constructs, especially for efficacy against solid tumors. Among the many features that are important, the dimensions and stoichiometries of CAR/antigen complexes at the synapse have recently begun to be appreciated. In TCR-mediated approaches, recent evidence that mutated peptides (neoantigens) serve as targets for endogenous T-cell responses suggests that these neoantigens may also provide new opportunities for adoptive T-cell therapies with TCRs.
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Affiliation(s)
- Preeti Sharma
- Department of Biochemistry, University of Illinois, Urbana, IL, USA
| | - David M Kranz
- Department of Biochemistry, University of Illinois, Urbana, IL, USA
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204
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Phosphoproteomic Analyses of Interleukin 2 Signaling Reveal Integrated JAK Kinase-Dependent and -Independent Networks in CD8(+) T Cells. Immunity 2016; 45:685-700. [PMID: 27566939 PMCID: PMC5040828 DOI: 10.1016/j.immuni.2016.07.022] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/03/2016] [Accepted: 07/08/2016] [Indexed: 12/20/2022]
Abstract
Interleukin-2 (IL-2) is a fundamental cytokine that controls proliferation and differentiation of T cells. Here, we used high-resolution mass spectrometry to generate a comprehensive and detailed map of IL-2 protein phosphorylations in cytotoxic T cells (CTL). The data revealed that Janus kinases (JAKs) couple IL-2 receptors to the coordinated phosphorylation of transcription factors, regulators of chromatin, mRNA translation, GTPases, vesicle trafficking, and the actin and microtubule cytoskeleton. We identified an IL-2-JAK-independent SRC family Tyr-kinase-controlled signaling network that regulates ∼10% of the CTL phosphoproteome, the production of phosphatidylinositol (3,4,5)-trisphosphate (PIP3), and the activity of the serine/threonine kinase AKT. These data reveal a signaling framework wherein IL-2-JAK-controlled pathways coordinate with IL-2-independent networks of kinase activity and provide a resource toward the further understanding of the networks of protein phosphorylation that program CTL fate.
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205
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Dustin ML, Choudhuri K. Signaling and Polarized Communication Across the T Cell Immunological Synapse. Annu Rev Cell Dev Biol 2016; 32:303-325. [PMID: 27501450 DOI: 10.1146/annurev-cellbio-100814-125330] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
T cells express a somatically recombined antigen receptor (αβTCR) that is calibrated during development to respond to changes in peptides displayed by major histocompatibility complex proteins (pMHC) on the surface of antigen-presenting cells (APC). A key characteristic of pMHC for adaptive immunity is the ability to sample internal states of cells and tissues to sensitively detect changes associated with infection, cell derangement, or tissue injury. Physical T cell-APC contact sets up an axis for polarization of TCR, adhesion molecules, kinases, cytoskeletal elements, and organelles inherent in this mode of juxtacrine signaling. The discovery of further lateral organization of the TCR and adhesion molecules into radially symmetric compartments, the immunological synapse, revealed an intersecting plane of symmetry and potential for regulated symmetry breaking to control duration of T cell-APC interactions. In addition to organizing signaling machinery, the immunological synapse directs the polarized transport and secretion of cytokines and cytolytic agents across the synaptic cleft and is a site for the generation and exocytic release of bioactive microvesicles that can functionally affect recipient APC and other cells in the environment. This machinery is coopted by retroviruses, and human immune deficiency virus-1 may even use antigen-specific synapses for infection of healthy T cells. Here, we discuss recent advances in the molecular and cell biological mechanisms of immunological synapse assembly and signaling and its role in intercellular communication across the synaptic cleft.
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Affiliation(s)
- Michael L Dustin
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford OX3 7FY, United Kingdom;
| | - Kaushik Choudhuri
- Department of Microbiology & Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109-5620;
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206
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Freeman SA, Goyette J, Furuya W, Woods EC, Bertozzi CR, Bergmeier W, Hinz B, van der Merwe PA, Das R, Grinstein S. Integrins Form an Expanding Diffusional Barrier that Coordinates Phagocytosis. Cell 2016; 164:128-140. [PMID: 26771488 DOI: 10.1016/j.cell.2015.11.048] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 09/07/2015] [Accepted: 11/14/2015] [Indexed: 01/12/2023]
Abstract
Phagocytosis is initiated by lateral clustering of receptors, which in turn activates Src-family kinases (SFKs). Activation of SFKs requires depletion of tyrosine phosphatases from the area of particle engagement. We investigated how the major phosphatase CD45 is excluded from contact sites, using single-molecule tracking. The mobility of CD45 increased markedly upon engagement of Fcγ receptors. While individual CD45 molecules moved randomly, they were displaced from the advancing phagocytic cup by an expanding diffusional barrier. By micropatterning IgG, the ligand of Fcγ receptors, we found that the barrier extended well beyond the perimeter of the receptor-ligand engagement zone. Second messengers generated by Fcγ receptors activated integrins, which formed an actin-tethered diffusion barrier that excluded CD45. The expanding integrin wave facilitates the zippering of Fcγ receptors onto the target and integrates the information from sparse receptor-ligand complexes, coordinating the progression and ultimate closure of the phagocytic cup.
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Affiliation(s)
- Spencer A Freeman
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Jesse Goyette
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Wendy Furuya
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Elliot C Woods
- Department of Chemistry and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305-4401, USA
| | - Carolyn R Bertozzi
- Department of Chemistry and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305-4401, USA
| | - Wolfgang Bergmeier
- Department of Biochemistry and Biophysics, University of North Carolina, 120 Mason Farm Road, Chapel Hill, NC 27599-7260, USA
| | - Boris Hinz
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON M5S 3E2, Canada
| | | | - Raibatak Das
- Department of Integrative Biology, University of Colorado, Denver, CO 80217-3364, USA
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; Keenan Research Centre, St. Michael's Hospital, Toronto, ON M5S 1T8, Canada.
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