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Dean WF, Albert RM, Nawara TJ, Ubil M, Beggs RR, Mattheyses AL. Dsg2 ectodomain organization increases throughout desmosome assembly. Cell Adh Migr 2024; 18:1-13. [PMID: 38566311 PMCID: PMC10993919 DOI: 10.1080/19336918.2024.2333366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 03/18/2024] [Indexed: 04/04/2024] Open
Abstract
Desmosomes are intercellular junctions that regulate mechanical integrity in epithelia and cardiac muscle. Dynamic desmosome remodeling is essential for wound healing and development, yet the mechanisms governing junction assembly remain elusive. While we and others have shown that cadherin ectodomains are highly organized, how this ordered architecture emerges during assembly is unknown. Using fluorescence polarization microscopy, we show that desmoglein 2 (Dsg2) ectodomain order gradually increases during 8 h of assembly, coinciding with increasing adhesive strength. In a scratch wound assay, we observed a similar increase in order in desmosomes assembling at the leading edge of migratory cells. Together, our findings indicate that cadherin organization is a hallmark of desmosome maturity and may play a role in conferring adhesive strength.
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Affiliation(s)
- William F. Dean
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Rose M. Albert
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tomasz J. Nawara
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Melanie Ubil
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Reena R. Beggs
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alexa L. Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
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2
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Zimmer SE, Giang W, Levental I, Kowalczyk AP. The transmembrane domain of the desmosomal cadherin desmoglein-1 governs lipid raft association to promote desmosome adhesive strength. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.24.590936. [PMID: 38712246 PMCID: PMC11071526 DOI: 10.1101/2024.04.24.590936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Cholesterol- and sphingolipid-enriched domains called lipid rafts are hypothesized to selectively coordinate protein complex assembly within the plasma membrane to regulate cellular functions. Desmosomes are mechanically resilient adhesive junctions that associate with lipid raft membrane domains, yet the mechanisms directing raft association of the desmosomal proteins, particularly the transmembrane desmosomal cadherins, are poorly understood. We identified the desmoglein-1 (DSG1) transmembrane domain (TMD) as a key determinant of desmoglein lipid raft association and designed a panel of DSG1 TMD variants to assess the contribution of TMD physicochemical properties (length, bulkiness, and palmitoylation) to DSG1 lipid raft association. Sucrose gradient fractionations revealed that TMD length and bulkiness, but not palmitoylation, govern DSG1 lipid raft association. Further, DSG1 raft association determines plakoglobin recruitment to raft domains. Super-resolution imaging and functional assays uncovered a strong relationship between the efficiency of DSG1 TMD lipid raft association and the formation of morphologically and functionally robust desmosomes. Lipid raft association regulated both desmosome assembly dynamics and DSG1 cell surface stability, indicating that DSG1 lipid raft association is required for both desmosome formation and maintenance. These studies identify the biophysical properties of desmoglein transmembrane domains as key determinants of lipid raft association and desmosome adhesive function.
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3
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Steinert L, Fuchs M, Sigmund AM, Didona D, Hudemann C, Möbs C, Hertl M, Hashimoto T, Waschke J, Vielmuth F. Desmosomal Hyper-adhesion Affects Direct Inhibition of Desmoglein Interactions in Pemphigus. J Invest Dermatol 2024:S0022-202X(24)00308-7. [PMID: 38677661 DOI: 10.1016/j.jid.2024.03.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/06/2024] [Accepted: 03/02/2024] [Indexed: 04/29/2024]
Abstract
During differentiation, keratinocytes acquire a strong, hyper-adhesive state, where desmosomal cadherins interact calcium ion independently. Previous data indicate that hyper-adhesion protects keratinocytes from pemphigus vulgaris autoantibody-induced loss of intercellular adhesion, although the underlying mechanism remains to be elucidated. Thus, in this study, we investigated the effect of hyper-adhesion on pemphigus vulgaris autoantibody-induced direct inhibition of desmoglein (DSG) 3 interactions by atomic force microscopy. Hyper-adhesion abolished loss of intercellular adhesion and corresponding morphological changes of all pathogenic antibodies used. Pemphigus autoantibodies putatively targeting several parts of the DSG3 extracellular domain and 2G4, targeting a membrane-proximal domain of DSG3, induced direct inhibition of DSG3 interactions only in non-hyper-adhesive keratinocytes. In contrast, AK23, targeting the N-terminal extracellular domain 1 of DSG3, caused direct inhibition under both adhesive states. However, antibody binding to desmosomal cadherins was not different between the distinct pathogenic antibodies used and was not changed during acquisition of hyper-adhesion. In addition, heterophilic DSC3-DSG3 and DSG2-DSG3 interactions did not cause reduced susceptibility to direct inhibition under hyper-adhesive condition in wild-type keratinocytes. Taken together, the data suggest that hyper-adhesion reduces susceptibility to autoantibody-induced direct inhibition in dependency on autoantibody-targeted extracellular domain but also demonstrate that further mechanisms are required for the protective effect of desmosomal hyper-adhesion in pemphigus vulgaris.
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Affiliation(s)
- Letyfee Steinert
- Vegetative Anatomy, Institute of Anatomy, Faculty of Medicine, Ludwig Maximilian University of Munich, Munich, Germany
| | - Michael Fuchs
- Vegetative Anatomy, Institute of Anatomy, Faculty of Medicine, Ludwig Maximilian University of Munich, Munich, Germany
| | - Anna M Sigmund
- Vegetative Anatomy, Institute of Anatomy, Faculty of Medicine, Ludwig Maximilian University of Munich, Munich, Germany
| | - Dario Didona
- Department of Dermatology and Allergology, Philipps-Universität Marburg, Marburg, Germany
| | - Christoph Hudemann
- Department of Dermatology and Allergology, Philipps-Universität Marburg, Marburg, Germany
| | - Christian Möbs
- Department of Dermatology and Allergology, Philipps-Universität Marburg, Marburg, Germany
| | - Michael Hertl
- Department of Dermatology and Allergology, Philipps-Universität Marburg, Marburg, Germany
| | - Takashi Hashimoto
- Department of Dermatology, Graduate School of Medicine, Osaka City Metropolitan University, Osaka, Japan
| | - Jens Waschke
- Vegetative Anatomy, Institute of Anatomy, Faculty of Medicine, Ludwig Maximilian University of Munich, Munich, Germany
| | - Franziska Vielmuth
- Vegetative Anatomy, Institute of Anatomy, Faculty of Medicine, Ludwig Maximilian University of Munich, Munich, Germany.
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4
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Dean WF, Mattheyses AL. Defining domain-specific orientational order in the desmosomal cadherins. Biophys J 2022; 121:4325-4341. [PMID: 36225113 PMCID: PMC9703042 DOI: 10.1016/j.bpj.2022.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 09/12/2022] [Accepted: 10/06/2022] [Indexed: 01/25/2023] Open
Abstract
Desmosomes are large, macromolecular protein assemblies that mechanically couple the intermediate filament cytoskeleton to sites of cadherin-mediated cell adhesion, thereby providing structural integrity to tissues that routinely experience large forces. Proper desmosomal adhesion is necessary for the normal development and maintenance of vertebrate tissues, such as epithelia and cardiac muscle, while dysfunction can lead to severe disease of the heart and skin. Therefore, it is important to understand the relationship between desmosomal adhesion and the architecture of the molecules that form the adhesive interface, the desmosomal cadherins (DCs). However, desmosomes are embedded in two plasma membranes and are linked to the cytoskeletal networks of two cells, imposing extreme difficulty on traditional structural studies of DC architecture, which have yielded conflicting results. Consequently, the relationship between DC architecture and adhesive function remains unclear. To overcome these challenges, we utilized excitation-resolved fluorescence polarization microscopy to quantify the orientational order of the extracellular and intracellular domains of three DC isoforms: desmoglein 2, desmocollin 2, and desmoglein 3. We found that DC ectodomains were significantly more ordered than their cytoplasmic counterparts, indicating a drastic difference in DC architecture between opposing sides of the plasma membrane. This difference was conserved among all DCs tested, suggesting that it may be an important feature of desmosomal architecture. Moreover, our findings suggest that the organization of DC ectodomains is predominantly the result of extracellular adhesive interactions. We employed azimuthal orientation mapping to show that DC ectodomains are arranged with rotational symmetry about the membrane normal. Finally, we performed a series of mathematical simulations to test the feasibility of a recently proposed antiparallel arrangement of DC ectodomains, finding that it is supported by our experimental data. Importantly, the strategies employed here have the potential to elucidate molecular mechanisms for diseases that result from defective desmosome architecture.
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Affiliation(s)
- William F Dean
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Alexa L Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama.
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5
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Pitfalls in the Application of Dispase-Based Keratinocyte Dissociation Assay for In Vitro Analysis of Pemphigus Vulgaris. Vaccines (Basel) 2022; 10:vaccines10020208. [PMID: 35214667 PMCID: PMC8878461 DOI: 10.3390/vaccines10020208] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/23/2022] [Accepted: 01/26/2022] [Indexed: 12/12/2022] Open
Abstract
Pemphigus vulgaris (PV) is a chronic, life-altering autoimmune disease due to the production of anti-desmoglein antibodies causing the loss of cell–cell adhesion in keratinocytes (acantholysis) and blister formation in both skin and mucous membranes. The dispase-based keratinocyte dissociation assay (DDA) is the method of choice to examine the pathogenic effect of antibodies and additional co-stimuli on cell adhesion in vitro. Despite its widespread use, there is a high variability of experimental conditions, leading to inconsistent results. In this paper, we identify and discuss pitfalls in the application of DDA, including generation of a monolayer with optimized density, appropriate culturing conditions to obtain said monolayer, application of mechanical stress in a standardized manner, and performing consistent data processing. Importantly, we describe a detailed protocol for a successful and reliable DDA and the respective ideal conditions for three different types of human keratinocytes: (1) primary keratinocytes, (2) the HaCaT spontaneously immortalized keratinocyte cell line, and (3) the recently characterized HaSKpw spontaneously immortalized keratinocyte cell line. Our study provides detailed protocols which guarantee intra- and inter-experimental comparability of DDA.
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6
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Fülle JB, Huppert H, Liebl D, Liu J, Alves de Almeida R, Yanes B, Wright GD, Lane EB, Garrod DR, Ballestrem C. Desmosome dualism - most of the junction is stable, but a plakophilin moiety is persistently dynamic. J Cell Sci 2021; 134:272445. [PMID: 34635908 DOI: 10.1242/jcs.258906] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 10/05/2021] [Indexed: 01/06/2023] Open
Abstract
Desmosomes, strong cell-cell junctions of epithelia and cardiac muscle, link intermediate filaments to cell membranes and mechanically integrate cells across tissues, dissipating mechanical stress. They comprise five major protein classes - desmocollins and desmogleins (the desmosomal cadherins), plakoglobin, plakophilins and desmoplakin - whose individual contribution to the structure and turnover of desmosomes is poorly understood. Using live-cell imaging together with fluorescence recovery after photobleaching (FRAP) and fluorescence loss and localisation after photobleaching (FLAP), we show that desmosomes consist of two contrasting protein moieties or modules: a very stable moiety of desmosomal cadherins, desmoplakin and plakoglobin, and a highly mobile plakophilin (Pkp2a). As desmosomes mature from Ca2+ dependence to Ca2+-independent hyper-adhesion, their stability increases, but Pkp2a remains highly mobile. We show that desmosome downregulation during growth-factor-induced cell scattering proceeds by internalisation of whole desmosomes, which still retain a stable moiety and highly mobile Pkp2a. This molecular mobility of Pkp2a suggests a transient and probably regulatory role for Pkp2a in desmosomes. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Judith B Fülle
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, UK.,Skin Research Institute of Singapore, Agency of Science Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, 138648 Singapore, Singapore
| | - Henri Huppert
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, UK.,Institute of Medical Biology, Agency of Science Technology and Research (A*STAR), 61 Biopolis Dr, 138673 Singapore, Singapore
| | - David Liebl
- A*STAR Microscopy Platform, Research Support Centre, Agency of Science Technology and Research (A*STAR), Biopolis 138673 Singapore, Singapore
| | - Jaron Liu
- Institute of Medical Biology, Agency of Science Technology and Research (A*STAR), 61 Biopolis Dr, 138673 Singapore, Singapore
| | - Rogerio Alves de Almeida
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, UK
| | - Bian Yanes
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, UK
| | - Graham D Wright
- Skin Research Institute of Singapore, Agency of Science Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, 138648 Singapore, Singapore.,A*STAR Microscopy Platform, Research Support Centre, Agency of Science Technology and Research (A*STAR), Biopolis 138673 Singapore, Singapore
| | - E Birgitte Lane
- Skin Research Institute of Singapore, Agency of Science Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, 138648 Singapore, Singapore
| | - David R Garrod
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, UK
| | - Christoph Ballestrem
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9PT, UK
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7
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Blanchard A, Combs JD, Brockman JM, Kellner AV, Glazier R, Su H, Bender RL, Bazrafshan AS, Chen W, Quach ME, Li R, Mattheyses AL, Salaita K. Turn-key mapping of cell receptor force orientation and magnitude using a commercial structured illumination microscope. Nat Commun 2021; 12:4693. [PMID: 34344862 PMCID: PMC8333341 DOI: 10.1038/s41467-021-24602-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 06/22/2021] [Indexed: 02/07/2023] Open
Abstract
Many cellular processes, including cell division, development, and cell migration require spatially and temporally coordinated forces transduced by cell-surface receptors. Nucleic acid-based molecular tension probes allow one to visualize the piconewton (pN) forces applied by these receptors. Building on this technology, we recently developed molecular force microscopy (MFM) which uses fluorescence polarization to map receptor force orientation with diffraction-limited resolution (~250 nm). Here, we show that structured illumination microscopy (SIM), a super-resolution technique, can be used to perform super-resolution MFM. Using SIM-MFM, we generate the highest resolution maps of both the magnitude and orientation of the pN traction forces applied by cells. We apply SIM-MFM to map platelet and fibroblast integrin forces, as well as T cell receptor forces. Using SIM-MFM, we show that platelet traction force alignment occurs on a longer timescale than adhesion. Importantly, SIM-MFM can be implemented on any standard SIM microscope without hardware modifications.
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Affiliation(s)
- Aaron Blanchard
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - J Dale Combs
- Department of Chemistry, Emory University, Atlanta, GA, USA
| | - Joshua M Brockman
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Anna V Kellner
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Roxanne Glazier
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Hanquan Su
- Department of Chemistry, Emory University, Atlanta, GA, USA
| | | | | | - Wenchun Chen
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - M Edward Quach
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, USA
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Alexa L Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Khalid Salaita
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
- Department of Chemistry, Emory University, Atlanta, GA, USA.
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8
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Bartle EI, Rao TC, Beggs RR, Dean WF, Urner TM, Kowalczyk AP, Mattheyses AL. Protein exchange is reduced in calcium-independent epithelial junctions. J Cell Biol 2020; 219:151763. [PMID: 32399559 PMCID: PMC7265307 DOI: 10.1083/jcb.201906153] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 01/29/2020] [Accepted: 03/11/2020] [Indexed: 12/29/2022] Open
Abstract
Desmosomes are cell–cell junctions that provide mechanical integrity to epithelial and cardiac tissues. Desmosomes have two distinct adhesive states, calcium-dependent and hyperadhesive, which balance tissue plasticity and strength. A highly ordered array of cadherins in the adhesive interface is hypothesized to drive hyperadhesion, but how desmosome structure confers adhesive state is still elusive. We employed fluorescence polarization microscopy to show that cadherin order is not required for hyperadhesion induced by pharmacologic and genetic approaches. FRAP experiments in cells treated with the PKCα inhibitor Gö6976 revealed that cadherins, plakoglobin, and desmoplakin have significantly reduced exchange in and out of hyperadhesive desmosomes. To test whether this was a result of enhanced keratin association, we used the desmoplakin mutant S2849G, which conferred reduced protein exchange. We propose that inside-out regulation of protein exchange modulates adhesive function, whereby proteins are “locked in” to hyperadhesive desmosomes while protein exchange confers plasticity on calcium-dependent desmosomes, thereby providing rapid control of adhesion.
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Affiliation(s)
- Emily I Bartle
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL
| | - Tejeshwar C Rao
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL
| | - Reena R Beggs
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL
| | - William F Dean
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL
| | - Tara M Urner
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL
| | - Andrew P Kowalczyk
- Departments of Cell Biology and Dermatology, Emory University, Atlanta, GA
| | - Alexa L Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL
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9
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Zimmer SE, Kowalczyk AP. The desmosome as a model for lipid raft driven membrane domain organization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183329. [PMID: 32376221 DOI: 10.1016/j.bbamem.2020.183329] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/20/2020] [Accepted: 04/23/2020] [Indexed: 01/14/2023]
Abstract
Desmosomes are cadherin-based adhesion structures that mechanically couple the intermediate filament cytoskeleton of adjacent cells to confer mechanical stress resistance to tissues. We have recently described desmosomes as mesoscale lipid raft membrane domains that depend on raft dynamics for assembly, function, and disassembly. Lipid raft microdomains are regions of the plasma membrane enriched in sphingolipids and cholesterol. These domains participate in membrane domain heterogeneity, signaling and membrane trafficking. Cellular structures known to be dependent on raft dynamics include the post-synaptic density in neurons, the immunological synapse, and intercellular junctions, including desmosomes. In this review, we discuss the current state of the desmosome field and put forward new hypotheses for the role of lipid rafts in desmosome adhesion, signaling and epidermal homeostasis. Furthermore, we propose that differential lipid raft affinity of intercellular junction proteins is a central driving force in the organization of the epithelial apical junctional complex.
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Affiliation(s)
- Stephanie E Zimmer
- Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University, Atlanta, GA 30322, United States of America; Department of Cell Biology, Emory University, Atlanta, GA 30322, United States of America
| | - Andrew P Kowalczyk
- Department of Cell Biology, Emory University, Atlanta, GA 30322, United States of America; Department of Dermatology, Emory University, Atlanta, GA 30322, United States of America.
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10
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Blanchard AT, Brockman JM, Salaita K, Mattheyses AL. Variable incidence angle linear dichroism (VALiD): a technique for unique 3D orientation measurement of fluorescent ensembles. OPTICS EXPRESS 2020; 28:10039-10061. [PMID: 32225599 PMCID: PMC7340377 DOI: 10.1364/oe.381676] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/10/2020] [Accepted: 01/13/2020] [Indexed: 06/02/2023]
Abstract
A fundamental challenge with fluorophore orientation measurement is degeneracy, which is the inability to distinguish between multiple unique fluorophore orientations. Techniques exist for the non-degenerate measurement of the orientations of single, static fluorophores. However, such techniques are unsuitable for densely labeled and/or dynamic samples common to biological research. Accordingly, a rapid, widefield microscopy technique that can measure orientation parameters for ensembles of fluorophores in a non-degenerate manner is desirable. We propose that exciting samples with polarized light and multiple incidence angles could enable such a technique. We use Monte Carlo simulations to validate this approach for specific axially symmetric ensembles of fluorophores and obtain optimal experimental parameters for its future implementation.
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Affiliation(s)
- Aaron T. Blanchard
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30322, USA
| | - Joshua M. Brockman
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30322, USA
| | - Khalid Salaita
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30322, USA
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
| | - Alexa L. Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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