1
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Recouvreux P, Pai P, Dunsing V, Torro R, Ludanyi M, Mélénec P, Boughzala M, Bertrand V, Lenne PF. Transfer of polarity information via diffusion of Wnt ligands in C. elegans embryos. Curr Biol 2024; 34:1853-1865.e6. [PMID: 38604167 DOI: 10.1016/j.cub.2024.03.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 10/26/2023] [Accepted: 03/18/2024] [Indexed: 04/13/2024]
Abstract
Different signaling mechanisms concur to ensure robust tissue patterning and cell fate instruction during animal development. Most of these mechanisms rely on signaling proteins that are produced, transported, and detected. The spatiotemporal dynamics of signaling molecules are largely unknown, yet they determine signal activity's spatial range and time frame. Here, we use the Caenorhabditis elegans embryo to study how Wnt ligands, an evolutionarily conserved family of signaling proteins, dynamically organize to establish cell polarity in a developing tissue. We identify how Wnt ligands, produced in the posterior half of the embryos, spread extracellularly to transmit information to distant target cells in the anterior half. With quantitative live imaging and fluorescence correlation spectroscopy, we show that Wnt ligands diffuse through the embryo over a timescale shorter than the cell cycle, in the intercellular space, and outside the tissue below the eggshell. We extracted diffusion coefficients of Wnt ligands and their receptor Frizzled and characterized their co-localization. Integrating our different measurements and observations in a simple computational framework, we show how fast diffusion in the embryo can polarize individual cells through a time integration of the arrival of the ligands at the target cells. The polarity established at the tissue level by a posterior Wnt source can be transferred to the cellular level. Our results support a diffusion-based long-range Wnt signaling, which is consistent with the dynamics of developing processes.
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Affiliation(s)
- Pierre Recouvreux
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France.
| | - Pritha Pai
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
| | - Valentin Dunsing
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
| | - Rémy Torro
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
| | - Monika Ludanyi
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
| | - Pauline Mélénec
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
| | - Mariem Boughzala
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
| | - Vincent Bertrand
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
| | - Pierre-François Lenne
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
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2
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Ashby G, Keng KE, Hayden CC, Gollapudi S, Houser JR, Jamal S, Stachowiak JC. Selective Endocytic Uptake of Targeted Liposomes Occurs within a Narrow Range of Liposome Diameters. ACS APPLIED MATERIALS & INTERFACES 2023; 15:49988-50001. [PMID: 37862704 PMCID: PMC11165932 DOI: 10.1021/acsami.3c09399] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2023]
Abstract
Cell surface receptors facilitate signaling and nutrient uptake. These processes are dynamic, requiring receptors to be actively recycled by endocytosis. Due to their differential expression in disease states, receptors are often the target of drug-carrier particles, which are adorned with ligands that bind specifically to receptors. These targeted particles are taken into the cell by multiple routes of internalization, where the best-characterized pathway is clathrin-mediated endocytosis. Most studies of particle uptake have utilized bulk assays rather than observing individual endocytic events. As a result, the detailed mechanisms of particle uptake remain obscure. To address this gap, we employed a live-cell imaging approach to study the uptake of individual liposomes as they interact with clathrin-coated structures. By tracking individual internalization events, we find that the size of liposomes rather than the density of the ligands on their surfaces primarily determines their probability of uptake. Interestingly, targeting has the greatest impact on endocytosis of liposomes of intermediate diameters, with the smallest and largest liposomes being internalized or excluded, respectively, regardless of whether they are targeted. These findings, which highlight a previously unexplored limitation of targeted delivery, can be used to design more effective drug carriers.
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Affiliation(s)
- Grant Ashby
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
| | - Kayla E. Keng
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
| | - Carl C. Hayden
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
| | - Sadhana Gollapudi
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
| | - Justin R. Houser
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
| | - Sabah Jamal
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
| | - Jeanne C. Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, 78712, United States of America
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3
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Harish RK, Gupta M, Zöller D, Hartmann H, Gheisari A, Machate A, Hans S, Brand M. Real-time monitoring of an endogenous Fgf8a gradient attests to its role as a morphogen during zebrafish gastrulation. Development 2023; 150:dev201559. [PMID: 37665167 PMCID: PMC10565248 DOI: 10.1242/dev.201559] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 08/29/2023] [Indexed: 09/05/2023]
Abstract
Morphogen gradients impart positional information to cells in a homogenous tissue field. Fgf8a, a highly conserved growth factor, has been proposed to act as a morphogen during zebrafish gastrulation. However, technical limitations have so far prevented direct visualization of the endogenous Fgf8a gradient and confirmation of its morphogenic activity. Here, we monitor Fgf8a propagation in the developing neural plate using a CRISPR/Cas9-mediated EGFP knock-in at the endogenous fgf8a locus. By combining sensitive imaging with single-molecule fluorescence correlation spectroscopy, we demonstrate that Fgf8a, which is produced at the embryonic margin, propagates by diffusion through the extracellular space and forms a graded distribution towards the animal pole. Overlaying the Fgf8a gradient curve with expression profiles of its downstream targets determines the precise input-output relationship of Fgf8a-mediated patterning. Manipulation of the extracellular Fgf8a levels alters the signaling outcome, thus establishing Fgf8a as a bona fide morphogen during zebrafish gastrulation. Furthermore, by hindering Fgf8a diffusion, we demonstrate that extracellular diffusion of the protein from the source is crucial for it to achieve its morphogenic potential.
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Affiliation(s)
- Rohit Krishnan Harish
- CRTD – Center for Regenerative Therapies TU Dresden, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
- PoL – Cluster of Excellence Physics of Life, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
| | - Mansi Gupta
- CRTD – Center for Regenerative Therapies TU Dresden, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
- PoL – Cluster of Excellence Physics of Life, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
| | - Daniela Zöller
- CRTD – Center for Regenerative Therapies TU Dresden, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
- PoL – Cluster of Excellence Physics of Life, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
| | - Hella Hartmann
- CRTD – Center for Regenerative Therapies TU Dresden, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
- CMCB Technology Platform, Technische Universität Dresden, Tatzberg 47-51, 01307 Dresden, Germany
| | - Ali Gheisari
- CRTD – Center for Regenerative Therapies TU Dresden, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
- CMCB Technology Platform, Technische Universität Dresden, Tatzberg 47-51, 01307 Dresden, Germany
| | - Anja Machate
- CRTD – Center for Regenerative Therapies TU Dresden, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
- PoL – Cluster of Excellence Physics of Life, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
| | - Stefan Hans
- CRTD – Center for Regenerative Therapies TU Dresden, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
- PoL – Cluster of Excellence Physics of Life, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
| | - Michael Brand
- CRTD – Center for Regenerative Therapies TU Dresden, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
- PoL – Cluster of Excellence Physics of Life, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany
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4
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Karki S, Saadaoui M, Dunsing V, Kerridge S, Da Silva E, Philippe JM, Maurange C, Lecuit T. Serotonin signaling regulates actomyosin contractility during morphogenesis in evolutionarily divergent lineages. Nat Commun 2023; 14:5547. [PMID: 37684231 PMCID: PMC10491668 DOI: 10.1038/s41467-023-41178-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 08/24/2023] [Indexed: 09/10/2023] Open
Abstract
Serotonin is a neurotransmitter that signals through 5-HT receptors to control key functions in the nervous system. Serotonin receptors are also ubiquitously expressed in various organs and have been detected in embryos of different organisms. Potential morphogenetic functions of serotonin signaling have been proposed based on pharmacological studies but a mechanistic understanding is still lacking. Here, we uncover a role of serotonin signaling in axis extension of Drosophila embryos by regulating Myosin II (MyoII) activation, cell contractility and cell intercalation. We find that serotonin and serotonin receptors 5HT2A and 5HT2B form a signaling module that quantitatively regulates the amplitude of planar polarized MyoII contractility specified by Toll receptors and the GPCR Cirl. Remarkably, serotonin signaling also regulates actomyosin contractility at cell junctions, cellular flows and epiblast morphogenesis during chicken gastrulation. This phylogenetically conserved mechanical function of serotonin signaling in regulating actomyosin contractility and tissue flow reveals an ancestral role in morphogenesis of multicellular organisms.
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Affiliation(s)
- Sanjay Karki
- Aix-Marseille Université & CNRS, IBDM-UMR7288 & Turing Centre for Living Systems, Marseille, France
| | - Mehdi Saadaoui
- Aix-Marseille Université & CNRS, IBDM-UMR7288 & Turing Centre for Living Systems, Marseille, France
| | - Valentin Dunsing
- Aix-Marseille Université & CNRS, IBDM-UMR7288 & Turing Centre for Living Systems, Marseille, France
| | - Stephen Kerridge
- Aix-Marseille Université & CNRS, IBDM-UMR7288 & Turing Centre for Living Systems, Marseille, France
| | - Elise Da Silva
- Aix-Marseille Université & CNRS, IBDM-UMR7288 & Turing Centre for Living Systems, Marseille, France
| | - Jean-Marc Philippe
- Aix-Marseille Université & CNRS, IBDM-UMR7288 & Turing Centre for Living Systems, Marseille, France
| | - Cédric Maurange
- Aix-Marseille Université & CNRS, IBDM-UMR7288 & Turing Centre for Living Systems, Marseille, France
| | - Thomas Lecuit
- Aix-Marseille Université & CNRS, IBDM-UMR7288 & Turing Centre for Living Systems, Marseille, France.
- Collège de France, Paris, France.
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5
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Sankaran J, Wohland T. Current capabilities and future perspectives of FCS: super-resolution microscopy, machine learning, and in vivo applications. Commun Biol 2023; 6:699. [PMID: 37419967 PMCID: PMC10328937 DOI: 10.1038/s42003-023-05069-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 06/23/2023] [Indexed: 07/09/2023] Open
Abstract
Fluorescence correlation spectroscopy (FCS) is a single molecule sensitive tool for the quantitative measurement of biomolecular dynamics and interactions. Improvements in biology, computation, and detection technology enable real-time FCS experiments with multiplexed detection even in vivo. These new imaging modalities of FCS generate data at the rate of hundreds of MB/s requiring efficient data processing tools to extract information. Here, we briefly review FCS's capabilities and limitations before discussing recent directions that address these limitations with a focus on imaging modalities of FCS, their combinations with super-resolution microscopy, new evaluation strategies, especially machine learning, and applications in vivo.
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Affiliation(s)
- Jagadish Sankaran
- Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, 138632, Singapore.
| | - Thorsten Wohland
- Department of Biological Sciences, National University of Singapore, Singapore, 117558, Singapore.
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6
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Ashby G, Keng KE, Hayden CC, Gollapudi S, Houser JR, Jamal S, Stachowiak JC. Selective endocytic uptake of targeted liposomes occurs within a narrow range of liposome diameter. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.06.548000. [PMID: 37461728 PMCID: PMC10350051 DOI: 10.1101/2023.07.06.548000] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Abstract
Cell surface receptors facilitate signaling and nutrient uptake. These processes are dynamic, requiring receptors to be actively recycled by endocytosis. Due to their differential expression in disease states, receptors are often the target of drug-carrier particles, which are adorned with ligands that bind specifically to receptors. These targeted particles are taken into the cell by multiple routes of internalization, where the best-characterized pathway is clathrin-mediated endocytosis. Most studies of particle uptake have utilized bulk assays, rather than observing individual endocytic events. As a result, the detailed mechanisms of particle uptake remain obscure. To address this gap, we have employed a live-cell imaging approach to study the uptake of individual liposomes as they interact with clathrin-coated structures. By tracking individual internalization events, we find that the size of liposomes, rather than the density of the ligands on their surfaces, primarily determines their probability of uptake. Interestingly, targeting has the greatest impact on endocytosis of liposomes of intermediate diameters, with the smallest and largest liposomes being internalized or excluded, respectively, regardless of whether they are targeted. These findings, which highlight a previously unexplored limitation of targeted delivery, can be used to design more effective drug carriers.
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Affiliation(s)
- Grant Ashby
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Kayla E Keng
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Carl C Hayden
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Sadhana Gollapudi
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Justin R Houser
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Sabah Jamal
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Jeanne C Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin
- Department of Chemical Engineering, The University of Texas at Austin
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7
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Kohler J, Hur KH, Mueller JD. Autocorrelation function of finite-length data in fluorescence correlation spectroscopy. Biophys J 2023; 122:241-253. [PMID: 36266971 PMCID: PMC9822791 DOI: 10.1016/j.bpj.2022.10.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 10/06/2022] [Accepted: 10/18/2022] [Indexed: 01/11/2023] Open
Abstract
The experimental autocorrelation function of fluorescence correlation spectroscopy calculated from finite-length data is a biased estimator of the theoretical correlation function. This study presents a new theoretical framework that explicitly accounts for the data length to allow for unbiased analysis of experimental autocorrelation functions. To validate our theory, we applied it to experiments and simulations of diffusion and characterized the accuracy and precision of the resulting parameter estimates. Because measurements in living cells are often affected by instabilities of the fluorescence signal, autocorrelation functions are typically calculated on segmented data to improve their robustness. Our reformulated theory extends the range of usable segment times down to timescales approaching the diffusion time. This flexibility confers unique advantages for live-cell data that contain intensity variations and instabilities. We describe several applications of short segmentation to analyze data contaminated with unwanted fluctuations, drifts, or spikes in the intensity that are not suited for conventional fluorescence correlation analysis. These results demonstrate the potential of our theoretical framework to significantly expand the experimental systems accessible to fluorescence correlation spectroscopy.
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Affiliation(s)
- John Kohler
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kwang-Ho Hur
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA
| | - Joachim Dieter Mueller
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA; Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, USA; Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
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8
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Mørch AM, Schneider F. Investigating Diffusion Dynamics and Interactions with Scanning Fluorescence Correlation Spectroscopy (sFCS). Methods Mol Biol 2023; 2654:61-89. [PMID: 37106176 DOI: 10.1007/978-1-0716-3135-5_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Activation of immune cells and formation of immunological synapses (IS) rely critically on the reorganization of the plasma membrane. These highly orchestrated processes are driven by diffusion and oligomerization dynamics, as well as by single molecule interactions. While slow macro- and meso-scale changes in organization can be observed with conventional imaging, fast nano-scale dynamics are often missed with traditional approaches, but resolving them is, nonetheless, essential to understand the underlying biological mechanisms at play. Here, we describe the use of scanning fluorescence correlation spectroscopy (sFCS) and scanning fluorescence cross-correlation spectroscopy (sFCCS) to study reorganization and changes in molecular diffusion dynamics and interactions during IS formation and in other biological settings. We focus on the practical aspects of the measurements including calibration and alignment of the optical setup, present a comprehensive protocol to perform the measurements, and provide data analysis pipelines and strategies. Finally, we show an exemplary application of the technology to studying Lck diffusion during T-cell signaling.
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Affiliation(s)
| | - Falk Schneider
- Translational Imaging Center, University of Southern California, Los Angeles, California, USA.
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9
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Kuhn T, Landge AN, Mörsdorf D, Coßmann J, Gerstenecker J, Čapek D, Müller P, Gebhardt JCM. Single-molecule tracking of Nodal and Lefty in live zebrafish embryos supports hindered diffusion model. Nat Commun 2022; 13:6101. [PMID: 36243734 PMCID: PMC9569377 DOI: 10.1038/s41467-022-33704-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 09/28/2022] [Indexed: 12/24/2022] Open
Abstract
The hindered diffusion model postulates that the movement of a signaling molecule through an embryo is affected by tissue geometry and binding-mediated hindrance, but these effects have not been directly demonstrated in vivo. Here, we visualize extracellular movement and binding of individual molecules of the activator-inhibitor signaling pair Nodal and Lefty in live developing zebrafish embryos using reflected light-sheet microscopy. We observe that diffusion coefficients of molecules are high in extracellular cavities, whereas mobility is reduced and bound fractions are high within cell-cell interfaces. Counterintuitively, molecules nevertheless accumulate in cavities, which we attribute to the geometry of the extracellular space by agent-based simulations. We further find that Nodal has a larger bound fraction than Lefty and shows a binding time of tens of seconds. Together, our measurements and simulations provide direct support for the hindered diffusion model and yield insights into the nanometer-to-micrometer-scale mechanisms that lead to macroscopic signal dispersal.
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Affiliation(s)
- Timo Kuhn
- grid.6582.90000 0004 1936 9748Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Amit N. Landge
- grid.9811.10000 0001 0658 7699University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - David Mörsdorf
- grid.418026.90000 0004 0492 0357Friedrich Miescher Laboratory of the Max Planck Society, Max-Planck-Ring 9, 72076 Tübingen, Germany ,grid.10420.370000 0001 2286 1424University of Vienna, Department of Neurosciences and Developmental Biology, Djerassiplatz 1, 1030 Vienna, Austria
| | - Jonas Coßmann
- grid.6582.90000 0004 1936 9748Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Johanna Gerstenecker
- grid.6582.90000 0004 1936 9748Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Daniel Čapek
- grid.9811.10000 0001 0658 7699University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - Patrick Müller
- grid.9811.10000 0001 0658 7699University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany ,grid.418026.90000 0004 0492 0357Friedrich Miescher Laboratory of the Max Planck Society, Max-Planck-Ring 9, 72076 Tübingen, Germany
| | - J. Christof M. Gebhardt
- grid.6582.90000 0004 1936 9748Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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10
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Abstract
Metazoan embryos develop from a single cell into three-dimensional structured organisms while groups of genetically identical cells attain specialized identities. Cells of the developing embryo both create and accurately interpret morphogen gradients to determine their positions and make specific decisions in response. Here, we first cover intellectual roots of morphogen and positional information concepts. Focusing on animal embryos, we then provide a review of current understanding on how morphogen gradients are established and how their spans are controlled. Lastly, we cover how gradients evolve in time and space during development, and how they encode information to control patterning. In sum, we provide a list of patterning principles for morphogen gradients and review recent advances in quantitative methodologies elucidating information provided by morphogens.
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Affiliation(s)
- M. Fethullah Simsek
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Ertuğrul M. Özbudak
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
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11
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Hsiao AS, Huang JY. Bioimaging tools move plant physiology studies forward. FRONTIERS IN PLANT SCIENCE 2022; 13:976627. [PMID: 36204075 PMCID: PMC9530904 DOI: 10.3389/fpls.2022.976627] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/05/2022] [Indexed: 06/16/2023]
Affiliation(s)
- An-Shan Hsiao
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Ji-Ying Huang
- Cell Biology Core Lab, Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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12
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Barbiero M, Cirillo L, Veerapathiran S, Coates C, Ruffilli C, Pines J. Cell cycle-dependent binding between Cyclin B1 and Cdk1 revealed by time-resolved fluorescence correlation spectroscopy. Open Biol 2022; 12:220057. [PMID: 35765818 PMCID: PMC9240681 DOI: 10.1098/rsob.220057] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 06/07/2022] [Indexed: 01/04/2023] Open
Abstract
Measuring the dynamics with which the regulatory complexes assemble and disassemble is a crucial barrier to our understanding of how the cell cycle is controlled that until now has been difficult to address. This considerable gap in our understanding is due to the difficulty of reconciling biochemical assays with single cell-based techniques, but recent advances in microscopy and gene editing techniques now enable the measurement of the kinetics of protein-protein interaction in living cells. Here, we apply fluorescence correlation spectroscopy and fluorescence cross-correlation spectroscopy to study the dynamics of the cell cycle machinery, beginning with Cyclin B1 and its binding to its partner kinase Cdk1 that together form the major mitotic kinase. Although Cyclin B1 and Cdk1 are known to bind with high affinity, our results reveal that in living cells there is a pool of Cyclin B1 that is not bound to Cdk1. Furthermore, we provide evidence that the affinity of Cyclin B1 for Cdk1 increases during the cell cycle, indicating that the assembly of the complex is a regulated step. Our work lays the groundwork for studying the kinetics of protein complex assembly and disassembly during the cell cycle in living cells.
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Affiliation(s)
- Martina Barbiero
- Cancer Biology, The Institute of Cancer Research Chester Beatty Laboratories, 237 Fulham Road, London, London SW3 6JB, UK
| | - Luca Cirillo
- Cancer Biology, The Institute of Cancer Research Chester Beatty Laboratories, 237 Fulham Road, London, London SW3 6JB, UK
| | - Sapthaswaran Veerapathiran
- Cancer Biology, The Institute of Cancer Research Chester Beatty Laboratories, 237 Fulham Road, London, London SW3 6JB, UK
| | - Catherine Coates
- Cancer Biology, The Institute of Cancer Research Chester Beatty Laboratories, 237 Fulham Road, London, London SW3 6JB, UK
| | - Camilla Ruffilli
- Cancer Biology, The Institute of Cancer Research Chester Beatty Laboratories, 237 Fulham Road, London, London SW3 6JB, UK
| | - Jonathon Pines
- Cancer Biology, The Institute of Cancer Research Chester Beatty Laboratories, 237 Fulham Road, London, London SW3 6JB, UK
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13
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Dunsing V, Petrich A, Chiantia S. Multicolor fluorescence fluctuation spectroscopy in living cells via spectral detection. eLife 2021; 10:e69687. [PMID: 34494547 PMCID: PMC8545396 DOI: 10.7554/elife.69687] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 09/07/2021] [Indexed: 01/20/2023] Open
Abstract
Signaling pathways in biological systems rely on specific interactions between multiple biomolecules. Fluorescence fluctuation spectroscopy provides a powerful toolbox to quantify such interactions directly in living cells. Cross-correlation analysis of spectrally separated fluctuations provides information about intermolecular interactions but is usually limited to two fluorophore species. Here, we present scanning fluorescence spectral correlation spectroscopy (SFSCS), a versatile approach that can be implemented on commercial confocal microscopes, allowing the investigation of interactions between multiple protein species at the plasma membrane. We demonstrate that SFSCS enables cross-talk-free cross-correlation, diffusion, and oligomerization analysis of up to four protein species labeled with strongly overlapping fluorophores. As an example, we investigate the interactions of influenza A virus (IAV) matrix protein 2 with two cellular host factors simultaneously. We furthermore apply raster spectral image correlation spectroscopy for the simultaneous analysis of up to four species and determine the stoichiometry of ternary IAV polymerase complexes in the cell nucleus.
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Affiliation(s)
- Valentin Dunsing
- Universität Potsdam, Institute of Biochemistry and BiologyPotsdamGermany
| | - Annett Petrich
- Universität Potsdam, Institute of Biochemistry and BiologyPotsdamGermany
| | - Salvatore Chiantia
- Universität Potsdam, Institute of Biochemistry and BiologyPotsdamGermany
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14
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Danial JSH, Klenerman D. Single molecule imaging of protein aggregation in Dementia: Methods, insights and prospects. Neurobiol Dis 2021; 153:105327. [PMID: 33705938 PMCID: PMC8039184 DOI: 10.1016/j.nbd.2021.105327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/21/2021] [Accepted: 03/04/2021] [Indexed: 02/06/2023] Open
Abstract
The aggregation of misfolded proteins is a fundamental pathology in neurodegeneration which remains poorly understood due to its exceptional complexity and lack of appropriate characterization tools that can probe the role of the low concentrations of heterogeneous protein aggregates formed during the progression of the disease. In this review, we explain the principles underlying the operation of single molecule microscopy, an imaging method that can resolve molecules one-by-one, its application to imaging and characterizing individual protein aggregates in human samples and in vitro as well as the important questions in neurobiology this has answered and can answer.
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Affiliation(s)
- John S H Danial
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom; UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.
| | - David Klenerman
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom; UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.
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15
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Dhasmana D, Veerapathiran S, Azbazdar Y, Nelanuthala AVS, Teh C, Ozhan G, Wohland T. Wnt3 Is Lipidated at Conserved Cysteine and Serine Residues in Zebrafish Neural Tissue. Front Cell Dev Biol 2021; 9:671218. [PMID: 34124053 PMCID: PMC8189181 DOI: 10.3389/fcell.2021.671218] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/28/2021] [Indexed: 12/22/2022] Open
Abstract
Wnt proteins are a family of hydrophobic cysteine-rich secreted glycoproteins that regulate a gamut of physiological processes involved in embryonic development and tissue homeostasis. Wnt ligands are post-translationally lipidated in the endoplasmic reticulum (ER), a step essential for its membrane targeting, association with lipid domains, secretion and interaction with receptors. However, at which residue(s) Wnts are lipidated remains an open question. Initially it was proposed that Wnts are lipid-modified at their conserved cysteine and serine residues (C77 and S209 in mWnt3a), and mutations in either residue impedes its secretion and activity. Conversely, some studies suggested that serine is the only lipidated residue in Wnts, and substitution of serine with alanine leads to retention of Wnts in the ER. In this work, we investigate whether in zebrafish neural tissues Wnt3 is lipidated at one or both conserved residues. To this end, we substitute the homologous cysteine and serine residues of zebrafish Wnt3 with alanine (C80A and S212A) and investigate their influence on Wnt3 membrane organization, secretion, interaction and signaling activity. Collectively, our results indicate that Wnt3 is lipid modified at its C80 and S212 residues. Further, we find that lipid addition at either C80 or S212 is sufficient for its secretion and membrane organization, while the lipid modification at S212 is indispensable for receptor interaction and signaling.
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Affiliation(s)
- Divya Dhasmana
- Department of Biological Sciences and Center for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Sapthaswaran Veerapathiran
- Department of Biological Sciences and Center for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Yagmur Azbazdar
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Izmir, Turkey
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Izmir, Turkey
| | | | - Cathleen Teh
- Department of Biological Sciences and Center for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Gunes Ozhan
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Izmir, Turkey
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Izmir, Turkey
| | - Thorsten Wohland
- Department of Biological Sciences and Center for BioImaging Sciences, National University of Singapore, Singapore, Singapore
- Department of Chemistry, National University of Singapore, Singapore, Singapore
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16
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Gao P, Nienhaus GU. Axial line-scanning stimulated emission depletion fluorescence correlation spectroscopy. OPTICS LETTERS 2021; 46:2184-2187. [PMID: 33929450 DOI: 10.1364/ol.420765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/01/2021] [Indexed: 06/12/2023]
Abstract
Investigating the dynamics and interactions of biomolecules within or attached to membranes of living cells is crucial for understanding biology at the molecular level. In this pursuit, classical, diffraction-limited optical fluorescence microscopy is widely used, but it faces limitations due to (1) the heterogeneity of biomembranes on the nanoscale and (2) the intrinsic motion of membranes with respect to the focus. Here we introduce a new confocal microscopy-based fluctuation spectroscopy technique aimed at alleviating these two problems, called axial line-scanning stimulated emission depletion fluorescence correlation spectroscopy (axial ls-STED-FCS). Axial line scanning by means of a tunable acoustic gradient index of refraction lens provides a time resolution of a few microseconds, which is more than two orders of magnitude greater than that of conventional, lateral line-scanning fluorescence correlation spectroscopy (typically around 1 ms). Using STED excitation, the observation area on the membrane can be reduced 10-100 fold, resulting in sub-diffraction spatial resolution and the ability to study samples with densely labeled membranes. Due to these attractive properties, we expect that the axial ls-STED-FCS will find wide application, especially in the biomolecular sciences.
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17
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Characterization of clostridium botulinum neurotoxin serotype A (BoNT/A) and fibroblast growth factor receptor interactions using novel receptor dimerization assay. Sci Rep 2021; 11:7832. [PMID: 33837264 PMCID: PMC8035261 DOI: 10.1038/s41598-021-87331-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 03/24/2021] [Indexed: 01/03/2023] Open
Abstract
Clostridium botulinum neurotoxin serotype A (BoNT/A) is a potent neurotoxin that serves as an effective therapeutic for several neuromuscular disorders via induction of temporary muscular paralysis. Specific binding and internalization of BoNT/A into neuronal cells is mediated by its binding domain (HC/A), which binds to gangliosides, including GT1b, and protein cell surface receptors, including SV2. Previously, recombinant HC/A was also shown to bind to FGFR3. As FGFR dimerization is an indirect measure of ligand-receptor binding, an FCS & TIRF receptor dimerization assay was developed to measure rHC/A-induced dimerization of fluorescently tagged FGFR subtypes (FGFR1-3) in cells. rHC/A dimerized FGFR subtypes in the rank order FGFR3c (EC50 ≈ 27 nM) > FGFR2b (EC50 ≈ 70 nM) > FGFR1c (EC50 ≈ 163 nM); rHC/A dimerized FGFR3c with similar potency as the native FGFR3c ligand, FGF9 (EC50 ≈ 18 nM). Mutating the ganglioside binding site in HC/A, or removal of GT1b from the media, resulted in decreased dimerization. Interestingly, reduced dimerization was also observed with an SV2 mutant variant of HC/A. Overall, the results suggest that the FCS & TIRF receptor dimerization assay can assess FGFR dimerization with known and novel ligands and support a model wherein HC/A, either directly or indirectly, interacts with FGFRs and induces receptor dimerization.
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18
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Dadsena S, Jenner A, García-Sáez AJ. Mitochondrial outer membrane permeabilization at the single molecule level. Cell Mol Life Sci 2021; 78:3777-3790. [PMID: 33576840 PMCID: PMC8106609 DOI: 10.1007/s00018-021-03771-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2021] [Indexed: 12/12/2022]
Abstract
Apoptotic cell death is essential for development, immune function or tissue homeostasis, and its mis-regulation is linked to various diseases. Mitochondrial outer membrane permeabilization (MOMP) is a central event in the intrinsic apoptotic pathway and essential to control the execution of cell death. Here we review current concepts in regulation of MOMP focusing on the interaction network of the Bcl-2 family proteins as well as further regulatory elements influencing MOMP. As MOMP is a complex spatially and temporally controlled process, we point out the importance of single-molecule techniques to unveil processes which would be masked by ensemble measurements. We report key single-molecule studies applied to decipher the composition, assembly mechanism and structure of protein complexes involved in MOMP regulation.
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Affiliation(s)
- Shashank Dadsena
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany
| | - Andreas Jenner
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Ana J García-Sáez
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany.
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19
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Schneider F, Colin-York H, Fritzsche M. Quantitative Bio-Imaging Tools to Dissect the Interplay of Membrane and Cytoskeletal Actin Dynamics in Immune Cells. Front Immunol 2021; 11:612542. [PMID: 33505401 PMCID: PMC7829180 DOI: 10.3389/fimmu.2020.612542] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/23/2020] [Indexed: 12/13/2022] Open
Abstract
Cellular function is reliant on the dynamic interplay between the plasma membrane and the actin cytoskeleton. This critical relationship is of particular importance in immune cells, where both the cytoskeleton and the plasma membrane work in concert to organize and potentiate immune signaling events. Despite their importance, there remains a critical gap in understanding how these respective dynamics are coupled, and how this coupling in turn may influence immune cell function from the bottom up. In this review, we highlight recent optical technologies that could provide strategies to investigate the simultaneous dynamics of both the cytoskeleton and membrane as well as their interplay, focusing on current and future applications in immune cells. We provide a guide of the spatio-temporal scale of each technique as well as highlighting novel probes and labels that have the potential to provide insights into membrane and cytoskeletal dynamics. The quantitative biophysical tools presented here provide a new and exciting route to uncover the relationship between plasma membrane and cytoskeletal dynamics that underlies immune cell function.
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Affiliation(s)
- Falk Schneider
- Medical Research Council (MRC) Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Huw Colin-York
- Medical Research Council (MRC) Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
- Kennedy Institute for Rheumatology, University of Oxford, Oxford, United Kingdom
| | - Marco Fritzsche
- Medical Research Council (MRC) Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
- Kennedy Institute for Rheumatology, University of Oxford, Oxford, United Kingdom
- Rosalind Franklin Institute, Harwell Campus, Didcot, United Kingdom
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20
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Isthmin1, a secreted signaling protein, acts downstream of diverse embryonic patterning centers in development. Cell Tissue Res 2020; 383:987-1002. [PMID: 33367974 PMCID: PMC7960586 DOI: 10.1007/s00441-020-03318-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/06/2020] [Indexed: 11/25/2022]
Abstract
Extracellular signals play essential roles during embryonic patterning by providing positional information in a concentration-dependent manner, and many such signals, like Wnt, fibroblast growth factor (FGF), Hedgehog (Hh), and retinoic acid, act by being secreted into the extracellular space, thereby triggering receptor-mediated responses in other cells. Isthmin1 (ism1) is a secreted protein whose gene expression pattern coincides with that of early dorsal determinants, nodal ligand genes like sqt and cyc, and with fgf8 during various phases of zebrafish development. Ism1 functions in early embryonic patterning and development are poorly understood; however, it has recently been shown to interact with nodal pathway genes to control organ asymmetry in chicken. Here, we show that misexpression of ism1 deletion constructs disrupts embryonic patterning in zebrafish and exhibits genetic interactions with both Fgf and nodal signaling. Unlike Fgf and nodal pathway mutants, CRISPR/Cas9-engineered ism1 mutants did not show obvious developmental defects. Further, in vivo single molecule fluorescence correlation spectroscopy (FCCS) showed that Ism1 diffuses freely in the extra-cellular space, with a diffusion coefficient similar to that of Fgf8a; however, our measurements do not support direct molecular interactions between Ism1 and either nodal ligands or Fgf8a in the developing zebrafish embryo. Together, data from gain- and loss-of-function experiments suggest that zebrafish Ism1 plays a complex role in regulating extracellular signals during early embryonic development.
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21
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Veerapathiran S, Teh C, Zhu S, Kartigayen I, Korzh V, Matsudaira PT, Wohland T. Wnt3 distribution in the zebrafish brain is determined by expression, diffusion and multiple molecular interactions. eLife 2020; 9:e59489. [PMID: 33236989 PMCID: PMC7725503 DOI: 10.7554/elife.59489] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 11/23/2020] [Indexed: 12/19/2022] Open
Abstract
Wnt3 proteins are lipidated and glycosylated signaling molecules that play an important role in zebrafish neural patterning and brain development. However, the transport mechanism of lipid-modified Wnts through the hydrophilic extracellular environment for long-range action remains unresolved. Here we determine how Wnt3 accomplishes long-range distribution in the zebrafish brain. First, we characterize the Wnt3-producing source and Wnt3-receiving target regions. Subsequently, we analyze Wnt3 mobility at different length scales by fluorescence correlation spectroscopy and fluorescence recovery after photobleaching. We demonstrate that Wnt3 spreads extracellularly and interacts with heparan sulfate proteoglycans (HSPG). We then determine the binding affinity of Wnt3 to its receptor, Frizzled1 (Fzd1), using fluorescence cross-correlation spectroscopy and show that the co-receptor, low-density lipoprotein receptor-related protein 5 (Lrp5), is required for Wnt3-Fzd1 interaction. Our results are consistent with the extracellular distribution of Wnt3 by a diffusive mechanism that is modified by tissue morphology, interactions with HSPG, and Lrp5-mediated receptor binding, to regulate zebrafish brain development.
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Affiliation(s)
- Sapthaswaran Veerapathiran
- Department of Biological Sciences, National University of SingaporeSingaporeSingapore
- Center for BioImaging Sciences, National University of SingaporeSingaporeSingapore
| | - Cathleen Teh
- Department of Biological Sciences, National University of SingaporeSingaporeSingapore
- Center for BioImaging Sciences, National University of SingaporeSingaporeSingapore
| | - Shiwen Zhu
- Department of Biological Sciences, National University of SingaporeSingaporeSingapore
- Center for BioImaging Sciences, National University of SingaporeSingaporeSingapore
| | - Indira Kartigayen
- Department of Biological Sciences, National University of SingaporeSingaporeSingapore
- Center for BioImaging Sciences, National University of SingaporeSingaporeSingapore
| | - Vladimir Korzh
- International Institute of Molecular and Cell Biology in WarsawWarsawPoland
| | - Paul T Matsudaira
- Department of Biological Sciences, National University of SingaporeSingaporeSingapore
- Center for BioImaging Sciences, National University of SingaporeSingaporeSingapore
| | - Thorsten Wohland
- Department of Biological Sciences, National University of SingaporeSingaporeSingapore
- Center for BioImaging Sciences, National University of SingaporeSingaporeSingapore
- Department of Chemistry, National University of SingaporeSingaporeSingapore
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22
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Dawes ML, Soeller C, Scholpp S. Studying molecular interactions in the intact organism: fluorescence correlation spectroscopy in the living zebrafish embryo. Histochem Cell Biol 2020; 154:507-519. [PMID: 33067656 PMCID: PMC7609432 DOI: 10.1007/s00418-020-01930-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2020] [Indexed: 02/07/2023]
Abstract
Cell behaviour and function is determined through the interactions of a multitude of molecules working in concert. To observe these molecular dynamics, biophysical studies have been developed that track single interactions. Fluorescence correlation spectroscopy (FCS) is an optical biophysical technique that non-invasively resolves single molecules through recording the signal intensity at the femtolitre scale. However, recording the behaviour of these biomolecules using in vitro-based assays often fails to recapitulate the full range of variables in vivo that directly confer dynamics. Therefore, there has been an increasing interest in observing the state of these biomolecules within living organisms such as the zebrafish Danio rerio. In this review, we explore the advancements of FCS within the zebrafish and compare and contrast these findings to those found in vitro.
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Affiliation(s)
- Michael L Dawes
- Living Systems Institute, School of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Christian Soeller
- Living Systems Institute, College of Engineering, Mathematics, and Physical Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Steffen Scholpp
- Living Systems Institute, School of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK.
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23
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Wohland T. Splitting the Difference: Sorting Photons to Improve Quantitative Measurements in Correlation Spectroscopy. Biophys J 2020; 119:1268-1269. [PMID: 32891219 DOI: 10.1016/j.bpj.2020.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 08/12/2020] [Indexed: 10/23/2022] Open
Affiliation(s)
- Thorsten Wohland
- Departments of Biological Sciences and Chemistry, and NUS Centre for Bio-Imaging Sciences, National University of Singapore, Singapore, Singapore.
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24
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Eckert AF, Gao P, Wesslowski J, Wang X, Rath J, Nienhaus K, Davidson G, Nienhaus GU. Measuring ligand-cell surface receptor affinities with axial line-scanning fluorescence correlation spectroscopy. eLife 2020; 9:55286. [PMID: 32441251 PMCID: PMC7289602 DOI: 10.7554/elife.55286] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/21/2020] [Indexed: 12/12/2022] Open
Abstract
Development and homeostasis of multicellular organisms is largely controlled by complex cell-cell signaling networks that rely on specific binding of secreted ligands to cell surface receptors. The Wnt signaling network, as an example, involves multiple ligands and receptors to elicit specific cellular responses. To understand the mechanisms of such a network, ligand-receptor interactions should be characterized quantitatively, ideally in live cells or tissues. Such measurements are possible using fluorescence microscopy yet challenging due to sample movement, low signal-to-background ratio and photobleaching. Here, we present a robust approach based on fluorescence correlation spectroscopy with ultra-high speed axial line scanning, yielding precise equilibrium dissociation coefficients of interactions in the Wnt signaling pathway. Using CRISPR/Cas9 editing to endogenously tag receptors with fluorescent proteins, we demonstrate that the method delivers precise results even with low, near-native amounts of receptors.
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Affiliation(s)
| | - Peng Gao
- Institute of Applied Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Janine Wesslowski
- Institute of Biological and Chemical Systems, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Xianxian Wang
- Institute of Biological and Chemical Systems, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Jasmijn Rath
- Institute of Applied Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Karin Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Gary Davidson
- Institute of Biological and Chemical Systems, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Gerd Ulrich Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Institute of Biological and Chemical Systems, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
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25
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Barbotin A, Urbančič I, Galiani S, Eggeling C, Booth M, Sezgin E. z-STED Imaging and Spectroscopy to Investigate Nanoscale Membrane Structure and Dynamics. Biophys J 2020; 118:2448-2457. [PMID: 32359408 PMCID: PMC7231928 DOI: 10.1016/j.bpj.2020.04.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/12/2020] [Accepted: 04/06/2020] [Indexed: 12/23/2022] Open
Abstract
Super-resolution stimulated emission depletion (STED) microcopy provides optical resolution beyond the diffraction limit. The resolution can be increased laterally (xy) or axially (z). Two-dimensional STED has been extensively used to elucidate the nanoscale membrane structure and dynamics via imaging or combined with spectroscopy techniques such as fluorescence correlation spectroscopy (FCS) and spectral imaging. On the contrary, z-STED has not been used in this context. Here, we show that a combination of z-STED with FCS or spectral imaging enables us to see previously unobservable aspects of cellular membranes. We show that thanks to an axial resolution of ∼100 nm, z-STED can be used to distinguish axially close-by membranes, early endocytic vesicles, or tubular membrane structures. Combination of z-STED with FCS and spectral imaging showed diffusion dynamics and lipid organization in these structures, respectively.
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Affiliation(s)
- Aurélien Barbotin
- Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Iztok Urbančič
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom; Jožef Stefan Institute, Ljubljana, Slovenia
| | - Silvia Galiani
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom; Wolfson Imaging Centre Oxford, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Christian Eggeling
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom; Wolfson Imaging Centre Oxford, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom; Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany; Leibniz Institute of Photonic Technology e.V., Jena, Germany
| | - Martin Booth
- Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Erdinc Sezgin
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom; Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden.
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26
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Liu B, Gregor I, Müller HA, Großhans J. Fluorescence fluctuation analysis reveals PpV dependent Cdc25 protein dynamics in living embryos. PLoS Genet 2020; 16:e1008735. [PMID: 32251417 PMCID: PMC7162543 DOI: 10.1371/journal.pgen.1008735] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 04/16/2020] [Accepted: 03/25/2020] [Indexed: 12/21/2022] Open
Abstract
The protein phosphatase Cdc25 is a key regulator of the cell cycle by activating Cdk-cyclin complexes. Cdc25 is regulated by its expression levels and post-translational mechanisms. In early Drosophila embryogenesis, Cdc25/Twine drives the fast and synchronous nuclear cycles. A pause in the cell cycle and the remodeling to a more generic cell cycle mode with a gap phase are determined by Twine inactivation and destruction in early interphase 14, in response to zygotic genome activation. Although the pseudokinase Tribbles contributes to the timely degradation of Twine, Twine levels are controlled by additional yet unknown post-translational mechanisms. Here, we apply a non-invasive method based on fluorescence fluctuation analysis (FFA) to record the absolute concentration profiles of Twine with minute-scale resolution in single living embryos. Employing this assay, we found that Protein phosphatase V (PpV), the homologue of the catalytic subunit of human PP6, ensures appropriately low Twine protein levels at the onset of interphase 14. PpV controls directly or indirectly the phosphorylation of Twine at multiple serine and threonine residues as revealed by phosphosite mapping. Mutational analysis confirmed that these sites are involved in control of Twine protein dynamics, and cell cycle remodeling is delayed in a fraction of the phosphosite mutant embryos. Our data reveal a novel mechanism for control of Twine protein levels and their significance for embryonic cell cycle remodeling.
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Affiliation(s)
- Boyang Liu
- Fachbereich Biologie (FB17), Philipps-Universität Marburg, Marburg, Germany
- Institut für Entwicklungsbiochemie, Universitätsmedizin, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Ingo Gregor
- Drittes Physikalisches Institut, Georg-August-Universität Göttingen, Göttingen, Germany
| | - H.-Arno Müller
- Fachgebiet Entwicklungsgenetik, Institut für Biologie, Universität Kassel, Kassel, Germany
| | - Jörg Großhans
- Fachbereich Biologie (FB17), Philipps-Universität Marburg, Marburg, Germany
- Institut für Entwicklungsbiochemie, Universitätsmedizin, Georg-August-Universität Göttingen, Göttingen, Germany
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27
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Gupta A, Sankaran J, Wohland T. Fluorescence correlation spectroscopy: The technique and its applications in soft matter. PHYSICAL SCIENCES REVIEWS 2019. [DOI: 10.1515/psr-2017-0104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Abstract
Fluorescence correlation spectroscopy (FCS) is a well-established single-molecule method used for the quantitative spatiotemporal analysis of dynamic processes in a wide range of samples. It possesses single-molecule sensitivity but provides ensemble averaged molecular parameters such as mobility, concentration, chemical reaction kinetics, photophysical properties and interaction properties. These parameters have been utilized to characterize a variety of soft matter systems. This review provides an overview of the basic principles of various FCS modalities, their instrumentation, data analysis, and the applications of FCS to soft matter systems.
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28
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Mörsdorf D, Müller P. Tuning Protein Diffusivity with Membrane Tethers. Biochemistry 2019; 58:177-181. [PMID: 30562001 PMCID: PMC6344912 DOI: 10.1021/acs.biochem.8b01150] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/09/2018] [Indexed: 12/18/2022]
Abstract
Diffusion is essential for biochemical processes because it dominates molecular movement on small scales. Enzymatic reactions, for example, require fast exchange of substrate and product molecules in the local environment of the enzyme to ensure efficient turnover. On larger spatial scales, diffusion of secreted signaling proteins is thought to limit the spatial extent of tissue differentiation during embryonic development. While it is possible to measure diffusion in vivo, specifically interfering with diffusion processes and testing diffusion models directly remains challenging. The development of genetically encoded nanobodies that bind specific proteins has provided the opportunity to alter protein localization and reduce protein mobility. Here, we extend the nanobody toolbox with a membrane-tethered low-affinity diffusion regulator that can be used to tune the effective diffusivity of extracellular molecules over an order of magnitude in living embryos. This opens new avenues for future applications to functionally interfere with diffusion-dependent processes.
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Affiliation(s)
- David Mörsdorf
- Friedrich Miescher Laboratory of the
Max Planck Society, Max-Planck-Ring 9, 72076 Tübingen, Germany
| | - Patrick Müller
- Friedrich Miescher Laboratory of the
Max Planck Society, Max-Planck-Ring 9, 72076 Tübingen, Germany
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29
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Betaneli V, Mücksch J, Schwille P. Fluorescence Correlation Spectroscopy to Examine Protein-Lipid Interactions in Membranes. Methods Mol Biol 2019; 2003:415-447. [PMID: 31218628 DOI: 10.1007/978-1-4939-9512-7_18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Fluorescence correlation spectroscopy (FCS) is a versatile technique to study membrane dynamics and protein-lipid interactions. It can provide information about diffusion coefficients, concentrations, and molecular interactions of proteins and lipids in the membrane. These parameters allow for the determination of protein partitioning into different lipid environments, the identification of lipid domains, and the detection of lipid-protein complexes on the membrane. During the last decades, FCS studies were successfully performed on model membrane systems as also on living cells, to characterize protein-lipid interactions. Recent developments of the method described here improved quantitative measurements on membranes and decreased the number of potential artifacts. The aim of this chapter is to provide the reader with the necessary information and some practical guidelines to perform FCS studies on artificial and cellular membranes.
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Affiliation(s)
- Viktoria Betaneli
- Medical Faculty "Carl Gustav Carus", Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Jonas Mücksch
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Petra Schwille
- Max Planck Institute of Biochemistry, Martinsried, Germany.
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30
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Gao X, Gao P, Prunsche B, Nienhaus K, Nienhaus GU. Pulsed interleaved excitation-based line-scanning spatial correlation spectroscopy (PIE-lsSCS). Sci Rep 2018; 8:16722. [PMID: 30425308 PMCID: PMC6233157 DOI: 10.1038/s41598-018-35146-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/31/2018] [Indexed: 11/09/2022] Open
Abstract
We report pulsed interleaved excitation (PIE) based line-scanning spatial correlation spectroscopy (PIE-lsSCS), a quantitative fluorescence microscopy method for the study of dynamics in free-standing lipid bilayer membranes. Using a confocal microscope, we scan multiple lines perpendicularly through the membrane, each one laterally displaced from the previous one by several ten nanometers. Scanning through the membrane enables us to eliminate intensity fluctuations due to membrane displacements with respect to the observation volume. The diffusion of fluorescent molecules within the membrane is quantified by spatial correlation analysis, based on the fixed lag times between successive line scans. PIE affords dual-color excitation within a single line scan and avoids channel crosstalk. PIE-lsSCS data are acquired from a larger membrane region so that sampling is more efficient. Moreover, the local photon flux is reduced compared with single-point experiments, resulting in a smaller fraction of photobleached molecules for identical exposure times. This is helpful for precise measurements on live cells and tissues. We have evaluated the method with experiments on fluorescently labeled giant unilamellar vesicles (GUVs) and membrane-stained live cells.
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Affiliation(s)
- Xiang Gao
- Institute of Applied Physics, Karlsruhe Institute of Technology, 76128, Karlsruhe, Germany
| | - Peng Gao
- Institute of Applied Physics, Karlsruhe Institute of Technology, 76128, Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany
| | - Benedikt Prunsche
- Institute of Applied Physics, Karlsruhe Institute of Technology, 76128, Karlsruhe, Germany
| | - Karin Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of Technology, 76128, Karlsruhe, Germany
| | - Gerd Ulrich Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of Technology, 76128, Karlsruhe, Germany.
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany.
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany.
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA.
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31
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Unsay JD, Murad F, Hermann E, Ries J, García-Sáez AJ. Scanning Fluorescence Correlation Spectroscopy for Quantification of the Dynamics and Interactions in Tube Organelles of Living Cells. Chemphyschem 2018; 19:3273-3278. [PMID: 30335213 DOI: 10.1002/cphc.201800705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Indexed: 01/03/2023]
Abstract
Single-molecule spectroscopic quantification of protein-protein interactions directly in the organelles of living cells is highly desirable but remains challenging. Bulk methods, such as Förster resonance energy transfer (FRET), currently only give a relative quantification of the strength of protein-protein interactions. Here, we introduce tube scanning fluorescence cross-correlation spectroscopy (tubeSFCCS) for the absolute quantification of diffusion and complex formation of fluorescently labeled molecules in the mitochondrial compartments. We determined the extent of association between the apoptosis regulators Bcl-xL and tBid at the mitochondrial outer membrane of living cells and discovered that practically all mitochondria-bound Bcl-xL and tBid are associated with each other, in contrast to undetectable association in the cytosol. Furthermore, we show further applicability of our method to other mitochondrial proteins, as well as to proteins in the endoplasmic reticulum (ER) membrane.
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Affiliation(s)
- Joseph D Unsay
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076, Tübingen, Germany
- Max Planck Insitute for Intteligen Systems, Heisenbergstrasse 3, 70569, Stuttgart, Germany
- German Cancer Research Center, Im Neuenheimer Feld 280, 62120, Heidelberg, Germany
| | - Fabronia Murad
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076, Tübingen, Germany
| | - Eduard Hermann
- Max Planck Insitute for Intteligen Systems, Heisenbergstrasse 3, 70569, Stuttgart, Germany
| | - Jonas Ries
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Ana J García-Sáez
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076, Tübingen, Germany
- Max Planck Insitute for Intteligen Systems, Heisenbergstrasse 3, 70569, Stuttgart, Germany
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32
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Dunsing V, Luckner M, Zühlke B, Petazzi RA, Herrmann A, Chiantia S. Optimal fluorescent protein tags for quantifying protein oligomerization in living cells. Sci Rep 2018; 8:10634. [PMID: 30006597 PMCID: PMC6045628 DOI: 10.1038/s41598-018-28858-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/02/2018] [Indexed: 11/30/2022] Open
Abstract
Fluorescence fluctuation spectroscopy has become a popular toolbox for non-disruptive analysis of molecular interactions in living cells. The quantification of protein oligomerization in the native cellular environment is highly relevant for a detailed understanding of complex biological processes. An important parameter in this context is the molecular brightness, which serves as a direct measure of oligomerization and can be easily extracted from temporal or spatial fluorescence fluctuations. However, fluorescent proteins (FPs) typically used in such studies suffer from complex photophysical transitions and limited maturation, inducing non-fluorescent states. Here, we show how these processes strongly affect molecular brightness measurements. We perform a systematic characterization of non-fluorescent states for commonly used FPs and provide a simple guideline for accurate, unbiased oligomerization measurements in living cells. Further, we focus on novel red FPs and demonstrate that mCherry2, an mCherry variant, possesses superior properties with regards to precise quantification of oligomerization.
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Affiliation(s)
- Valentin Dunsing
- Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Madlen Luckner
- Institute for Biology, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Boris Zühlke
- Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Roberto A Petazzi
- Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Andreas Herrmann
- Institute for Biology, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Salvatore Chiantia
- Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany.
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33
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Schwille P. There and back again: from the origin of life to single molecules. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2018; 47:493-498. [PMID: 29569181 PMCID: PMC5982444 DOI: 10.1007/s00249-018-1295-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 03/08/2018] [Accepted: 03/13/2018] [Indexed: 11/27/2022]
Abstract
What is life? There is hardly a more fundamental question raised by aspiring researchers, and one less prone to ever be answered in a scientifically satisfying way. In the long, productive and highly influential period of research following his Nobel-recognised work on relaxation kinetics, Manfred Eigen made seminal contributions towards a quantifiable definition of life, with a strong focus on its evolutionary character. In the last years of his time as an active researcher, however, he devoted himself to another, purely experimental topic: the detection and analysis of single biomolecules in aqueous solution. In this short review, I will give an overview of the groundbreaking contributions to the field of single molecule research made by Eigen and coworkers, and show that both, in its intrinsic motivation, and in its consequences, single molecule research strongly relates to the question of the physical-chemical essence of life. In fact, research on living systems with single molecule sensitivity will always refer the researcher to the question of the simplest possible representation, and thus the origin, of any biological phenomenon.
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Affiliation(s)
- Petra Schwille
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany.
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34
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Kindt LM, Coughlin AR, Perosino TR, Ersfeld HN, Hampton M, Liang JO. Identification of transcripts potentially involved in neural tube closure using RNA sequencing. Genesis 2018; 56:e23096. [PMID: 29488319 DOI: 10.1002/dvg.23096] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 02/02/2018] [Accepted: 02/19/2018] [Indexed: 01/08/2023]
Abstract
Anencephaly is a fatal human neural tube defect (NTD) in which the anterior neural tube remains open. Zebrafish embryos with reduced Nodal signaling display an open anterior neural tube phenotype that is analogous to anencephaly. Previous work from our laboratory suggests that Nodal signaling acts through induction of the head mesendoderm and mesoderm. Head mesendoderm/mesoderm then, through an unknown mechanism, promotes formation of the polarized neuroepithelium that is capable of undergoing the movements required for closure. We compared the transcriptome of embryos treated with a Nodal signaling inhibitor at sphere stage, which causes NTDs, to embryos treated at 30% epiboly, which does not cause NTDs. This screen identified over 3,000 transcripts with potential roles in anterior neurulation. Expression of several genes encoding components of tight and adherens junctions was significantly reduced, supporting the model that Nodal signaling regulates formation of the neuroepithelium. mRNAs involved in Wnt, FGF, and BMP signaling were also differentially expressed, suggesting these pathways might regulate anterior neurulation. In support of this, we found that pharmacological inhibition of FGF-receptor function causes an open anterior NTD as well as loss of mesodermal derivatives. This suggests that Nodal and FGF signaling both promote anterior neurulation through induction of head mesoderm.
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Affiliation(s)
- Lexy M Kindt
- Department of Biology, University of Minnesota Duluth, Duluth.,Integrated Biosciences Graduate Program, University of Minnesota, Duluth
| | - Alicia R Coughlin
- Department of Biology, University of Minnesota Duluth, Duluth.,Integrated Biosciences Graduate Program, University of Minnesota, Duluth
| | | | - Haley N Ersfeld
- Department of Biology, University of Minnesota Duluth, Duluth
| | - Marshall Hampton
- Integrated Biosciences Graduate Program, University of Minnesota, Duluth.,Department of Mathematics and Statistics, University of Minnesota Duluth, Duluth
| | - Jennifer O Liang
- Department of Biology, University of Minnesota Duluth, Duluth.,Integrated Biosciences Graduate Program, University of Minnesota, Duluth
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35
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Staaf E, Hedde PN, Bagawath Singh S, Piguet J, Gratton E, Johansson S. Educated natural killer cells show dynamic movement of the activating receptor NKp46 and confinement of the inhibitory receptor Ly49A. Sci Signal 2018; 11:11/517/eaai9200. [PMID: 29440510 DOI: 10.1126/scisignal.aai9200] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Educated natural killer (NK) cells have inhibitory receptors specific for self major histocompatibility complex (MHC) class I molecules and kill cancer cells more efficiently than do NK cells that do not have such receptors (hyporesponsive NK cells). The mechanism behind this functional empowerment through education has so far not been fully described. In addition, distinctive phenotypic markers of educated NK cells at the single-cell level are lacking. We developed a refined version of the image mean square displacement (iMSD) method (called iMSD carpet analysis) and used it in combination with single-particle tracking to characterize the dynamics of the activating receptor NKp46 and the inhibitory receptor Ly49A on resting educated versus hyporesponsive murine NK cells. Most of the NKp46 and Ly49A molecules were restricted to microdomains; however, individual NKp46 molecules resided in these domains for shorter periods and diffused faster on the surface of educated, compared to hyporesponsive, NK cells. In contrast, the movement of Ly49A was more constrained in educated NK cells compared to hyporesponsive NK cells. Either disrupting the actin cytoskeleton or adding cholesterol to the cells prohibited activating signaling, suggesting that the dynamics of receptor movements within the cell membrane are critical for the proper activation of NK cells. The faster and more dynamic movement of NKp46 in educated NK cells may facilitate a swifter response to interactions with target cells.
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Affiliation(s)
- Elina Staaf
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Per Niklas Hedde
- Laboratory for Fluorescence Dynamics, University of California, Irvine, Irvine, CA 92697-2715, USA
| | - Sunitha Bagawath Singh
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Joachim Piguet
- Experimental Biomolecular Physics, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, University of California, Irvine, Irvine, CA 92697-2715, USA
| | - Sofia Johansson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
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36
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Noble DB, Mochrie SGJ, O'Hern CS, Pollard TD, Regan L. Promoting convergence: The integrated graduate program in physical and engineering biology at Yale University, a new model for graduate education. BIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION : A BIMONTHLY PUBLICATION OF THE INTERNATIONAL UNION OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 44:537-549. [PMID: 27292366 PMCID: PMC5132113 DOI: 10.1002/bmb.20977] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/28/2016] [Indexed: 06/01/2023]
Abstract
In 2008, we established the Integrated Graduate Program in Physical and Engineering Biology (IGPPEB) at Yale University. Our goal was to create a comprehensive graduate program to train a new generation of scientists who possess a sophisticated understanding of biology and who are capable of applying physical and quantitative methodologies to solve biological problems. Here we describe the framework of the training program, report on its effectiveness, and also share the insights we gained during its development and implementation. The program features co-teaching by faculty with complementary specializations, student peer learning, and novel hands-on courses that facilitate the seamless blending of interdisciplinary research and teaching. It also incorporates enrichment activities to improve communication skills, engage students in science outreach, and foster a cohesive program cohort, all of which promote the development of transferable skills applicable in a variety of careers. The curriculum of the graduate program is integrated with the curricular requirements of several Ph.D.-granting home programs in the physical, engineering, and biological sciences. Moreover, the wide-ranging recruiting activities of the IGPPEB serve to enhance the quality and diversity of students entering graduate school at Yale. We also discuss some of the challenges we encountered in establishing and optimizing the program, and describe the institution-level changes that were catalyzed by the introduction of the new graduate program. The goal of this article is to serve as both an inspiration and as a practical "how to" manual for those who seek to establish similar programs at their own institutions. © 2016 by The International Union of Biochemistry and Molecular Biology, 44(6):537-549, 2016.
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Affiliation(s)
- Dorottya B. Noble
- Integrated Graduate Program in Physical and Engineering Biology
- Department of Molecular Biophysics and Biochemistry
| | - Simon G. J. Mochrie
- Integrated Graduate Program in Physical and Engineering Biology
- Department of Physics
- Department of Applied Physics
| | - Corey S. O'Hern
- Integrated Graduate Program in Physical and Engineering Biology
- Department of Physics
- Department of Applied Physics
- Department of Mechanical Engineering and Materials Science
- Graduate Program in Computational Biology and Bioinformatics
| | - Thomas D. Pollard
- Integrated Graduate Program in Physical and Engineering Biology
- Department of Molecular Biophysics and Biochemistry
- Department of Molecular, Cellular, and Developmental Biology
- Department of Cell Biology
| | - Lynne Regan
- Integrated Graduate Program in Physical and Engineering Biology
- Department of Molecular Biophysics and Biochemistry
- Graduate Program in Computational Biology and Bioinformatics
- Department of Chemistry, Yale UniversityNew HavenConnecticut 06520USA
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37
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Nienhaus K, Nienhaus GU. Chromophore photophysics and dynamics in fluorescent proteins of the GFP family. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:443001. [PMID: 27604321 DOI: 10.1088/0953-8984/28/44/443001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Proteins of the green fluorescent protein (GFP) family are indispensable for fluorescence imaging experiments in the life sciences, particularly of living specimens. Their essential role as genetically encoded fluorescence markers has motivated many researchers over the last 20 years to further advance and optimize these proteins by using protein engineering. Amino acids can be exchanged by site-specific mutagenesis, starting with naturally occurring proteins as templates. Optical properties of the fluorescent chromophore are strongly tuned by the surrounding protein environment, and a targeted modification of chromophore-protein interactions requires a profound knowledge of the underlying photophysics and photochemistry, which has by now been well established from a large number of structural and spectroscopic experiments and molecular-mechanical and quantum-mechanical computations on many variants of fluorescent proteins. Nevertheless, such rational engineering often does not meet with success and thus is complemented by random mutagenesis and selection based on the optical properties. In this topical review, we present an overview of the key structural and spectroscopic properties of fluorescent proteins. We address protein-chromophore interactions that govern ground state optical properties as well as processes occurring in the electronically excited state. Special emphasis is placed on photoactivation of fluorescent proteins. These light-induced reactions result in large structural changes that drastically alter the fluorescence properties of the protein, which enables some of the most exciting applications, including single particle tracking, pulse chase imaging and super-resolution imaging. We also present a few examples of fluorescent protein application in live-cell imaging experiments.
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Affiliation(s)
- Karin Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), Wolfgang Gaede-Straße 1, 76131 Karlsruhe, Germany
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38
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Perez-Camps M, Tian J, Chng SC, Sem KP, Sudhaharan T, Teh C, Wachsmuth M, Korzh V, Ahmed S, Reversade B. Quantitative imaging reveals real-time Pou5f3-Nanog complexes driving dorsoventral mesendoderm patterning in zebrafish. eLife 2016; 5. [PMID: 27684073 PMCID: PMC5042653 DOI: 10.7554/elife.11475] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 08/04/2016] [Indexed: 12/11/2022] Open
Abstract
Formation of the three embryonic germ layers is a fundamental developmental process that initiates differentiation. How the zebrafish pluripotency factor Pou5f3 (homologous to mammalian Oct4) drives lineage commitment is unclear. Here, we introduce fluorescence lifetime imaging microscopy and fluorescence correlation spectroscopy to assess the formation of Pou5f3 complexes with other transcription factors in real-time in gastrulating zebrafish embryos. We show, at single-cell resolution in vivo, that Pou5f3 complexes with Nanog to pattern mesendoderm differentiation at the blastula stage. Later, during gastrulation, Sox32 restricts Pou5f3–Nanog complexes to the ventrolateral mesendoderm by binding Pou5f3 or Nanog in prospective dorsal endoderm. In the ventrolateral endoderm, the Elabela / Aplnr pathway limits Sox32 levels, allowing the formation of Pou5f3–Nanog complexes and the activation of downstream BMP signaling. This quantitative model shows that a balance in the spatiotemporal distribution of Pou5f3–Nanog complexes, modulated by Sox32, regulates mesendoderm specification along the dorsoventral axis. DOI:http://dx.doi.org/10.7554/eLife.11475.001 As an animal embryo develops, cells divide and establish three distinct layers called the ectoderm, mesoderm and endoderm. Proteins called transcription factors control this process by regulating the activity of particular genes. Two or more transcription factors may interact to modulate each other’s activity. Zebrafish embryos provide an ideal model system for monitoring how these embryonic layers form and the interactions between transcription factors in real-time because they are transparent and develop outside their parents. Pou5f3 and Nanog are two key transcription factors involved in this process in zebrafish. However, it is not clear how Pou5f3 and Nanog instruct cells to become ectoderm, mesoderm or endoderm. Perez Camps et al. used imaging techniques to study Pou5f3 and Nanog. The experiments show that Pou5f3 and Nanog bind together to form complexes that instruct cells to form the temporary layer that later gives rise to both the mesoderm and endoderm. The cells in which there are less Pou5f3 and Nanog complexes form the ectoderm layer. To develop the body shape of adult zebrafish, the embryos need to give individual cells information about their location in the body. For example, a signal protein called bone morphogenetic protein (BMP) accumulates on the side of the embryo that will become the underside of the fish. Perez Camps et al. show that once the endoderm, mesoderm and ectoderm have formed, Pou5f3–Nanog complexes regulate BMP signalling to specify the underside of the fish. Meanwhile, in the endoderm on the opposite side, another transcription factor called Sox32 binds to individual Pou5f3 and Nanog proteins. This prevents Pou5f3 and Nanog from forming complexes and determines which side of the embryo will make the topside of the fish. A future challenge is to explore other transcription factors that may prevent Pou5f1 and Nanog from binding in the mesoderm and ectoderm of the topside of the fish. DOI:http://dx.doi.org/10.7554/eLife.11475.002
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Affiliation(s)
| | - Jing Tian
- Institute of Medical Biology, A*STAR, Singapore, Singapore
| | - Serene C Chng
- Institute of Medical Biology, A*STAR, Singapore, Singapore
| | - Kai Pin Sem
- Institute of Medical Biology, A*STAR, Singapore, Singapore
| | | | - Cathleen Teh
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore
| | - Malte Wachsmuth
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Vladimir Korzh
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Sohail Ahmed
- Institute of Medical Biology, A*STAR, Singapore, Singapore
| | - Bruno Reversade
- Institute of Medical Biology, A*STAR, Singapore, Singapore.,Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore
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39
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Li X, Xing J, Qiu Z, He Q, Lin J. Quantification of Membrane Protein Dynamics and Interactions in Plant Cells by Fluorescence Correlation Spectroscopy. MOLECULAR PLANT 2016; 9:1229-1239. [PMID: 27381442 DOI: 10.1016/j.molp.2016.06.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/25/2016] [Accepted: 06/27/2016] [Indexed: 05/25/2023]
Abstract
Deciphering the dynamics of protein and lipid molecules on appropriate spatial and temporal scales may shed light on protein function and membrane organization. However, traditional bulk approaches cannot unambiguously quantify the extremely diverse mobility and interactions of proteins in living cells. Fluorescence correlation spectroscopy (FCS) is a powerful technique to describe events that occur at the single-molecule level and on the nanosecond to second timescales; therefore, FCS can provide data on the heterogeneous organization of membrane systems. FCS can also be combined with other microscopy techniques, such as super-resolution techniques. More importantly, FCS is minimally invasive, which makes it an ideal approach to detect the heterogeneous distribution and dynamics of key proteins during development. In this review, we give a brief introduction about the development of FCS and summarize the significant contributions of FCS in understanding the organization of plant cell membranes and the dynamics and interactions of membrane proteins. We also discuss the potential applications of this technique in plant biology.
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Affiliation(s)
- Xiaojuan Li
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Jingjing Xing
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 10049, China
| | - Zongbo Qiu
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Qihua He
- The Health Science Center, Peking University, Beijing 100191, China
| | - Jinxing Lin
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China.
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40
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Lawson BA, Flegg MB. A mathematical model for the induction of the mammalian ureteric bud. J Theor Biol 2016; 394:43-56. [DOI: 10.1016/j.jtbi.2015.12.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 12/22/2015] [Accepted: 12/24/2015] [Indexed: 01/18/2023]
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41
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Eroshkin FM, Nesterenko AM, Borodulin AV, Martynova NY, Ermakova GV, Gyoeva FK, Orlov EE, Belogurov AA, Lukyanov KA, Bayramov AV, Zaraisky AG. Noggin4 is a long-range inhibitor of Wnt8 signalling that regulates head development in Xenopus laevis. Sci Rep 2016; 6:23049. [PMID: 26973133 PMCID: PMC4789793 DOI: 10.1038/srep23049] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/25/2016] [Indexed: 12/05/2022] Open
Abstract
Noggin4 is a Noggin family secreted protein whose molecular and physiological functions remain unknown. In this study, we demonstrate that in contrast to other Noggins, Xenopus laevis Noggin4 cannot antagonise BMP signalling; instead, it specifically binds to Wnt8 and inhibits the Wnt/β -catenin pathway. Live imaging demonstrated that Noggin4 diffusivity in embryonic tissues significantly exceeded that of other Noggins. Using the Fluorescence Recovery After Photobleaching (FRAP) assay and mathematical modelling, we directly estimated the affinity of Noggin4 for Wnt8 in living embryos and determined that Noggin4 fine-tune the Wnt8 posterior-to-anterior gradient. Our results suggest a role for Noggin4 as a unique, freely diffusing, long-range inhibitor of canonical Wnt signalling, thus explaining its ability to promote head development.
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Affiliation(s)
- Fedor M Eroshkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Alexey M Nesterenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie gory, 1/40, 119991 Moscow, Russia
| | - Alexander V Borodulin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Natalia Yu Martynova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Galina V Ermakova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Fatima K Gyoeva
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, 142290 Moscow Region, Russia
| | - Eugeny E Orlov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Alexey A Belogurov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Konstantin A Lukyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Andrey V Bayramov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Andrey G Zaraisky
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
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Nienhaus K, Nienhaus GU. Where Do We Stand with Super-Resolution Optical Microscopy? J Mol Biol 2016; 428:308-322. [DOI: 10.1016/j.jmb.2015.12.020] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 12/23/2015] [Accepted: 12/23/2015] [Indexed: 10/22/2022]
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Trinh LA, Fraser SE. Imaging the Cell and Molecular Dynamics of Craniofacial Development: Challenges and New Opportunities in Imaging Developmental Tissue Patterning. Curr Top Dev Biol 2015; 115:599-629. [PMID: 26589939 DOI: 10.1016/bs.ctdb.2015.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The development of the vertebrate head requires cell-cell and tissue-tissue interactions between derivatives of the three germ layers to coordinate morphogenetic movements in four dimensions (4D: x, y, z, t). The high spatial and temporal resolution offered by optical microscopy has made it the main imaging modularity for capturing the molecular and cellular dynamics of developmental processes. In this chapter, we highlight the challenges and new opportunities provided by emerging technologies that enable dynamic, high-information-content imaging of craniofacial development. We discuss the challenges of varying spatial and temporal scales encountered from the biological and technological perspectives. We identify molecular and fluorescence imaging technology that can provide solutions to some of the challenges. Application of the techniques described within this chapter combined with considerations of the biological and technical challenges will aid in formulating the best image-based studies to extend our understanding of the genetic and environmental influences underlying craniofacial anomalies.
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Affiliation(s)
- Le A Trinh
- Molecular and Computational Biology, University of Southern California, Los Angeles, California, USA
| | - Scott E Fraser
- Molecular and Computational Biology, University of Southern California, Los Angeles, California, USA.
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44
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Measuring fast stochastic displacements of bio-membranes with dynamic optical displacement spectroscopy. Nat Commun 2015; 6:8162. [PMID: 26437911 PMCID: PMC4600712 DOI: 10.1038/ncomms9162] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 07/25/2015] [Indexed: 01/09/2023] Open
Abstract
Stochastic displacements or fluctuations of biological membranes are increasingly recognized as an important aspect of many physiological processes, but hitherto their precise quantification in living cells was limited due to a lack of tools to accurately record them. Here we introduce a novel technique—dynamic optical displacement spectroscopy (DODS), to measure stochastic displacements of membranes with unprecedented combined spatiotemporal resolution of 20 nm and 10 μs. The technique was validated by measuring bending fluctuations of model membranes. DODS was then used to explore the fluctuations in human red blood cells, which showed an ATP-induced enhancement of non-Gaussian behaviour. Plasma membrane fluctuations of human macrophages were quantified to this accuracy for the first time. Stimulation with a cytokine enhanced non-Gaussian contributions to these fluctuations. Simplicity of implementation, and high accuracy make DODS a promising tool for comprehensive understanding of stochastic membrane processes. Precise quantification of stochastic motions of biological membranes is limited by a lack of suitable detection methods. Here Monzel et al. develop dynamic optical displacement spectroscopy to measure stochastic membrane displacements at 20 nm/10 μs spatiotemporal resolution.
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45
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Teh C, Sun G, Shen H, Korzh V, Wohland T. Modulating the expression level of secreted Wnt3 influences cerebellum development in zebrafish transgenics. Development 2015; 142:3721-33. [PMID: 26395493 DOI: 10.1242/dev.127589] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/28/2015] [Indexed: 12/13/2022]
Abstract
The boundaries of brain regions are associated with the tissue-specific secretion of ligands from different signaling pathways. The dynamics of these ligands in vivo and the impact of its disruption remain largely unknown. Using light and fluorescence microscopy for the overall imaging of the specimen and fluorescence correlation spectroscopy (FCS) to determine Wnt3 dynamics, we demonstrated that Wnt3 regulates cerebellum development during embryogenesis using zebrafish wnt3 transgenics with either tissue-specific expression of an EGFP reporter or a functionally active fusion protein, Wnt3EGFP. The results suggest a state of dynamic equilibrium of Wnt3EGFP mobility in polarized neuroepithelial-like progenitors in the dorsal midline and cerebellar progenitors on the lateral side. Wnt3EGFP is secreted from the cerebellum as shown by measurements of its mobility in the ventricular cavity. The importance of Wnt secretion in brain patterning was validated with the Porcn inhibitor Wnt-C59 (C59), which, when applied early, reduced membrane-bound and secreted fractions of Wnt3EGFP and led to a malformed brain characterized by the absence of epithalamus, optic tectum and cerebellum. Likewise, interference with Wnt secretion later on during cerebellar development negatively impacted cerebellar growth and patterning. Our work, supported by quantitative analysis of protein dynamics in vivo, highlights the importance of membrane-localized and secreted Wnt3 during cerebellum development.
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Affiliation(s)
- Cathleen Teh
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, 138673 Singapore
| | - Guangyu Sun
- Department of Chemistry, National University of Singapore, 117543 Singapore Center for Bioimaging Sciences, National University of Singapore, 117557 Singapore
| | - Hongyuan Shen
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, 138673 Singapore
| | - Vladimir Korzh
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, 138673 Singapore Department of Biological Sciences, National University of Singapore, 117543 Singapore
| | - Thorsten Wohland
- Department of Chemistry, National University of Singapore, 117543 Singapore Center for Bioimaging Sciences, National University of Singapore, 117557 Singapore Department of Biological Sciences, National University of Singapore, 117543 Singapore
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46
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Cross-Scale Integrin Regulation Organizes ECM and Tissue Topology. Dev Cell 2015; 34:33-44. [PMID: 26096733 DOI: 10.1016/j.devcel.2015.05.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 03/23/2015] [Accepted: 04/29/2015] [Indexed: 11/23/2022]
Abstract
The diverse morphologies of animal tissues are underlain by different configurations of adherent cells and extracellular matrix (ECM). Here, we elucidate a cross-scale mechanism for tissue assembly and ECM remodeling involving Cadherin 2, the ECM protein Fibronectin, and its receptor Integrin α5. Fluorescence cross-correlation spectroscopy within the zebrafish paraxial mesoderm mesenchyme reveals a physical association between Integrin α5 on adjacent cell membranes. This Integrin-Integrin complex correlates with conformationally inactive Integrin. Cadherin 2 stabilizes both the Integrin association and inactive Integrin conformation. Thus, Integrin repression within the adherent mesenchymal interior of the tissue biases Fibronectin fibrillogenesis to the tissue surface lacking cell-cell adhesions. Along nascent somite boundaries, Cadherin 2 levels decrease, becoming anti-correlated with levels of Integrin α5. Simultaneously, Integrin α5 clusters and adopts the active conformation and then commences ECM assembly. This cross-scale regulation of Integrin activation organizes a stereotypic pattern of ECM necessary for vertebrate body elongation and segmentation.
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47
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Dual-color dual-focus line-scanning FCS for quantitative analysis of receptor-ligand interactions in living specimens. Sci Rep 2015; 5:10149. [PMID: 25951521 PMCID: PMC4423563 DOI: 10.1038/srep10149] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 03/31/2015] [Indexed: 01/27/2023] Open
Abstract
Cellular communication in multi-cellular organisms is mediated to a large extent by a multitude of cell-surface receptors that bind specific ligands. An in-depth understanding of cell signaling networks requires quantitative information on ligand-receptor interactions within living systems. In principle, fluorescence correlation spectroscopy (FCS) based methods can provide such data, but live-cell applications have proven extremely challenging. Here, we have developed an integrated dual-color dual-focus line-scanning fluorescence correlation spectroscopy (2c2f lsFCS) technique that greatly facilitates live-cell and tissue experiments. Absolute ligand and receptor concentrations and their diffusion coefficients within the cell membrane can be quantified without the need to perform additional calibration experiments. We also determine the concentration of ligands diffusing in the medium outside the cell within the same experiment by using a raster image correlation spectroscopy (RICS) based analysis. We have applied this robust technique to study the interactions of two Wnt antagonists, Dickkopf1 and Dickkopf2 (Dkk1/2), to their cognate receptor, low-density-lipoprotein-receptor related protein 6 (LRP6), in the plasma membrane of living HEK293T cells. We obtained significantly lower affinities than previously reported using in vitro studies, underscoring the need to measure such data on living cells or tissues.
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48
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Annibale P, Gratton E. Single cell visualization of transcription kinetics variance of highly mobile identical genes using 3D nanoimaging. Sci Rep 2015; 5:9258. [PMID: 25788248 PMCID: PMC4365385 DOI: 10.1038/srep09258] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 02/25/2015] [Indexed: 12/11/2022] Open
Abstract
Multi-cell biochemical assays and single cell fluorescence measurements revealed that the elongation rate of Polymerase II (PolII) in eukaryotes varies largely across different cell types and genes. However, there is not yet a consensus whether intrinsic factors such as the position, local mobility or the engagement by an active molecular mechanism of a genetic locus could be the determinants of the observed heterogeneity. Here by employing high-speed 3D fluorescence nanoimaging techniques we resolve and track at the single cell level multiple, distinct regions of mRNA synthesis within the model system of a large transgene array. We demonstrate that these regions are active transcription sites that release mRNA molecules in the nucleoplasm. Using fluctuation spectroscopy and the phasor analysis approach we were able to extract the local PolII elongation rate at each site as a function of time. We measured a four-fold variation in the average elongation between identical copies of the same gene measured simultaneously within the same cell, demonstrating a correlation between local transcription kinetics and the movement of the transcription site. Together these observations demonstrate that local factors, such as chromatin local mobility and the microenvironment of the transcription site, are an important source of transcription kinetics variability.
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Affiliation(s)
- Paolo Annibale
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California Irvine
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California Irvine
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Wallkamm V, Dörlich R, Rahm K, Klessing T, Nienhaus GU, Wedlich D, Gradl D. Live imaging of Xwnt5A-ROR2 complexes. PLoS One 2014; 9:e109428. [PMID: 25313906 PMCID: PMC4196911 DOI: 10.1371/journal.pone.0109428] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 08/30/2014] [Indexed: 12/26/2022] Open
Abstract
Secreted molecules of the Wnt family regulate key decisions in embryogenesis and adult tissue homeostasis by activating a complex network of Wnt signaling pathways. Although the different branches of Wnt signaling have been studied for more than 25 years, fluorophore tagged constructs for live cell imaging of Wnt molecules activating the Wnt/β-catenin pathway have become available only recently. We have generated a fluorophore tagged Wnt construct of the Xenopus Wnt5a protein (Xwnt5A) with the enhanced green fluorescent protein (EGFP), Xwnt5A-EGFP. This construct activates non-canonical Wnt pathways in an endocytosis dependent manner and is capable of compensating for the loss of endogenous Xwnt5A in Xenopus embryos. Strikingly, non-canonical Wnt pathway activation was restricted to short-range signaling while an inhibitory effect was observed in transwell cell cultures taken as long-range signaling model sytem. We used our Xwnt5A-EGFP construct to analyze in vivo binding of Wnt5A to its co-receptor ROR2 on the microscopic and on the molecular level. On the microscopic level, Xwnt5A-EGFP clusters in the membrane and recruits ROR2-mCherry to these clusters. Applying dual-colour dual-focus line-scanning fluorescence correlation spectroscopy on dorsal marginal zone explants, we identified membrane tethered Xwnt5A-EGFP molecules binding to ROR2-mCherry molecules. Our data favour a model, in which membrane-tethered Wnt-5A recruits ROR2 to form large ligand/receptor clusters and signals in an endocytosis-dependent manner.
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Affiliation(s)
- Veronika Wallkamm
- Zoological Institute, Department of Cell and Developmental Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Rene Dörlich
- Institute of Applied Physics and Insitute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Karolin Rahm
- Zoological Institute, Department of Cell and Developmental Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Tina Klessing
- Zoological Institute, Department of Cell and Developmental Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Gerd Ulrich Nienhaus
- Institute of Applied Physics and Insitute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Doris Wedlich
- Zoological Institute, Department of Cell and Developmental Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Dietmar Gradl
- Zoological Institute, Department of Cell and Developmental Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
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50
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In vivo single-molecule imaging identifies altered dynamics of calcium channels in dystrophin-mutant C. elegans. Nat Commun 2014; 5:4974. [PMID: 25232639 PMCID: PMC4199201 DOI: 10.1038/ncomms5974] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 08/12/2014] [Indexed: 01/15/2023] Open
Abstract
Single-molecule (SM) fluorescence microscopy allows the imaging of biomolecules in cultured cells with a precision of a few nanometres but has yet to be implemented in living adult animals. Here we used split-GFP (green fluorescent protein) fusions and complementation-activated light microscopy (CALM) for subresolution imaging of individual membrane proteins in live Caenorhabditis elegans (C. elegans). In vivo tissue-specific SM tracking of transmembrane CD4 and voltage-dependent Ca2+ channels (VDCC) was achieved with a precision of 30 nm within neuromuscular synapses and at the surface of muscle cells in normal and dystrophin-mutant worms. Through diffusion analyses, we reveal that dystrophin is involved in modulating the confinement of VDCC within sarcolemmal membrane nanodomains in response to varying tonus of C. elegans body-wall muscles. CALM expands the applications of SM imaging techniques beyond the petri dish and opens the possibility to explore the molecular basis of homeostatic and pathological cellular processes with subresolution precision, directly in live animals. Single molecule fluorescence microscopy is a powerful technique to study protein dynamics in cells, but it has not been applied to adult animals. The authors use complementation-activated light microscopy in C. elegansto discover that dystrophin regulates the diffusion properties of voltage-dependent calcium ion channels at the surface of body-wall muscle cells.![]()
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