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Mayorga C, Ariza A, Muñoz-Cano R, Sabato V, Doña I, Torres MJ. Biomarkers of immediate drug hypersensitivity. Allergy 2024; 79:601-612. [PMID: 37947156 DOI: 10.1111/all.15933] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 09/29/2023] [Accepted: 10/17/2023] [Indexed: 11/12/2023]
Abstract
Immediate drug hypersensitivity reactions (IDHRs) are a burden for patients and the health systems. This problem increases when taking into account that only a small proportion of patients initially labelled as allergic are finally confirmed after an allergological workup. The diverse nature of drugs involved will imply different interactions with the immunological system. Therefore, IDHRs can be produced by a wide array of mechanisms mediated by the drug interaction with specific antibodies or directly on effector target cells. These heterogeneous mechanisms imply an enhanced complexity for an accurate diagnosis and the identification of the phenotype and endotype at early stages of the reaction is of vital importance. Currently, several endophenotypic categories (type I IgE/non-IgE, cytokine release, Mast-related G-protein coupled receptor X2 (MRGPRX2) or Cyclooxygenase-1 (COX-1) inhibition and their associated biomarkers have been proposed. A precise knowledge of endotypes will permit to discriminate patients within the same phenotype, which is crucial in order to personalise diagnosis, future treatment and prevention to improve the patient's quality of life.
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Affiliation(s)
- Cristobalina Mayorga
- Allergy Research Group, Instituto de Investigación Biomédica de Málaga y Plataforma en Nanomedicina - IBIMA Plataforma BIONAND, Málaga, Spain
- Allergy Unit, Hospital Regional Universitario de Málaga-HRUM, Málaga, Spain
| | - Adriana Ariza
- Allergy Research Group, Instituto de Investigación Biomédica de Málaga y Plataforma en Nanomedicina - IBIMA Plataforma BIONAND, Málaga, Spain
| | - Rosa Muñoz-Cano
- Allergy Department, Hospital Clinic, Institut d'Investigacions Biomediques August Pi i Sunyer - IDIBAPS, University of Barcelona, Barcelona, Spain
| | - Vito Sabato
- Department of Immunology, Allergology, Rheumatology, Infla-Med Centre of Excellence, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Inmaculada Doña
- Allergy Unit, Hospital Regional Universitario de Málaga-HRUM, Málaga, Spain
| | - Maria J Torres
- Allergy Research Group, Instituto de Investigación Biomédica de Málaga y Plataforma en Nanomedicina - IBIMA Plataforma BIONAND, Málaga, Spain
- Allergy Unit, Hospital Regional Universitario de Málaga-HRUM, Málaga, Spain
- Medicine Department, Universidad de Málaga-UMA, Málaga, Spain
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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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3
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Schneider L, Rabe KS, Domínguez CM, Niemeyer CM. Hapten-Decorated DNA Nanostructures Decipher the Antigen-Mediated Spatial Organization of Antibodies Involved in Mast Cell Activation. ACS NANO 2023; 17:6719-6730. [PMID: 36990450 PMCID: PMC10100567 DOI: 10.1021/acsnano.2c12647] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/07/2023] [Indexed: 06/19/2023]
Abstract
The immunological response of mast cells is controlled by the multivalent binding of antigens to immunoglobulin E (IgE) antibodies bound to the high-affinity receptor FcεRI on the cell membrane surface. However, the spatial organization of antigen-antibody-receptor complexes at the nanometer scale and the structural constraints involved in the initial events at the cell surface are not yet fully understood. For example, it is unclear what influence the affinity and nanoscale distance between the binding partners involved have on the activation of mast cells to degranulate inflammatory mediators from storage granules. We report the use of DNA origami nanostructures (DON) functionalized with different arrangements of the haptenic 2,4-dinitrophenyl (DNP) ligand to generate multivalent artificial antigens with full control over valency and nanoscale ligand architecture. To investigate the spatial requirements for mast cell activation, the DNP-DON complexes were initially used in surface plasmon resonance (SPR) analysis to study the binding kinetics of isolated IgE under physiological conditions. The most stable binding was observed in a narrow window of approximately 16 nm spacing between haptens. In contrast, affinity studies with FcεRI-linked IgE antibodies on the surface of rat basophilic leukemia cells (RBL-2H3) indicated virtually no distance-dependent variations in the binding of the differently structured DNP-DON complexes but suggested a supramolecular oligovalent nature of the interaction. Finally, the use of DNP-DON complexes for mast cell activation revealed that antigen-directed tight assembly of antibody-receptor complexes is the critical factor for triggering degranulation, even more critical than ligand valence. Our study emphasizes the significance of DNA nanostructures for the study of fundamental biological processes.
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4
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Sabato V, Ebo DG, Van Der Poorten MLM, Toscano A, Van Gasse AL, Mertens C, Van Houdt M, Beyens M, Elst J. Allergenic and Mas-Related G Protein-Coupled Receptor X2-Activating Properties of Drugs: Resolving the Two. THE JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY. IN PRACTICE 2023; 11:395-404. [PMID: 36581077 DOI: 10.1016/j.jaip.2022.12.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/02/2022] [Accepted: 12/11/2022] [Indexed: 12/27/2022]
Abstract
Since the seminal description implicating occupation of the Mas-related G protein-coupled receptor X2 (MRGPRX2) in mast cell (MC) degranulation by drugs, many investigations have been undertaken into this potential new endotype of immediate drug hypersensitivity reaction. However, current evidence for this mechanism predominantly comes from (mutant) animal models or in vitro studies, and irrefutable clinical evidence in humans is still missing. Moreover, translation of these preclinical findings into clinical relevance in humans is difficult and should be critically interpreted. Starting from our clinical priorities and experience with flow-assisted functional analyses of basophils and cultured human MCs, the objectives of this rostrum are to identify some of these difficulties, emphasize the obstacles that might hamper translation from preclinical observations into the clinics, and highlight differences between IgE- and MRPGRX2-mediated reactions. Inevitably, as with any subject still beset by many questions, alternative interpretations, hypotheses, or explanations expressed here may not find universal acceptance. Nevertheless, we believe that for the time being, many questions remain unanswered. Finally, a theoretical mechanistic algorithm is proposed that might advance discrimination between MC degranulation from MRGPRX2 activation and cross-linking of membrane-bound drug-reactive IgE antibodies.
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Affiliation(s)
- Vito Sabato
- Faculty of Medicine and Health Sciences, Department of Immunology, Allergology, Rheumatology and the Infla-Med Centre of Excellence, Antwerp (Belgium) and Immunology, Allergology, Rheumatology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium; Department of Immunology and Allergology, AZ Jan Palfijn Gent, Ghent, Belgium
| | - Didier G Ebo
- Faculty of Medicine and Health Sciences, Department of Immunology, Allergology, Rheumatology and the Infla-Med Centre of Excellence, Antwerp (Belgium) and Immunology, Allergology, Rheumatology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium; Department of Immunology and Allergology, AZ Jan Palfijn Gent, Ghent, Belgium.
| | - Marie-Line M Van Der Poorten
- Faculty of Medicine and Health Sciences, Department of Immunology, Allergology, Rheumatology and the Infla-Med Centre of Excellence, Antwerp (Belgium) and Immunology, Allergology, Rheumatology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Department of Paediatrics and the Infla-Med Centre of Excellence, Antwerp, Belgium, and Paediatrics, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium
| | - Alessandro Toscano
- Faculty of Medicine and Health Sciences, Department of Immunology, Allergology, Rheumatology and the Infla-Med Centre of Excellence, Antwerp (Belgium) and Immunology, Allergology, Rheumatology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium
| | - Athina L Van Gasse
- Faculty of Medicine and Health Sciences, Department of Immunology, Allergology, Rheumatology and the Infla-Med Centre of Excellence, Antwerp (Belgium) and Immunology, Allergology, Rheumatology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Department of Paediatrics and the Infla-Med Centre of Excellence, Antwerp, Belgium, and Paediatrics, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium
| | - Christel Mertens
- Faculty of Medicine and Health Sciences, Department of Immunology, Allergology, Rheumatology and the Infla-Med Centre of Excellence, Antwerp (Belgium) and Immunology, Allergology, Rheumatology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium
| | - Michel Van Houdt
- Faculty of Medicine and Health Sciences, Department of Immunology, Allergology, Rheumatology and the Infla-Med Centre of Excellence, Antwerp (Belgium) and Immunology, Allergology, Rheumatology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium
| | - Michiel Beyens
- Faculty of Medicine and Health Sciences, Department of Immunology, Allergology, Rheumatology and the Infla-Med Centre of Excellence, Antwerp (Belgium) and Immunology, Allergology, Rheumatology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium
| | - Jessy Elst
- Faculty of Medicine and Health Sciences, Department of Immunology, Allergology, Rheumatology and the Infla-Med Centre of Excellence, Antwerp (Belgium) and Immunology, Allergology, Rheumatology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium
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5
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Tsai MC, Spendier K. RBL-2H3 Mast Cell Receptor Dynamics in the Immunological Synapse. BIOPHYSICA 2022; 2:428-439. [PMID: 37654558 PMCID: PMC10470655 DOI: 10.3390/biophysica2040038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
The RBL-2H3 mast cell immunological synapse dynamics is often simulated with reaction-diffusion and Fokker-Planck equations. The equations focus on how the cell synapse captures receptors following an immune response, where the receptor capture at the immunological site appears to be a delayed process. This article investigates the physical nature and mathematics behind such time-dependent delays. Using signal processing methods, convolution and cross-correlation-type delay capture simulations give a χ -squared range of 22 to 60, in good agreement with experimental results. The cell polarization event is offered as a possible explanation for these capture delays, where polarizing rates measure how fast the cell polarization event occurs. In the case of RBL-2H3 mast cells, polarization appears to be associated with cytoskeletal rearrangement; thus, both cytoskeletal and diffusional components are considered. From these simulations, a maximum polarizing rate ranging from 0.0057 s-2 to 0.031 s-2 is obtained. These results indicate that RBL-2H3 mast cells possess both temporal and spatial memory, and cell polarization is possibly linked to a Turing-type pattern formation.
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Affiliation(s)
- Ming Chih Tsai
- Department of Physics and Energy Science, University of Colorado Colorado Springs, Colorado Springs, CO 80918, USA
- BioFrontiers Center, University of Colorado Colorado Springs, Colorado Springs, CO 80918, USA
| | - Kathrin Spendier
- BioFrontiers Center, University of Colorado Colorado Springs, Colorado Springs, CO 80918, USA
- Quantinuum, Broomfield, CO 80021, USA
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Abstract
Mast cells originate from the CD34+/CD117+ hematopoietic progenitors in the bone marrow, migrate into circulation, and ultimately mature and reside in peripheral tissues. Microbiota/metabolites and certain immune cells (e.g., Treg cells) play a key role in maintaining immune tolerance. Cross-linking of allergen-specific IgE on mast cells activates the high-affinity membrane-bound receptor FcεRI, thereby initiating an intracellular signal cascade, leading to degranulation and release of pro-inflammatory mediators. The intracellular signal transduction is intricately regulated by various kinases, transcription factors, and cytokines. Importantly, multiple signal components in the FcεRI-mast cell–mediated allergic cascade can be targeted for therapeutic purposes. Pharmacological interventions that include therapeutic antibodies against IgE, FcεRI, and cytokines as well as inhibitors/activators of several key intracellular signaling molecues have been used to inhibit allergic reactions. Other factors that are not part of the signal pathway but can enhance an individual’s susceptibility to allergen stimulation are referred to as cofactors. Herein, we provide a mechanistic overview of the FcεRI-mast cell–mediated allergic signaling. This will broaden our scope and visions on specific preventive and therapeutic strategies for the clinical management of mast cell–associated hypersensitivity reactions.
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Kenkre V, Spendier K. A theory of coalescence of signaling receptor clusters in immune cells. PHYSICA A 2022; 602:127650. [PMID: 35966144 PMCID: PMC9365117 DOI: 10.1016/j.physa.2022.127650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A theory of coalescence of signal receptor clusters in mast cells is developed in close connection with experiments. It is based on general considerations involving a feedback procedure and a time-dependent capture as part of a reaction-diffusion process. Characteristic features of observations that need to be explained are indicated and it is shown why calculations available in the literature are not satisfactory. While the latter involves static centers at which the reaction part of the phenomenon occurs, by its very nature, coalescence involves dynamically evolving centers. This is so because the process continuously modifies the size of the cluster aggregate which then proceeds to capture more material. We develop a procedure that consists of first solving a static reaction-diffusion problem and then imbuing the center with changing size. The consequence is a dependence of the size of the signal receptor cluster aggregate on time. A preliminary comparison with experiment is shown to reveal a sharp difference between theory and data. The observation indicates that the reaction occurs slowly at first and then picks up rapidly as time proceeds. Parameter modification to fit the observations cannot solve the problem. We use this observation to build into the theory an accumulation rate that is itself dependent on time. A memory representation and its physical basis are explained. The consequence is a theory that can be fit to observations successfully.
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Affiliation(s)
- V.M. Kenkre
- Department of Physics and Astronomy, University of New Mexico, 210 Yale Blvd NE, Albuquerque, 87131, NM, USA
| | - K. Spendier
- Department of Physics and Energy Science and UCCS Center for the Biofrontiers Institute, University of Colorado Colorado Springs, 1420 Austin Bluffs Pkwy, Colorado Springs, 80918, CO, USA
- Corresponding author. (K. Spendier)
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Activation of Free Fatty Acid Receptor 4 (FFA4) Ameliorates Ovalbumin-Induced Allergic Asthma by Suppressing Activation of Dendritic and Mast Cells in Mice. Int J Mol Sci 2022; 23:ijms23095270. [PMID: 35563671 PMCID: PMC9100770 DOI: 10.3390/ijms23095270] [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: 04/14/2022] [Revised: 05/03/2022] [Accepted: 05/06/2022] [Indexed: 12/22/2022] Open
Abstract
Epidemiological and clinical studies have suggested that intake of n-3 polyunsaturated fatty acids (PUFA) reduces the incidence of allergic airway diseases and improves pulmonary function in patients with allergic asthma. However, the pharmacological targets of PUFA have not been elucidated upon. We investigated whether free fatty acid receptor 4 (FFA4, also known as GPR120) is a molecular target for beneficial PUFA in asthma therapy. In an ovalbumin (OVA)-induced allergic asthma model, compound A (a selective agonist of FFA4) was administrated before OVA sensitization or OVA challenge in FFA4 wild-type (WT) and knock-out (KO) mice. Compound A treatment of RBL-2H3 cells suppressed mast cell degranulation in vitro in a concentration-dependent manner. Administration of compound A suppressed in vivo allergic characteristics in bronchoalveolar lavage fluid (BALF) and lungs, such as inflammatory cytokine levels and eosinophil accumulation in BALF, inflammation and mucin secretion in the lungs. Compound A-induced suppression was not only observed in mice treated with compound A before OVA challenge, but in mice treated before OVA sensitization as well, implying that compound A acts on mast cells as well as dendritic cells. Furthermore, this suppression by compound A was only observed in FFA4-WT mice and was absent in FFA4-KO mice, implying that compound A action is mediated through FFA4. Activation of FFA4 may be a therapeutic target of PUFA in allergic asthma by suppressing the activation of dendritic cells and mast cells, suggesting that highly potent specific agonists of FFA4 could be a novel therapy for allergic asthma.
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Nagata Y, Suzuki R. FcεRI: A Master Regulator of Mast Cell Functions. Cells 2022; 11:cells11040622. [PMID: 35203273 PMCID: PMC8870323 DOI: 10.3390/cells11040622] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/29/2022] [Accepted: 02/09/2022] [Indexed: 02/04/2023] Open
Abstract
Mast cells (MCs) perform multiple functions thought to underlie different manifestations of allergies. Various aspects of antigens (Ags) and their interactions with immunoglobulin E (IgE) cause diverse responses in MCs. FcεRI, a high-affinity IgE receptor, deciphers the Ag–IgE interaction and drives allergic responses. FcεRI clustering is essential for signal transduction and, therefore, determines the quality of MC responses. Ag properties precisely regulate FcεRI dynamics, which consequently initiates differential outcomes by switching the intracellular-signaling pathway, suggesting that Ag properties can control MC responses, both qualitatively and quantitatively. Thus, the therapeutic benefits of FcεRI-targeting strategies have long been examined. Disrupting IgE–FcεRI interactions is a potential therapeutic strategy because the binding affinity between IgE and FcεRI is extremely high. Specifically, FcεRI desensitization, due to internalization, is also a potential therapeutic target that is involved in the mechanisms of allergen-specific immunotherapy. Several recent findings have suggested that silent internalization is strongly associated with FcεRI dynamics. A comprehensive understanding of the role of FcεRI may lead to the development of novel therapies for allergies. Here, we review the qualitatively diverse responses of MCs that impact the attenuation/development of allergies with a focus on the role of FcεRI toward Ag exposure.
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Li M, Yu Y. Innate immune receptor clustering and its role in immune regulation. J Cell Sci 2021; 134:134/4/jcs249318. [PMID: 33597156 DOI: 10.1242/jcs.249318] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The discovery of receptor clustering in the activation of adaptive immune cells has revolutionized our understanding of the physical basis of immune signal transduction. In contrast to the extensive studies of adaptive immune cells, particularly T cells, there is a lesser, but emerging, recognition that the formation of receptor clusters is also a key regulatory mechanism in host-pathogen interactions. Many kinds of innate immune receptors have been found to assemble into nano- or micro-sized domains on the surfaces of cells. The clusters formed between diverse categories of innate immune receptors function as a multi-component apparatus for pathogen detection and immune response regulation. Here, we highlight these pioneering efforts and the outstanding questions that remain to be answered regarding this largely under-explored research topic. We provide a critical analysis of the current literature on the clustering of innate immune receptors. Our emphasis is on studies that draw connections between the phenomenon of receptor clustering and its functional role in innate immune regulation.
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Affiliation(s)
- Miao Li
- Department of Chemistry, Indiana University, Bloomington, IN 47401, USA
| | - Yan Yu
- Department of Chemistry, Indiana University, Bloomington, IN 47401, USA
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Connexin-Mediated Signaling at the Immunological Synapse. Int J Mol Sci 2020; 21:ijms21103736. [PMID: 32466338 PMCID: PMC7279457 DOI: 10.3390/ijms21103736] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 12/22/2022] Open
Abstract
The immunological synapse (IS) is an intercellular communication platform, organized at the contact site of two adjacent cells, where at least one is an immune cell. Functional IS formation is fundamental for the modulation of the most relevant immune system activities, such as T cell activation by antigen presenting cells and T cell/natural killer (NK) cell-mediated target cell (infected or cancer) killing. Extensive evidence suggests that connexins, in particular connexin-43 (Cx43) hemichannels and/or gap junctions, regulate signaling events in different types of IS. Although the underlying mechanisms are not fully understood, the current evidence suggests that Cx43 channels could act as facilitators for calcium ions, cyclic adenosine monophosphate, and/or adenosine triphosphate uptake and/or release at the interface of interacting cells. These second messengers have relevant roles in the IS signaling during dendritic cell-mediated T and NK cell activation, regulatory T cell-mediated immune suppression, and cytotoxic T lymphocyte or NK cell-mediated target tumor cell killing. Additionally, as the cytoplasmic C-terminus domain of Cx43 interacts with a plethora of proteins, Cx43 may act as scaffolds for integration of various regulatory proteins at the IS, as suggested by the high number of Cx43-interacting proteins that translocate at these cell-cell interface domains. In this review, we provide an updated overview and analysis on the role and possible underlying mechanisms of Cx43 in IS signaling.
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12
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Drawbond R, Spendier K. TIRF Microscope Image Sequences of Fluorescent IgE-FcεRI Receptor Complexes inside a FcεRI-Centric Synapse in RBL-2H3 Cells. DATA 2019. [PMID: 32704503 DOI: 10.17632/6kvzv95w7r.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
Total internal reflection fluorescence (TIRF) microscope image sequences are commonly used to study receptors in live cells. The dataset presented herein facilitates the study of the IgE-FcεRI receptor signaling complex (IgE-RC) in rat basophilic leukemia (RBL-2H3) cells coming into contact with a supported lipid bilayer with 25 mol% N-dinitrophenyl-aminocaproyl phosphatidylethanolamine, modeling an immunological synapse. TIRF microscopy was used to image IgE-RCs within this FcεRI-centric synapse by loading RBL-2H3 cells with fluorescent anti-dinitrophenyl (anti-DNP) immunoglobulin E (IgE) in suspension for 24 h. Fluorescent anti-DNP IgE (IgE488) concentrations of this suspension increased from 10% to 100% and corresponding non-fluorescent anti-DNP IgE concentrations decreased from 90% to 0%. After the removal of unbound anti-DNP IgE, multiple image sequences were taken for each of these ten conditions. Prior to imaging, anti-DNP IgE-primed RBL-2H3 cells were either kept for a few minutes, for about 30 min, or for about one hour in Hanks buffer. The dataset contains 482 RBL-2H3 model synapse image stacks, dark images to correct for background intensity, and TIRF illumination profile images to correct for non-uniform TIRF illumination. After background subtraction, non-uniform illumination correction, and conversion of pixel units from analog-to-digital units to photo electrons, the average pixel intensity was calculated. The average pixel intensity within FcεRI-centric synapses for all three Hanks buffer conditions increased linearly at a rate of 0.42 ± 0.02 photo electrons per pixel per % IgE488 in suspension. RBL-2H3 cell degranulation was tested by detecting β-hexosaminidase activity. Prolonged RBL-2H3 cell exposure to Hanks buffer inhibited exocytosis in RBL-2H3 cells.
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Affiliation(s)
- Rachel Drawbond
- UCCS Center of the Biofrontiers Institute, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
- Department of Mathematics, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
| | - Kathrin Spendier
- Department of Mathematics, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
- Department of Physics and Energy Science, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
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13
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Drawbond R, Spendier K. TIRF Microscope Image Sequences of Fluorescent IgE-FcεRI Receptor Complexes inside a FcεRI-Centric Synapse in RBL-2H3 Cells. DATA 2019; 4:111. [PMID: 32704503 PMCID: PMC7377353 DOI: 10.3390/data4030111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Total internal reflection fluorescence (TIRF) microscope image sequences are commonly used to study receptors in live cells. The dataset presented herein facilitates the study of the IgE-FcεRI receptor signaling complex (IgE-RC) in rat basophilic leukemia (RBL-2H3) cells coming into contact with a supported lipid bilayer with 25 mol% N-dinitrophenyl-aminocaproyl phosphatidylethanolamine, modeling an immunological synapse. TIRF microscopy was used to image IgE-RCs within this FcεRI-centric synapse by loading RBL-2H3 cells with fluorescent anti-dinitrophenyl (anti-DNP) immunoglobulin E (IgE) in suspension for 24 h. Fluorescent anti-DNP IgE (IgE488) concentrations of this suspension increased from 10% to 100% and corresponding non-fluorescent anti-DNP IgE concentrations decreased from 90% to 0%. After the removal of unbound anti-DNP IgE, multiple image sequences were taken for each of these ten conditions. Prior to imaging, anti-DNP IgE-primed RBL-2H3 cells were either kept for a few minutes, for about 30 min, or for about one hour in Hanks buffer. The dataset contains 482 RBL-2H3 model synapse image stacks, dark images to correct for background intensity, and TIRF illumination profile images to correct for non-uniform TIRF illumination. After background subtraction, non-uniform illumination correction, and conversion of pixel units from analog-to-digital units to photo electrons, the average pixel intensity was calculated. The average pixel intensity within FcεRI-centric synapses for all three Hanks buffer conditions increased linearly at a rate of 0.42 ± 0.02 photo electrons per pixel per % IgE488 in suspension. RBL-2H3 cell degranulation was tested by detecting β-hexosaminidase activity. Prolonged RBL-2H3 cell exposure to Hanks buffer inhibited exocytosis in RBL-2H3 cells.
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Affiliation(s)
- Rachel Drawbond
- UCCS Center of the Biofrontiers Institute, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
- Department of Mathematics, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
| | - Kathrin Spendier
- Department of Mathematics, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
- Department of Physics and Energy Science, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
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14
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Membrane Organization and Physical Regulation of Lymphocyte Antigen Receptors: A Biophysicist's Perspective. J Membr Biol 2019; 252:397-412. [PMID: 31352492 DOI: 10.1007/s00232-019-00085-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/18/2019] [Indexed: 12/19/2022]
Abstract
Receptors at the membrane of immune cells are the central players of innate and adaptative immunity, providing effective defence mechanisms against pathogens or cancer cells. Their function is intimately linked to their position at and within the membrane which provides accessibility, mobility as well as membrane proximal cytoskeleton anchoring, all of these elements playing important roles in the final function and links to cellular actions. Understanding how immune cells integrate the specific signals received at their membrane to take a decision remains an immense challenge and a very active field of fundamental and applied research. Recent progress in imaging and micromanipulation techniques have led to an unprecedented refinement in the description of molecular structures and supramolecular assemblies at the immune cell membrane, and provided a glimpse into their dynamics and regulation by force. Several key elements have been scrutinized such as the roles of relative sizes of molecules, lateral organisation, motion in the membrane of the receptors, but also physical cues such as forces, mediated by cellular substrates of different rigidities or applied by the cell itself, in conjunction with its partner cell. We review here these recent discoveries associated with a description of the biophysical methods used. While a conclusive picture integrating all of these components is still lacking, mainly due to the implication of diverse and different mechanisms and spatio-temporal scales involved, the amount of quantitative data available opens the way for physical modelling and numerical simulations and new avenues for experimental research.
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15
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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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16
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Machado R, Bendesky J, Brown M, Spendier K, Hagen GM. Imaging Membrane Curvature inside a FcεRI-Centric Synapse in RBL-2H3 Cells Using TIRF Microscopy with Polarized Excitation. J Imaging 2019; 5:63. [PMID: 31360699 PMCID: PMC6663088 DOI: 10.3390/jimaging5070063] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/28/2019] [Indexed: 01/06/2023] Open
Abstract
Total internal reflection fluorescence microscopy with polarized excitation (P-TIRF) can be used to image nanoscale curvature phenomena in live cells. We used P-TIRF to visualize rat basophilic leukemia cells (RBL-2H3 cells) primed with fluorescent anti-dinitrophenyl (anti-DNP) immunoglobulin E (IgE) coming into contact with a supported lipid bilayer containing mobile, monovalent DNP, modeling an immunological synapse. The spatial relationship of the IgE-bound high affinity IgE receptor (FcεRI) to the ratio image of P-polarized excitation and S-polarized excitation was analyzed. These studies help correlate the dynamics of cell surface molecules with the mechanical properties of the plasma membrane during synapse formation.
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Affiliation(s)
- Rosa Machado
- UCCS Center for the Biofrontiers Institute, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
| | - Justin Bendesky
- UCCS Center for the Biofrontiers Institute, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
| | - Madison Brown
- UCCS Center for the Biofrontiers Institute, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
- Department of Physics and Energy Science, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
| | - Kathrin Spendier
- UCCS Center for the Biofrontiers Institute, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
- Department of Physics and Energy Science, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
| | - Guy M. Hagen
- UCCS Center for the Biofrontiers Institute, University of Colorado at Colorado Springs, Colorado Springs, CO 80918, USA
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17
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Felce JH, Sezgin E, Wane M, Brouwer H, Dustin ML, Eggeling C, Davis SJ. CD45 exclusion- and cross-linking-based receptor signaling together broaden FcεRI reactivity. Sci Signal 2018; 11:11/561/eaat0756. [PMID: 30563863 DOI: 10.1126/scisignal.aat0756] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
For many years, the high-affinity receptor for immunoglobulin E (IgE) FcεRI, which is expressed by mast cells and basophils, has been widely held to be the exemplar of cross-linking (that is, aggregation dependent) signaling receptors. We found, however, that FcεRI signaling could occur in the presence or absence of receptor cross-linking. Using both cell and cell-free systems, we showed that FcεRI signaling was stimulated by surface-associated monovalent ligands through the passive, size-dependent exclusion of the receptor-type tyrosine phosphatase CD45 from plasma membrane regions of FcεRI-ligand engagement. Similarly to the T cell receptor, FcεRI signaling could also be initiated in a ligand-independent manner. These data suggest that a simple mechanism of CD45 exclusion-based receptor triggering could function together with cross-linking-based FcεRI signaling, broadening mast cell and basophil reactivity by enabling these cells to respond to both multivalent and surface-presented monovalent antigens. These findings also strengthen the case that a size-dependent, phosphatase exclusion-based receptor triggering mechanism might serve generally to facilitate signaling by noncatalytic immune receptors.
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Affiliation(s)
- James H Felce
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.,Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK.,Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK
| | - Erdinc Sezgin
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Madina Wane
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.,Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
| | - Heather Brouwer
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.,Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
| | - Michael L Dustin
- Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK.
| | - Christian Eggeling
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.
| | - Simon J Davis
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK. .,Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
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18
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New roles and controls of mast cells. Curr Opin Immunol 2018; 50:39-47. [DOI: 10.1016/j.coi.2017.10.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/13/2017] [Accepted: 10/28/2017] [Indexed: 12/14/2022]
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19
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Lateral Organization of Influenza Virus Proteins in the Budozone Region of the Plasma Membrane. J Virol 2017; 91:JVI.02104-16. [PMID: 28202765 DOI: 10.1128/jvi.02104-16] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 02/12/2017] [Indexed: 12/24/2022] Open
Abstract
Influenza virus assembles and buds at the plasma membrane of virus-infected cells. The viral proteins assemble at the same site on the plasma membrane for budding to occur. This involves a complex web of interactions among viral proteins. Some proteins, like hemagglutinin (HA), NA, and M2, are integral membrane proteins. M1 is peripherally membrane associated, whereas NP associates with viral RNA to form an RNP complex that associates with the cytoplasmic face of the plasma membrane. Furthermore, HA and NP have been shown to be concentrated in cholesterol-rich membrane raft domains, whereas M2, although containing a cholesterol binding motif, is not raft associated. Here we identify viral proteins in planar sheets of plasma membrane using immunogold staining. The distribution of these proteins was examined individually and pairwise by using the Ripley K function, a type of nearest-neighbor analysis. Individually, HA, NA, M1, M2, and NP were shown to self-associate in or on the plasma membrane. HA and M2 are strongly coclustered in the plasma membrane; however, in the case of NA and M2, clustering depends upon the expression system used. Despite both proteins being raft resident, HA and NA occupy distinct but adjacent membrane domains. M2 and M1 strongly cocluster, but the association of M1 with HA or NA is dependent upon the means of expression. The presence of HA and NP at the site of budding depends upon the coexpression of other viral proteins. Similarly, M2 and NP occupy separate compartments, but an association can be bridged by the coexpression of M1.IMPORTANCE The complement of influenza virus proteins necessary for the budding of progeny virions needs to accumulate at budozones. This is complicated by HA and NA residing in lipid raft-like domains, whereas M2, although an integral membrane protein, is not raft associated. Other necessary protein components such as M1 and NP are peripherally associated with the membrane. Our data define spatial relationships between viral proteins in the plasma membrane. Some proteins, such as HA and M2, inherently cocluster within the membrane, although M2 is found mostly at the periphery of regions of HA, consistent with the proposed role of M2 in scission at the end of budding. The association between some pairs of influenza virus proteins, such as M2 and NP, appears to be brokered by additional influenza virus proteins, in this case M1. HA and NA, while raft associated, reside in distinct domains, reflecting their distributions in the viral membrane.
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20
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Woo SS, James DJ, Martin TFJ. Munc13-4 functions as a Ca 2+ sensor for homotypic secretory granule fusion to generate endosomal exocytic vacuoles. Mol Biol Cell 2017; 28:792-808. [PMID: 28100639 PMCID: PMC5349786 DOI: 10.1091/mbc.e16-08-0617] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 01/06/2017] [Accepted: 01/11/2017] [Indexed: 12/22/2022] Open
Abstract
Munc13-4 is a Ca2+-dependent SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor)- and phospholipid-binding protein that localizes to and primes secretory granules (SGs) for Ca2+-evoked secretion in various secretory cells. Studies in mast cell-like RBL-2H3 cells provide direct evidence that Munc13-4 with its two Ca2+-binding C2 domains functions as a Ca2+ sensor for SG exocytosis. Unexpectedly, Ca2+ stimulation also generated large (>2.4 μm in diameter) Munc13-4+/Rab7+/Rab11+ endosomal vacuoles. Vacuole generation involved the homotypic fusion of Munc13-4+/Rab7+ SGs, followed by a merge with Rab11+ endosomes, and depended on Ca2+ binding to Munc13-4. Munc13-4 promoted the Ca2+-stimulated fusion of VAMP8-containing liposomes with liposomes containing exocytic or endosomal Q-SNAREs and directly interacted with late endosomal SNARE complexes. Thus Munc13-4 is a tethering/priming factor and Ca2+ sensor for both heterotypic SG-plasma membrane and homotypic SG-SG fusion. Total internal reflection fluorescence microscopy imaging revealed that vacuoles were exocytic and mediated secretion of β-hexosaminidase and cytokines accompanied by Munc13-4 diffusion onto the plasma membrane. The results provide new molecular insights into the mechanism of multigranular compound exocytosis commonly observed in various secretory cells.
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Affiliation(s)
- Sang Su Woo
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
| | - Declan J James
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
| | - Thomas F J Martin
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
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21
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Valvo S, Mayya V, Seraia E, Afrose J, Novak-Kotzer H, Ebner D, Dustin ML. Comprehensive Analysis of Immunological Synapse Phenotypes Using Supported Lipid Bilayers. Methods Mol Biol 2017; 1584:423-441. [PMID: 28255717 DOI: 10.1007/978-1-4939-6881-7_26] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Supported lipid bilayers (SLB) formed on glass substrates have been a useful tool for study of immune cell signaling since the early 1980s. The mobility of lipid-anchored proteins in the system, first described for antibodies binding to synthetic phospholipid head groups, allows for the measurement of two-dimensional binding reactions and signaling processes in a single imaging plane over time or for fixed samples. The fragility of SLB and the challenges of building and validating individual substrates limit most experimenters to ~10 samples per day, perhaps increasing this few-fold when examining fixed samples. Successful experiments might then require further days to fully analyze. We present methods for automation of many steps in SLB formation, imaging in 96-well glass bottom plates, and analysis that enables >100-fold increase in throughput for fixed samples and wide-field fluorescence. This increased throughput will allow better coverage of relevant parameters and more comprehensive analysis of aspects of the immunological synapse that are well reconstituted by SLB.
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Affiliation(s)
- Salvatore Valvo
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, The University of Oxford, Oxford, OX3 7FY, UK
| | - Viveka Mayya
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, The University of Oxford, Oxford, OX3 7FY, UK
| | - Elena Seraia
- Target Discovery Institute, Nuffield Department of Medicine, The University of Oxford, Oxford, OX3 7FZ, UK
| | - Jehan Afrose
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, The University of Oxford, Oxford, OX3 7FY, UK
| | - Hila Novak-Kotzer
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, The University of Oxford, Oxford, OX3 7FY, UK
| | - Daniel Ebner
- Target Discovery Institute, Nuffield Department of Medicine, The University of Oxford, Oxford, OX3 7FZ, UK.
| | - Michael L Dustin
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, The University of Oxford, Oxford, OX3 7FY, UK.
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22
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Abstract
Immunological synapses are specialized cell-cell junctions characterized by (1) close apposition of the immune cell membrane with the membrane of another cell driven by adaptive or innate immune recognition, (2) adhesion, (3) stability, and (4) directed secretion. This phenomenon was first recognized in the 1970s and the early 1980s through electron microscopy of ex vivo functioning immune cells. Progressive advances in fluorescence microscopy and molecular immunology in the past 20 years have led to rapid progress on understanding the modes of cell-cell interaction and underlying molecular events. This volume contains a diverse range of protocols that can be applied to the study of the immunological synapses and related immune cell junctions both in vitro and in vivo; and in disease settings in animal models and humans. We have also included chapters on critical molecular tools such as protein expression and mRNA electroporation that underpin or expand imaging approaches, although they are not specific to the study of immune synapses. We hope that these chapters will be of use to people entering the field as well as seasoned practitioners looking to expand their repertoire of methods.
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23
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N-terminal amphipathic helix of Amphiphysin can change the spatial distribution of immunoglobulin E receptors (FcεRI) in the RBL-2H3 mast cell synapse. RESULTS IN IMMUNOLOGY 2015; 6:1-4. [PMID: 26835247 DOI: 10.1016/j.rinim.2015.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/13/2015] [Accepted: 11/30/2015] [Indexed: 11/23/2022]
Abstract
Biomembranes undergo extensive shape changes as they perform vital cellular functions or become diseased. To understand the mechanisms by which lipids and proteins control membrane curvature during various processes, researchers have identified and engineered many curvature-inducing and curvature-sensing proteins and peptides. In this paper, a simple experiment was performed to show qualitatively how membrane remodeling by N-terminal amphipathic helix of Amphiphysin affects the spatial distribution of the transmembrane Fc receptor protein (FcεRI) in mast cells. Results indicate that an elevated concentration of amphipathic helices can interfere with the formation of a typical mast cell synapse.
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24
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Anthony S, Carroll-Portillo A, Timlin J. Dynamics and Interactions of Individual Proteins in the Membrane of Single, Living Cells. Methods Mol Biol 2015; 1346:185-207. [PMID: 26542723 DOI: 10.1007/978-1-4939-2987-0_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Total internal reflection fluorescence (TIRF) microscopy is a powerful technique for interrogating protein dynamics in the membranes of living single cells. Receptor-ligand interactions are of particular interest for improving our understanding of cell signaling networks in a variety of applications. Here, we describe methods for fluorescently labeling individual receptors and their ligands, conducting single-molecule TIRF microscopy of receptors and ligands in single, living cells, and importantly, performing image analysis on the resulting time sequence of images to extract quantitative dynamics. While we use Toll-like receptor 4 and its ligand lipopolysaccharide as a specific example, the methods are general and readily extendable to other receptor-ligand systems of importance in cellular biology.
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Affiliation(s)
- Stephen Anthony
- Sandia National Laboratories, Bioenergy and Defense Technologies, 5800, Albuquerque, NM, 87185, USA
| | - Amanda Carroll-Portillo
- Sandia National Laboratories, Bioenergy and Defense Technologies, 5800, Albuquerque, NM, 87185, USA
| | - Jerilyn Timlin
- Sandia National Laboratories, Bioenergy and Defense Technologies, 5800, Albuquerque, NM, 87185, USA.
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25
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Freedman TS, Tan YX, Skrzypczynska KM, Manz BN, Sjaastad FV, Goodridge HS, Lowell CA, Weiss A. LynA regulates an inflammation-sensitive signaling checkpoint in macrophages. eLife 2015; 4. [PMID: 26517880 PMCID: PMC4626889 DOI: 10.7554/elife.09183] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 09/19/2015] [Indexed: 12/11/2022] Open
Abstract
Clustering of receptors associated with immunoreceptor tyrosine-based activation motifs (ITAMs) initiates the macrophage antimicrobial response. ITAM receptors engage Src-family tyrosine kinases (SFKs) to initiate phagocytosis and macrophage activation. Macrophages also encounter nonpathogenic molecules that cluster receptors weakly and must tune their sensitivity to avoid inappropriate responses. To investigate this response threshold, we compared signaling in the presence and absence of receptor clustering using a small-molecule inhibitor of Csk, which increased SFK activation and produced robust membrane-proximal signaling. Surprisingly, receptor-independent SFK activation led to a downstream signaling blockade associated with rapid degradation of the SFK LynA. Inflammatory priming of macrophages upregulated LynA and promoted receptor-independent signaling. In contrast, clustering the hemi-ITAM receptor Dectin-1 induced signaling that did not require LynA or inflammatory priming. Together, the basal-state signaling checkpoint regulated by LynA expression and degradation and the signaling reorganization initiated by receptor clustering allow cells to discriminate optimally between pathogens and nonpathogens.
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Affiliation(s)
- Tanya S Freedman
- Russell/Engleman Rheumatology Research Center, Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, United States.,Department of Pharmacology, Center for Immunology, University of Minnesota, Minneapolis, United States
| | - Ying X Tan
- Russell/Engleman Rheumatology Research Center, Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, United States
| | - Katarzyna M Skrzypczynska
- Russell/Engleman Rheumatology Research Center, Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, United States
| | - Boryana N Manz
- Russell/Engleman Rheumatology Research Center, Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, United States
| | - Frances V Sjaastad
- Department of Pharmacology, Center for Immunology, University of Minnesota, Minneapolis, United States
| | - Helen S Goodridge
- Regenerative Medicine Institute and Research Division of Immunology, Cedars-Sinai Medical Center, Los Angeles, United States
| | - Clifford A Lowell
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, United States
| | - Arthur Weiss
- Russell/Engleman Rheumatology Research Center, Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, United States.,Howard Hughes Medical Institute, University of California, San Francisco, Chevy Chase, United States
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26
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Carroll-Portillo A, Cannon JL, te Riet J, Holmes A, Kawakami Y, Kawakami T, Cambi A, Lidke DS. Mast cells and dendritic cells form synapses that facilitate antigen transfer for T cell activation. J Cell Biol 2015; 210:851-64. [PMID: 26304724 PMCID: PMC4555818 DOI: 10.1083/jcb.201412074] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 07/17/2015] [Indexed: 11/30/2022] Open
Abstract
Mast cells (MCs) and dendritic cells (DCs) form synapses that are dependent on MC activation and integrin engagement, and these direct interactions stimulate changes in the secretion profile of select cytokines and facilitate transfer of endosomal contents from activated MCs to DCs. Mast cells (MCs) produce soluble mediators such as histamine and prostaglandins that are known to influence dendritic cell (DC) function by stimulating maturation and antigen processing. Whether direct cell–cell interactions are important in modulating MC/DC function is unclear. In this paper, we show that direct contact between MCs and DCs occurs and plays an important role in modulating the immune response. Activation of MCs through FcεRI cross-linking triggers the formation of stable cell–cell interactions with immature DCs that are reminiscent of the immunological synapse. Direct cellular contact differentially regulates the secreted cytokine profile, indicating that MC modulation of DC populations is influenced by the nature of their interaction. Synapse formation requires integrin engagement and facilitates the transfer of internalized MC-specific antigen from MCs to DCs. The transferred material is ultimately processed and presented by DCs and can activate T cells. The physiological outcomes of the MC–DC synapse suggest a new role for intercellular crosstalk in defining the immune response.
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Affiliation(s)
- Amanda Carroll-Portillo
- Department of Pathology, The University of New Mexico School of Medicine, Albuquerque, NM 87131
| | - Judy L Cannon
- Department of Pathology, The University of New Mexico School of Medicine, Albuquerque, NM 87131 Department of Molecular Genetics and Microbiology, The University of New Mexico School of Medicine, Albuquerque, NM 87131 Cancer Research and Treatment Center, The University of New Mexico, Albuquerque, NM 87131
| | - Joost te Riet
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, Netherlands
| | - Anna Holmes
- Department of Pathology, The University of New Mexico School of Medicine, Albuquerque, NM 87131
| | - Yuko Kawakami
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037
| | - Toshiaki Kawakami
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037 Laboratory for Allergic Disease, RIKEN Center for Integrative Medical Sciences (IMS-RCAI), Tsurumi-ku, Yokohama 230-0045, Japan
| | - Alessandra Cambi
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, Netherlands
| | - Diane S Lidke
- Department of Pathology, The University of New Mexico School of Medicine, Albuquerque, NM 87131 Cancer Research and Treatment Center, The University of New Mexico, Albuquerque, NM 87131
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27
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Mast cells form antibody-dependent degranulatory synapse for dedicated secretion and defence. Nat Commun 2015; 6:6174. [PMID: 25629393 DOI: 10.1038/ncomms7174] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 12/22/2014] [Indexed: 02/02/2023] Open
Abstract
Mast cells are tissue-resident immune cells that play a key role in inflammation and allergy. Here we show that interaction of mast cells with antibody-targeted cells induces the polarized exocytosis of their granules resulting in a sustained exposure of effector enzymes, such as tryptase and chymase, at the cell-cell contact site. This previously unidentified mast cell effector mechanism, which we name the antibody-dependent degranulatory synapse (ADDS), is triggered by both IgE- and IgG-targeted cells. ADDSs take place within an area of cortical actin cytoskeleton clearance in the absence of microtubule organizing centre and Golgi apparatus repositioning towards the stimulating cell. Remarkably, IgG-mediated degranulatory synapses also occur upon contact with opsonized Toxoplasma gondii tachyzoites resulting in tryptase-dependent parasite death. Our results broaden current views of mast cell degranulation by revealing that human mast cells form degranulatory synapses with antibody-targeted cells and pathogens for dedicated secretion and defence.
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28
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Suzuki R, Scheffel J, Rivera J. New insights on the signaling and function of the high-affinity receptor for IgE. Curr Top Microbiol Immunol 2015; 388:63-90. [PMID: 25553795 DOI: 10.1007/978-3-319-13725-4_4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Clustering of the high-affinity receptor for immunoglobulin E (FcεRI) through the interaction of receptor-bound immunoglobulin E (IgE) antibodies with their cognate antigen is required to couple IgE antibody production to cellular responses and physiological consequences. IgE-induced responses through FcεRI are well known to defend the host against certain infectious agents and to lead to unwanted allergic responses to normally innocuous substances. However, the cellular and/or physiological response of individuals that produce IgE antibodies may be markedly different and such antibodies (even to the same antigenic epitope) can differ in their antigen-binding affinity. How affinity variation in the interaction of FcεRI-bound IgE antibodies with antigen is interpreted into cellular responses and how the local environment may influence these responses is of interest. In this chapter, we focus on recent advances that begin to unravel how FcεRI distinguishes differences in the affinity of IgE-antigen interactions and how such discrimination along with surrounding environmental stimuli can shape the (patho) physiological response.
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Affiliation(s)
- Ryo Suzuki
- Molecular Immunology Section, Laboratory of Molecular Immunogenetics, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
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29
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Spycher PR, Hall H, Vogel V, Reimhult E. Patterning of supported lipid bilayers and proteins using material selective nitrodopamine-mPEG. Biomater Sci 2015. [DOI: 10.1039/c4bm00090k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We present a generic patterning process by which biomolecules in a passivated background are patterned directly from physiological buffer to microfabricated surfaces without the need for further processing.
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Affiliation(s)
- Philipp R. Spycher
- Laboratory of Applied Mechanobiology
- Department of Health Sciences and Technology
- ETH Zurich
- Switzerland
| | - Heike Hall
- Laboratory of Applied Mechanobiology
- Department of Health Sciences and Technology
- ETH Zurich
- Switzerland
| | - Viola Vogel
- Laboratory of Applied Mechanobiology
- Department of Health Sciences and Technology
- ETH Zurich
- Switzerland
| | - Erik Reimhult
- Laboratory for Surface Science and Technology
- Department of Materials
- ETH Zurich
- Switzerland
- Institute for Biologically Inspired Materials
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30
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Kalkur RS, Ballast AC, Triplett AR, Spendier K. Effects of deuterium oxide on cell growth and vesicle speed in RBL-2H3 cells. PeerJ 2014; 2:e553. [PMID: 25237603 PMCID: PMC4157235 DOI: 10.7717/peerj.553] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 08/10/2014] [Indexed: 12/31/2022] Open
Abstract
For the first time we show the effects of deuterium oxide on cell growth and vesicle transport in rat basophilic leukemia (RBL-2H3) cells. RBL-2H3 cells cultured with 15 moles/L deuterium showed decreased cell growth which was attributed to cells not doubling their DNA content. Experimental observations also showed an increase in vesicle speed for cells cultured in deuterium oxide. This increase in vesicle speed was not observed in deuterium oxide cultures treated with a microtubule-destabilizing drug, suggesting that deuterium oxide affects microtubule-dependent vesicle transport.
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Affiliation(s)
- Roshni S Kalkur
- BioFrontiers Center, University of Colorado at Colorado Springs, Colorado Springs, CO, USA
| | - Andrew C Ballast
- BioFrontiers Center, University of Colorado at Colorado Springs, Colorado Springs, CO, USA.,Department of Physics and Energy Science, University of Colorado at Colorado Springs, Colorado Springs, CO, USA
| | - Ashley R Triplett
- BioFrontiers Center, University of Colorado at Colorado Springs, Colorado Springs, CO, USA
| | - Kathrin Spendier
- BioFrontiers Center, University of Colorado at Colorado Springs, Colorado Springs, CO, USA.,Department of Physics and Energy Science, University of Colorado at Colorado Springs, Colorado Springs, CO, USA
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31
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Ketchum C, Miller H, Song W, Upadhyaya A. Ligand mobility regulates B cell receptor clustering and signaling activation. Biophys J 2014; 106:26-36. [PMID: 24411234 DOI: 10.1016/j.bpj.2013.10.043] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 09/19/2013] [Accepted: 10/28/2013] [Indexed: 11/15/2022] Open
Abstract
Antigen binding to the B cell receptor (BCR) induces receptor clustering, cell spreading, and the formation of signaling microclusters, triggering B cell activation. Although the biochemical pathways governing early B cell signaling have been well studied, the role of the physical properties of antigens, such as antigen mobility, has not been fully examined. We study the interaction of B cells with BCR ligands coated on glass or tethered to planar lipid bilayer surfaces to investigate the differences in B cell response to immobile and mobile ligands. Using high-resolution total internal reflection fluorescence (TIRF) microscopy of live cells, we followed the movement and spatial organization of BCR clusters and the associated signaling. Although ligands on either surface were able to cross-link BCRs and induce clustering, B cells interacting with mobile ligands displayed greater signaling than those interacting with immobile ligands. Quantitative analysis revealed that mobile ligands enabled BCR clusters to move farther and merge more efficiently than immobile ligands. These differences in physical reorganization of receptor clusters were associated with differences in actin remodeling. Perturbation experiments revealed that a dynamic actin cytoskeleton actively reorganized receptor clusters. These results suggest that ligand mobility is an important parameter for regulating B cell signaling.
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Affiliation(s)
- Christina Ketchum
- Biophysics Graduate Program, University of Maryland, College Park, MD 20742
| | - Heather Miller
- Department of Cell Biology & Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Wenxia Song
- Department of Cell Biology & Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Arpita Upadhyaya
- Biophysics Graduate Program, University of Maryland, College Park, MD 20742; Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742; Department of Physics, University of Maryland, College Park, MD 20742.
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32
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Narui Y, Salaita K. Membrane tethered delta activates notch and reveals a role for spatio-mechanical regulation of the signaling pathway. Biophys J 2014; 105:2655-65. [PMID: 24359737 DOI: 10.1016/j.bpj.2013.11.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 10/17/2013] [Accepted: 11/04/2013] [Indexed: 11/18/2022] Open
Abstract
Short-range Notch receptor signaling is necessary for coordinating developmental activities in metazoa. To investigate this juxtacrine pathway, we mimic receptor-ligand binding within the cell-cell junction by engaging Notch1-eGFP expressing cells to a supported lipid membrane displaying Delta-like protein 4 (DLL4). DLL4-Notch1 binding, oligomerization, and transport were observed in real time, and the molecular density and stoichiometry of the complexes were determined using quantitative fluorescence imaging. A Notch transcriptional reporter readout was used to quantify how ligand lateral mobility, orientation, and density modulate receptor activation levels. These experiments demonstrate that limiting the lateral mobility of DLL4 can enhance Notch activation by 2.6-fold, thus supporting the existence of a spatio-mechanical mechanism of signal regulation.
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Affiliation(s)
- Yoshie Narui
- Department of Chemistry, Emory University, Atlanta, Georgia
| | - Khalid Salaita
- Department of Chemistry, Emory University, Atlanta, Georgia.
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33
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Greene AC, Lord SJ, Tian A, Rhodes C, Kai H, Groves JT. Spatial organization of EphA2 at the cell-cell interface modulates trans-endocytosis of ephrinA1. Biophys J 2014; 106:2196-205. [PMID: 24853748 PMCID: PMC4052362 DOI: 10.1016/j.bpj.2014.03.043] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 03/26/2014] [Accepted: 03/31/2014] [Indexed: 11/21/2022] Open
Abstract
EphA2 is a receptor tyrosine kinase (RTK) that is sensitive to spatial and mechanical aspects of the cell's microenvironment. Misregulation of EphA2 occurs in many aggressive cancers. Although its juxtacrine signaling geometry (EphA2's cognate ligand ephrinA1 is expressed on the surface of an apposing cell) provides a mechanism by which the receptor may experience extracellular forces, this also renders the system challenging to decode. By depositing living cells on synthetic supported lipid membranes displaying ephrinA1, we have reconstituted key features of the juxtacrine EphA2-ephrinA1 signaling system while maintaining the ability to perturb the spatial and mechanical properties of the membrane-cell interface with precision. In addition, we developed a trans-endocytosis assay to monitor internalization of ephrinA1 from a supported membrane into the apposing cell using a quantitative three-dimensional fluorescence microscopy assay. Using this experimental platform to mimic a cell-cell junction, we found that the signaling complex is not efficiently internalized when lateral reorganization at the membrane-cell contact sites is physically hindered. This suggests that EphA2-ephrinA1 trans-endocytosis is sensitive to the mechanical properties of a cell's microenvironment and may have implications in physical aspects of tumor biology.
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Affiliation(s)
- Adrienne C Greene
- Howard Hughes Medical Institute, Department of Chemistry, University of California, Berkeley, California; Physical Biosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California; Department of Molecular and Cell Biology, University of California, Berkeley, California
| | - Samuel J Lord
- Howard Hughes Medical Institute, Department of Chemistry, University of California, Berkeley, California; Physical Biosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California
| | - Aiwei Tian
- Howard Hughes Medical Institute, Department of Chemistry, University of California, Berkeley, California; Physical Biosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California
| | - Christopher Rhodes
- Howard Hughes Medical Institute, Department of Chemistry, University of California, Berkeley, California; Physical Biosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California; Department of Mechanical Engineering, University of California, Berkeley, California
| | - Hiroyuki Kai
- Howard Hughes Medical Institute, Department of Chemistry, University of California, Berkeley, California; Physical Biosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California
| | - Jay T Groves
- Howard Hughes Medical Institute, Department of Chemistry, University of California, Berkeley, California; Physical Biosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California; Mechanobiology Institute, National University of Singapore, Singapore.
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34
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Ye F, Petrich BG, Anekal P, Lefort CT, Kasirer-Friede A, Shattil SJ, Ruppert R, Moser M, Fässler R, Ginsberg MH. The mechanism of kindlin-mediated activation of integrin αIIbβ3. Curr Biol 2013; 23:2288-2295. [PMID: 24210614 DOI: 10.1016/j.cub.2013.09.050] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 08/30/2013] [Accepted: 09/24/2013] [Indexed: 01/11/2023]
Abstract
Increased ligand binding to cellular integrins ("activation") plays important roles in processes such as development, cell migration, extracellular matrix assembly, tumor metastasis, hemostasis, and thrombosis. Integrin activation encompasses both increased integrin monomer affinity and increased receptor clustering and depends on integrin-talin interactions. Loss of kindlins results in reduced activation of integrins. Kindlins might promote talin binding to integrins through a cooperative mechanism; however, kindlins do not increase talin association with integrins. Here, we report that, unlike talin head domain (THD), kindlin-3 has little effect on the affinity of purified monomeric αIIbβ3, and it does not enhance activation by THD. Furthermore, studies with ligands of varying valency show that kindlins primarily increase cellular αIIbβ3 avidity rather than monomer affinity. In platelets or nucleated cells, loss of kindlins markedly reduces αIIbβ3 binding to multivalent but not monovalent ligands. Finally, silencing of kindlins reduces the clustering of ligand-occupied αIIbβ3 as revealed by total internal reflection fluorescence and electron microscopy. Thus, in contrast to talins, kindlins have little primary effect on integrin αIIbβ3 affinity for monovalent ligands and increase multivalent ligand binding by promoting the clustering of talin-activated integrins.
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Affiliation(s)
- Feng Ye
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Brian G Petrich
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Praju Anekal
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Craig T Lefort
- La Jolla Institute for Allergy & Immunology, La Jolla, CA 92093, USA
| | - Ana Kasirer-Friede
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sanford J Shattil
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Raphael Ruppert
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Markus Moser
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Reinhard Fässler
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Mark H Ginsberg
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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35
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Al-Qatati A, Fontes FL, Barisas BG, Zhang D, Roess DA, Crans DC. Raft localization of type I Fcε receptor and degranulation of RBL-2H3 cells exposed to decavanadate, a structural model for V2O5. Dalton Trans 2013; 42:11912-20. [PMID: 23861175 DOI: 10.1039/c3dt50398d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vanadium oxides (VOs) have been identified as low molecular weight sensitizing agents associated with occupational asthma and compromised pulmonary immunocompetence. Symptoms of adult onset asthma result, in part, from increased signal transduction by Type I Fcε receptors (FcεRI) leading to release of vasoactive compounds including histamine from mast cells. Exposure to (VOs) typically occurs in the form of particles which are insoluble. Upon contact with water or biological fluids, (VOs) form a series of soluble oxoanions, one of which is decavanadate, V10O28(6-) abbreviated V10, which is structurally related to a common vanadium oxide, that is vanadium pentoxide, V2O5. Here we investigate whether V10 may be initiating plasma membrane events associated with activation of FcεRI signal transduction. We show that exposure of RBL-2H3 cells to V10 causes a concentration-dependent increase in degranulation of RBL-2H3 and, in addition, an increase in plasma membrane lipid packing as measured by the fluorescent probe, di-4-ANEPPDHQ. V10 also increases FcεRI accumulation in low-density membrane fragments, i.e., lipid rafts, which may facilitate FcεRI signaling. To determine whether V10 effects on plasma membrane lipid packing were similarly observed in Langmuir monolayers formed from dipalmitoylphosphatidylcholine (DPPC), the extent of lipid packing in the presence and absence of V10 and vanadate was compared. V10 increased the surface area of DPPC Langmuir monolayers by 6% and vanadate decreased the surface area by 4%. These results are consistent with V10 interacting with this class of membrane lipids and altering DPPC packing.
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Affiliation(s)
- Abeer Al-Qatati
- Cell and Molecular Biology Program, Colorado State University, Fort Collins, Colorado 80523, USA
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36
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Zhao J, Wu J, Veatch SL. Adhesion stabilizes robust lipid heterogeneity in supercritical membranes at physiological temperature. Biophys J 2013; 104:825-34. [PMID: 23442961 DOI: 10.1016/j.bpj.2012.12.047] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 11/13/2012] [Accepted: 12/03/2012] [Indexed: 01/08/2023] Open
Abstract
Regions of contact between cells are frequently enriched in or depleted of certain protein or lipid species. Here, we explore a possible physical basis that could contribute to this membrane heterogeneity using a model system of a giant vesicle tethered to a planar supported bilayer. Vesicles contain coexisting liquid-ordered (L(o)) and liquid-disordered (L(d)) phases at low temperatures and are tethered using trace quantities of adhesion molecules that preferentially partition into one liquid phase. We find that the L(d) marker DiI-C(12) is enriched or depleted in the adhered region when adhesion molecules partition into L(d) or L(o) phases, respectively. Remarkably, adhesion stabilizes an extended zone enriched or depleted of DiI-C(12) even at temperatures >15°C above the miscibility phase transition when membranes have compositions that are in close proximity to a critical point. A stable adhesion zone is also observed in plasma membrane vesicles isolated from living RBL-2H3 cells, and probe partitioning at 37°C is diminished in vesicles isolated from cells with altered cholesterol levels. Probe partitioning is in good quantitative agreement with predictions of the two-dimensional Ising model with a weak applied field for both types of model membranes. These studies experimentally demonstrate that large and stable domain structure can be mediated by lipids in single-phase membranes with supercritical fluctuations.
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Affiliation(s)
- Jiang Zhao
- Department of Biophysics, University of Michigan, Ann Arbor, MI, USA
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37
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Liu Y, Barua D, Liu P, Wilson BS, Oliver JM, Hlavacek WS, Singh AK. Single-cell measurements of IgE-mediated FcεRI signaling using an integrated microfluidic platform. PLoS One 2013; 8:e60159. [PMID: 23544131 PMCID: PMC3609784 DOI: 10.1371/journal.pone.0060159] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 02/21/2013] [Indexed: 11/18/2022] Open
Abstract
Heterogeneity in responses of cells to a stimulus, such as a pathogen or allergen, can potentially play an important role in deciding the fate of the responding cell population and the overall systemic response. Measuring heterogeneous responses requires tools capable of interrogating individual cells. Cell signaling studies commonly do not have single-cell resolution because of the limitations of techniques used such as Westerns, ELISAs, mass spectrometry, and DNA microarrays. Microfluidics devices are increasingly being used to overcome these limitations. Here, we report on a microfluidic platform for cell signaling analysis that combines two orthogonal single-cell measurement technologies: on-chip flow cytometry and optical imaging. The device seamlessly integrates cell culture, stimulation, and preparation with downstream measurements permitting hands-free, automated analysis to minimize experimental variability. The platform was used to interrogate IgE receptor (FcεRI) signaling, which is responsible for triggering allergic reactions, in RBL-2H3 cells. Following on-chip crosslinking of IgE-FcεRI complexes by multivalent antigen, we monitored signaling events including protein phosphorylation, calcium mobilization and the release of inflammatory mediators. The results demonstrate the ability of our platform to produce quantitative measurements on a cell-by-cell basis from just a few hundred cells. Model-based analysis of the Syk phosphorylation data suggests that heterogeneity in Syk phosphorylation can be attributed to protein copy number variations, with the level of Syk phosphorylation being particularly sensitive to the copy number of Lyn.
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Affiliation(s)
- Yanli Liu
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, California, United States of America
| | - Dipak Barua
- Theoretical Biology and Biophysics Group, Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Peng Liu
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, California, United States of America
| | - Bridget S. Wilson
- Department of Pathology and Cancer Center, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Janet M. Oliver
- Department of Pathology and Cancer Center, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - William S. Hlavacek
- Theoretical Biology and Biophysics Group, Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Anup K. Singh
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, California, United States of America
- * E-mail:
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38
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Abstract
Fc receptors and their interaction with antibodies will be a major theme at the forthcoming FASEB Science Research Conference on Immunoreceptors to be held in Snowmass this July (details available at www.faseb.org/src/home.aspx, follow the tabs for Immunoreceptors). Since its inception in the mid 1980s, this meeting series has maintained a focus on Fc receptors, and this year’s meeting will be no exception.
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Carroll-Portillo A, Surviladze Z, Cambi A, Lidke DS, Wilson BS. Mast cell synapses and exosomes: membrane contacts for information exchange. Front Immunol 2012; 3:46. [PMID: 22566928 PMCID: PMC3342342 DOI: 10.3389/fimmu.2012.00046] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 02/27/2012] [Indexed: 11/16/2022] Open
Abstract
In addition to their central role in allergy, mast cells are involved in a wide variety of cellular interactions during homeostasis and disease. In this review, we discuss the ability of mast cells to extend their mechanisms for intercellular communication beyond the release of soluble mediators. These include formation of mast cell synapses on antigen presenting surfaces, as well as cell–cell contacts with dendritic cells and T cells. Release of membrane bound exosomes also provide for the transfer of antigen, mast cell proteins, and RNA to other leukocytes. With the recognition of the extended role mast cells have during immune modulation, further investigation of the processes in which mast cells are involved is necessary. This reopens mast cell research to exciting possibilities, demonstrating it to be an immunological frontier.
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Affiliation(s)
- Amanda Carroll-Portillo
- Department of Pathology, University of New Mexico Health Sciences Center Albuquerque, NM, USA
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40
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Hsu CJ, Hsieh WT, Waldman A, Clarke F, Huseby ES, Burkhardt JK, Baumgart T. Ligand mobility modulates immunological synapse formation and T cell activation. PLoS One 2012; 7:e32398. [PMID: 22384241 PMCID: PMC3284572 DOI: 10.1371/journal.pone.0032398] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 01/30/2012] [Indexed: 12/11/2022] Open
Abstract
T cell receptor (TCR) engagement induces clustering and recruitment to the plasma membrane of many signaling molecules, including the protein tyrosine kinase zeta-chain associated protein of 70 kDa (ZAP70) and the adaptor SH2 domain-containing leukocyte protein of 76 kDa (SLP76). This molecular rearrangement results in formation of the immunological synapse (IS), a dynamic protein array that modulates T cell activation. The current study investigates the effects of apparent long-range ligand mobility on T cell signaling activity and IS formation. We formed stimulatory lipid bilayers on glass surfaces from binary lipid mixtures with varied composition, and characterized these surfaces with respect to diffusion coefficient and fluid connectivity. Stimulatory ligands coupled to these surfaces with similar density and orientation showed differences in their ability to activate T cells. On less mobile membranes, central supramolecular activation cluster (cSMAC) formation was delayed and the overall accumulation of CD3ζ at the IS was reduced. Analysis of signaling microcluster (MC) dynamics showed that ZAP70 MCs exhibited faster track velocity and longer trajectories as a function of increased ligand mobility, whereas movement of SLP76 MCs was relatively insensitive to this parameter. Actin retrograde flow was observed on all surfaces, but cell spreading and subsequent cytoskeletal contraction were more pronounced on mobile membranes. Finally, increased tyrosine phosphorylation and persistent elevation of intracellular Ca2+ were observed in cells stimulated on fluid membranes. These results point to ligand mobility as an important parameter in modulating T cell responses.
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Affiliation(s)
- Chih-Jung Hsu
- Department of Chemistry, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Wan-Ting Hsieh
- Department of Chemistry, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Abraham Waldman
- Department of Chemistry, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Fiona Clarke
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Eric S. Huseby
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Janis K. Burkhardt
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (TB); (JKB)
| | - Tobias Baumgart
- Department of Chemistry, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (TB); (JKB)
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41
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Cambi A, Lidke DS. Nanoscale membrane organization: where biochemistry meets advanced microscopy. ACS Chem Biol 2012; 7:139-49. [PMID: 22004174 DOI: 10.1021/cb200326g] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Understanding the molecular mechanisms that shape an effective cellular response is a fundamental question in biology. Biochemical measurements have revealed critical information about the order of protein-protein interactions along signaling cascades but lack the resolution to determine kinetics and localization of interactions on the plasma membrane. Furthermore, the local membrane environment influences membrane receptor distributions and dynamics, which in turn influences signal transduction. To measure dynamic protein interactions and elucidate the consequences of membrane architecture interplay, direct measurements at high spatiotemporal resolution are needed. In this review, we discuss the biochemical principles regulating membrane nanodomain formation and protein function, ranging from the lipid nanoenvironment to the cortical cytoskeleton. We also discuss recent advances in fluorescence microscopy that are making it possible to quantify protein organization and biochemical events at the nanoscale in the living cell membrane.
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Affiliation(s)
- Alessandra Cambi
- Department of Tumor Immunology,
Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Diane S. Lidke
- Department of Pathology and
Cancer Research and Treatment Center, University of New Mexico, Albuquerque, New Mexico, United States
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Singleton KL, Gosh M, Dandekar RD, Au-Yeung BB, Ksionda O, Tybulewicz VLJ, Altman A, Fowell DJ, Wülfing C. Itk controls the spatiotemporal organization of T cell activation. Sci Signal 2012; 4:ra66. [PMID: 21971040 DOI: 10.1126/scisignal.2001821] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
During T cell activation by antigen-presenting cells (APCs), the diverse spatiotemporal organization of components of T cell signaling pathways modulates the efficiency of activation. Here, we found that loss of the tyrosine kinase interleukin-2 (IL-2)-inducible T cell kinase (Itk) in mice altered the spatiotemporal distributions of 14 of 16 sensors of T cell signaling molecules in the region of the interface between the T cell and the APC, which reduced the segregation of signaling intermediates into distinct spatiotemporal patterns. Activation of the Rho family guanosine triphosphatase Cdc42 at the center of the cell-cell interface was impaired, although the total cellular amount of active Cdc42 remained intact. The defect in Cdc42 localization resulted in impaired actin accumulation at the T cell-APC interface in Itk-deficient T cells. Reconstitution of cells with active Cdc42 that was specifically directed to the center of the interface restored actin accumulation in Itk-deficient T cells. Itk also controlled the central localization of the guanine nucleotide exchange factor SLAT [Switch-associated protein 70 (SWAP-70)-like adaptor of T cells], which may contribute to the activation of Cdc42 at the center of the interface. Together, these data illustrate how control of the spatiotemporal organization of T cell signaling controls critical aspects of T cell function.
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Affiliation(s)
- Kentner L Singleton
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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43
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Spendier K, Lidke KA, Lidke DS, Thomas JL. Single-particle tracking of immunoglobulin E receptors (FcεRI) in micron-sized clusters and receptor patches. FEBS Lett 2012; 586:416-21. [PMID: 22265688 DOI: 10.1016/j.febslet.2012.01.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 01/04/2012] [Accepted: 01/09/2012] [Indexed: 01/29/2023]
Abstract
When mast cells contact a monovalent antigen-bearing fluid lipid bilayer, IgE-loaded FcεRI receptors aggregate at contact points and trigger degranulation and the release of immune activators. We used two-color total internal reflection fluorescence microscopy and single-particle tracking to show that most fluorescently labeled receptor complexes diffuse freely within these micron-size clusters, with a diffusion coefficient comparable to free receptors in resting cells. At later times, when the small clusters coalesce to form larger patches, receptors diffuse even more rapidly. In all cases, Monte Carlo diffusion simulations ensured that the tracking results were free of bias, and distinguished biological from statistical variation. These results show the diversity in receptor mobility in mast cells, demonstrating at least three distinct states of receptor diffusivity.
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Affiliation(s)
- Kathrin Spendier
- Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131, USA
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44
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Draber P, Halova I, Levi-Schaffer F, Draberova L. Transmembrane adaptor proteins in the high-affinity IgE receptor signaling. Front Immunol 2012; 2:95. [PMID: 22566884 PMCID: PMC3342071 DOI: 10.3389/fimmu.2011.00095] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/28/2011] [Indexed: 11/24/2022] Open
Abstract
Aggregation of the high-affinity IgE receptor (FcεRI) initiates a cascade of signaling events leading to release of preformed inflammatory and allergy mediators and de novo synthesis and secretion of cytokines and other compounds. The first biochemically well defined step of this signaling cascade is tyrosine phosphorylation of the FcεRI subunits by Src family kinase Lyn, followed by recruitment and activation of spleen tyrosine kinase (Syk). Activity of Syk is decisive for the formation of multicomponent signaling assemblies, the signalosomes, in the vicinity of the receptors. Formation of the signalosomes is dependent on the presence of transmembrane adaptor proteins (TRAPs). These proteins are characterized by a short extracellular domain, a single transmembrane domain, and a cytoplasmic tail with various motifs serving as anchors for cytoplasmic signaling molecules. In mast cells five TRAPs have been identified [linker for activation of T cells (LAT), non-T cell activation linker (NTAL), linker for activation of X cells (LAX), phosphoprotein associated with glycosphingolipid-enriched membrane microdomains (PAG), and growth factor receptor-bound protein 2 (Grb2)-binding adaptor protein, transmembrane (GAPT)]; engagement of four of them (LAT, NTAL, LAX, and PAG) in FcεRI signaling has been documented. Here we discuss recent progress in the understanding of how TRAPs affect FcεRI-mediated mast cell signaling. The combined data indicate that individual TRAPs have irreplaceable roles in important signaling events such as calcium response, degranulation, cytokines production, and chemotaxis.
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Affiliation(s)
- Petr Draber
- Department of Signal Transduction, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic Prague, Czech Republic
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45
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Spatio-temporal signaling in mast cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 716:91-106. [PMID: 21713653 DOI: 10.1007/978-1-4419-9533-9_6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
This chapter summarizes the evidence for localized signaling domains in mast cells and basophils, with a particular focus on the high affinity IgE receptor, FcεRI and its crosstalk with other membrane proteins. It is noteworthy that a literature spanning 30 years established the FcεRI as a model receptor for studying activation-induced changes in receptor diffusion and lipid raft association. Now a combination of high resolution microscopy methods, including immunoelectron microscopy and sophisticated fluorescence-based techniques, provide new insight into the nanoscale spatial and temporal aspects of receptor topography on the mast cell plasma membrane. Physical crosslinking of FcεRI with multivalent ligands leads to formation of IgE receptor clusters, termed "signaling patches," that recruit downstream signaling molecules. However, classes of receptors that engage solely withmono valent ligands can also form distinctive signaling patches. The dynamic relationships between receptor diffusion, aggregation state, clustering, signal initiation and signal strength are discussed in the context of these recent findings.
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46
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Balagopalan L, Sherman E, Barr VA, Samelson LE. Imaging techniques for assaying lymphocyte activation in action. Nat Rev Immunol 2011; 11:21-33. [PMID: 21179118 PMCID: PMC3403683 DOI: 10.1038/nri2903] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Imaging techniques have greatly improved our understanding of lymphocyte activation. Technical advances in spatial and temporal resolution and new labelling tools have enabled researchers to directly observe the activation process. Consequently, research using imaging approaches to study lymphocyte activation has expanded, providing an unprecedented level of cellular and molecular detail in the field. As a result, certain models of lymphocyte activation have been verified, others have been revised and yet others have been replaced with new concepts. In this article, we review the current imaging techniques that are used to assess lymphocyte activation in different contexts, from whole animals to single molecules, and discuss the advantages and potential limitations of these methods.
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Affiliation(s)
- Lakshmi Balagopalan
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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47
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Spendier K, Carroll-Portillo A, Lidke KA, Wilson BS, Timlin JA, Thomas J. Distribution and dynamics of rat basophilic leukemia immunoglobulin E receptors (FcepsilonRI) on planar ligand-presenting surfaces. Biophys J 2010; 99:388-97. [PMID: 20643056 PMCID: PMC2905106 DOI: 10.1016/j.bpj.2010.04.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 03/22/2010] [Accepted: 04/14/2010] [Indexed: 10/19/2022] Open
Abstract
There is considerable interest in the signaling mechanisms of immunoreceptors, especially when triggered with membrane-bound ligands. We have quantified the spatiotemporal dynamics of the redistribution of immunoglobulin E-loaded receptors (IgE-FcepsilonRI) on rat basophilic leukemia-2H3 mast cells in contact with fluid and gel-phase membranes displaying ligands for immunoglobulin E, using total internal reflection fluorescence microscopy. To clearly separate the kinetics of receptor redistribution from cell spreading, and to precisely define the initial contact time (+/-50 ms), micropipette cell manipulation was used to bring individual cells into contact with surfaces. On ligand-free surfaces, there are micron-scale heterogeneities in fluorescence that likely reflect regions of the cell that are more closely apposed to the substrate. When ligands are present, receptor clusters form with this same size scale. The initial rate of accumulation of receptors into the clusters is consistent with diffusion-limited trapping with D approximately 10(-1) microm2/s. These results support the hypothesis that clusters form by diffusion to cell-surface contact regions. Over longer timescales (>10 s), individual clusters moved with both diffusive and directed motion components. The dynamics of the cluster motion is similar to the dynamics of membrane fluctuations of cells on ligand-free fluid membranes. Thus, the same cellular machinery may be responsible for both processes.
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Affiliation(s)
- Kathrin Spendier
- Consortium of the Americas for Interdisciplinary Science, University of New Mexico, Albuquerque, New Mexico
- Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico
| | | | - Keith A. Lidke
- Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico
| | - Bridget S. Wilson
- Departments of Pathology, University of New Mexico, Albuquerque, New Mexico
| | - Jerilyn A. Timlin
- Biofuels and Biodefense Technologies, Sandia National Laboratories, Albuquerque, New Mexico
| | - James L. Thomas
- Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico
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