scholarly journals A method for imaging single molecules at the plasma membrane of live cells within tissue slices

2020 ◽  
Vol 153 (1) ◽  
Author(s):  
Gregory I. Mashanov ◽  
Tatiana A. Nenasheva ◽  
Tatiana Mashanova ◽  
Catherine Maclachlan ◽  
Nigel J.M. Birdsall ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Lines ◽  
Single Molecule ◽  
Cardiac Tissue ◽  
Single Molecules ◽  
Live Cells ◽  
Biological Macromolecules ◽  
Tissue Slices ◽  
Tissue Samples ◽  
Mammalian Cell Lines

Recent advances in light microscopy allow individual biological macromolecules to be visualized in the plasma membrane and cytosol of live cells with nanometer precision and ∼10-ms time resolution. This allows new discoveries to be made because the location and kinetics of molecular interactions can be directly observed in situ without the inherent averaging of bulk measurements. To date, the majority of single-molecule imaging studies have been performed in either unicellular organisms or cultured, and often chemically fixed, mammalian cell lines. However, primary cell cultures and cell lines derived from multi-cellular organisms might exhibit different properties from cells in their native tissue environment, in particular regarding the structure and organization of the plasma membrane. Here, we describe a simple approach to image, localize, and track single fluorescently tagged membrane proteins in freshly prepared live tissue slices and demonstrate how this method can give information about the movement and localization of a G protein–coupled receptor in cardiac tissue slices. In principle, this experimental approach can be used to image the dynamics of single molecules at the plasma membrane of many different soft tissue samples and may be combined with other experimental techniques.

scholarly journals Live cell micropatterning reveals the dynamics of signaling complexes at the plasma membrane

2014 ◽  
Vol 207 (3) ◽  
pp. 407-418 ◽  
Author(s):  
Sara Löchte ◽  
Sharon Waichman ◽  
Oliver Beutel ◽  
Changjiang You ◽  
Jacob Piehler
Keyword(s):  
Plasma Membrane ◽  
Single Molecule ◽  
Spatial Organization ◽  
Polymer Brush ◽  
Effector Proteins ◽  
Live Cells ◽  
Type I ◽  
Rgd Peptides ◽  
Single Molecule Level ◽  
Cell Micropatterning

Interactions of proteins in the plasma membrane are notoriously challenging to study under physiological conditions. We report in this paper a generic approach for spatial organization of plasma membrane proteins into micropatterns as a tool for visualizing and quantifying interactions with extracellular, intracellular, and transmembrane proteins in live cells. Based on a protein-repellent poly(ethylene glycol) polymer brush, micropatterned surface functionalization with the HaloTag ligand for capturing HaloTag fusion proteins and RGD peptides promoting cell adhesion was devised. Efficient micropatterning of the type I interferon (IFN) receptor subunit IFNAR2 fused to the HaloTag was achieved, and highly specific IFN binding to the receptor was detected. The dynamics of this interaction could be quantified on the single molecule level, and IFN-induced receptor dimerization in micropatterns could be monitored. Assembly of active signaling complexes was confirmed by immunostaining of phosphorylated Janus family kinases, and the interaction dynamics of cytosolic effector proteins recruited to the receptor complex were unambiguously quantified by fluorescence recovery after photobleaching.

scholarly journals Single-molecule light-sheet microscopy with local nanopipette delivery

2020 ◽  
Author(s):  
B. Li ◽  
A. Ponjavic ◽  
W. H. Chen ◽  
L. Hopkins ◽  
C. Hughes ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Single Molecule ◽  
Single Molecules ◽  
Light Sheet ◽  
Local Delivery ◽  
Live Cells ◽  
Biological Processes ◽  
Light Sheet Microscopy ◽  
Wide Range

AbstractDetection of single molecules in biological systems has rapidly increased in resolution over the past decade. However, delivery of single molecules has remained a challenge. Currently there is no effective method that can both introduce a precise amount of molecules onto or into a single cell at a defined position, and then image the cellular response. Here we have combined light sheet microscopy with local delivery, using a nanopipette, to accurately deliver individual proteins to a defined position. We call this method local delivery selective plane illumination microscopy (ldSPIM). ldSPIM uses a nanopipette and the ionic feedback current at the nanopipette tip to control the position from which molecules are delivered. The number of proteins delivered can be controlled by varying the voltage applied. For single-molecule detection, we implemented single-objective SPIM using a reflective atomic force microscopy cantilever to create a 2µm thin sheet. Using this setup, we demonstrate that ldSPIM can deliver single fluorescently-labeled proteins onto the plasma membrane of HK293 cells or into the cytoplasm. Next, we deposited aggregates of amyloid-β, which causes proteotoxicity relevant to Alzheimer’s disease, onto a single macrophage stably expressing a MyDD88-eGFP fusion construct. Whole-cell imaging in 3D mode enables live detection of MyDD88 accumulation and formation of MyDDosome signaling complexes, as a result of aggregate-induced triggering of toll-like receptor 4. Overall, we demonstrate a novel multifunctional imaging system capable of precise delivery of single proteins to a specific location on the cell surface or inside the cytoplasm and high-speed 3D detection at single-molecule resolution within live cells.Statement of SignificanceThis paper describes and validates a new method to study biological processes based on the controlled local delivery of molecules onto or into the cell, combined with single molecule imaging using light sheet microscopy. we not only demonstrate the instrument’s capability of delivering controlled numbers of molecules to a defined position, down to the level of single molecules, but also its potential in study of the triggering of the innate immune response by protein aggregates, a key process in the development of neurodegenerative diseases such as Alzheimer’s disease. The same approach could be applied to a wide range of other important biological processes allowing them to be followed in live cells in real-time, hence it will be of great interest to the biophysical community.

Cell biochemistry studied by single-molecule imaging

2006 ◽  
Vol 34 (5) ◽  
pp. 983-988 ◽  
Author(s):  
G.I. Mashanov ◽  
T.A. Nenasheva ◽  
M. Peckham ◽  
J.E. Molloy
Keyword(s):  
Plasma Membrane ◽  
Single Molecule ◽  
Molecular Complexes ◽  
Live Cells ◽  
Diffusion Constants ◽  
Powerful Analytical Tool ◽  
Cellular Context ◽  
Molecular Information ◽  
Temporal And Spatial ◽  
Spatial Trajectories

Over the last decade, there have been remarkable developments in live-cell imaging. We can now readily observe individual protein molecules within living cells and this should contribute to a systems level understanding of biological pathways. Direct observation of single fluorophores enables several types of molecular information to be gathered. Temporal and spatial trajectories enable diffusion constants and binding kinetics to be deduced, while analyses of fluorescence lifetime, intensity, polarization or spectra give chemical and conformational information about molecules in their cellular context. By recording the spatial trajectories of pairs of interacting molecules, formation of larger molecular complexes can be studied. In the future, multicolour and multiparameter imaging of single molecules in live cells will be a powerful analytical tool for systems biology. Here, we discuss measurements of single-molecule mobility and residency at the plasma membrane of live cells. Analysis of diffusional paths at the plasma membrane gives information about its physical properties and measurement of temporal trajectories enables rates of binding and dissociation to be derived. Meanwhile, close scrutiny of individual fluorophore trajectories enables ideas about molecular dimerization and oligomerization related to function to be tested directly.

scholarly journals Super-Resolution Image Reconstruction Based on Single-Molecule Localization Algorithm

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 273
Author(s):  
Lixin Liu ◽  
Meijie Qi ◽  
Yujie Liu ◽  
Xinzhu Xue ◽  
Danni Chen ◽  
...  
Keyword(s):  
Image Reconstruction ◽  
Single Molecule ◽  
Cell Biology ◽  
Imaging System ◽  
Particle Density ◽  
Super Resolution ◽  
Live Cells ◽  
Biological Macromolecules ◽  
Localization Algorithm ◽  
Fluorescent Molecules

Fluorescence imaging is an important and efficient tool in cell biology and biomedical research. In order to observe the dynamics of biological macromolecules such as DNA, RNA and proteins in live cells, it is extremely necessary to surpass the Abbe diffraction limit in microscopic imaging. Single-molecule localization microscopy (SMLM) is a sort of super-resolution imaging technique that can obtain a large number of images of sparse fluorescent molecules by the use of photoswitchable fluorescent probes and single-molecule localization technology. The center positions of fluorescent molecules in the images are precisely located, and then the entire sample pattern is reconstructed with super resolution. In this paper, we present a single-molecule localization algorithm (SMLA) that is based on blind deconvolution and centroid localization (BDCL) method. Single-molecule localization and image reconstruction of 15,000/9990 frames of original images of tubulins are accomplished. In addition, this fluorophore localization algorithm is used to localize high particle-density images. The results show that our BDCL-SMLA method is a reasonable attempt and useful method for SMLM imaging when the imaging system is unknown.

scholarly journals Plasma membrane asymmetry of lipid organization: fluorescence lifetime microscopy and correlation spectroscopy analysis

2019 ◽  
Vol 61 (2) ◽  
pp. 252-266 ◽  
Author(s):  
Anjali Gupta ◽  
Thomas Korte ◽  
Andreas Herrmann ◽  
Thorsten Wohland
Keyword(s):  
Plasma Membrane ◽  
Cell Lines ◽  
Fluorescence Lifetime ◽  
Mammalian Cells ◽  
Correlation Spectroscopy ◽  
Fluorescence Lifetime Imaging ◽  
Outer Leaflet ◽  
Mammalian Cell Lines ◽  
Liquid Ordered ◽  
Fluorescent Lipid

A fundamental feature of the eukaryotic cell membrane is the asymmetric arrangement of lipids in its two leaflets. A cell invests significant energy to maintain this asymmetry and uses it to regulate important biological processes, such as apoptosis and vesiculation. The dynamic coupling of the inner or cytoplasmic and outer or exofacial leaflets is a challenging open question in membrane biology. Here, we combined fluorescence lifetime imaging microscopy (FLIM) with imaging total internal reflection fluorescence correlation spectroscopy (ITIR-FCS) to differentiate the dynamics and organization of the two leaflets of live mammalian cells. We characterized the biophysical properties of fluorescent analogs of phosphatidylcholine, sphingomyelin, and phosphatidylserine in the plasma membrane of two mammalian cell lines (CHO-K1 and RBL-2H3). Because of their specific transverse membrane distribution, these probes allowed leaflet-specific investigation of the plasma membrane. We compared the results of the two methods having different temporal and spatial resolution. Fluorescence lifetimes of fluorescent lipid analogs were in ranges characteristic for the liquid ordered phase in the outer leaflet and for the liquid disordered phase in the inner leaflet. The observation of a more fluid inner leaflet was supported by free diffusion in the inner leaflet, with high average diffusion coefficients. The liquid ordered phase in the outer leaflet was accompanied by slower diffusion and diffusion with intermittent transient trapping. Our results show that the combination of FLIM and ITIR-FCS with specific fluorescent lipid analogs is a powerful tool for investigating lateral and transbilayer characteristics of plasma membrane in live cell lines.

Probing Single Molecules in Single Living Cells

2001 ◽  
Vol 7 (S2) ◽  
pp. 28-29
Author(s):  
Tyler A. Byassee ◽  
Warren C. W. Chan ◽  
Shuming Nie
Keyword(s):  
Single Molecule ◽  
Intracellular Transport ◽  
Single Molecules ◽  
Cancer Cell Line ◽  
Living Cells ◽  
Cervical Cancer Cell Line ◽  
Biological Macromolecules ◽  
Background Fluorescence ◽  
Molecular Events

Direct observation of single molecules and single molecular events inside living cells could dramatically improve our understanding of basic cellular processes (e.g., signal transduction and gene transcription) as well as improving our knowledge on the intracellular transport and fate of therapeutic agents (e.g., antisense RNA and gene therapy vectors). However, a key remaining question is whether single-molecule methodologies could be developed to study complex molecular processes in living cells. in contrast to clean and well-controlled conditions in-vitro, the intracellular environment contains a broad collection of biological macromolecules and fluorescent materials such as porphyrins and flavins. This complex environment is known to produce intense background fluorescence, commonly known as autofluorescence. Thus, a major concern is that this intracellular background could overwhelm the relatively weak signals arising from single molecules.We demonstrate that fluorescence detection of single molecules can be achieved by tightly focusing a laser beam into a living cell (see Figure 1). The observed background fluorescence is indeed higher than that in-vitro (e.g., pure biological buffer), but this background is continuous and stable, and does not significantly interfere with the measurement of single-molecule photon bursts. Specifically, we report single-molecule results on three types of extrinsic fluorescent molecules in cultured human HeLa cells (a cervical cancer cell line).

scholarly journals Directed manipulation of membrane proteins by fluorescent magnetic nanoparticles

2020 ◽  
Author(s):  
Jia Hui Li ◽  
Paula Santos-Otte ◽  
Braedyn Au ◽  
Jakob Rentsch ◽  
Stephan Block ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Magnetic Nanoparticles ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Single Molecule ◽  
Super Resolution ◽  
Single Particle Tracking ◽  
Live Cells ◽  
Single Molecule Level ◽  
Membrane Components

AbstractThe plasma membrane is the interface through which cells interact with their environment. Membrane proteins are embedded in the lipid bilayer of the plasma membrane and their function in this context is often linked to their specific location and dynamics within the membrane. However, few methods are available for nanoscale manipulation of membrane protein location at the single molecule level. Here, we report the use of fluorescent magnetic nanoparticles (FMNPs) to track membrane molecules and to manipulate their movement. FMNPs allow single-particle tracking (SPT) at 10 nm spatial and 5 ms temporal resolution, and using a magnetic needle, we pull membrane components laterally through the membrane with femtonewton-range forces. In this way, we successfully dragged lipid-anchored and transmembrane proteins over the surface of living cells. Doing so, we detected submembrane barriers and in combination with super-resolution microscopy could localize these barriers to the actin cytoskeleton. We present here a versatile approach to probe membrane processes in live cells via the magnetic control of membrane protein motion.

scholarly journals Revealing compartmentalised membrane diffusion in living cells with interferometric scattering microscopy

2016 ◽  
Author(s):  
G. de Wit ◽  
D. Albrecht ◽  
H. Ewers ◽  
P. Kukura
Keyword(s):  
Plasma Membrane ◽  
Single Molecule ◽  
Particle Tracking ◽  
Single Particle ◽  
Hippocampal Neurons ◽  
Living Cells ◽  
Single Particle Tracking ◽  
Unique Combination ◽  
Membrane Diffusion ◽  
Mammalian Cell Lines

AbstractSingle-particle tracking is a powerful tool for studying single molecule behaviour involving plasma membrane-associated events in cells. Here, we show that interferometric scattering microscopy (iSCAT) combined with gold nanoparticle labeling can be used to follow the motion of membrane proteins in the plasma membrane of live cultured mammalian cell lines and hippocampal neurons. The unique combination of microsecond temporal resolution and nanometer spatial precision reveals signatures of a compartmentalised plasma membrane in neurons.

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