scholarly journals Quantitative single-protein imaging reveals molecular complex formation of integrin, talin, and kindlin during cell adhesion

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lisa S. Fischer ◽  
Christoph Klingner ◽  
Thomas Schlichthaerle ◽  
Maximilian T. Strauss ◽  
Ralph Böttcher ◽  
...  
Keyword(s):  
Complex Formation ◽  
Single Molecule ◽  
Molecular Mechanisms ◽  
Detection Efficiency ◽  
Imaging Techniques ◽  
Super Resolution ◽  
Absolute Quantification ◽  
Molecular Probes ◽  
Single Protein ◽  
In Cells

AbstractSingle-molecule localization microscopy (SMLM) enabling the investigation of individual proteins on molecular scales has revolutionized how biological processes are analysed in cells. However, a major limitation of imaging techniques reaching single-protein resolution is the incomplete and often unknown labeling and detection efficiency of the utilized molecular probes. As a result, fundamental processes such as complex formation of distinct molecular species cannot be reliably quantified. Here, we establish a super-resolution microscopy framework, called quantitative single-molecule colocalization analysis (qSMCL), which permits the identification of absolute molecular quantities and thus the investigation of molecular-scale processes inside cells. The method combines multiplexed single-protein resolution imaging, automated cluster detection, in silico data simulation procedures, and widely applicable experimental controls to determine absolute fractions and spatial coordinates of interacting species on a true molecular level, even in highly crowded subcellular structures. The first application of this framework allowed the identification of a long-sought ternary adhesion complex—consisting of talin, kindlin and active β1-integrin—that specifically forms in cell-matrix adhesion sites. Together, the experiments demonstrate that qSMCL allows an absolute quantification of multiplexed SMLM data and thus should be useful for investigating molecular mechanisms underlying numerous processes in cells.

scholarly journals Comparing Super-Resolution Microscopy Techniques to Analyze Chromosomes

2021 ◽  
Vol 22 (4) ◽  
pp. 1903
Author(s):  
Ivona Kubalová ◽  
Alžběta Němečková ◽  
Klaus Weisshart ◽  
Eva Hřibová ◽  
Veit Schubert
Keyword(s):  
Single Molecule ◽  
Imaging Techniques ◽  
Chromatin Condensation ◽  
Super Resolution ◽  
Stimulated Emission ◽  
Wide Field ◽  
Structured Illumination Microscopy ◽  
Metaphase Chromosomes ◽  
Localization Microscopy ◽  
Super Resolution Microscopy

The importance of fluorescence light microscopy for understanding cellular and sub-cellular structures and functions is undeniable. However, the resolution is limited by light diffraction (~200–250 nm laterally, ~500–700 nm axially). Meanwhile, super-resolution microscopy, such as structured illumination microscopy (SIM), is being applied more and more to overcome this restriction. Instead, super-resolution by stimulated emission depletion (STED) microscopy achieving a resolution of ~50 nm laterally and ~130 nm axially has not yet frequently been applied in plant cell research due to the required specific sample preparation and stable dye staining. Single-molecule localization microscopy (SMLM) including photoactivated localization microscopy (PALM) has not yet been widely used, although this nanoscopic technique allows even the detection of single molecules. In this study, we compared protein imaging within metaphase chromosomes of barley via conventional wide-field and confocal microscopy, and the sub-diffraction methods SIM, STED, and SMLM. The chromosomes were labeled by DAPI (4′,6-diamidino-2-phenylindol), a DNA-specific dye, and with antibodies against topoisomerase IIα (Topo II), a protein important for correct chromatin condensation. Compared to the diffraction-limited methods, the combination of the three different super-resolution imaging techniques delivered tremendous additional insights into the plant chromosome architecture through the achieved increased resolution.

scholarly journals FluoSim: simulator of single molecule dynamics for fluorescence live-cell and super-resolution imaging of membrane proteins

2020 ◽  
Author(s):  
Matthieu Lagardère ◽  
Ingrid Chamma ◽  
Emmanuel Bouilhol ◽  
Macha Nikolski ◽  
Olivier Thoumine
Keyword(s):  
Real Time ◽  
Protein Dynamics ◽  
Single Molecule ◽  
Imaging Techniques ◽  
Simulated Data ◽  
Super Resolution ◽  
Molecular Complexes ◽  
Live Cell ◽  
Single Molecule Level ◽  
Resolution Imaging

AbstractFluorescence live-cell and super-resolution microscopy methods have considerably advanced our understanding of the dynamics and mesoscale organization of macro-molecular complexes that drive cellular functions. However, different imaging techniques can provide quite disparate information about protein motion and organization, owing to their respective experimental ranges and limitations. To address these limitations, we present here a unified computer program that allows one to model and predict membrane protein dynamics at the ensemble and single molecule level, so as to reconcile imaging paradigms and quantitatively characterize protein behavior in complex cellular environments. FluoSim is an interactive real-time simulator of protein dynamics for live-cell imaging methods including SPT, FRAP, PAF, and FCS, and super-resolution imaging techniques such as PALM, dSTORM, and uPAINT. The software, thoroughly validated against experimental data on the canonical neurexin-neuroligin adhesion complex, integrates diffusion coefficients, binding rates, and fluorophore photo-physics to calculate in real time the distribution of thousands of independent molecules in 2D cellular geometries, providing simulated data of protein dynamics and localization directly comparable to actual experiments.

scholarly journals 4polar-STORM polarized super-resolution imaging of actin filament organization in cells

2021 ◽  
Author(s):  
Caio Vaz Rimoli ◽  
Cesar Augusto Valades Cruz ◽  
Valentina Curcio ◽  
Manos Mavrakis ◽  
Sophie Brasselet
Keyword(s):  
Actin Filament ◽  
Single Molecule ◽  
Protein Function ◽  
Super Resolution ◽  
New Method ◽  
Nanometer Scale ◽  
Protein Assemblies ◽  
Cellular Context ◽  
Resolution Imaging ◽  
In Cells

Advances in single-molecule localization microscopy are providing unprecedented insights into the nanometer-scale organization of protein assemblies in cells and thus a powerful means for interrogating biological function. However, localization imaging alone does not contain information on protein conformation and orientation, which constitute additional key signatures of protein function. Here, we present a new microscopy method which combines for the first time Stochastic Optical Reconstruction Microscopy (STORM) super-resolution imaging with single molecule orientation and wobbling measurements using a four polarization-resolved image splitting scheme. This new method, called 4polar-STORM, allows us to determine both single molecule localization and orientation in 2D and to infer their 3D orientation, and is compatible with high labelling densities and thus ideally placed for the determination of the organization of dense protein assemblies in cells. We demonstrate the potential of this new method by studying the nanometer-scale organization of dense actin filament assemblies driving cell adhesion and motility, and reveal bimodal distributions of actin filament orientations in the lamellipodium, which were previously only observed in electron microscopy studies. 4polar-STORM is fully compatible with 3D localization schemes and amenable to live-cell observations, and thus promises to provide new functional readouts by enabling nanometer-scale studies of orientational dynamics in a cellular context.

scholarly journals Fast widefield scan provides tunable and uniform illumination optimizing super-resolution microscopy on large fields

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Adrien Mau ◽  
Karoline Friedl ◽  
Christophe Leterrier ◽  
Nicolas Bourg ◽  
Sandrine Lévêque-Fort
Keyword(s):  
Single Molecule ◽  
Imaging Techniques ◽  
Super Resolution ◽  
Uniform Illumination ◽  
Optical Sectioning ◽  
Coated Pits ◽  
Laser Illumination ◽  
Quantitative Analyses ◽  
Super Resolution Microscopy ◽  
Single Molecule Localization Microscopy

AbstractNon-uniform illumination limits quantitative analyses of fluorescence imaging techniques. In particular, single molecule localization microscopy (SMLM) relies on high irradiances, but conventional Gaussian-shaped laser illumination restricts the usable field of view to around 40 µm × 40 µm. We present Adaptable Scanning for Tunable Excitation Regions (ASTER), a versatile illumination technique that generates uniform and adaptable illumination. ASTER is also highly compatible with optical sectioning techniques such as total internal reflection fluorescence (TIRF). For SMLM, ASTER delivers homogeneous blinking kinetics at reasonable laser power over fields-of-view up to 200 µm × 200 µm. We demonstrate that ASTER improves clustering analysis and nanoscopic size measurements by imaging nanorulers, microtubules and clathrin-coated pits in COS-7 cells, and β2-spectrin in neurons. ASTER’s sharp and quantitative illumination paves the way for high-throughput quantification of biological structures and processes in classical and super-resolution fluorescence microscopies.

scholarly journals FluoSim: simulator of single molecule dynamics for fluorescence live-cell and super-resolution imaging of membrane proteins

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Matthieu Lagardère ◽  
Ingrid Chamma ◽  
Emmanuel Bouilhol ◽  
Macha Nikolski ◽  
Olivier Thoumine
Keyword(s):  
Membrane Protein ◽  
Protein Dynamics ◽  
Single Molecule ◽  
Imaging Techniques ◽  
Simulated Data ◽  
Super Resolution ◽  
Molecular Complexes ◽  
Live Cell ◽  
Resolution Imaging ◽  
Membrane Protein Dynamics

AbstractFluorescence live-cell and super-resolution microscopy methods have considerably advanced our understanding of the dynamics and mesoscale organization of macro-molecular complexes that drive cellular functions. However, different imaging techniques can provide quite disparate information about protein motion and organization, owing to their respective experimental ranges and limitations. To address these issues, we present here a robust computer program, called FluoSim, which is an interactive simulator of membrane protein dynamics for live-cell imaging methods including SPT, FRAP, PAF, and FCS, and super-resolution imaging techniques such as PALM, dSTORM, and uPAINT. FluoSim integrates diffusion coefficients, binding rates, and fluorophore photo-physics to calculate in real time the localization and intensity of thousands of independent molecules in 2D cellular geometries, providing simulated data directly comparable to actual experiments. FluoSim was thoroughly validated against experimental data obtained on the canonical neurexin-neuroligin adhesion complex at cell–cell contacts. This unified software allows one to model and predict membrane protein dynamics and localization at the ensemble and single molecule level, so as to reconcile imaging paradigms and quantitatively characterize protein behavior in complex cellular environments.

Single-Molecule Localization Super-Resolution Microscopy: Deeper and Faster

2012 ◽  
Vol 18 (6) ◽  
pp. 1419-1429 ◽  
Author(s):  
Sébastien Herbert ◽  
Helena Soares ◽  
Christophe Zimmer ◽  
Ricardo Henriques
Keyword(s):  
Single Molecule ◽  
Imaging Techniques ◽  
Super Resolution ◽  
Fluorescence Labeling ◽  
High Temporal Resolution ◽  
Wide Field ◽  
Resolution Limit ◽  
Localization Microscopy ◽  
Recent Developments ◽  
Potential Applications

AbstractFor over a decade fluorescence microscopy has demonstrated the capacity to achieve single-molecule localization accuracies of a few nanometers, well below the ∼200 nm lateral and ∼500 nm axial resolution limit of conventional microscopy. Yet, only the recent development of new fluorescence labeling modalities, the increase in sensitivity of imaging hardware, and the creation of novel image analysis tools allow for the emergence of single-molecule-based super-resolution imaging techniques. Novel methods such as photoactivated localization microscopy and stochastic optical reconstruction microscopy can typically reach a tenfold increase in resolution compared to standard microscopy methods. Their implementation is relatively easy only requiring minimal changes to a conventional wide-field or total internal reflection fluorescence microscope. The recent translation of these two methods into commercial imaging systems has made them further accessible to researchers in biology. However, these methods are still evolving rapidly toward imaging live samples with high temporal resolution and depth. In this review, we recall the roots of single-molecule localization microscopy, summarize major recent developments, and offer perspective on potential applications.

scholarly journals Nanoscopy on the Chea(i)p

2020 ◽  
Author(s):  
Benedict Diederich ◽  
Øystein Helle ◽  
Patrick Then ◽  
Pablo Carravilla ◽  
Kay Oliver Schink ◽  
...  
Keyword(s):  
Single Molecule ◽  
Imaging Techniques ◽  
Low Cost ◽  
Super Resolution ◽  
Image Sensor ◽  
Optical Diffraction ◽  
Sensor Technology ◽  
Safety Level ◽  
Resolution Imaging ◽  
Super Resolution Microscopy

AbstractSuper-resolution microscopy allows for stunning images with a resolution well beyond the optical diffraction limit, but the imaging techniques are demanding in terms of instrumentation and software. Using scientific-grade cameras, solid-state lasers and top-shelf microscopy objective lenses drives the price and complexity of the system, limiting its use to well-funded institutions. However, by harnessing recent developments in CMOS image sensor technology and low-cost illumination strategies, super-resolution microscopy can be made available to the mass-markets for a fraction of the price. Here, we present a 3D printed, self-contained super-resolution microscope with a price tag below 1000 $ including the objective and a cellphone. The system relies on a cellphone to both acquire and process images as well as control the hardware, and a photonic-chip enabled illumination. The system exhibits 100nm optical resolution using single-molecule localization microscopy and can provide live super-resolution imaging using light intensity fluctuation methods. Furthermore, due to its compactness, we demonstrate its potential use inside bench-top incubators and high biological safety level environments imaging SARS-CoV-2 viroids. By the development of low-cost instrumentation and by sharing the designs and manuals, the stage for democratizing super-resolution imaging is set.

scholarly journals Hessian single molecule localization microscopy using sCMOS camera

2018 ◽  
Author(s):  
Fudong Xue ◽  
Wenting He ◽  
Fan Xu ◽  
Mingshu Zhang ◽  
Liangyi Chen ◽  
...  
Keyword(s):  
Single Molecule ◽  
Signal To Noise Ratio ◽  
Imaging Techniques ◽  
Super Resolution ◽  
Fast Imaging ◽  
Large Field ◽  
Localization Microscopy ◽  
Readout Noise ◽  
Single Pixel ◽  
Single Molecule Localization Microscopy

AbstractSingle-molecule localization microscopy (SMLM) has the highest spatial resolution among the existing super-resolution (SR) imaging techniques, but its temporal resolution needs further improvement. An sCMOS camera can effectively increase the imaging rate due to its large field of view and fast imaging speed. Using an sCMOS camera for SMLM imaging can significantly improve the imaging time resolution, but the unique single pixel-dependent readout noise of sCMOS cameras severely limits their application in SMLM imaging. This paper develops a Hessian-based SMLM (Hessian-SMLM) method that can correct the variance, gain and offset of a single pixel of a camera and effectively eliminate the pixel-dependent readout noise of sCMOS cameras, especially when the signal-to-noise ratio is low. Using Hessian SMLM to image mEos3.2-labeled actin was able to significantly reduce the artifacts due to camera noise.

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