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Santos RF, de Sousa Linhares A, Steinberger P, Davis SJ, Oliveira L, Carmo AM. The CD6 interactome orchestrates ligand-independent T cell inhibitory signaling. Cell Commun Signal 2024; 22:286. [PMID: 38790044 PMCID: PMC11127300 DOI: 10.1186/s12964-024-01658-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
BACKGROUND T-cell membrane scaffold proteins are pivotal in T cell function, acting as versatile signaling hubs. While CD6 forms a large intracellular signalosome, it is distinguished from typical scaffolds like LAT or PAG by possessing a substantial ectodomain that binds CD166, a well-characterized ligand expressed on most antigen-presenting cells (APC), through the third domain (d3) of the extracellular region. Although the intact form of CD6 is the most abundant in T cells, an isoform lacking d3 (CD6∆d3) is transiently expressed on activated T cells. Still, the precise character of the signaling transduced by CD6, whether costimulatory or inhibitory, and the influence of its ectodomain on these activities are unclear. METHODS We expressed CD6 variants with extracellular deletions or cytosolic mutations in Jurkat cells containing eGFP reporters for NF-κB and NF-AT transcription factor activation. Cell activation was assessed by eGFP flow cytometry following Jurkat cell engagement with superantigen-presenting Raji cells. Using imaging flow cytometry, we evaluated the impact of the CD6-CD166 pair on cell adhesiveness during the antigen-dependent and -independent priming of T cells. We also examined the role of extracellular or cytosolic sequences on CD6 translocation to the immunological synapse, using immunofluorescence-based imaging. RESULTS Our investigation dissecting the functions of the extracellular and cytosolic regions of CD6 revealed that CD6 was trafficked to the immunological synapse and exerted tonic inhibition wholly dependent on its cytosolic tail. Surprisingly, however, translocation to the synapse occurred independently of the extracellular d3 and of engagement to CD166. On the other hand, CD6 binding to CD166 significantly increased T cell:APC adhesion. However, this activity was most evident in the absence of APC priming with superantigen, and thus, in the absence of TCR engagement. CONCLUSIONS Our study identifies CD6 as a novel 'on/off' scaffold-receptor capable of modulating responsiveness in two ways. Firstly, and independently of ligand binding, it establishes signaling thresholds through tonic inhibition, functioning as a membrane-bound scaffold. Secondly, CD6 has the capacity for alternative splicing-dependent variable ligand engagement, modulating its checkpoint-like activity.
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Affiliation(s)
- Rita F Santos
- IBMC - Instituto de Biologia Molecular e Celular, Porto, Porto, Portugal
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- ESS - IPP School of Health, Polytechnic of Porto, Porto, Portugal
| | - Annika de Sousa Linhares
- Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Peter Steinberger
- Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Simon J Davis
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
- Medical Research Council, Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Liliana Oliveira
- IBMC - Instituto de Biologia Molecular e Celular, Porto, Porto, Portugal
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Alexandre M Carmo
- IBMC - Instituto de Biologia Molecular e Celular, Porto, Porto, Portugal.
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.
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2
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Janakaloti Narayanareddy BR, Allipeta NR, Allard J, Gross SP. A new method to experimentally quantify dynamics of initial protein-protein interactions. Commun Biol 2024; 7:311. [PMID: 38472292 PMCID: PMC10933273 DOI: 10.1038/s42003-024-05914-2] [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] [Received: 09/08/2023] [Accepted: 02/12/2024] [Indexed: 03/14/2024] Open
Abstract
Cells run on initiation of protein-protein interactions, which are dynamically tuned spatially and temporally to modulate cellular events. This tuning can be physical, such as attaching the protein to a cargo or protein complex, thereby altering its diffusive properties, or modulating the distance between protein pairs, or chemical, by altering the proteins' conformations (e.g., nucleotide binding state of an enzyme, post-translational modification of a protein, etc.). Because a dynamic and changing subset of proteins in the cell could be in any specific state, ensemble measurements are not ideal-to untangle which of the factors are important, and how, we need single-molecule measurements. Experimentally, until now we have not had good tools to precisely measure initiation of such protein-protein interactions at the single-molecule level. Here, we develop a new method to measure dynamics of initial protein-protein interactions, allowing measurement of how properties such as the distance between proteins, and their tethered length can modulate the rate of interactions. In addition to precise measurement distance dependent motor-MT rebinding dynamics, we demonstrate the use of a dithered optical trap to measure dynamic motor-MT interactions and further discuss the possibilities of this technique being applicable to other systems.
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Affiliation(s)
| | - Nathan Reddy Allipeta
- Developmental and Cell Biology, University of California Irvine, Irvine, CA, USA
- Arcadia High School, Arcadia, CA, USA
| | - Jun Allard
- Department of Mathematics, University of California Irvine, Irvine, CA, USA
| | - Steven P Gross
- Developmental and Cell Biology, University of California Irvine, Irvine, CA, USA.
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3
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Lippert AH, Paluch C, Gaglioni M, Vuong MT, McColl J, Jenkins E, Fellermeyer M, Clarke J, Sharma S, Moreira da Silva S, Akkaya B, Anzilotti C, Morgan SH, Jessup CF, Körbel M, Gileadi U, Leitner J, Knox R, Chirifu M, Huo J, Yu S, Ashman N, Lui Y, Wilkinson I, Attfield KE, Fugger L, Robertson NJ, Lynch CJ, Murray L, Steinberger P, Santos AM, Lee SF, Cornall RJ, Klenerman D, Davis SJ. Antibody agonists trigger immune receptor signaling through local exclusion of receptor-type protein tyrosine phosphatases. Immunity 2024; 57:256-270.e10. [PMID: 38354703 DOI: 10.1016/j.immuni.2024.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/30/2023] [Accepted: 01/09/2024] [Indexed: 02/16/2024]
Abstract
Antibodies can block immune receptor engagement or trigger the receptor machinery to initiate signaling. We hypothesized that antibody agonists trigger signaling by sterically excluding large receptor-type protein tyrosine phosphatases (RPTPs) such as CD45 from sites of receptor engagement. An agonist targeting the costimulatory receptor CD28 produced signals that depended on antibody immobilization and were sensitive to the sizes of the receptor, the RPTPs, and the antibody itself. Although both the agonist and a non-agonistic anti-CD28 antibody locally excluded CD45, the agonistic antibody was more effective. An anti-PD-1 antibody that bound membrane proximally excluded CD45, triggered Src homology 2 domain-containing phosphatase 2 recruitment, and suppressed systemic lupus erythematosus and delayed-type hypersensitivity in experimental models. Paradoxically, nivolumab and pembrolizumab, anti-PD-1-blocking antibodies used clinically, also excluded CD45 and were agonistic in certain settings. Reducing these agonistic effects using antibody engineering improved PD-1 blockade. These findings establish a framework for developing new and improved therapies for autoimmunity and cancer.
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Affiliation(s)
- Anna H Lippert
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Christopher Paluch
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; Nuffield Department of Medicine, University of Oxford, Oxford, UK; MiroBio Ltd, Winchester House, Oxford Science Park, Oxford, UK
| | - Meike Gaglioni
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Mai T Vuong
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - James McColl
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Edward Jenkins
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Martin Fellermeyer
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Joseph Clarke
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Sumana Sharma
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | | | - Billur Akkaya
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Consuelo Anzilotti
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK; Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Sara H Morgan
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Claire F Jessup
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Markus Körbel
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Uzi Gileadi
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Judith Leitner
- Division of Immune Receptors and T cell Activation, Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - Rachel Knox
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Mami Chirifu
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Jiandong Huo
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Susan Yu
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Nicole Ashman
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Yuan Lui
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | | | - Kathrine E Attfield
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Oxford Centre for Neuroinflammation, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Lars Fugger
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Oxford Centre for Neuroinflammation, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | | | | | - Lynne Murray
- MiroBio Ltd, Winchester House, Oxford Science Park, Oxford, UK
| | - Peter Steinberger
- Division of Immune Receptors and T cell Activation, Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - Ana Mafalda Santos
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Richard J Cornall
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, UK.
| | - Simon J Davis
- MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK; Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK.
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Rinaldi DA, Kanagy WK, Kaye HC, Grattan RM, Lucero SR, Pérez MP, Wester MJ, Lidke KA, Wilson BS, Lidke DS. Antigen Geometry Tunes Mast Cell Signaling Through Distinct FcεRI Aggregation and Structural Changes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.04.552060. [PMID: 37609336 PMCID: PMC10441289 DOI: 10.1101/2023.08.04.552060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Immunoreceptor tyrosine-based activation motif (ITAM)-containing Fc receptors are critical components of the innate and adaptive immune systems. FcεRI mediates the allergic response via crosslinking of IgE-bound receptors by multivalent antigens. Yet, the underlying molecular mechanisms that govern the response of FcεRI to specific antigens remain poorly understood. We compared responses induced by two antigens with distinct geometries, high valency DNP-BSA and trivalent DF3, and found unique secretion and receptor phosphorylation profiles that are due to differential recruitment of Lyn and SHIP1. To understand how these two antigens can cause such markedly different outcomes, we used direct stochastic optical reconstruction microscopy (dSTORM) super-resolution imaging combined with Bayesian Grouping of Localizations (BaGoL) analysis to compare the nanoscale characteristics of FcεRI aggregates. DF3 aggregates were found to be smaller and more densely packed than DNP-BSA aggregates. Using lifetime-based Förster resonance energy transfer (FRET) measurements, we discovered that FcεRI subunits undergo structural rearrangements upon crosslinking with either antigen, and in response to interaction with monovalent antigen presented on a supported lipid bilayer. The extent of conformational change is positively correlated with signaling efficiency. Finally, we provide evidence for forces in optimizing FcεRI signaling, such that immobilizing DF3 on a rigid surface promoted degranulation while increasing DNP-BSA flexibility lowered degranulation. These results provide a link between the physical attributes of allergens, including size, shape, valency, and flexibility, and FcεRI signaling strength. Thus, the antigen modulates mast cell outcomes by creating unique aggregate geometries that tune FcεRI conformation, phosphorylation and signaling partner recruitment.
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Affiliation(s)
- Derek A. Rinaldi
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131
| | - William K. Kanagy
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131
- Present address: Department of Immunology, University of Minnesota, Minneapolis, MN 55455
| | - Hannah C. Kaye
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131
| | - Rachel M. Grattan
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131
| | - Shayna R. Lucero
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131
| | | | - Michael J. Wester
- Department Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131
| | - Keith A. Lidke
- Department Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131
- Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - Bridget S. Wilson
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131
- Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - Diane S. Lidke
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131
- Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
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5
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Strazza M, Moore EK, Adam K, Azoulay-Alfaguter I, Mor A. Neutralization of the adaptor protein PAG by monoclonal antibody limits murine tumor growth. Mol Ther Methods Clin Dev 2022; 27:380-390. [PMID: 36419471 PMCID: PMC9664140 DOI: 10.1016/j.omtm.2022.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 10/21/2022] [Indexed: 11/11/2022]
Abstract
The transmembrane adaptor phosphoprotein associated with glycosphingolipid-enriched microdomains 1 (PAG) is phosphorylated in T cells downstream of PD-1 signaling and contributes to the resulting functional inhibition of multiple cellular processes. Furthermore, PAG expression is negatively correlated with survival in multiple human tumors and is a driver of murine tumor growth and immune evasion. Here we develop an antibody that targets the extracellular domain of human PAG, with cross-reactivity to murine PAG. We demonstrate that this antibody binds to extracellular PAG on intact cells and affects T cell activation. Finally, we show that administration of anti-PAG monoclonal antibody in combination with anti-PD-1 antibody to mice bearing MC38 tumors limited tumor growth and enhanced T cell infiltration to tumors.
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Affiliation(s)
- Marianne Strazza
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY 10032, USA
| | - Emily K. Moore
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY 10032, USA
| | - Kieran Adam
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY 10032, USA
| | | | - Adam Mor
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, NY 10032, USA
- Division of Rheumatology, Department of Medicine, Columbia University Medical Center, New York, NY 10032, USA
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6
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Henriques SN, Oliveira L, Santos RF, Carmo AM. CD6-mediated inhibition of T cell activation via modulation of Ras. Cell Commun Signal 2022; 20:184. [PMID: 36414966 PMCID: PMC9682754 DOI: 10.1186/s12964-022-00998-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 10/16/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND CD6 is one of many cell surface receptors known to regulate signal transduction upon T cell activation. However, whether CD6 mediates costimulatory or inhibitory signals is controversial. When T cells engage with antigen presenting cells (APCs), CD6 interacts with its ligand CD166 at the cell-cell interface while the cytosolic tail assembles a complex signalosome composed of adaptors and effector enzymes, that may either trigger activating signaling cascades, or instead modulate the intensity of signaling. Except for a few cytosolic adaptors that connect different components of the CD6 signalosome, very little is known about the mechanistic effects of the cytosolic effectors that bind CD6. METHODS Jurkat model T cells were transfected to express wild-type (WT) CD6, or a cytoplasmic truncation, signaling-disabled mutant, CD6Δcyt. The two resulting cell lines were directly activated by superantigen (sAg)-loaded Raji cells, used as APCs, to assess the net signaling function of CD6. The Jurkat cell lines were further adapted to express a FRET-based unimolecular HRas biosensor that reported the activity of this crucial GTPase at the immunological synapse. RESULTS We show that deletion of the cytosolic tail of CD6 enhances T-cell responses, indicating that CD6 restrains T-cell activation. One component of the CD6-associated inhibitory apparatus was found to be the GTPase activating protein of Ras (RasGAP), that we show to associate with CD6 in a phosphorylation-dependent manner. The FRET HRas biosensor that we developed was demonstrated to be functional and reporting the activation of the T cell lines. This allowed to determine that the presence of the cytosolic tail of CD6 results in the down-regulation of HRas activity at the immunological synapse, implicating this fundamental GTPase as one of the targets inhibited by CD6. CONCLUSIONS This study provides the first description of a mechanistic sequence of events underlying the CD6-mediated inhibition of T-cell activation, involving the modulation of the MAPK pathway at several steps, starting with the coupling of RasGAP to the CD6 signalosome, the repression of the activity of Ras, and culminating in the reduction of ERK1/2 phosphorylation and of the expression of the T-cell activation markers CD69 and IL-2R α chain. Video abstract.
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Affiliation(s)
- Sónia N. Henriques
- grid.5808.50000 0001 1503 7226i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal ,grid.5808.50000 0001 1503 7226IBMC - Instituto de Biologia Molecular e Celular, Porto, Portugal ,grid.5808.50000 0001 1503 7226Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Liliana Oliveira
- grid.5808.50000 0001 1503 7226i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal ,grid.5808.50000 0001 1503 7226IBMC - Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Rita F. Santos
- grid.5808.50000 0001 1503 7226i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal ,grid.5808.50000 0001 1503 7226IBMC - Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Alexandre M. Carmo
- grid.5808.50000 0001 1503 7226i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal ,grid.5808.50000 0001 1503 7226IBMC - Instituto de Biologia Molecular e Celular, Porto, Portugal
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7
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Gurdap CO, Wedemann L, Sych T, Sezgin E. Influence of the extracellular domain size on the dynamic behavior of membrane proteins. Biophys J 2022; 121:3826-3836. [PMID: 36110044 PMCID: PMC9674980 DOI: 10.1016/j.bpj.2022.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 08/15/2022] [Accepted: 09/12/2022] [Indexed: 11/29/2022] Open
Abstract
The dynamic behavior of plasma membrane proteins mediates various cellular processes such as cellular motility, communication, and signaling. It is widely accepted that the dynamics of the membrane proteins is determined either by the interactions of the transmembrane domain with the surrounding lipids or by the interactions of the intracellular domain with cytosolic components such as cortical actin. Although initiation of different cellular signaling events at the plasma membrane has been attributed to the extracellular domain (ECD) properties recently, the impact of ECDs on the dynamic behavior of membrane proteins is rather unexplored. Here, we investigate how ECD properties influence protein dynamics in the lipid bilayer by reconstituting ECDs of different sizes or glycosylation in model membrane systems and analyzing ECD-driven protein sorting in lipid domains as well as protein mobility. Our data show that increasing the ECD mass or glycosylation leads to a decrease in ordered domain partitioning and diffusivity. Our data reconcile different mechanisms proposed for the initiation of cellular signaling by linking the ECD size of membrane proteins with their localization and diffusion dynamics in the plasma membrane.
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Affiliation(s)
- Cenk Onur Gurdap
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Linda Wedemann
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Taras Sych
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Erdinc Sezgin
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden.
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8
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Abstract
As the targets of chimeric antigen receptor (CAR)-T cells expand to a variety of cancers, autoimmune diseases, viral infections, and fibrosis, there is an increasing demand for identifying new antigens and designing new CARs that can be effectively activated. However, the rational selection of antigens and the design of CARs are limited by a lack of knowledge regarding the molecular mechanism by which CARs are activated by antigens. Here, we present data supporting a "size exclusion" model explaining how antigen signals are transmitted across the plasma membrane to activate the intracellular domains of CARs. In this model, antigen engagement with CAR results in a narrow intermembrane space that physically excludes CD45, a bulky phosphatase, out of the CAR zone, thus favoring CAR phosphorylation by kinases, which further triggers downstream pathways leading to T cell activation. Aligned with this model, increasing the size of CAR extracellular domains diminished CAR-T activation both in vitro and in a mouse lymphoma model; membrane-proximal epitopes activated CAR-Ts better than membrane-distal epitopes. Moreover, increasing the size of CD45 by antibody conjugation enhanced the activation of CARs that recognize membrane-distal epitopes. Consistently, CAR-Ts expressing CD45RABC, the larger isoform, were activated to a higher level than those expressing a smaller isoform CD45RO. Together, our work revealed that CAR-T activation depends on the size difference between the CAR-antigen pair and CD45; the size of CAR, antigen, and CD45 can thus be targets for tuning CAR-T activation.
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Affiliation(s)
- Qian Xiao
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, 06520, USA,Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 08903, USA,Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08854, USA
| | - Xinyan Zhang
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Liqun Tu
- Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 08903, USA
| | - Jian Cao
- Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 08903, USA,Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08854, USA
| | - Christian S. Hinrichs
- Duncan and Nancy MacMillan Cancer Immunology and Metabolism Center of Excellence, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, 08903, USA,Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08854, USA
| | - Xiaolei Su
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, 06520, USA,Yale Cancer Center, Yale University, New Haven, CT, 06520, USA,Corresponding author: Xiaolei Su,
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9
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Understanding immune signaling using advanced imaging techniques. Biochem Soc Trans 2022; 50:853-866. [PMID: 35343569 PMCID: PMC9162467 DOI: 10.1042/bst20210479] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 12/13/2022]
Abstract
Advanced imaging is key for visualizing the spatiotemporal regulation of immune signaling which is a complex process involving multiple players tightly regulated in space and time. Imaging techniques vary in their spatial resolution, spanning from nanometers to micrometers, and in their temporal resolution, ranging from microseconds to hours. In this review, we summarize state-of-the-art imaging methodologies and provide recent examples on how they helped to unravel the mysteries of immune signaling. Finally, we discuss the limitations of current technologies and share our insights on how to overcome these limitations to visualize immune signaling with unprecedented fidelity.
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10
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Simulation of receptor triggering by kinetic segregation shows role of oligomers and close-contacts. Biophys J 2022; 121:1660-1674. [PMID: 35367423 PMCID: PMC9117938 DOI: 10.1016/j.bpj.2022.03.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/07/2022] [Accepted: 03/28/2022] [Indexed: 11/23/2022] Open
Abstract
The activation of T cells, key players of the immune system, involves local evacuation of phosphatase CD45 from a region of the T cell's surface, segregating it from the T cell receptor. What drives this evacuation? In the presence of antigen, what ensures evacuation happens in the subsecond timescales necessary to initiate signaling? In the absence of antigen, what mechanisms ensure that evacuation does not happen spontaneously, which could cause signaling errors? Phenomena known to influence spatial organization of CD45 or similar surface molecules include diffusive motion in the lipid bilayer, oligomerization reactions, and mechanical compression against a nearby surface, such as that of the cell presenting the antigen. Computer simulations can investigate hypothesized spatiotemporal mechanisms of T cell signaling. The challenge to computational studies of evacuation is that the base process, spontaneous evacuation by simple diffusion, is in the extreme rare event limit, meaning direct stochastic simulation is unfeasible. Here, we combine particle-based spatial stochastic simulation with the weighted ensemble method for rare events to compute the mean first passage time for cell surface availability by surface reorganization of CD45. We confirm mathematical estimates that, at physiological concentrations, spontaneous evacuation is extremely rare, roughly 300 years. We find that dimerization decreases the time required for evacuation. A weak bimolecular interaction (dissociation constant estimate 460 μM) is sufficient for an order of magnitude reduction of spontaneous evacuation times, and oligomerization to hexamers reduces times to below 1 s. This introduces a mechanism whereby externally induced CD45 oligomerization could significantly modify T cell function. For large regions of close contact, such as those induced by large microvilli, molecular size and compressibility imply a nonzero reentry probability of 60%, decreasing evacuation times. Simulations show that these reduced evacuation times are still unrealistically long (even with a fourfold variation centered around previous estimates of parameters), suggesting that a yet-to-be-described mechanism, besides compressional exclusion at a close contact, drives evacuation.
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11
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Jang HY, Ha DH, Rah SY, Lee DH, Lee SM, Park BH. Sirtuin 6 is a negative regulator of FcεRI signaling and anaphylactic responses. J Allergy Clin Immunol 2022; 149:156-167.e7. [PMID: 34051221 DOI: 10.1016/j.jaci.2021.05.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 04/29/2021] [Accepted: 05/04/2021] [Indexed: 11/20/2022]
Abstract
BACKGROUND Binding IgE to a cognate allergen causes aggregation of Fcε receptor I (FcεRI) in mast cells, resulting in activation of receptor-associated Src family tyrosine kinases, including Lyn and Syk. Protein tyrosine phosphatase, receptor type C (PTPRC), also known as CD45, has emerged as a positive regulator of FcεRI signaling by dephosphorylation of the inhibitory tyrosine of Lyn. OBJECTIVE Sirtuin 6 (Sirt6), a NAD+-dependent deacetylase, exhibits an anti-inflammatory property. It remains to be determined, however, whether Sirt6 attenuates mast cell-associated diseases, including anaphylaxis. METHODS FcεRI signaling and mast cell degranulation were measured after IgE cross-linking in murine bone marrow-derived mast cells (BMMCs) and human cord blood-derived mast cells. To investigate the function of Sirt6 in mast cell activation in vivo, we used mast cell-dependent animal models of passive systemic anaphylaxis (PSA) and passive cutaneous anaphylaxis (PCA). RESULTS Sirt6-deficient BMMCs augmented IgE-FcεRI-mediated signaling and degranulation compared to wild-type BMMCs. Reconstitution of mast cell-deficient KitW-sh/W-sh mice with BMMCs received from Sirt6 knockout mice developed more severe PSA and PCA compared to mice engrafted with wild-type BMMCs. Similarly, genetic overexpression or pharmacologic activation of Sirt6 suppressed mast cell degranulation and blunted responses to PCA. Mechanistically, Sirt6 deficiency increased PTPRC transcription via acetylating histone H3, leading to enhanced aggregation of FcεRI in BMMCs. Finally, we recapitulated the Sirt6 regulation of PTPRC and FcεRI signaling in human mast cells. CONCLUSIONS Sirt6 acts as a negative regulator of FcεRI signaling cascade in mast cells by suppressing PTPRC transcription. Activation of Sirt6 may therefore represent a promising and novel therapeutic strategy for anaphylaxis.
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Affiliation(s)
- Hyun-Young Jang
- Department of Biochemistry and Molecular Biology, Chonbuk National University Medical School, Jeonju, Korea
| | - Do Hyun Ha
- Division of Biotechnology, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan, Korea
| | - So-Young Rah
- Department of Biochemistry and Molecular Biology, Chonbuk National University Medical School, Jeonju, Korea
| | - Dong-Hyun Lee
- Department of Obstetrics and Gynecology, Chonbuk National University Medical School, Jeonju, Korea
| | - Sang-Myeong Lee
- College of Veterinary Medicine, Chungbuk National University, Cheongju, Korea.
| | - Byung-Hyun Park
- Department of Biochemistry and Molecular Biology, Chonbuk National University Medical School, Jeonju, Korea.
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12
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Greene JT, Brian BF, Senevirathne SE, Freedman TS. Regulation of myeloid-cell activation. Curr Opin Immunol 2021; 73:34-42. [PMID: 34601225 DOI: 10.1016/j.coi.2021.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 12/24/2022]
Abstract
Myeloid cells (macrophages, monocytes, dendritic cells, and granulocytes) survey the body for signs of infection and damage and regulate tissue homeostasis, organogenesis, and immunity. They express receptors that initiate the inflammatory response, send signals that alter the vascular and cytokine milieu, and oversee the recruitment, differentiation, and activation of other myeloid and adaptive immune cells. Their activation must therefore be tightly regulated, optimized for maximal innate-immune protection with a minimum of collateral tissue damage or disorganization. In this review we discuss what it means for myeloid cells to become activated, with emphasis on the receptors and signaling molecules important for the recognition of pathogen-associated and damage-associated molecular patterns. We also outline how these signals are regulated by the steric properties of proteins, by adhesive and cytoskeletal interactions, and by negative feedback to keep inflammation in check and support healthy tissue development and homeostasis. Throughout the text we highlight recent publications and reviews and direct readers therein for a comprehensive bibliography.
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Affiliation(s)
- Joseph T Greene
- Department of Pharmacology, Center for Immunology, Masonic Cancer Center, and Center for Autoimmune Diseases Research, University of Minnesota, Minneapolis, MN, 55455, United States
| | - Ben F Brian
- Department of Pharmacology, Center for Immunology, Masonic Cancer Center, and Center for Autoimmune Diseases Research, University of Minnesota, Minneapolis, MN, 55455, United States
| | - S Erandika Senevirathne
- Department of Pharmacology, Center for Immunology, Masonic Cancer Center, and Center for Autoimmune Diseases Research, University of Minnesota, Minneapolis, MN, 55455, United States
| | - Tanya S Freedman
- Department of Pharmacology, Center for Immunology, Masonic Cancer Center, and Center for Autoimmune Diseases Research, University of Minnesota, Minneapolis, MN, 55455, United States.
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13
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Urbančič I, Schiffelers L, Jenkins E, Gong W, Santos AM, Schneider F, O'Brien-Ball C, Vuong MT, Ashman N, Sezgin E, Eggeling C. Aggregation and mobility of membrane proteins interplay with local lipid order in the plasma membrane of T cells. FEBS Lett 2021; 595:2127-2146. [PMID: 34160065 DOI: 10.1002/1873-3468.14153] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/07/2021] [Accepted: 06/18/2021] [Indexed: 01/17/2023]
Abstract
To disentangle the elusive lipid-protein interactions in T-cell activation, we investigate how externally imposed variations in mobility of key membrane proteins (T-cell receptor [TCR], kinase Lck, and phosphatase CD45) affect the local lipid order and protein colocalisation. Using spectral imaging with polarity-sensitive membrane probes in model membranes and live Jurkat T cells, we find that partial immobilisation of proteins (including TCR) by aggregation or ligand binding changes their preference towards a more ordered lipid environment, which can recruit Lck. Our data suggest that the cellular membrane is poised to modulate the frequency of protein encounters upon alterations of their mobility, for example in ligand binding, which offers new mechanistic insight into the involvement of lipid-mediated interactions in membrane-hosted signalling events.
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Affiliation(s)
- Iztok Urbančič
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
- Jožef Stefan Institute, Ljubljana, Slovenia
| | - Lisa Schiffelers
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Edward Jenkins
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Weijian Gong
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Ana Mafalda Santos
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Falk Schneider
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | | | - Mai Tuyet Vuong
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Nicole Ashman
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Erdinc Sezgin
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
- Science for Life Laboratory, Karolinska Institutet, Solna, Sweden
| | - Christian Eggeling
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Jena, Germany
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14
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Ando T, Kitaura J. Tuning IgE: IgE-Associating Molecules and Their Effects on IgE-Dependent Mast Cell Reactions. Cells 2021; 10:cells10071697. [PMID: 34359869 PMCID: PMC8305778 DOI: 10.3390/cells10071697] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 06/30/2021] [Accepted: 07/02/2021] [Indexed: 12/15/2022] Open
Abstract
The recent emergence of anti-immunoglobulin E (IgE) drugs and their candidates for humans has endorsed the significance of IgE-dependent pathways in allergic disorders. IgE is distributed locally in the tissues or systemically to confer a sensory mechanism in a domain of adaptive immunity to the otherwise innate type of effector cells, namely, mast cells and basophils. Bound on the high-affinity IgE receptor FcεRI, IgE enables fast memory responses against revisiting threats of venoms, parasites, and bacteria. However, the dysregulation of IgE-dependent reactions leads to potentially life-threatening allergic diseases, such as asthma and anaphylaxis. Therefore, reactivity of the IgE sensor is fine-tuned by various IgE-associating molecules. In this review, we discuss the mechanistic basis for how IgE-dependent mast cell activation is regulated by the IgE-associating molecules, including the newly developed therapeutic candidates.
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Affiliation(s)
- Tomoaki Ando
- Atopy (Allergy) Research Center, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan
- Correspondence: (T.A.); (J.K.); Tel.: +81-3-5802-1591 (T.A. & J.K.)
| | - Jiro Kitaura
- Atopy (Allergy) Research Center, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan
- Department of Science of Allergy and Inflammation, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan
- Correspondence: (T.A.); (J.K.); Tel.: +81-3-5802-1591 (T.A. & J.K.)
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15
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Jung Y, Wen L, Altman A, Ley K. CD45 pre-exclusion from the tips of T cell microvilli prior to antigen recognition. Nat Commun 2021; 12:3872. [PMID: 34162836 PMCID: PMC8222282 DOI: 10.1038/s41467-021-23792-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 05/11/2021] [Indexed: 12/18/2022] Open
Abstract
The tyrosine phosphatase CD45 is a major gatekeeper for restraining T cell activation. Its exclusion from the immunological synapse (IS) is crucial for T cell receptor (TCR) signal transduction. Here, we use expansion super-resolution microscopy to reveal that CD45 is mostly pre-excluded from the tips of microvilli (MV) on primary T cells prior to antigen encounter. This pre-exclusion is diminished by depleting cholesterol or by engineering the transmembrane domain of CD45 to increase its membrane integration length, but is independent of the CD45 extracellular domain. We further show that brief MV-mediated contacts can induce Ca2+ influx in mouse antigen-specific T cells engaged by antigen-pulsed antigen presenting cells (APC). We propose that the scarcity of CD45 phosphatase activity at the tips of MV enables or facilitates TCR triggering from brief T cell-APC contacts before formation of a stable IS, and that these MV-mediated contacts represent the earliest step in the initiation of a T cell adaptive immune response.
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Affiliation(s)
- Yunmin Jung
- Center for Autoimmunity and Inflammation, La Jolla Institute for Immunology, La Jolla, CA, USA.
| | - Lai Wen
- Center for Autoimmunity and Inflammation, La Jolla Institute for Immunology, La Jolla, CA, USA
| | - Amnon Altman
- Center for Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, CA, USA
| | - Klaus Ley
- Center for Autoimmunity and Inflammation, La Jolla Institute for Immunology, La Jolla, CA, USA
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
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16
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Belardi B, Son S, Felce JH, Dustin ML, Fletcher DA. Cell-cell interfaces as specialized compartments directing cell function. Nat Rev Mol Cell Biol 2020; 21:750-764. [PMID: 33093672 DOI: 10.1038/s41580-020-00298-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2020] [Indexed: 12/14/2022]
Abstract
Cell-cell interfaces are found throughout multicellular organisms, from transient interactions between motile immune cells to long-lived cell-cell contacts in epithelia. Studies of immune cell interactions, epithelial cell barriers, neuronal contacts and sites of cell-cell fusion have identified a core set of features shared by cell-cell interfaces that critically control their function. Data from diverse cell types also show that cells actively and passively regulate the localization, strength, duration and cytoskeletal coupling of receptor interactions governing cell-cell signalling and physical connections between cells, indicating that cell-cell interfaces have a unique membrane organization that emerges from local molecular and cellular mechanics. In this Review, we discuss recent findings that support the emerging view of cell-cell interfaces as specialized compartments that biophysically constrain the arrangement and activity of their protein, lipid and glycan components. We also review how these biophysical features of cell-cell interfaces allow cells to respond with high selectivity and sensitivity to multiple inputs, serving as the basis for wide-ranging cellular functions. Finally, we consider how the unique properties of cell-cell interfaces present opportunities for therapeutic intervention.
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Affiliation(s)
- Brian Belardi
- Department of Bioengineering & Biophysics Program, UC Berkeley, Berkeley, CA, USA
| | - Sungmin Son
- Department of Bioengineering & Biophysics Program, UC Berkeley, Berkeley, CA, USA
| | | | | | - Daniel A Fletcher
- Department of Bioengineering & Biophysics Program, UC Berkeley, Berkeley, CA, USA. .,Division of Biological Systems & Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. .,Chan Zuckerberg Biohub, San Francisco, CA, USA.
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17
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Céspedes PF, Beckers D, Dustin ML, Sezgin E. Model membrane systems to reconstitute immune cell signaling. FEBS J 2020; 288:1070-1090. [DOI: 10.1111/febs.15488] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/26/2020] [Accepted: 07/14/2020] [Indexed: 12/26/2022]
Affiliation(s)
- Pablo F. Céspedes
- Kennedy Institute of Rheumatology Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences University of Oxford UK
| | - Daniel Beckers
- MRC Human Immunology Unit MRC Weatherall Institute of Molecular Medicine University of Oxford UK
| | - Michael L. Dustin
- Kennedy Institute of Rheumatology Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences University of Oxford UK
| | - Erdinc Sezgin
- MRC Human Immunology Unit MRC Weatherall Institute of Molecular Medicine University of Oxford UK
- Science for Life Laboratory Department of Women's and Children's Health Karolinska Institutet Stockholm Sweden
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18
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FcεRI Signaling in the Modulation of Allergic Response: Role of Mast Cell-Derived Exosomes. Int J Mol Sci 2020; 21:ijms21155464. [PMID: 32751734 PMCID: PMC7432241 DOI: 10.3390/ijms21155464] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 07/28/2020] [Accepted: 07/28/2020] [Indexed: 12/20/2022] Open
Abstract
Mast cells (MCs) are immune cells that act as environment resident sentinels playing a crucial role in Th2-mediated immune responses, including allergic reactions. Distinguishing features of MCs are the presence of numerous cytoplasmic granules that encapsulate a wide array of preformed bio-active molecules and the constitutive expression of the high affinity receptor of IgE (FcεRI). Upon FcεRI engagement by means of IgE and multivalent antigens, aggregated receptors trigger biochemical pathways that ultimately lead to the release of granule-stored and newly synthesized pro-inflammatory mediators. Additionally, MCs are also able to release exosomes either constitutively or upon stimulation. Exosomes are nanosized vesicles of endocytic origin endowed with important immunoregulatory properties, and represent an additional way of intercellular communication. Interestingly, exosomes generated upon FcεRI engagement contain co-stimulatory and adhesion molecules, lipid mediators, and MC-specific proteases, as well as receptor subunits together with IgE and antigens. These findings support the notion that FcεRI signaling plays an important role in influencing the composition and functions of exosomes derived by MCs depending on their activation status.
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19
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Son S, Takatori SC, Belardi B, Podolski M, Bakalar MH, Fletcher DA. Molecular height measurement by cell surface optical profilometry (CSOP). Proc Natl Acad Sci U S A 2020; 117:14209-14219. [PMID: 32513731 PMCID: PMC7322024 DOI: 10.1073/pnas.1922626117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The physical dimensions of proteins and glycans on cell surfaces can critically affect cell function, for example, by preventing close contact between cells and limiting receptor accessibility. However, high-resolution measurements of molecular heights on native cell membranes have been difficult to obtain. Here we present a simple and rapid method that achieves nanometer height resolution by localizing fluorophores at the tip and base of cell surface molecules and determining their separation by radially averaging across many molecules. We use this method, which we call cell surface optical profilometry (CSOP), to quantify the height of key multidomain proteins on a model cell, as well as to capture average protein and glycan heights on native cell membranes. We show that average height of a protein is significantly smaller than its contour length, due to thermally driven bending and rotation on the membrane, and that height strongly depends on local surface and solution conditions. We find that average height increases with cell surface molecular crowding but decreases with solution crowding by solutes, both of which we confirm with molecular dynamics simulations. We also use experiments and simulations to determine the height of an epitope, based on the location of an antibody, which allows CSOP to profile various proteins and glycans on a native cell surface using antibodies and lectins. This versatile method for profiling cell surfaces has the potential to advance understanding of the molecular landscape of cells and the role of the molecular landscape in cell function.
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Affiliation(s)
- Sungmin Son
- Department of Bioengineering and Biophysics Program, University of California, Berkeley, CA 94720
| | - Sho C Takatori
- Department of Bioengineering and Biophysics Program, University of California, Berkeley, CA 94720
| | - Brian Belardi
- Department of Bioengineering and Biophysics Program, University of California, Berkeley, CA 94720
| | - Marija Podolski
- Department of Bioengineering and Biophysics Program, University of California, Berkeley, CA 94720
| | - Matthew H Bakalar
- Department of Bioengineering and Biophysics Program, University of California, Berkeley, CA 94720
| | - Daniel A Fletcher
- Department of Bioengineering and Biophysics Program, University of California, Berkeley, CA 94720;
- Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Chan Zuckerberg Biohub, San Francisco, CA 94158
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20
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Kulenkampff K, Lippert AH, McColl J, Santos AM, Ponjavic A, Jenkins E, Humphrey J, Winkel A, Franze K, Lee SF, Davis SJ, Klenerman D. The Costs of Close Contacts: Visualizing the Energy Landscape of Cell Contacts at the Nanoscale. Biophys J 2020; 118:1261-1269. [PMID: 32075748 PMCID: PMC7091464 DOI: 10.1016/j.bpj.2020.01.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 12/27/2022] Open
Abstract
Cell-cell contacts often underpin signaling between cells. For immunology, the binding of a T cell receptor to an antigen-presenting pMHC initiates downstream signaling and an immune response. Although this contact is mediated by proteins on both cells creating interfaces with gap sizes typically around 14 nm, many, often contradictory observations have been made regarding the influence of the contact on parameters such as the binding kinetics, spatial distribution, and diffusion of signaling proteins within the contact. Understanding the basic physical constraints on probes inside this crowded environment will help inform studies on binding kinetics and dynamics of signaling of relevant proteins in the synapse. By tracking quantum dots of different dimensions for extended periods of time, we have shown that it is possible to obtain the probability of a molecule entering the contact, the change in its diffusion upon entry, and the impact of spatial heterogeneity of adhesion protein density in the contact. By analyzing the contacts formed by a T cell interacting with adhesion proteins anchored to a supported lipid bilayer, we find that probes are excluded from contact entry in a size-dependent manner for gap-to-probe differences of 4.1 nm. We also observed probes being trapped inside the contact and a decrease in diffusion of up to 85% in dense adhesion protein contacts. This approach provides new, to our knowledge, insights into the nature of cell-cell contacts, revealing that cell contacts are highly heterogeneous because of topography- and protein-density-related processes. These effects are likely to profoundly influence signaling between cells.
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Affiliation(s)
- Klara Kulenkampff
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Anna H Lippert
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - James McColl
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Ana Mafalda Santos
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Aleks Ponjavic
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Edward Jenkins
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Jane Humphrey
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Alexander Winkel
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Kristian Franze
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Simon J Davis
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom.
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21
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Engeroff P, Caviezel F, Mueller D, Thoms F, Bachmann MF, Vogel M. CD23 provides a noninflammatory pathway for IgE-allergen complexes. J Allergy Clin Immunol 2019; 145:301-311.e4. [PMID: 31437490 DOI: 10.1016/j.jaci.2019.07.045] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/21/2019] [Accepted: 07/09/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND Type I hypersensitivity is mediated by allergen-specific IgE, which sensitizes the high-affinity IgE receptor FcεRI on mast cells and basophils and drives allergic inflammation upon secondary allergen contact. CD23/FcεRII, the low-affinity receptor for IgE, is constitutively expressed on B cells and has been shown to regulate immune responses. Simultaneous binding of IgE to FcεRI and CD23 is blocked by reciprocal allosteric inhibition, suggesting that the 2 receptors exert distinct roles in IgE handling. OBJECTIVE We aimed to study how free IgE versus precomplexed IgE-allergen immune complexes (IgE-ICs) target the 2 IgE receptors FcεRI and CD23, and we investigated the functional implications of the 2 pathways. METHODS We performed binding and activation assays with human cells in vitro and IgE pharmacokinetics and anaphylaxis experiments in vivo. RESULTS We demonstrate that FcεRI preferentially binds free IgE and CD23 preferentially binds IgE-ICs. We further show that those different binding properties directly translate to distinct biological functions: free IgE initiated allergic inflammation through FcεRI on allergic effector cells, while IgE-ICs were noninflammatory because of reduced FcεRI binding and enhanced CD23-dependent serum clearance. CONCLUSION We propose that IgE-ICs are noninflammatory through reduced engagement by FcεRI but increased targeting of the CD23 pathway.
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Affiliation(s)
- Paul Engeroff
- Department of Rheumatology, Immunology and Allergology, University Hospital Bern, Bern, Switzerland; Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Flurin Caviezel
- Department of Rheumatology, Immunology and Allergology, University Hospital Bern, Bern, Switzerland; Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - David Mueller
- Department of Rheumatology, Immunology and Allergology, University Hospital Bern, Bern, Switzerland; Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Franziska Thoms
- Department of Dermatology, Zurich University Hospital, Schlieren, Switzerland
| | - Martin F Bachmann
- Department of Rheumatology, Immunology and Allergology, University Hospital Bern, Bern, Switzerland; Department of BioMedical Research, University of Bern, Bern, Switzerland; Nuffield Department of Medicine, Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Monique Vogel
- Department of Rheumatology, Immunology and Allergology, University Hospital Bern, Bern, Switzerland; Department of BioMedical Research, University of Bern, Bern, Switzerland.
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22
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Fernandes RA, Ganzinger KA, Tzou JC, Jönsson P, Lee SF, Palayret M, Santos AM, Carr AR, Ponjavic A, Chang VT, Macleod C, Lagerholm BC, Lindsay AE, Dushek O, Tilevik A, Davis SJ, Klenerman D. A cell topography-based mechanism for ligand discrimination by the T cell receptor. Proc Natl Acad Sci U S A 2019; 116:14002-14010. [PMID: 31221762 PMCID: PMC6628812 DOI: 10.1073/pnas.1817255116] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The T cell receptor (TCR) initiates the elimination of pathogens and tumors by T cells. To avoid damage to the host, the receptor must be capable of discriminating between wild-type and mutated self and nonself peptide ligands presented by host cells. Exactly how the TCR does this is unknown. In resting T cells, the TCR is largely unphosphorylated due to the dominance of phosphatases over the kinases expressed at the cell surface. However, when agonist peptides are presented to the TCR by major histocompatibility complex proteins expressed by antigen-presenting cells (APCs), very fast receptor triggering, i.e., TCR phosphorylation, occurs. Recent work suggests that this depends on the local exclusion of the phosphatases from regions of contact of the T cells with the APCs. Here, we developed and tested a quantitative treatment of receptor triggering reliant only on TCR dwell time in phosphatase-depleted cell contacts constrained in area by cell topography. Using the model and experimentally derived parameters, we found that ligand discrimination likely depends crucially on individual contacts being ∼200 nm in radius, matching the dimensions of the surface protrusions used by T cells to interrogate their targets. The model not only correctly predicted the relative signaling potencies of known agonists and nonagonists but also achieved this in the absence of kinetic proofreading. Our work provides a simple, quantitative, and predictive molecular framework for understanding why TCR triggering is so selective and fast and reveals that, for some receptors, cell topography likely influences signaling outcomes.
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Affiliation(s)
- Ricardo A Fernandes
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, OX3 9DS Oxford, United Kingdom
- Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, OX3 9DS Oxford, United Kingdom
| | - Kristina A Ganzinger
- Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Justin C Tzou
- Department of Applied & Computational Mathematics & Statistics, University of Notre Dame, Notre Dame, IN 46556
| | - Peter Jönsson
- Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Matthieu Palayret
- Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Ana Mafalda Santos
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, OX3 9DS Oxford, United Kingdom
- Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, OX3 9DS Oxford, United Kingdom
| | - Alexander R Carr
- Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Aleks Ponjavic
- Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Veronica T Chang
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, OX3 9DS Oxford, United Kingdom
- Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, OX3 9DS Oxford, United Kingdom
| | - Charlotte Macleod
- Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - B Christoffer Lagerholm
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, OX3 9DS Oxford, United Kingdom
| | - Alan E Lindsay
- Mathematics Department, University of British Columbia, Vancouver, BC V6T 1Z2, Canada
| | - Omer Dushek
- Sir William Dunn School of Pathology, University of Oxford, OX1 3RE Oxford, United Kingdom
- Wolfson Centre for Mathematical Biology, University of Oxford, OX1 3RE Oxford, United Kingdom
| | - Andreas Tilevik
- School of Bioscience, University of Skövde, 541 28 Skövde, Sweden
| | - Simon J Davis
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, OX3 9DS Oxford, United Kingdom;
- Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, OX3 9DS Oxford, United Kingdom
| | - David Klenerman
- Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom;
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23
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Brian BF, Jolicoeur AS, Guerrero CR, Nunez MG, Sychev ZE, Hegre SA, Sætrom P, Habib N, Drake JM, Schwertfeger KL, Freedman TS. Unique-region phosphorylation targets LynA for rapid degradation, tuning its expression and signaling in myeloid cells. eLife 2019; 8:e46043. [PMID: 31282857 PMCID: PMC6660195 DOI: 10.7554/elife.46043] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 07/06/2019] [Indexed: 12/23/2022] Open
Abstract
The activity of Src-family kinases (SFKs), which phosphorylate immunoreceptor tyrosine-based activation motifs (ITAMs), is a critical factor regulating myeloid-cell activation. We reported previously that the SFK LynA is uniquely susceptible to rapid ubiquitin-mediated degradation in macrophages, functioning as a rheostat regulating signaling (Freedman et al., 2015). We now report the mechanism by which LynA is preferentially targeted for degradation and how cell specificity is built into the LynA rheostat. Using genetic, biochemical, and quantitative phosphopeptide analyses, we found that the E3 ubiquitin ligase c-Cbl preferentially targets LynA via a phosphorylated tyrosine (Y32) in its unique region. This distinct mode of c-Cbl recognition depresses steady-state expression of LynA in macrophages derived from mice. Mast cells, however, express little c-Cbl and have correspondingly high LynA. Upon activation, mast-cell LynA is not rapidly degraded, and SFK-mediated signaling is amplified relative to macrophages. Cell-specific c-Cbl expression thus builds cell specificity into the LynA checkpoint.
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Affiliation(s)
- Ben F Brian
- Department of PharmacologyUniversity of MinnesotaMinneapolisUnited States
| | | | - Candace R Guerrero
- College of Biological Sciences Center for Mass Spectrometry and ProteomicsUniversity of MinnesotaMinneapolisUnited States
| | - Myra G Nunez
- Department of PharmacologyUniversity of MinnesotaMinneapolisUnited States
| | - Zoi E Sychev
- Department of PharmacologyUniversity of MinnesotaMinneapolisUnited States
| | - Siv A Hegre
- Department of Clinical and Molecular MedicineNorwegian University of Science and TechnologyTrondheimNorway
| | - Pål Sætrom
- Department of Clinical and Molecular MedicineNorwegian University of Science and TechnologyTrondheimNorway
- Department of Computer ScienceNorwegian University of Science and TechnologyTrondheimNorway
| | - Nagy Habib
- Department of Surgery and CancerHammersmith Hospital, Imperial College LondonLondonUnited Kingdom
| | - Justin M Drake
- Department of PharmacologyUniversity of MinnesotaMinneapolisUnited States
- Masonic Cancer CenterUniversity of MinnesotaMinneapolisUnited States
- Department of UrologyUniversity of MinnesotaMinneapolisUnited States
| | - Kathryn L Schwertfeger
- Department of PharmacologyUniversity of MinnesotaMinneapolisUnited States
- Masonic Cancer CenterUniversity of MinnesotaMinneapolisUnited States
- Center for ImmunologyUniversity of MinnesotaMinneapolisUnited States
- Department of Laboratory Medicine and PathologyUniversity of MinnesotaMinneapolisUnited States
| | - Tanya S Freedman
- Department of PharmacologyUniversity of MinnesotaMinneapolisUnited States
- Masonic Cancer CenterUniversity of MinnesotaMinneapolisUnited States
- Center for ImmunologyUniversity of MinnesotaMinneapolisUnited States
- Center for Autoimmune Diseases ResearchUniversity of MinnesotaMinneapolisUnited States
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24
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Santos RF, Oliveira L, Brown MH, Carmo AM. Domain-specific CD6 monoclonal antibodies identify CD6 isoforms generated by alternative-splicing. Immunology 2019; 157:296-303. [PMID: 31162836 PMCID: PMC6620187 DOI: 10.1111/imm.13087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 05/10/2019] [Accepted: 05/21/2019] [Indexed: 12/18/2022] Open
Abstract
The characterization of the architecture, structure and extracellular interactions of the CD6 glycoprotein, a transmembrane receptor expressed in medullary thymocytes and all mature T‐cell populations, has been enhanced by the existence of monoclonal antibodies (mAbs) that specifically recognize the various scavenger receptor cysteine‐rich (SRCR) domains of the ectodomain. Using engineered isoforms of CD6 including or excluding each of the three SRCR domains, either expressed at the membranes of cells or in soluble forms, we provide conclusive and definitive evidence that domain 2 of CD6, previously not identifiable, can be recognized by the CD6 mAbs OX125 and OX126, and that OX124 targets domain 3 and can block the interaction at the cell surface of CD6 with its major ligand CD166. Alternative splicing‐dependent CD6 isoforms can now be confidently identified. We confirm that following T‐cell activation there is a partial replacement of full‐length CD6 by the CD6Δd3 isoform, which lacks the CD166‐binding domain, and we find no evidence for the expression of other CD6 isoforms at the mRNA or protein levels.
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Affiliation(s)
- Rita F Santos
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Porto, Portugal.,Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Liliana Oliveira
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Marion H Brown
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Alexandre M Carmo
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Porto, Portugal
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25
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Colin-York H, Li D, Korobchevskaya K, Chang VT, Betzig E, Eggeling C, Fritzsche M. Cytoskeletal actin patterns shape mast cell activation. Commun Biol 2019; 2:93. [PMID: 30854485 PMCID: PMC6405992 DOI: 10.1038/s42003-019-0322-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/22/2019] [Indexed: 01/05/2023] Open
Abstract
Activation of immune cells relies on a dynamic actin cytoskeleton. Despite detailed knowledge of molecular actin assembly, the exact processes governing actin organization during activation remain elusive. Using advanced microscopy, we here show that Rat Basophilic Leukemia (RBL) cells, a model mast cell line, employ an orchestrated series of reorganization events within the cortical actin network during activation. In response to IgE antigen-stimulation of FCε receptors (FCεR) at the RBL cell surface, we observed symmetry breaking of the F-actin network and subsequent rapid disassembly of the actin cortex. This was followed by a reassembly process that may be driven by the coordinated transformation of distinct nanoscale F-actin architectures, reminiscent of self-organizing actin patterns. Actin patterns co-localized with zones of Arp2/3 nucleation, while network reassembly was accompanied by myosin-II activity. Strikingly, cortical actin disassembly coincided with zones of granule secretion, suggesting that cytoskeletal actin patterns contribute to orchestrate RBL cell activation. Huw Colin-York et al. use advanced microscopy techniques to show that the cortical actin network within a model mast cell line undergoes a series of reorganizational events at the basal interface during activation. They find that actin patterns co-localize with zones of Arp2/3 nucleation and myosin-II activity accompanies network reassembly.
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Affiliation(s)
- Huw Colin-York
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS, UK
| | - Dong Li
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA, 20147, USA.,National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Kseniya Korobchevskaya
- Kennedy Institute for Rheumatology, University of Oxford, Roosevelt Drive, Oxford, OX3 7LF, UK
| | - Veronica T Chang
- MRC Laboratory of Molecular Biology, University of Cambridge, Cambridge, CB2 0QH, UK
| | - Eric Betzig
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA, 20147, USA
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS, UK
| | - Marco Fritzsche
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS, UK. .,Kennedy Institute for Rheumatology, University of Oxford, Roosevelt Drive, Oxford, OX3 7LF, UK.
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