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Veatch SL, Rogers N, Decker A, Shelby SA. The plasma membrane as an adaptable fluid mosaic. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184114. [PMID: 36581017 PMCID: PMC9922517 DOI: 10.1016/j.bbamem.2022.184114] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/18/2022] [Accepted: 12/20/2022] [Indexed: 12/27/2022]
Abstract
The fluid mosaic model proposed by Singer and Nicolson established a powerful framework to interrogate biological membranes that has stood the test of time. They proposed that the membrane is a simple fluid, meaning that proteins and lipids are randomly distributed over distances larger than those dictated by direct interactions. Here we present an update to this model that describes a spatially adaptable fluid membrane capable of tuning local composition in response to forces originating outside the membrane plane. This revision is rooted in the thermodynamics of lipid mixtures, draws from recent experimental results, and suggests new modes of membrane function.
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Affiliation(s)
- Sarah L Veatch
- Program in Biophysics, University of Michigan, Ann Arbor, MI, USA.
| | - Nat Rogers
- Program in Biophysics, University of Michigan, Ann Arbor, MI, USA
| | - Adam Decker
- Program in Biophysics, University of Michigan, Ann Arbor, MI, USA
| | - Sarah A Shelby
- Program in Biophysics, University of Michigan, Ann Arbor, MI, USA.
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2
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Shelby SA, Shaw TR, Veatch SL. Measuring the Co-Localization and Dynamics of Mobile Proteins in Live Cells Undergoing Signaling Responses. Methods Mol Biol 2023; 2654:1-23. [PMID: 37106172 PMCID: PMC10758997 DOI: 10.1007/978-1-0716-3135-5_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Single molecule imaging in live cells enables the study of protein interactions and dynamics as they participate in signaling processes. When combined with fluorophores that stochastically transition between fluorescent and reversible dark states, as in super-resolution localization imaging, labeled molecules can be visualized in single cells over time. This improvement in sampling enables the study of extended cellular responses at the resolution of single molecule localization. This chapter provides optimized experimental and analytical methods used to quantify protein interactions and dynamics within the membranes of adhered live cells. Importantly, the use of pair-correlation functions resolved in both space and time allows researchers to probe interactions between proteins on biologically relevant distance and timescales, even though fluorescence localization methods typically require long times to assemble well-sampled reconstructed images. We describe an application of this approach to measure protein interactions in B cell receptor signaling and include sample analysis code for post-processing of imaging data. These methods are quantitative, sensitive, and broadly applicable to a range of signaling systems.
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Affiliation(s)
- Sarah A Shelby
- Program in Biophysics, University of Michigan, Ann Arbor, MI, USA
| | - Thomas R Shaw
- Program in Applied Physics, University of Michigan, Ann Arbor, MI, USA
| | - Sarah L Veatch
- Program in Biophysics, University of Michigan, Ann Arbor, MI, USA.
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3
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Carravilla P, Dasgupta A, Zhurgenbayeva G, Danylchuk DI, Klymchenko AS, Sezgin E, Eggeling C. Long-term STED imaging of membrane packing and dynamics by exchangeable polarity-sensitive dyes. BIOPHYSICAL REPORTS 2021; 1:None. [PMID: 34939048 PMCID: PMC8651516 DOI: 10.1016/j.bpr.2021.100023] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/08/2021] [Indexed: 12/28/2022]
Abstract
Understanding the plasma membrane nanoscale organization and dynamics in living cells requires microscopy techniques with high spatial and temporal resolution that permit for long acquisition times and allow for the quantification of membrane biophysical properties, such as lipid ordering. Among the most popular super-resolution techniques, stimulated emission depletion (STED) microscopy offers one of the highest temporal resolutions, ultimately defined by the scanning speed. However, monitoring live processes using STED microscopy is significantly limited by photobleaching, which recently has been circumvented by exchangeable membrane dyes that only temporarily reside in the membrane. Here, we show that NR4A, a polarity-sensitive exchangeable plasma membrane probe based on Nile red, permits the super-resolved quantification of membrane biophysical parameters in real time with high temporal and spatial resolution as well as long acquisition times. The potential of this polarity-sensitive exchangeable dye is showcased by live-cell real-time three-dimensional STED recordings of bleb formation and lipid exchange during membrane fusion as well as by STED-fluorescence correlation spectroscopy experiments for the simultaneous quantification of membrane dynamics and lipid packing that correlate in model and live-cell membranes.
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Affiliation(s)
- Pablo Carravilla
- Leibniz Institute of Photonic Technology e.V., Jena, Germany
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
| | - Anindita Dasgupta
- Leibniz Institute of Photonic Technology e.V., Jena, Germany
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
| | - Gaukhar Zhurgenbayeva
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
- Jena School for Microbial Communication, Friedrich Schiller University Jena, Jena, Germany
| | - Dmytro I. Danylchuk
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Illkirch, France
| | - Andrey S. Klymchenko
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Illkirch, France
| | - Erdinc Sezgin
- Science for Life Laboratory, Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden
| | - Christian Eggeling
- Leibniz Institute of Photonic Technology e.V., Jena, Germany
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
- Jena School for Microbial Communication, Friedrich Schiller University Jena, Jena, Germany
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
- Jena Center for Soft Matter, Jena, Germany
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4
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Lipid-based and protein-based interactions synergize transmembrane signaling stimulated by antigen clustering of IgE receptors. Proc Natl Acad Sci U S A 2021; 118:2026583118. [PMID: 34433665 DOI: 10.1073/pnas.2026583118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Antigen (Ag) crosslinking of immunoglobulin E-receptor (IgE-FcεRI) complexes in mast cells stimulates transmembrane (TM) signaling, requiring phosphorylation of the clustered FcεRI by lipid-anchored Lyn tyrosine kinase. Previous studies showed that this stimulated coupling between Lyn and FcεRI occurs in liquid ordered (Lo)-like nanodomains of the plasma membrane and that Lyn binds directly to cytosolic segments of FcεRI that it initially phosphorylates for amplified activity. Net phosphorylation above a nonfunctional threshold is achieved in the stimulated state but not in the resting state, and current evidence supports the hypothesis that this relies on Ag crosslinking to disrupt a balance between Lyn and tyrosine phosphatase activities. However, the structural interactions that underlie the stimulation process remain poorly defined. This study evaluates the relative contributions and functional importance of different types of interactions leading to suprathreshold phosphorylation of Ag-crosslinked IgE-FcεRI in live rat basophilic leukemia mast cells. Our high-precision diffusion measurements by imaging fluorescence correlation spectroscopy on multiple structural variants of Lyn and other lipid-anchored probes confirm subtle, stimulated stabilization of the Lo-like nanodomains in the membrane inner leaflet and concomitant sharpening of segregation from liquid disordered (Ld)-like regions. With other structural variants, we determine that lipid-based interactions are essential for access by Lyn, leading to phosphorylation of and protein-based binding to clustered FcεRI. By contrast, TM tyrosine phosphatase, PTPα, is excluded from these regions due to its Ld-preference and steric exclusion of TM segments. Overall, we establish a synergy of lipid-based, protein-based, and steric interactions underlying functional TM signaling in mast cells.
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5
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Salter AI, Rajan A, Kennedy JJ, Ivey RG, Shelby SA, Leung I, Templeton ML, Muhunthan V, Voillet V, Sommermeyer D, Whiteaker JR, Gottardo R, Veatch SL, Paulovich AG, Riddell SR. Comparative analysis of TCR and CAR signaling informs CAR designs with superior antigen sensitivity and in vivo function. Sci Signal 2021; 14:14/697/eabe2606. [PMID: 34429382 DOI: 10.1126/scisignal.abe2606] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Chimeric antigen receptor (CAR)-modified T cell therapy is effective in treating lymphomas, leukemias, and multiple myeloma in which the tumor cells express high amounts of target antigen. However, achieving durable remission for these hematological malignancies and extending CAR T cell therapy to patients with solid tumors will require receptors that can recognize and eliminate tumor cells with a low density of target antigen. Although CARs were designed to mimic T cell receptor (TCR) signaling, TCRs are at least 100-fold more sensitive to antigen. To design a CAR with improved antigen sensitivity, we directly compared TCR and CAR signaling in primary human T cells. Global phosphoproteomic analysis revealed that key T cell signaling proteins-such as CD3δ, CD3ε, and CD3γ, which comprise a portion of the T cell co-receptor, as well as the TCR adaptor protein LAT-were either not phosphorylated or were only weakly phosphorylated by CAR stimulation. Modifying a commonplace 4-1BB/CD3ζ CAR sequence to better engage CD3ε and LAT using embedded CD3ε or GRB2 domains resulted in enhanced T cell activation in vitro in settings of a low density of antigen, and improved efficacy in in vivo models of lymphoma, leukemia, and breast cancer. These CARs represent examples of alterations in receptor design that were guided by in-depth interrogation of T cell signaling.
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Affiliation(s)
- Alexander I Salter
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. .,Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Anusha Rajan
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.,Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Jacob J Kennedy
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Richard G Ivey
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Sarah A Shelby
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Isabel Leung
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.,Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Megan L Templeton
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.,Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Vishaka Muhunthan
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.,Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Valentin Voillet
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.,Cape Town HVTN Immunology Laboratory, Hutchinson Centre Research Institute of South Africa, NPC (HCRISA), Cape Town 8001, South Africa
| | - Daniel Sommermeyer
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.,Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Jeffrey R Whiteaker
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Raphael Gottardo
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Sarah L Veatch
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amanda G Paulovich
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Stanley R Riddell
- Program in Immunology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. .,Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.,Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
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6
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Urbančič I, Schiffelers L, Jenkins E, Gong W, Santos AM, Schneider F, O'Brien-Ball C, Vuong MT, Ashman N, Sezgin E, Eggeling C. Aggregation and mobility of membrane proteins interplay with local lipid order in the plasma membrane of T cells. FEBS Lett 2021; 595:2127-2146. [PMID: 34160065 DOI: 10.1002/1873-3468.14153] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/07/2021] [Accepted: 06/18/2021] [Indexed: 01/17/2023]
Abstract
To disentangle the elusive lipid-protein interactions in T-cell activation, we investigate how externally imposed variations in mobility of key membrane proteins (T-cell receptor [TCR], kinase Lck, and phosphatase CD45) affect the local lipid order and protein colocalisation. Using spectral imaging with polarity-sensitive membrane probes in model membranes and live Jurkat T cells, we find that partial immobilisation of proteins (including TCR) by aggregation or ligand binding changes their preference towards a more ordered lipid environment, which can recruit Lck. Our data suggest that the cellular membrane is poised to modulate the frequency of protein encounters upon alterations of their mobility, for example in ligand binding, which offers new mechanistic insight into the involvement of lipid-mediated interactions in membrane-hosted signalling events.
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Affiliation(s)
- Iztok Urbančič
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
- Jožef Stefan Institute, Ljubljana, Slovenia
| | - Lisa Schiffelers
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Edward Jenkins
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Weijian Gong
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Ana Mafalda Santos
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Falk Schneider
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | | | - Mai Tuyet Vuong
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Nicole Ashman
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
| | - Erdinc Sezgin
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
- Science for Life Laboratory, Karolinska Institutet, Solna, Sweden
| | - Christian Eggeling
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, UK
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Jena, Germany
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7
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Abstract
Lateral organization in the plane of the plasma membrane is an important driver of biological processes. The past dozen years have seen increasing experimental support for the notion that lipid organization plays an important role in modulating this heterogeneity. Various biophysical mechanisms rooted in the concept of liquid-liquid phase separation have been proposed to explain diverse experimental observations of heterogeneity in model and cell membranes with distinct but overlapping applicability. In this review, we focus on the evidence for and the consequences of the hypothesis that the plasma membrane is poised near an equilibrium miscibility critical point. Critical phenomena explain certain features of the heterogeneity observed in cells and model systems but also go beyond heterogeneity to predict other interesting phenomena, including responses to perturbations in membrane composition.
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Affiliation(s)
- Thomas R Shaw
- Program in Applied Physics, University of Michigan, Ann Arbor, Michigan 48109, USA;
| | - Subhadip Ghosh
- Program in Biophysics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Sarah L Veatch
- Program in Applied Physics, University of Michigan, Ann Arbor, Michigan 48109, USA; .,Program in Biophysics, University of Michigan, Ann Arbor, Michigan 48109, USA.,Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
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8
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Lamerton RE, Lightfoot A, Nieves DJ, Owen DM. The Role of Protein and Lipid Clustering in Lymphocyte Activation. Front Immunol 2021; 12:600961. [PMID: 33767692 PMCID: PMC7986720 DOI: 10.3389/fimmu.2021.600961] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 02/12/2021] [Indexed: 12/30/2022] Open
Abstract
Lymphocytes must strike a delicate balance between activating in response to signals from potentially pathogenic organisms and avoiding activation from stimuli emanating from the body's own cells. For cells, such as T or B cells, maximizing the efficiency and fidelity, whilst minimizing the crosstalk, of complex signaling pathways is crucial. One way of achieving this control is by carefully orchestrating the spatiotemporal organization of signaling molecules, thereby regulating the rates of protein-protein interactions. This is particularly true at the plasma membrane where proximal signaling events take place and the phenomenon of protein microclustering has been extensively observed and characterized. This review will focus on what is known about the heterogeneous distribution of proteins and lipids at the cell surface, illustrating how such distributions can influence signaling in health and disease. We particularly focus on nanoscale molecular organization, which has recently become accessible for study through advances in microscope technology and analysis methodology.
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Affiliation(s)
- Rachel E Lamerton
- Institute of Immunology and Immunotherapy, School of Mathematics and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, United Kingdom
| | - Abbey Lightfoot
- Institute of Immunology and Immunotherapy, School of Mathematics and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, United Kingdom
| | - Daniel J Nieves
- Institute of Immunology and Immunotherapy, School of Mathematics and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, United Kingdom
| | - Dylan M Owen
- Institute of Immunology and Immunotherapy, School of Mathematics and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, United Kingdom
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9
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Miller EJ, Ratajczak AM, Anthony AA, Mottau M, Rivera Gonzalez XI, Honerkamp-Smith AR. Divide and conquer: How phase separation contributes to lateral transport and organization of membrane proteins and lipids. Chem Phys Lipids 2020; 233:104985. [DOI: 10.1016/j.chemphyslip.2020.104985] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 09/18/2020] [Accepted: 09/28/2020] [Indexed: 01/06/2023]
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