1
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Moura S, Hartl I, Brumovska V, Calabrese PP, Yasari A, Striedner Y, Bishara M, Mair T, Ebner T, Schütz GJ, Sevcsik E, Tiemann-Boege I. Exploring FGFR3 Mutations in the Male Germline: Implications for Clonal Germline Expansions and Paternal Age-Related Dysplasias. Genome Biol Evol 2024; 16:evae015. [PMID: 38411226 PMCID: PMC10898338 DOI: 10.1093/gbe/evae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2024] [Indexed: 02/28/2024] Open
Abstract
Delayed fatherhood results in a higher risk of inheriting a new germline mutation that might result in a congenital disorder in the offspring. In particular, some FGFR3 mutations increase in frequency with age, but there are still a large number of uncharacterized FGFR3 mutations that could be expanding in the male germline with potentially early- or late-onset effects in the offspring. Here, we used digital polymerase chain reaction to assess the frequency and spatial distribution of 10 different FGFR3 missense substitutions in the sexually mature male germline. Our functional assessment of the receptor signaling of the variants with biophysical methods showed that 9 of these variants resulted in a higher activation of the receptor´s downstream signaling, resulting in 2 different expansion behaviors. Variants that form larger subclonal expansions in a dissected postmortem testis also showed a positive correlation of the substitution frequency with the sperm donor's age, and a high and ligand-independent FGFR3 activation. In contrast, variants that measured high FGFR3 signaling and elevated substitution frequencies independent of the donor's age did not result in measurable subclonal expansions in the testis. This suggests that promiscuous signal activation might also result in an accumulation of mutations before the sexual maturation of the male gonad with clones staying relatively constant in size throughout time. Collectively, these results provide novel insights into our understanding of the mutagenesis of driver mutations and their resulting mosaicism in the male germline with important consequences for the transmission and recurrence of associated disorders.
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Affiliation(s)
- Sofia Moura
- Institute of Biophysics, Johannes Kepler University, Linz, Austria
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, USA
| | - Ingrid Hartl
- Institute of Biophysics, Johannes Kepler University, Linz, Austria
| | | | - Peter P Calabrese
- Quantitative and Computational Biology, University of Southern California, Los Angeles, USA
| | - Atena Yasari
- Institute of Biophysics, Johannes Kepler University, Linz, Austria
| | - Yasmin Striedner
- Institute of Biophysics, Johannes Kepler University, Linz, Austria
| | | | - Theresa Mair
- Institute of Biophysics, Johannes Kepler University, Linz, Austria
| | - Thomas Ebner
- Department of Gynecology, Obstetrics and Gynecological Endocrinology, Johannes Kepler University, 4020 Linz, Austria
| | | | - Eva Sevcsik
- Institute of Applied Physics, TU Wien, Vienna, Austria
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2
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Schütz GJ, Pabst G. The asymmetric plasma membrane-A composite material combining different functionalities?: Balancing Barrier Function and Fluidity for Effective Signaling. Bioessays 2023; 45:e2300116. [PMID: 37712937 DOI: 10.1002/bies.202300116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 09/16/2023]
Abstract
One persistent puzzle in the life sciences is the asymmetric lipid composition of the cellular plasma membrane: while the exoplasmic leaflet is enriched in lipids carrying predominantly saturated fatty acids, the cytoplasmic leaflet hosts preferentially lipids with (poly-)unsaturated fatty acids. Given the high energy requirements necessary for cells to maintain this asymmetry, the question naturally arises regarding its inherent benefits. In this paper, we propose asymmetry to represent a potential solution for harmonizing two conflicting requirements for the plasma membrane: first, the need to build a barrier for the uncontrolled influx or efflux of substances; and second, the need to form a fluid and dynamic two-dimensional substrate for signaling processes. We hence view here the plasma membrane as a composite material, where the exoplasmic leaflet is mainly responsible for the functional integrity of the barrier and the cytoplasmic leaflet for fluidity. We reinforce the validity of the proposed mechanism by presenting quantitative data from the literature, along with multiple examples that bolster our model.
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Affiliation(s)
| | - Georg Pabst
- Biophysics, Institute of Molecular Bioscience (IMB), NAWI Graz, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
- Field of Excellence BioHealth-University of Graz, Graz, Austria
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3
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Platzer R, Hellmeier J, Göhring J, Perez ID, Schatzlmaier P, Bodner C, Focke‐Tejkl M, Schütz GJ, Sevcsik E, Stockinger H, Brameshuber M, Huppa JB. Monomeric agonist peptide/MHCII complexes activate T-cells in an autonomous fashion. EMBO Rep 2023; 24:e57842. [PMID: 37768718 PMCID: PMC10626418 DOI: 10.15252/embr.202357842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/04/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Molecular crowding of agonist peptide/MHC class II complexes (pMHCIIs) with structurally similar, yet per se non-stimulatory endogenous pMHCIIs is postulated to sensitize T-cells for the recognition of single antigens on the surface of dendritic cells and B-cells. When testing this premise with the use of advanced live cell microscopy, we observe pMHCIIs as monomeric, randomly distributed entities diffusing rapidly after entering the APC surface. Synaptic TCR engagement of highly abundant endogenous pMHCIIs is low or non-existent and affects neither TCR engagement of rare agonist pMHCII in early and advanced synapses nor agonist-induced TCR-proximal signaling. Our findings highlight the capacity of single freely diffusing agonist pMHCIIs to elicit the full T-cell response in an autonomous and peptide-specific fashion with consequences for adaptive immunity and immunotherapeutic approaches.
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Affiliation(s)
- René Platzer
- Center for Pathophysiology, Infectiology, Immunology, Institute for Hygiene and Applied ImmunologyMedical University of ViennaViennaAustria
| | - Joschka Hellmeier
- TU Wien, Institute of Applied PhysicsViennaAustria
- Present address:
Max Planck Institute of Biochemistry, Molecular Imaging and BionanotechnologyMartinsriedGermany
| | - Janett Göhring
- Center for Pathophysiology, Infectiology, Immunology, Institute for Hygiene and Applied ImmunologyMedical University of ViennaViennaAustria
| | - Iago Doel Perez
- Center for Pathophysiology, Infectiology, Immunology, Institute for Hygiene and Applied ImmunologyMedical University of ViennaViennaAustria
- Present address:
Takeda Manufacturing Austria AGViennaAustria
| | - Philipp Schatzlmaier
- Center for Pathophysiology, Infectiology, Immunology, Institute for Hygiene and Applied ImmunologyMedical University of ViennaViennaAustria
| | - Clara Bodner
- TU Wien, Institute of Applied PhysicsViennaAustria
| | - Margarete Focke‐Tejkl
- Center for Pathophysiology, Infectiology, Immunology, Institute for Pathophysiology and Allergy ResearchMedical University of ViennaViennaAustria
| | | | - Eva Sevcsik
- TU Wien, Institute of Applied PhysicsViennaAustria
| | - Hannes Stockinger
- Center for Pathophysiology, Infectiology, Immunology, Institute for Hygiene and Applied ImmunologyMedical University of ViennaViennaAustria
| | | | - Johannes B Huppa
- Center for Pathophysiology, Infectiology, Immunology, Institute for Hygiene and Applied ImmunologyMedical University of ViennaViennaAustria
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4
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Huppa JB, Schütz GJ. T-cell antigen recognition: catch-as-catch-can or catch-22? EMBO J 2023; 42:e113507. [PMID: 36808636 PMCID: PMC10068317 DOI: 10.15252/embj.2023113507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 02/08/2023] [Indexed: 02/22/2023] Open
Abstract
T-cell antigen recognition is invariably affected by tensile forces as they are exerted on T-cell antigen receptors (TCRs) transiently binding antigenic peptide/MHC complexes. In this issue of The EMBO Journal, Pettmann and colleagues promote the concept that forces reduce the lifetime of more stable stimulatory TCR-pMHC interactions to a larger extent than that of less stable non-stimulatory TCR-pMHC interactions. The authors argue that forces impede rather than boost T-cell antigen discrimination, which is promoted by force-shielding within the immunological synapse through cell adhesion via CD2/CD58 and LFA-1/ICAM-1.
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Affiliation(s)
- Johannes B Huppa
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology, ImmunologyMedical University of ViennaViennaAustria
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5
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Barden M, Holzinger A, Velas L, Mezősi-Csaplár M, Szöőr Á, Vereb G, Schütz GJ, Hombach AA, Abken H. CAR and TCR form individual signaling synapses and do not cross-activate, however, can co-operate in T cell activation. Front Immunol 2023; 14:1110482. [PMID: 36817444 PMCID: PMC9929185 DOI: 10.3389/fimmu.2023.1110482] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 01/17/2023] [Indexed: 02/04/2023] Open
Abstract
In engineered T cells the CAR is co-expressed along with the physiological TCR/CD3 complex, both utilizing the same downstream signaling machinery for T cell activation. It is unresolved whether CAR-mediated T cell activation depends on the presence of the TCR and whether CAR and TCR mutually cross-activate upon engaging their respective antigen. Here we demonstrate that the CD3ζ CAR level was independent of the TCR associated CD3ζ and could not replace CD3ζ to rescue the TCR complex in CD3ζ KO T cells. Upon activation, the CAR did not induce phosphorylation of TCR associated CD3ζ and, vice versa, TCR activation did not induce CAR CD3ζ phosphorylation. Consequently, CAR and TCR did not cross-signal to trigger T cell effector functions. On the membrane level, TCR and CAR formed separate synapses upon antigen engagement as revealed by total internal reflection fluorescence (TIRF) and fast AiryScan microscopy. Upon engaging their respective antigen, however, CAR and TCR could co-operate in triggering effector functions through combinatorial signaling allowing logic "AND" gating in target recognition. Data also imply that tonic TCR signaling can support CAR-mediated T cell activation emphasizing the potential relevance of the endogenous TCR for maintaining T cell capacities in the long-term.
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Affiliation(s)
- Markus Barden
- Leibniz Institute for Immunotherapy (LIT), Division of Genetic Immunotherapy, University Regensburg, Regensburg, Germany
| | - Astrid Holzinger
- Leibniz Institute for Immunotherapy (LIT), Division of Genetic Immunotherapy, University Regensburg, Regensburg, Germany
| | - Lukas Velas
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | - Marianna Mezősi-Csaplár
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Árpád Szöőr
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - György Vereb
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary,ELKH-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | | | - Andreas A. Hombach
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany,Department I Internal Medicine, University Hospital Cologne, Cologne, Germany
| | - Hinrich Abken
- Leibniz Institute for Immunotherapy (LIT), Division of Genetic Immunotherapy, University Regensburg, Regensburg, Germany,*Correspondence: Hinrich Abken,
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6
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Hartl I, Brumovska V, Striedner Y, Yasari A, Schütz GJ, Sevcsik E, Tiemann-Boege I. Measurement of FGFR3 signaling at the cell membrane via total internal reflection fluorescence microscopy to compare the activation of FGFR3 mutants. J Biol Chem 2023; 299:102832. [PMID: 36581204 PMCID: PMC9900515 DOI: 10.1016/j.jbc.2022.102832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 11/24/2022] [Accepted: 11/29/2022] [Indexed: 12/28/2022] Open
Abstract
Fibroblast growth factor receptors (FGFRs) initiate signal transduction via the RAS/mitogen-activated protein kinase pathway by their tyrosine kinase activation known to determine cell growth, tissue differentiation, and apoptosis. Recently, many missense mutations have been reported for FGFR3, but we only know the functional effect for a handful of them. Some mutations result in aberrant FGFR3 signaling and are associated with various genetic disorders and oncogenic conditions. Here, we employed micropatterned surfaces to specifically enrich fluorophore-tagged FGFR3 (monomeric GFP [mGFP]-FGFR3) in certain areas of the plasma membrane of living cells. We quantified receptor activation via total internal reflection fluorescence microscopy of FGFR3 signaling at the cell membrane that captured the recruitment of the downstream signal transducer growth factor receptor-bound 2 (GRB2) tagged with mScarlet (GRB2-mScarlet) to FGFR3 micropatterns. With this system, we tested the activation of FGFR3 upon ligand addition (fgf1 and fgf2) for WT and four FGFR3 mutants associated with congenital disorders (G380R, Y373C, K650Q, and K650E). Our data showed that ligand addition increased GRB2 recruitment to WT FGFR3, with fgf1 having a stronger effect than fgf2. For all mutants, we found an increased basal receptor activity, and only for two of the four mutants (G380R and K650Q), activity was further increased upon ligand addition. Compared with previous reports, two mutant receptors (K650Q and K650E) had either an unexpectedly high or low activation state, respectively. This can be attributed to the different methodology, since micropatterning specifically captures signaling events at the plasma membrane. Collectively, our results provide further insight into the functional effects of mutations to FGFR3.
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Affiliation(s)
- Ingrid Hartl
- Institute of Biophysics, Johannes Kepler University, Linz, Austria
| | | | - Yasmin Striedner
- Institute of Biophysics, Johannes Kepler University, Linz, Austria
| | - Atena Yasari
- Institute of Biophysics, Johannes Kepler University, Linz, Austria
| | | | - Eva Sevcsik
- Insitute of Applied Physics, TU Wien, Vienna, Austria.
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7
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Luethi D, Maier J, Rudin D, Szöllősi D, Angenoorth TJF, Stankovic S, Schittmayer M, Burger I, Yang JW, Jaentsch K, Holy M, Das AK, Brameshuber M, Camacho-Hernandez GA, Casiraghi A, Newman AH, Kudlacek O, Birner-Gruenberger R, Stockner T, Schütz GJ, Sitte HH. Phosphatidylinositol 4,5-bisphosphate (PIP 2) facilitates norepinephrine transporter dimerization and modulates substrate efflux. Commun Biol 2022; 5:1259. [PMID: 36396757 PMCID: PMC9672106 DOI: 10.1038/s42003-022-04210-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 11/01/2022] [Indexed: 11/19/2022] Open
Abstract
The plasmalemmal norepinephrine transporter (NET) regulates cardiovascular sympathetic activity by clearing extracellular norepinephrine in the synaptic cleft. Here, we investigate the subunit stoichiometry and function of NET using single-molecule fluorescence microscopy and flux assays. In particular, we show the effect of phosphatidylinositol 4,5-bisphosphate (PIP2) on NET oligomerization and efflux. NET forms monomers (~60%) and dimers (~40%) at the plasma membrane. PIP2 depletion results in a decrease in the average oligomeric state and decreases NET-mediated substrate efflux while not affecting substrate uptake. Mutation of the putative PIP2 binding residues R121, K334, and R440 to alanines does not affect NET dimerization but results in decreased substrate efflux that is not altered upon PIP2 depletion; this indicates that PIP2 interactions with these residues affect NET-mediated efflux. A dysregulation of norepinephrine and PIP2 signaling have both been implicated in neuropsychiatric and cardiovascular diseases. This study provides evidence that PIP2 directly regulates NET organization and function.
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Affiliation(s)
- Dino Luethi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
- Institute of Applied Physics, TU Wien, Lehargasse 6, 1060, Vienna, Austria
| | - Julian Maier
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Deborah Rudin
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Dániel Szöllősi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Thomas J F Angenoorth
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Stevan Stankovic
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Matthias Schittmayer
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
| | - Isabella Burger
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
| | - Jae-Won Yang
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Kathrin Jaentsch
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Marion Holy
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Anand Kant Das
- Institute of Applied Physics, TU Wien, Lehargasse 6, 1060, Vienna, Austria
- Physics Program, New York University Abu Dhabi, Saadiyat Island, 129188, Abu Dhabi, United Arab Emirates
| | - Mario Brameshuber
- Institute of Applied Physics, TU Wien, Lehargasse 6, 1060, Vienna, Austria
| | - Gisela Andrea Camacho-Hernandez
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, Baltimore, MD, 21224, USA
| | - Andrea Casiraghi
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, Baltimore, MD, 21224, USA
- Department of Pharmaceutical Sciences, University of Milan, Via Luigi Mangiagalli 25, 20133, Milan, Italy
| | - Amy Hauck Newman
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, Baltimore, MD, 21224, USA
| | - Oliver Kudlacek
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Ruth Birner-Gruenberger
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010, Graz, Austria
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Gerhard J Schütz
- Institute of Applied Physics, TU Wien, Lehargasse 6, 1060, Vienna, Austria.
| | - Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria.
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8
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Abstract
Efficient scanning of tissue that T cells encounter during their migratory life is pivotal to protective adaptive immunity. In fact, T cells can detect even a single antigenic peptide/MHC complex (pMHC) among thousands of structurally similar yet non-stimulatory endogenous pMHCs on the surface of antigen-presenting cells (APCs) or target cells. Of note, the glycocalyx of target cells, being composed of proteoglycans and bulky proteins, is bound to affect and even modulate antigen recognition by posing as a physical barrier. T cell-resident microvilli are actin-rich membrane protrusions that puncture through such barriers and thereby actively place the considerably smaller T-cell antigen receptors (TCRs) in close enough proximity to APC-presented pMHCs so that productive interactions may occur efficiently yet under force. We here review our current understanding of how the plasticity of T-cell microvilli and physicochemical properties of the glycocalyx may affect early events in T-cell activation. We assess insights gained from studies on T-cell plasma membrane ultrastructure and provide an update on current efforts to integrate biophysical aspects such as the amplitude and directionality of TCR-imposed mechanical forces and the distribution and lateral mobility of plasma membrane-resident signaling molecules into a more comprehensive view on sensitized T-cell antigen recognition.
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Affiliation(s)
- Janett Göhring
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
- Institute of Applied Physics, TU Wien, Vienna, Austria
- *Correspondence: Janett Göhring,
| | | | | | - Johannes B. Huppa
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
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9
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Luethi D, Schütz GJ, Sitte HH. Single Molecule Analysis Reveals Dimer Formation of the Norepinephrine Transporter at the Plasma Membrane of Live Cells. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r3997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Dino Luethi
- Institute of PharmacologyMedical University of ViennaVienna
- Institute of Applied PhysicsTU WienVienna
- Department of BiomedicineUniversity of BaselBasel
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10
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Hinterer F, Schneider MC, Hubmer S, López-Martinez M, Zelger P, Jesacher A, Ramlau R, Schütz GJ. Robust and bias-free localization of individual fixed dipole emitters achieving the Cramér Rao bound for applications in cryo-single molecule localization microscopy. PLoS One 2022; 17:e0263500. [PMID: 35120171 PMCID: PMC8815875 DOI: 10.1371/journal.pone.0263500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 01/20/2022] [Indexed: 11/18/2022] Open
Abstract
Single molecule localization microscopy (SMLM) has the potential to resolve structural details of biological samples at the nanometer length scale. Compared to room temperature experiments, SMLM performed under cryogenic temperature achieves higher photon yields and, hence, higher localization precision. However, to fully exploit the resolution it is crucial to account for the anisotropic emission characteristics of fluorescence dipole emitters with fixed orientation. In case of slight residual defocus, localization estimates may well be biased by tens of nanometers. We show here that astigmatic imaging in combination with information about the dipole orientation allows to extract the position of the dipole emitters without localization bias and down to a precision of 1 nm, thereby reaching the corresponding Cramér Rao bound. The approach is showcased with simulated data for various dipole orientations, and parameter settings realistic for real life experiments.
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Affiliation(s)
- Fabian Hinterer
- Institute of Industrial Mathematics, Johannes Kepler University Linz, Linz, Austria
| | | | | | | | - Philipp Zelger
- Division for Biomedical Physics, Medical University of Innsbruck, Innsbruck, Austria
| | - Alexander Jesacher
- Division for Biomedical Physics, Medical University of Innsbruck, Innsbruck, Austria
| | - Ronny Ramlau
- Institute of Industrial Mathematics, Johannes Kepler University Linz, Linz, Austria
- Johann Radon Institute Linz, Linz, Austria
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11
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Kopittke C, Hellmeier J, Fölser M, Schrangl L, Schütz GJ, Brameshuber MO. Immuno-modulating effect of temperature on early T cell activation. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.2284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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12
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Velas L, Brameshuber MO, Huppa JB, Kurz E, Dustin ML, Zelger P, Jesacher A, Schütz GJ. 3D superresolution microscopy on the immunological synapse at isotropic precision below 15 nm. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.1347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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13
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Schrangl L, Göhring J, Kellner F, Huppa JB, Schütz GJ. Automated Two-dimensional Spatiotemporal Analysis of Mobile Single-molecule FRET Probes. J Vis Exp 2021. [PMID: 34897275 DOI: 10.3791/63124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Single-molecule Förster resonance energy transfer (smFRET) is a versatile technique reporting on distances in the sub-nanometer to nanometer range. It has been used in a wide range of biophysical and molecular biological experiments, including the measurement of molecular forces, characterization of conformational dynamics of biomolecules, observation of intracellular colocalization of proteins, and determination of receptor-ligand interaction times. In a widefield microscopy configuration, experiments are typically performed using surface-immobilized probes. Here, a method combining single-molecule tracking with alternating excitation (ALEX) smFRET experiments is presented, permitting the acquisition of smFRET time traces of surface-bound, yet mobile probes in plasma membranes or glass-supported lipid bilayers. For the analysis of recorded data, an automated, open-source software collection was developed supporting (i) the localization of fluorescent signals, (ii) single-particle tracking, (iii) determination of FRET-related quantities including correction factors, (iv) stringent verification of smFRET traces, and (v) intuitive presentation of the results. The generated data can conveniently be used as input for further exploration via specialized software, e.g., for the assessment of the diffusional behavior of probes or the investigation of FRET transitions.
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Affiliation(s)
| | - Janett Göhring
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna
| | - Florian Kellner
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna
| | - Johannes B Huppa
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna
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14
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Velas L, Brameshuber M, Huppa JB, Kurz E, Dustin ML, Zelger P, Jesacher A, Schütz GJ. Three-Dimensional Single Molecule Localization Microscopy Reveals the Topography of the Immunological Synapse at Isotropic Precision below 15 nm. Nano Lett 2021; 21:9247-9255. [PMID: 34709845 PMCID: PMC8587899 DOI: 10.1021/acs.nanolett.1c03160] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
T-cells engage with antigen-presenting cells in search for antigenic peptides and form transient interfaces termed immunological synapses. Synapse topography affects receptor binding rates and the mutual segregation of proteins due to size exclusion effects. It is hence important to determine the 3D topography of the immunological synapse at high precision. Current methods provide only rather coarse images of the protein distribution within the synapse. Here, we applied supercritical angle fluorescence microscopy combined with defocused imaging, which allows three-dimensional single molecule localization microscopy (3D-SMLM) at an isotropic localization precision below 15 nm. Experiments were performed on hybrid synapses between primary T-cells and functionalized glass-supported lipid bilayers. We used 3D-SMLM to quantify the cleft size within the synapse by mapping the position of the T-cell receptor (TCR) with respect to the supported lipid bilayer, yielding average distances of 18 nm up to 31 nm for activating and nonactivating bilayers, respectively.
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Affiliation(s)
- Lukas Velas
- Institute
of Applied Physics, TU Wien, 1040 Vienna, Austria
| | | | - Johannes B. Huppa
- Institute
for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology
and Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Elke Kurz
- Kennedy
Institute of Rheumatology, University of
Oxford, OX3 7FY Oxford, United Kingdom
| | - Michael L. Dustin
- Kennedy
Institute of Rheumatology, University of
Oxford, OX3 7FY Oxford, United Kingdom
| | - Philipp Zelger
- Division
for Biomedical Physics, Medical University
of Innsbruck, 6020 Innsbruck, Austria
| | - Alexander Jesacher
- Division
for Biomedical Physics, Medical University
of Innsbruck, 6020 Innsbruck, Austria
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15
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Hellmeier J, Platzer R, Mühlgrabner V, Schneider MC, Kurz E, Schütz GJ, Huppa JB, Sevcsik E. Strategies for the Site-Specific Decoration of DNA Origami Nanostructures with Functionally Intact Proteins. ACS Nano 2021; 15:15057-15068. [PMID: 34463486 PMCID: PMC8482763 DOI: 10.1021/acsnano.1c05411] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
DNA origami structures provide flexible scaffolds for the organization of single biomolecules with nanometer precision. While they find increasing use for a variety of biological applications, the functionalization with proteins at defined stoichiometry, high yield, and under preservation of protein function remains challenging. In this study, we applied single molecule fluorescence microscopy in combination with a cell biological functional assay to systematically evaluate different strategies for the site-specific decoration of DNA origami structures, focusing on efficiency, stoichiometry, and protein functionality. Using an activating ligand of the T-cell receptor (TCR) as the protein of interest, we found that two commonly used methodologies underperformed with regard to stoichiometry and protein functionality. While strategies employing tetravalent wildtype streptavidin for coupling of a biotinylated TCR-ligand yielded mixed populations of DNA origami structures featuring up to three proteins, the use of divalent (dSAv) or DNA-conjugated monovalent streptavidin (mSAv) allowed for site-specific attachment of a single biotinylated TCR-ligand. The most straightforward decoration strategy, via covalent DNA conjugation, resulted in a 3-fold decrease in ligand potency, likely due to charge-mediated impairment of protein function. Replacing DNA with charge-neutral peptide nucleic acid (PNA) in a ligand conjugate emerged as the coupling strategy with the best overall performance in our study, as it produced the highest yield with no multivalent DNA origami structures and fully retained protein functionality. With our study we aim to provide guidelines for the stoichiometrically defined, site-specific functionalization of DNA origami structures with proteins of choice serving a wide range of biological applications.
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Affiliation(s)
| | - René Platzer
- Center
for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University
of Vienna, Vienna, 1090, Austria
| | - Vanessa Mühlgrabner
- Center
for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University
of Vienna, Vienna, 1090, Austria
| | | | - Elke Kurz
- Kennedy
Institute of Rheumatology, University of
Oxford, Oxford, OX3 7FY, U.K.
| | | | - Johannes B. Huppa
- Center
for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University
of Vienna, Vienna, 1090, Austria
| | - Eva Sevcsik
- Institute
of Applied Physics, TU Wien, Vienna, 1060, Austria
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16
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Schromm AB, Paulowski L, Kaconis Y, Kopp F, Koistinen M, Donoghue A, Keese S, Nehls C, Wernecke J, Garidel P, Sevcsik E, Lohner K, Sanchez-Gomez S, Martinez-de-Tejada G, Brandenburg K, Brameshuber M, Schütz GJ, Andrä J, Gutsmann T. Cathelicidin and PMB neutralize endotoxins by multifactorial mechanisms including LPS interaction and targeting of host cell membranes. Proc Natl Acad Sci U S A 2021; 118:e2101721118. [PMID: 34183393 PMCID: PMC8271772 DOI: 10.1073/pnas.2101721118] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Antimicrobial peptides (AMPs) contribute to an effective protection against infections. The antibacterial function of AMPs depends on their interactions with microbial membranes and lipids, such as lipopolysaccharide (LPS; endotoxin). Hyperinflammation induced by endotoxin is a key factor in bacterial sepsis and many other human diseases. Here, we provide a comprehensive profile of peptide-mediated LPS neutralization by systematic analysis of the effects of a set of AMPs and the peptide antibiotic polymyxin B (PMB) on the physicochemistry of endotoxin, macrophage activation, and lethality in mice. Mechanistic studies revealed that the host defense peptide LL-32 and PMB each reduce LPS-mediated activation also via a direct interaction of the peptides with the host cell. As a biophysical basis, we demonstrate modifications of the structure of cholesterol-rich membrane domains and the association of glycosylphosphatidylinositol (GPI)-anchored proteins. Our discovery of a host cell-directed mechanism of immune control contributes an important aspect in the development and therapeutic use of AMPs.
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Affiliation(s)
- Andra B Schromm
- Division of Immunobiophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany;
| | - Laura Paulowski
- Division of Immunobiophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Yani Kaconis
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Franziska Kopp
- Division of Immunobiophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Max Koistinen
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Annemarie Donoghue
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Susanne Keese
- Division of Immunobiophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Christian Nehls
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | - Julia Wernecke
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
- Deutsches Elektronen-Synchrotron, D-22607 Hamburg, Germany
| | - Patrick Garidel
- Biophysikalische Chemie, Martin-Luther-Universität Halle-Wittenberg, D-06108 Halle, Germany
| | - Eva Sevcsik
- Institute of Applied Physics at TU Wien, Vienna 1040, Austria
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, A-8010 Graz, Austria
- BioTechMed-Graz, A-8010 Graz, Austria
| | - Susana Sanchez-Gomez
- Department of Microbiology and Parasitology, University of Navarra, E-31008 Pamplona, Spain
| | - Guillermo Martinez-de-Tejada
- Department of Microbiology and Parasitology, University of Navarra, E-31008 Pamplona, Spain
- Navarra Institute for Health Research, E-31008 Pamplona, Spain
| | - Klaus Brandenburg
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
| | | | | | - Jörg Andrä
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
- Department of Biotechnology, Faculty of Life Sciences, Hamburg University of Applied Sciences, D-21033 Hamburg, Germany
| | - Thomas Gutsmann
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, D-23845 Borstel, Germany
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17
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Camacho-Hernandez GA, Casiraghi A, Rudin D, Luethi D, Ku TC, Guthrie DA, Straniero V, Valoti E, Schütz GJ, Sitte HH, Newman AH. Illuminating the norepinephrine transporter: fluorescent probes based on nisoxetine and talopram. RSC Med Chem 2021; 12:1174-1186. [PMID: 34355183 DOI: 10.1039/d1md00072a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 05/27/2021] [Indexed: 01/30/2023] Open
Abstract
The utilization of fluorescent ligands to study the monoamine transporters (MATs) has increased our knowledge of their function and distribution in live cell systems. In this study, we extend SAR for nisoxetine and talopram as parent compounds, to identify high affinity rhodamine-labeled fluorescent probes for the norepinephrine transporter (NET). Nisoxetine-based fluorescent probe 6 demonstrated high binding affinity (K i = 43 nM) for NET and an overall selectivity compared to the other transporters for dopamine (DAT; K i = 1540 nM) and serotonin (SERT; K i = 785 nM) in competitive radioligand binding assays. Using confocal microscopy, compound 6 was shown to stain both NET and SERT, but not DAT, at low nanomolar concentrations, in transporter-expressing cells.
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Affiliation(s)
- Gisela Andrea Camacho-Hernandez
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institutes of Drug Abuse - Intramural Research Program Baltimore MD 21224 USA
| | - Andrea Casiraghi
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institutes of Drug Abuse - Intramural Research Program Baltimore MD 21224 USA .,Department of Pharmaceutical Sciences, University of Milan Via Mangiagalli 25 20133 Milan Italy
| | - Deborah Rudin
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna Waehringer Strasse 13a 1090 Vienna Austria
| | - Dino Luethi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna Waehringer Strasse 13a 1090 Vienna Austria.,Institute of Applied Physics TU Wien, Lehárgasse 6 1060 Vienna Austria
| | - Therese C Ku
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institutes of Drug Abuse - Intramural Research Program Baltimore MD 21224 USA
| | - Daryl A Guthrie
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institutes of Drug Abuse - Intramural Research Program Baltimore MD 21224 USA
| | - Valentina Straniero
- Department of Pharmaceutical Sciences, University of Milan Via Mangiagalli 25 20133 Milan Italy
| | - Ermanno Valoti
- Department of Pharmaceutical Sciences, University of Milan Via Mangiagalli 25 20133 Milan Italy
| | - Gerhard J Schütz
- Institute of Applied Physics TU Wien, Lehárgasse 6 1060 Vienna Austria
| | - Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna Waehringer Strasse 13a 1090 Vienna Austria
| | - Amy Hauck Newman
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institutes of Drug Abuse - Intramural Research Program Baltimore MD 21224 USA
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18
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Göhring J, Kellner F, Schrangl L, Platzer R, Klotzsch E, Stockinger H, Huppa JB, Schütz GJ. Temporal analysis of T-cell receptor-imposed forces via quantitative single molecule FRET measurements. Nat Commun 2021; 12:2502. [PMID: 33947864 PMCID: PMC8096839 DOI: 10.1038/s41467-021-22775-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 03/25/2021] [Indexed: 02/01/2023] Open
Abstract
Mechanical forces acting on ligand-engaged T-cell receptors (TCRs) have previously been implicated in T-cell antigen recognition, yet their magnitude, spread, and temporal behavior are still poorly defined. We here report a FRET-based sensor equipped either with a TCR-reactive single chain antibody fragment or peptide-loaded MHC, the physiological TCR-ligand. The sensor was tethered to planar glass-supported lipid bilayers (SLBs) and informed most directly on the magnitude and kinetics of TCR-imposed forces at the single molecule level. When confronting T-cells with gel-phase SLBs we observed both prior and upon T-cell activation a single, well-resolvable force-peak of approximately 5 pN and force loading rates on the TCR of 1.5 pN per second. When facing fluid-phase SLBs instead, T-cells still exerted tensile forces yet of threefold reduced magnitude and only prior to but not upon activation.
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Affiliation(s)
- Janett Göhring
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.,Institute of Applied Physics, TU Wien, Vienna, Austria
| | - Florian Kellner
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | | | - René Platzer
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Enrico Klotzsch
- Institute of Applied Physics, TU Wien, Vienna, Austria.,Laboratory of Applied Mechanobiology, Department for Health Sciences and Technology, ETH Zürich, Zürich, Switzerland.,Institute of Biology, Experimental Biophysics/ Mechanobiology, Humboldt Universität zu Berlin, Berlin, Germany
| | - Hannes Stockinger
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Johannes B Huppa
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
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19
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Schneider MC, Telschow R, Mercier G, López-Martinez M, Scherzer O, Schütz GJ. A Workflow for Determining and Sizing Oligomeric Biomolecular Structures with Cryo Single Molecule Localization Microscopy. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.2219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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20
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Zelger P, Bodner L, Offterdinger M, Velas L, Schütz GJ, Jesacher A. Three-dimensional single molecule localization close to the coverslip: a comparison of methods exploiting supercritical angle fluorescence. Biomed Opt Express 2021; 12:802-822. [PMID: 33680543 PMCID: PMC7901312 DOI: 10.1364/boe.413018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/02/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
The precise spatial localization of single molecules in three dimensions is an important basis for single molecule localization microscopy (SMLM) and tracking. At distances up to a few hundred nanometers from the coverslip, evanescent wave coupling into the glass, also known as supercritical angle fluorescence (SAF), can strongly improve the axial precision, thus facilitating almost isotropic localization performance. Specific detection systems, introduced as Supercritical angle localization microscopy (SALM) or Direct optical nanoscopy with axially localized detection (DONALD), have been developed to exploit SAF in modified two-channel imaging schemes. Recently, our group has shown that off-focus microscopy, i.e., imaging at an intentional slight defocus, can perform equally well, but uses only a single detection arm. Here we compare SALM, off-focus imaging and the most commonly used 3D SMLM techniques, namely cylindrical lens and biplane imaging, regarding 3D localization in close proximity to the coverslip. We show that all methods gain from SAF, which leaves a high detection NA as the only major key requirement to unlock the SAF benefit. We find parameter settings for cylindrical lens and biplane imaging for highest z-precision. Further, we compare the methods in view of robustness to aberrations, fixed dipole emission and double-emitter events. We show that biplane imaging provides the best overall performance and support our findings by DNA-PAINT experiments on DNA-nanoruler samples. Our study sheds light on the effects of SAF for SMLM and is helpful for researchers who plan to employ localization-based 3D nanoscopy close to the coverslip.
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Affiliation(s)
- Philipp Zelger
- Division for Biomedical Physics, Medical University of Innsbruck, Müllerstraße 44, 6020 Innsbruck, Austria
| | - Lisa Bodner
- Division for Biomedical Physics, Medical University of Innsbruck, Müllerstraße 44, 6020 Innsbruck, Austria
| | - Martin Offterdinger
- Division of Neurobiochemistry, Biooptics, Medical University of Innsbruck, Innrain 80–82, 6020 Innsbruck, Austria
| | - Lukas Velas
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Gerhard J. Schütz
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Alexander Jesacher
- Division for Biomedical Physics, Medical University of Innsbruck, Müllerstraße 44, 6020 Innsbruck, Austria
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21
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Hellmeier J, Platzer R, Eklund AS, Schlichthaerle T, Karner A, Motsch V, Schneider MC, Kurz E, Bamieh V, Brameshuber M, Preiner J, Jungmann R, Stockinger H, Schütz GJ, Huppa JB, Sevcsik E. DNA origami demonstrate the unique stimulatory power of single pMHCs as T cell antigens. Proc Natl Acad Sci U S A 2021; 118:e2016857118. [PMID: 33468643 PMCID: PMC7848602 DOI: 10.1073/pnas.2016857118] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
T cells detect with their T cell antigen receptors (TCRs) the presence of rare agonist peptide/MHC complexes (pMHCs) on the surface of antigen-presenting cells (APCs). How extracellular ligand binding triggers intracellular signaling is poorly understood, yet spatial antigen arrangement on the APC surface has been suggested to be a critical factor. To examine this, we engineered a biomimetic interface based on laterally mobile functionalized DNA origami platforms, which allow for nanoscale control over ligand distances without interfering with the cell-intrinsic dynamics of receptor clustering. When targeting TCRs via stably binding monovalent antibody fragments, we found the minimum signaling unit promoting efficient T cell activation to consist of two antibody-ligated TCRs within a distance of 20 nm. In contrast, transiently engaging antigenic pMHCs stimulated T cells robustly as well-isolated entities. These results identify pairs of antibody-bound TCRs as minimal receptor entities for effective TCR triggering yet validate the exceptional stimulatory potency of single isolated pMHC molecules.
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Affiliation(s)
| | - Rene Platzer
- Center for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Alexandra S Eklund
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
- Faculty of Physics and Center for Nanoscience, Ludwig Maximilian University, 80539 Munich, Germany
| | - Thomas Schlichthaerle
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
- Faculty of Physics and Center for Nanoscience, Ludwig Maximilian University, 80539 Munich, Germany
| | - Andreas Karner
- University of Applied Sciences Upper Austria, 4020 Linz, Austria
| | | | | | - Elke Kurz
- Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, United Kingdom
| | - Victor Bamieh
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria
| | | | - Johannes Preiner
- University of Applied Sciences Upper Austria, 4020 Linz, Austria
| | - Ralf Jungmann
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
- Faculty of Physics and Center for Nanoscience, Ludwig Maximilian University, 80539 Munich, Germany
| | - Hannes Stockinger
- Center for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | | | - Johannes B Huppa
- Center for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Eva Sevcsik
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria;
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22
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Fölser M, Motsch V, Platzer R, Huppa JB, Schütz GJ. A Multimodal Platform for Simultaneous T-Cell Imaging, Defined Activation, and Mechanobiological Characterization. Cells 2021; 10:235. [PMID: 33504075 PMCID: PMC7910839 DOI: 10.3390/cells10020235] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 11/16/2022] Open
Abstract
T-cell antigen recognition is accompanied by extensive morphological rearrangements of the contact zone between the T-cell and the antigen-presenting cell (APC). This process involves binding of the T-cell receptor (TCR) complex to antigenic peptides presented via MHC on the APC surface, the interaction of costimulatory and adhesion proteins, remodeling of the actin cytoskeleton, and the initiation of downstream signaling processes such as the release of intracellular calcium. However, multiparametric time-resolved analysis of these processes is hampered by the difficulty in recording the different readout modalities at high quality in parallel. In this study, we present a platform for simultaneous quantification of TCR distribution via total internal reflection fluorescence microscopy, of intracellular calcium levels, and of T-cell-exerted forces via atomic force microscopy (AFM). In our method, AFM cantilevers were used to bring single T-cells into contact with the activating surface. We designed the platform specifically to enable the study of T-cell triggering via functionalized fluid-supported lipid bilayers, which represent a widely accepted model system to stimulate T-cells in an antigen-specific manner. In this paper, we showcase the possibilities of this platform using primary transgenic T-cells triggered specifically via their cognate antigen presented by MHCII.
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Affiliation(s)
- Martin Fölser
- Institute of Applied Physics, TU Wien, 1060 Vienna, Austria; (M.F.); (V.M.)
| | - Viktoria Motsch
- Institute of Applied Physics, TU Wien, 1060 Vienna, Austria; (M.F.); (V.M.)
- Institute of Agricultural Engineering, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - René Platzer
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria; (R.P.); (J.B.H.)
| | - Johannes B. Huppa
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria; (R.P.); (J.B.H.)
| | - Gerhard J. Schütz
- Institute of Applied Physics, TU Wien, 1060 Vienna, Austria; (M.F.); (V.M.)
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23
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Aramesh M, Mergenthal S, Issler M, Plochberger B, Weber F, Qin XH, Liska R, Duda GN, Huppa JB, Ries J, Schütz GJ, Klotzsch E. Functionalized Bead Assay to Measure Three-dimensional Traction Forces during T-cell Activation. Nano Lett 2021; 21:507-514. [PMID: 33305952 DOI: 10.1021/acs.nanolett.0c03964] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
When T-cells probe their environment for antigens, the bond between the T-cell receptor (TCR) and the peptide-loaded major histocompatibility complex (MHC) is put under tension, thereby influencing the antigen discrimination. Yet, the quantification of such forces in the context of T-cell signaling is technically challenging. Here, we developed a traction force microscopy platform which allows for quantifying the pulls and pushes exerted via T-cell microvilli, in both tangential and normal directions, during T-cell activation. We immobilized specific T-cell activating antibodies on the marker beads used to read out the hydrogel deformation. Microvilli targeted the functionalized beads, as confirmed by superresolution microscopy of the local actin organization. Moreover, we found that cellular components, such as actin, TCR, and CD45 reorganize upon interaction with the beads, such that actin forms a vortex-like ring structure around the beads and TCR is enriched at the bead surface, whereas CD45 is excluded from bead-microvilli contacts.
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Affiliation(s)
- Morteza Aramesh
- Laboratory of Applied Mechanobiology, Department for Health Sciences and Technology, ETH Zürich, 8093 Zürich, Switzerland
| | - Simon Mergenthal
- Institute of Biology, Experimental Biophysics/Mechanobiology, Humboldt Universität zu Berlin, 10115 Berlin, Germany
| | - Marcel Issler
- Institute of Biology, Experimental Biophysics/Mechanobiology, Humboldt Universität zu Berlin, 10115 Berlin, Germany
| | - Birgit Plochberger
- Upper Austria University of Applied Sciences, Campus Linz, Garnisonstrasse 21, 4020 Linz, Austria
| | - Florian Weber
- Upper Austria University of Applied Sciences, Campus Linz, Garnisonstrasse 21, 4020 Linz, Austria
| | - Xiao-Hua Qin
- Institute for Biomechanics, Department for Health Sciences and Technology, ETH Zürich, 8093 Zürich, Switzerland
| | - Robert Liska
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/163/MC, 1060 Vienna, Austria
| | - Georg N Duda
- Julius Wolff Institute for Biomechanics and Musculoskeletal Regeneration, Charité-Universitätsmedizin, BIH Center for Regenerative Therapies, Berlin Institute of Health, 13353 Berlin, Germany
| | - Johannes B Huppa
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Jonas Ries
- EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | | | - Enrico Klotzsch
- Laboratory of Applied Mechanobiology, Department for Health Sciences and Technology, ETH Zürich, 8093 Zürich, Switzerland
- Institute of Biology, Experimental Biophysics/Mechanobiology, Humboldt Universität zu Berlin, 10115 Berlin, Germany
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24
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Platzer R, Rossboth BK, Schneider MC, Sevcsik E, Baumgart F, Stockinger H, Schütz GJ, Huppa JB, Brameshuber M. Unscrambling fluorophore blinking for comprehensive cluster detection via photoactivated localization microscopy. Nat Commun 2020; 11:4993. [PMID: 33020470 PMCID: PMC7536177 DOI: 10.1038/s41467-020-18726-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 09/10/2020] [Indexed: 12/22/2022] Open
Abstract
Determining nanoscale protein distribution via Photoactivated Localization Microscopy (PALM) mandates precise knowledge of the applied fluorophore's blinking properties to counteract overcounting artifacts that distort the resulting biomolecular distributions. Here, we present a readily applicable methodology to determine, optimize and quantitatively account for the blinking behavior of any PALM-compatible fluorophore. Using a custom-designed platform, we reveal complex blinking of two photoswitchable fluorescence proteins (PS-CFP2 and mEOS3.2) and two photoactivatable organic fluorophores (PA Janelia Fluor 549 and Abberior CAGE 635) with blinking cycles on time scales of several seconds. Incorporating such detailed information in our simulation-based analysis package allows for robust evaluation of molecular clustering based on individually recorded single molecule localization maps.
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Affiliation(s)
- René Platzer
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | | | | | - Eva Sevcsik
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | | | - Hannes Stockinger
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | | | - Johannes B Huppa
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
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25
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Zelger P, Bodner L, Velas L, Schütz GJ, Jesacher A. Erratum: Defocused imaging exploits supercritical-angle fluorescence emission for precise axial single molecule localization microscopy: erratum. Biomed Opt Express 2020; 11:5456-5457. [PMID: 33149962 PMCID: PMC7587250 DOI: 10.1364/boe.408790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Indexed: 06/11/2023]
Abstract
[This corrects the article on p. 775 in vol. 11, PMID: 32206395.].
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Affiliation(s)
- Philipp Zelger
- Division for Biomedical Physics, Medical University of Innsbruck, Müllerstraße 44, 6020 Innsbruck, Austria
| | - Lisa Bodner
- Division for Biomedical Physics, Medical University of Innsbruck, Müllerstraße 44, 6020 Innsbruck, Austria
| | - Lukas Velas
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Gerhard J. Schütz
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Alexander Jesacher
- Division for Biomedical Physics, Medical University of Innsbruck, Müllerstraße 44, 6020 Innsbruck, Austria
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26
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Jayaraman K, Das AK, Luethi D, Szöllősi D, Schütz GJ, Reith MEA, Sitte HH, Stockner T. SLC6 transporter oligomerization. J Neurochem 2020; 157:919-929. [PMID: 32767560 PMCID: PMC8247324 DOI: 10.1111/jnc.15145] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/31/2020] [Accepted: 07/31/2020] [Indexed: 12/18/2022]
Abstract
Transporters of the solute carrier 6 (SLC6) family mediate the reuptake of neurotransmitters such as dopamine, norepinephrine, serotonin, GABA, and glycine. SLC6 family members are 12 transmembrane helix‐spanning proteins that operate using the transmembrane sodium gradient for transport. These transporters assume various quaternary arrangements ranging from monomers to complex stoichiometries with multiple subunits. Dopamine and serotonin transporter oligomerization has been implicated in trafficking of newly formed proteins from the endoplasmic reticulum to the plasma membrane with a pre‐fixed assembly. Once at the plasma membrane, oligomers are kept fixed in their quaternary assembly by interaction with phosphoinositides. While it remains unclear how oligomer formation precisely affects physiological transporter function, it has been shown that oligomerization supports the activity of release‐type psychostimulants. Most recently, single molecule microscopy experiments unveiled that the stoichiometry differs between individual members of the SLC6 family. The present overview summarizes our understanding of the influence of plasma membrane constituents on transporter oligomerization, describes the known interfaces between protomers and discusses open questions. ![]()
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Affiliation(s)
- Kumaresan Jayaraman
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Anand K Das
- Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| | - Dino Luethi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria.,Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| | - Dániel Szöllősi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Gerhard J Schütz
- Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| | - Maarten E A Reith
- Department of Psychiatry, New York University School of Medicine, New York City, NY, USA
| | - Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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27
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Reismann AW, Atanasova L, Zeilinger S, Schütz GJ. Single-Molecule Localization Microscopy to Study Protein Organization in the Filamentous Fungus Trichoderma atroviride. Molecules 2020; 25:E3199. [PMID: 32668792 PMCID: PMC7396978 DOI: 10.3390/molecules25143199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 11/16/2022] Open
Abstract
Single-molecule localization microscopy has boosted our understanding of biological samples by offering access to subdiffraction resolution using fluorescence microscopy methods. While in standard mammalian cells this approach has found wide-spread use, its application to filamentous fungi has been scarce. This is mainly due to experimental challenges that lead to high amounts of background signal because of ample autofluorescence. Here, we report the optimization of labeling, imaging and data analysis protocols to yield the first single-molecule localization microscopy images of the filamentous fungus Trichoderma atroviride. As an example, we show the spatial distribution of the Sur7 tetraspanin-family protein Sfp2 required for hyphal growth and cell wall stability in this mycoparasitic fungus.
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Affiliation(s)
- Alexander W.A.F. Reismann
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060 Vienna, Austria; (A.W.A.F.R.); (L.A.)
| | - Lea Atanasova
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060 Vienna, Austria; (A.W.A.F.R.); (L.A.)
- Department of Microbiology, University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
- Department of Food Science and Technology, University of Natural Resources and Life (BOKU), Muthgasse 18, A-1190 Vienna, Austria
| | - Susanne Zeilinger
- Department of Microbiology, University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorferstrasse 1a, A-1060 Vienna, Austria
| | - Gerhard J. Schütz
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060 Vienna, Austria; (A.W.A.F.R.); (L.A.)
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Arnold AM, Schneider MC, Hüsson C, Sablatnig R, Brameshuber M, Baumgart F, Schütz GJ. Verifying molecular clusters by 2-color localization microscopy and significance testing. Sci Rep 2020; 10:4230. [PMID: 32144344 PMCID: PMC7060173 DOI: 10.1038/s41598-020-60976-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/17/2020] [Indexed: 11/08/2022] Open
Abstract
While single-molecule localization microscopy (SMLM) offers the invaluable prospect to visualize cellular structures below the diffraction limit of light microscopy, its potential has not yet been fully capitalized due to its inherent susceptibility to blinking artifacts. Particularly, overcounting of single molecule localizations has impeded a reliable and sensitive detection of biomolecular nanoclusters. Here we introduce a 2-Color Localization microscopy And Significance Testing Approach (2-CLASTA), providing a parameter-free statistical framework for the qualitative analysis of two-dimensional SMLM data via significance testing methods. 2-CLASTA yields p-values for the null hypothesis of random biomolecular distributions, independent of the blinking behavior of the chosen fluorescent labels. The method is parameter-free and does not require any additional measurements nor grouping of localizations. We validated the method both by computer simulations as well as experimentally, using protein concatemers as a mimicry of biomolecular clustering. As the new approach is not affected by overcounting artifacts, it is able to detect biomolecular clustering of various shapes at high sensitivity down to a level of dimers.
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Affiliation(s)
- Andreas M Arnold
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060, Vienna, Austria
| | | | - Christoph Hüsson
- Institute of Visual Computing and Human-Centered Technology, TU Wien, Favoritenstrasse 9-11, A-1040, Vienna, Austria
| | - Robert Sablatnig
- Institute of Visual Computing and Human-Centered Technology, TU Wien, Favoritenstrasse 9-11, A-1040, Vienna, Austria
| | - Mario Brameshuber
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060, Vienna, Austria
| | - Florian Baumgart
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060, Vienna, Austria.
| | - Gerhard J Schütz
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060, Vienna, Austria.
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29
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Schneider MC, Arnold AM, Baumgart F, Sablatnig R, Hüsson C, Brameshuber MO, Schütz GJ. 2-Color Localization Microscopy and Significance Testing Approach (2-CLASTA). Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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30
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Zelger P, Bodner L, Velas L, Schütz GJ, Jesacher A. Defocused imaging exploits supercritical-angle fluorescence emission for precise axial single molecule localization microscopy. Biomed Opt Express 2020; 11:775-790. [PMID: 32206395 PMCID: PMC7041438 DOI: 10.1364/boe.375678] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 12/11/2019] [Accepted: 12/11/2019] [Indexed: 05/07/2023]
Abstract
Single molecule localization microscopy (SMLM) is one of the key techniques that break the classical resolution limit in optical imaging. It is based on taking multiple recordings of a sample, each showing only a sparse arrangement of spatially well separated fluorescent molecules which can be localized at nanometer precision. While localizing along the lateral directions is usually straightforward, estimating axial positions at a comparable precision is known to be much harder, which is due to the relatively large depth of focus provided by the microscope optics. Whenever a molecule is sufficiently close to the coverslip, it becomes feasible to draw additional information from near field coupling effects: super-critical angle fluorescence (SAF) appears and can be exploited to boost the axial localization precision. Here we propose defocused imaging as a SMLM strategy that is capable of leveraging the information contained in SAF. We show that, regarding axial localization precision, our approach is superior to established SAF-based approaches. At the same time it is simple and can be conducted on any research-grade microscope where controlled defocusing on the order of a few hundred nanometers is possible.
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Affiliation(s)
- Philipp Zelger
- Division for Biomedical Physics, Medical University of Innsbruck, Müllerstraße 44, 6020 Innsbruck, Austria
| | - Lisa Bodner
- Division for Biomedical Physics, Medical University of Innsbruck, Müllerstraße 44, 6020 Innsbruck, Austria
| | - Lukas Velas
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Gerhard J. Schütz
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Alexander Jesacher
- Division for Biomedical Physics, Medical University of Innsbruck, Müllerstraße 44, 6020 Innsbruck, Austria
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31
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Hellmeier JP, Platzer R, Karner A, Motsch V, Bamieh V, Preiner J, Brameshuber MO, Stockinger H, Schütz GJ, Huppa JB, Sevcsik E. Spatial Requirements for T-Cell Receptor Triggering Probed via Functionalized DNA Origami Platforms. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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32
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Velas L, Zelger P, Jesacher A, Brameshuber MO, Schütz GJ. 3D Superresolution Fluorescence Microscopy on T-Cells. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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33
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Bodner C, Brameshuber M, Schütz GJ. Determining the Oligomeric States of a GPI-Anchored Model Protein via Colocalization-Based Single-Molecule Microscopy. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.2685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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34
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Schrangl L, Goehring J, Kellner F, Huppa JB, Schütz GJ. A FRET-based Sensor for Probing Forces Exerted by Single T Cell Receptors on Their Ligands. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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35
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Váradi T, Schneider M, Sevcsik E, Kiesenhofer D, Baumgart F, Batta G, Kovács T, Platzer R, Huppa JB, Szöllősi J, Schütz GJ, Brameshuber M, Nagy P. Homo- and Heteroassociations Drive Activation of ErbB3. Biophys J 2019; 117:1935-1947. [PMID: 31653451 PMCID: PMC7018998 DOI: 10.1016/j.bpj.2019.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 10/01/2019] [Accepted: 10/03/2019] [Indexed: 01/19/2023] Open
Abstract
Dimerization or the formation of higher-order oligomers is required for the activation of ErbB receptor tyrosine kinases. The heregulin (HRG) receptor, ErbB3, must heterodimerize with other members of the family, preferentially ErbB2, to form a functional signal transducing complex. Here, we applied single molecule imaging capable of detecting long-lived and mobile associations to measure their stoichiometry and mobility and analyzed data from experiments globally, taking the different lateral mobility of monomeric and dimeric molecular species into account. Although ErbB3 was largely monomeric in the absence of stimulation and ErbB2 co-expression, a small fraction was present as constitutive homodimers exhibiting a ∼40% lower mobility than monomers. HRG stimulation increased the homodimeric fraction of ErbB3 significantly and reduced the mobility of homodimers fourfold compared to constitutive homodimers. Expression of ErbB2 elevated the homodimeric fraction of ErbB3 even in unstimulated cells and induced a ∼2-fold reduction in the lateral mobility of ErbB3 homodimers. The mobility of ErbB2 was significantly lower than that of ErbB3, and HRG induced a less pronounced decrease in the diffusion coefficient of all ErbB2 molecules and ErbB3/ErbB2 heterodimers than in the mobility of ErbB3. The slower diffusion of ErbB2 compared to ErbB3 was abolished by depolymerizing actin filaments, whereas ErbB2 expression induced a substantial rearrangement of microfilaments, implying a bidirectional interaction between ErbB2 and actin. HRG stimulation of cells co-expressing ErbB3 and ErbB2 led to the formation of ErbB3 homodimers and ErbB3/ErbB2 heterodimers in a competitive fashion. Although pertuzumab, an antibody binding to the dimerization arm of ErbB2, completely abolished the formation of constitutive and HRG-induced ErbB3/ErbB2 heterodimers, it only slightly blocked ErbB3 homodimerization. The results imply that a dynamic equilibrium exists between constitutive and ligand-induced homo- and heterodimers capable of shaping transmembrane signaling.
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Affiliation(s)
- Tímea Váradi
- Institute of Applied Physics, TU Wien, Vienna, Austria; Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | | | - Eva Sevcsik
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | | | | | - Gyula Batta
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Department of Genetics and Applied Microbiology, Faculty of Science of Technology, University of Debrecen, Debrecen, Hungary
| | - Tamás Kovács
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | - René Platzer
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Johannes B Huppa
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - János Szöllősi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; MTA-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | | | | | - Peter Nagy
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
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36
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Das AK, Kudlacek O, Baumgart F, Jaentsch K, Stockner T, Sitte HH, Schütz GJ. Dopamine transporter forms stable dimers in the live cell plasma membrane in a phosphatidylinositol 4,5-bisphosphate-independent manner. J Biol Chem 2019; 294:5632-5642. [PMID: 30705091 PMCID: PMC6462504 DOI: 10.1074/jbc.ra118.006178] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/28/2019] [Indexed: 01/01/2023] Open
Abstract
The human dopamine transporter (hDAT) regulates the level of the neurotransmitter dopamine (DA) in the synaptic cleft and recycles DA for storage in the presynaptic vesicular pool. Many neurotransmitter transporters exist as oligomers, but the physiological role of oligomerization remains unclear; for example, it has been speculated to be a prerequisite for amphetamine-induced release and protein trafficking. Previous studies point to an oligomeric quaternary structure of hDAT; however, the exact stoichiometry and the fraction of co-existing oligomeric states are not known. Here, we used single-molecule brightness analysis to quantify the degree of oligomerization of heterologously expressed hDAT fused to monomeric GFP (mGFP–hDAT) in Chinese hamster ovary (CHO) cells. We observed that monomers and dimers of mGFP–hDAT co-exist and that higher-order molecular complexes of mGFP–hDAT are absent at the plasma membrane. The mGFP–hDAT dimers were stable over several minutes, and the fraction of dimers was independent of the mGFP–hDAT surface density. Furthermore, neither oxidation nor depletion of cholesterol had any effect on the fraction of dimers. Unlike for the human serotonin transporter (hSERT), in which direct binding of phosphatidylinositol 4,5-bisphosphate (PIP2) stabilized the oligomers, the stability of mGFP–hDAT dimers was PIP2 independent.
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Affiliation(s)
- Anand Kant Das
- From the Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060, Vienna and
| | - Oliver Kudlacek
- the Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Waehringerstrasse 13a, A-1090 Vienna, Austria
| | - Florian Baumgart
- From the Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060, Vienna and
| | - Kathrin Jaentsch
- the Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Waehringerstrasse 13a, A-1090 Vienna, Austria
| | - Thomas Stockner
- the Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Waehringerstrasse 13a, A-1090 Vienna, Austria
| | - Harald H Sitte
- the Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Waehringerstrasse 13a, A-1090 Vienna, Austria
| | - Gerhard J Schütz
- From the Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060, Vienna and
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37
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Lindner M, Tresztenyak A, Fülöp G, Jahr W, Prinz A, Prinz I, Danzl JG, Schütz GJ, Sevcsik E. A Fast and Simple Contact Printing Approach to Generate 2D Protein Nanopatterns. Front Chem 2019; 6:655. [PMID: 30733939 PMCID: PMC6353799 DOI: 10.3389/fchem.2018.00655] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 12/17/2018] [Indexed: 01/02/2023] Open
Abstract
Protein micropatterning has become an important tool for many biomedical applications as well as in academic research. Current techniques that allow to reduce the feature size of patterns below 1 μm are, however, often costly and require sophisticated equipment. We present here a straightforward and convenient method to generate highly condensed nanopatterns of proteins without the need for clean room facilities or expensive equipment. Our approach is based on nanocontact printing and allows for the fabrication of protein patterns with feature sizes of 80 nm and periodicities down to 140 nm. This was made possible by the use of the material X-poly(dimethylsiloxane) (X-PDMS) in a two-layer stamp layout for protein printing. In a proof of principle, different proteins at various scales were printed and the pattern quality was evaluated by atomic force microscopy (AFM) and super-resolution fluorescence microscopy.
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Affiliation(s)
- Marco Lindner
- Institute of Applied Physics, TU Wien, Vienna, Austria
- Stratec Consumables GmbH, Anif, Austria
| | | | - Gergö Fülöp
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | - Wiebke Jahr
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | | | - Johann G. Danzl
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | - Eva Sevcsik
- Institute of Applied Physics, TU Wien, Vienna, Austria
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38
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Reismann AWAF, Atanasova L, Schrangl L, Zeilinger S, Schütz GJ. Temporal Filtering to Improve Single Molecule Identification in High Background Samples. Molecules 2018; 23:molecules23123338. [PMID: 30562966 PMCID: PMC6321103 DOI: 10.3390/molecules23123338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 12/06/2018] [Accepted: 12/13/2018] [Indexed: 11/16/2022] Open
Abstract
Single molecule localization microscopy is currently revolutionizing the life sciences as it offers, for the first time, insights into the organization of biological samples below the classical diffraction limit of light microscopy. While there have been numerous examples of new biological findings reported in the last decade, the technique could not reach its full potential due to a set of limitations immanent to the samples themselves. Particularly, high background signals impede the proper performance of most single-molecule identification and localization algorithms. One option is to exploit the characteristic blinking of single molecule signals, which differs substantially from the residual brightness fluctuations of the fluorescence background. To pronounce single molecule signals, we used a temporal high-pass filtering in Fourier space on a pixel-by-pixel basis. We evaluated the performance of temporal filtering by assessing statistical parameters such as true positive rate and false discovery rate. For this, ground truth signals were generated by simulations and overlaid onto experimentally derived movies of samples with high background signals. Compared to the nonfiltered case, we found an improvement of the sensitivity by up to a factor 3.5 while no significant change in the localization accuracy was observable.
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Affiliation(s)
| | - Lea Atanasova
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060 Vienna, Austria.
- Department of Microbiology, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
| | - Lukas Schrangl
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060 Vienna, Austria.
| | - Susanne Zeilinger
- Department of Microbiology, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorferstrasse 1a, A-1060 Vienna, Austria.
| | - Gerhard J Schütz
- Institute of Applied Physics, TU Wien, Getreidemarkt 9, A-1060 Vienna, Austria.
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39
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Hager R, Arnold A, Sevcsik E, Schütz GJ, Howorka S. Tunable DNA Hybridization Enables Spatially and Temporally Controlled Surface-Anchoring of Biomolecular Cargo. Langmuir 2018; 34:15021-15027. [PMID: 30160973 PMCID: PMC6291803 DOI: 10.1021/acs.langmuir.8b01942] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 07/30/2018] [Indexed: 05/04/2023]
Abstract
The controlled immobilization of biomolecules onto surfaces is relevant in biosensing and cell biological research. Spatial control is achieved by surface-tethering molecules in micro- or nanoscale patterns. Yet, there is an increasing demand for temporal control over how long biomolecular cargo stays immobilized until released into the medium. Here, we present a DNA hybridization-based approach to reversibly anchor biomolecular cargo onto micropatterned surfaces. Cargo is linked to a DNA oligonucleotide that hybridizes to a sequence-complementary, surface-tethered strand. The cargo is released from the substrate by the addition of an oligonucleotide that disrupts the duplex interaction via toehold-mediated strand displacement. The unbound tether strand can be reloaded. The generic strategy is implemented with small-molecule or protein cargo, varying DNA sequences, and multiple surface patterning routes. The approach may be used as a tool in biological research to switch membrane proteins from a locally fixed to a free state, or in biosensing to shed biomolecular receptors to regenerate the sensor surface.
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Affiliation(s)
- Roland Hager
- Center
for Advanced Bioanalysis GmbH. Linz, 4020, Austria
| | - Andreas Arnold
- Institute
of Applied Physics, TU Wien, Wien, 1040, Austria
| | - Eva Sevcsik
- Institute
of Applied Physics, TU Wien, Wien, 1040, Austria
| | | | - Stefan Howorka
- Center
for Advanced Bioanalysis GmbH. Linz, 4020, Austria
- Department
of Chemistry, Institute for Structural and Molecular Biology, University College London (UCL), London, WC1E 6BT, U.K.
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Zelger P, Kaser K, Rossboth B, Velas L, Schütz GJ, Jesacher A. Three-dimensional localization microscopy using deep learning. Opt Express 2018; 26:33166-33179. [PMID: 30645473 DOI: 10.1364/oe.26.033166] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 11/11/2018] [Indexed: 05/19/2023]
Abstract
Single molecule localization microscopy (SMLM) is one of the fastest evolving and most broadly used super-resolving imaging techniques in the biosciences. While image recordings could take up to hours only ten years ago, scientists are now reaching for real-time imaging in order to follow the dynamics of biology. To this end, it is crucial to have data processing strategies available that are capable of handling the vast amounts of data produced by the microscope. In this article, we report on the use of a deep convolutional neural network (CNN) for localizing particles in three dimensions on the basis of single images. In test experiments conducted on fluorescent microbeads, we show that the precision obtained with a CNN can be comparable to that of maximum likelihood estimation (MLE), which is the accepted gold standard. Regarding speed, the CNN performs with about 22k localizations per second more than three orders of magnitude faster than the MLE algorithm of ThunderSTORM. If only five parameters are estimated (3D position, signal and background), our CNN implementation is currently slower than the fastest, recently published GPU-based MLE algorithm. However, in this comparison the CNN catches up with every additional parameter, with only a few percent extra time required per additional dimension. Thus it may become feasible to estimate further variables such as molecule orientation, aberration functions or color. We experimentally demonstrate that jointly estimating Zernike mode magnitudes for aberration modeling can significantly improve the accuracy of the estimates.
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Abstract
Superresolution microscopy results have sparked the idea that many membrane proteins are not randomly distributed across the plasma membrane but are instead arranged in nanoclusters. Frequently, these new results seemed to confirm older data based on biochemical and electron microscopy experiments. Recently, however, it was recognized that multiple countings of the very same fluorescently labeled protein molecule can be easily confused with true protein clusters. Various strategies have been developed, which are intended to solve the problem of discriminating true protein clusters from imaging artifacts. We believe that there is currently no perfect algorithm for this problem; instead, different approaches have different strengths and weaknesses. In this review, we discuss single molecule localization microscopy in view of its ability to detect nanoclusters of membrane proteins. To capture the different views on nanoclustering, we chose an unconventional style for this article: we placed its scientific content in the setting of a fictive conference, where five researchers from different fields discuss the problem of detecting and quantifying nanoclusters. Using this style, we feel that the different approaches common for different research areas can be well illustrated. Similarities to a short story by Raymond Carver are not unintentional.
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Plochberger B, Axmann M, Röhrl C, Weghuber J, Brameshuber M, Rossboth BK, Mayr S, Ros R, Bittman R, Stangl H, Schütz GJ. Direct observation of cargo transfer from HDL particles to the plasma membrane. Atherosclerosis 2018; 277:53-59. [PMID: 30173079 DOI: 10.1016/j.atherosclerosis.2018.08.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/02/2018] [Accepted: 08/24/2018] [Indexed: 10/28/2022]
Abstract
BACKGROUND AND AIMS Exchange of cholesterol between high-density lipoprotein (HDL) particles and cells is a key process for maintaining cellular cholesterol homeostasis. Recently, we have shown that amphiphilic cargo derived from HDL can be transferred directly to lipid bilayers. Here we pursued this work using a fluorescence-based method to directly follow cargo transfer from HDL particles to the cell membrane. METHODS HDL was either immobilized on surfaces or added directly to cells, while transfer of fluorescent cargo was visualized via fluorescence imaging. RESULTS In Chinese hamster ovary (CHO) cells expressing the scavenger receptor class B type 1 (SR-B1), transfer of amphiphilic cargo from HDL particles to the plasma membrane was observed immediately after contact, whereas hydrophobic cargo remained associated with the particles; about 60% of the amphiphilic cargo of surface-bound HDL was transferred to the plasma membrane. Essentially no cargo transfer was observed in cells with low endogenous SR-B1 expression. Interestingly, transfer of fluorescently-labeled cholesterol was also facilitated by using an artificial linker to bind HDL to the cell surface. CONCLUSIONS Our data hence indicate that the tethering function of SR-B1 is sufficient for efficient transfer of free cholesterol to the plasma membrane.
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Affiliation(s)
- Birgit Plochberger
- TU Wien, Institute of Applied Physics, Vienna, 1040, Austria; Upper Austria University of Applied Sciences, Campus Linz, Garnisonstrasse 21, 4020, Linz, Austria
| | - Markus Axmann
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Institute of Medical Chemistry, Vienna, 1090, Austria
| | - Clemens Röhrl
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Institute of Medical Chemistry, Vienna, 1090, Austria
| | - Julian Weghuber
- Upper Austria University of Applied Sciences, Campus Wels, Stelzhamerstraße 23, 4600, Wels, Austria
| | | | | | - Sandra Mayr
- Upper Austria University of Applied Sciences, Campus Linz, Garnisonstrasse 21, 4020, Linz, Austria
| | - Robert Ros
- Arizona State University, Department of Physics, Tempe, AZ, 85287-1504, USA
| | - Robert Bittman
- Queens College of the City University of New York, Department of Chemistry and Biochemistry, Flushing, NY, 11367, USA
| | - Herbert Stangl
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Institute of Medical Chemistry, Vienna, 1090, Austria.
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Rossboth B, Arnold AM, Ta H, Platzer R, Kellner F, Huppa JB, Brameshuber M, Baumgart F, Schütz GJ. TCRs are randomly distributed on the plasma membrane of resting antigen-experienced T cells. Nat Immunol 2018; 19:821-827. [PMID: 30013143 PMCID: PMC6071872 DOI: 10.1038/s41590-018-0162-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 06/14/2018] [Indexed: 12/29/2022]
Abstract
The main function of T cells is to identify harmful antigens as quickly and precisely as possible. Super-resolution microscopy data have indicated that global clustering of T cell antigen receptors (TCRs) occurs before T cell activation. Such pre-activation clustering has been interpreted as representing a potential regulatory mechanism that fine tunes the T cell response. We found here that apparent TCR nanoclustering could be attributed to overcounting artifacts inherent to single-molecule-localization microscopy. Using complementary super-resolution approaches and statistical image analysis, we found no indication of global nanoclustering of TCRs on antigen-experienced CD4+ T cells under non-activating conditions. We also used extensive simulations of super-resolution images to provide quantitative limits for the degree of randomness of the TCR distribution. Together our results suggest that the distribution of TCRs on the plasma membrane is optimized for fast recognition of antigen in the first phase of T cell activation.
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Affiliation(s)
| | | | - Haisen Ta
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - René Platzer
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Florian Kellner
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Johannes B Huppa
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
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Fülöp G, Brameshuber M, Arnold AM, Schütz GJ, Sevcsik E. Determination of the Membrane Environment of CD59 in Living Cells. Biomolecules 2018; 8:E28. [PMID: 29772810 PMCID: PMC6023084 DOI: 10.3390/biom8020028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/24/2018] [Accepted: 05/14/2018] [Indexed: 11/24/2022] Open
Abstract
The organization and dynamics of proteins and lipids in the plasma membrane, and their role in membrane functionality, have been subject of a long-lasting debate. Specifically, it is unclear to what extent membrane proteins are affected by their immediate lipid environment and vice versa. Studies on model membranes and plasma membrane vesicles indicated preferences of proteins for lipid phases characterized by different acyl chain order; however, whether such phases do indeed exist in live cells is still not known. Here, we refine a previously developed micropatterning approach combined with single molecule tracking to quantify the influence of the glycosylphosphatidylinositol-anchored (GPI-anchored) protein CD59 on its molecular environment directly in the live cell plasma membrane. We find that locally enriched and immobilized CD59 presents obstacles to the diffusion of fluorescently labeled lipids with a different phase-partitioning behavior independent of cell cholesterol levels and type of lipid. Our results give no evidence for either specific binding of the lipids to CD59 or the existence of nanoscopic ordered membrane regions associated with CD59.
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Affiliation(s)
- Gergő Fülöp
- Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10, Vienna 1040, Austria.
| | - Mario Brameshuber
- Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10, Vienna 1040, Austria.
| | - Andreas M Arnold
- Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10, Vienna 1040, Austria.
| | - Gerhard J Schütz
- Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10, Vienna 1040, Austria.
| | - Eva Sevcsik
- Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10, Vienna 1040, Austria.
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Brameshuber M, Kellner F, Rossboth BK, Ta H, Alge K, Sevcsik E, Göhring J, Axmann M, Baumgart F, Gascoigne NRJ, Davis SJ, Stockinger H, Schütz GJ, Huppa JB. Monomeric TCRs drive T cell antigen recognition. Nat Immunol 2018; 19:487-496. [PMID: 29662172 DOI: 10.1038/s41590-018-0092-4] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 03/15/2018] [Indexed: 11/09/2022]
Abstract
T cell antigen recognition requires T cell antigen receptors (TCRs) engaging MHC-embedded antigenic peptides (pMHCs) within the contact region of a T cell with its conjugated antigen-presenting cell. Despite micromolar TCR:pMHC affinities, T cells respond to even a single antigenic pMHC, and higher-order TCRs have been postulated to maintain high antigen sensitivity and trigger signaling. We interrogated the stoichiometry of TCRs and their associated CD3 subunits on the surface of living T cells through single-molecule brightness and single-molecule coincidence analysis, photon-antibunching-based fluorescence correlation spectroscopy and Förster resonance energy transfer measurements. We found exclusively monomeric TCR-CD3 complexes driving the recognition of antigenic pMHCs, which underscores the exceptional capacity of single TCR-CD3 complexes to elicit robust intracellular signaling.
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Affiliation(s)
| | - Florian Kellner
- Center for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University of Vienna, Vienna, Austria
| | | | - Haisen Ta
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Kevin Alge
- Center for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University of Vienna, Vienna, Austria
| | - Eva Sevcsik
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | - Janett Göhring
- Institute of Applied Physics, TU Wien, Vienna, Austria.,Center for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University of Vienna, Vienna, Austria
| | - Markus Axmann
- Center for Pathobiochemistry and Genetics, Institute of Medical Chemistry and Pathobiochemistry, Medical University of Vienna, Vienna, Austria
| | | | - Nicholas R J Gascoigne
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Simon J Davis
- Radcliffe Department of Medicine and MRC Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Hannes Stockinger
- Center for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University of Vienna, Vienna, Austria
| | | | - Johannes B Huppa
- Center for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University of Vienna, Vienna, Austria.
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Affiliation(s)
- Lukas Schrangl
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8–10, 1040 Wien, Vienna, Austria
| | - Janett Göhring
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Lazarettgasse 19, 1090 Wien, Vienna, Austria
| | - Gerhard J. Schütz
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8–10, 1040 Wien, Vienna, Austria
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Baumgart F, Arnold AM, Schütz GJ. Detection of Small Molecular Complexes at the Plasma Membrane via Temporal Accumulation Analysis. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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48
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Fölser M, Appenroth J, Motsch V, Schütz GJ. Contribution of Adhesion to Early T Cell Signaling. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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49
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Baumgart F, Rossboth BK, Arnold AM, Brameshuber M, Ta H, Platzer R, Huppa JB, Schütz GJ. Superresolution Microscopy of the T Cell Receptor in the Immunological Synapse. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.2923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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50
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Plochberger B, Axmann M, Sezgin E, Preiner J, Karner A, Röhrl C, Brodesser MD, Eggeling C, Schütz GJ, Stangl H. Direct Visualization of Lipoprotein Mediated Cholesterol Transport at the Phospholipid Bilayer Interface. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.1939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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