scholarly journals Evidence of Presynaptic Localization and Function of the c-Jun N-Terminal Kinase

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Silvia Biggi ◽  
Lucia Buccarello ◽  
Alessandra Sclip ◽  
Pellegrino Lippiello ◽  
Noemi Tonna ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Physiological Role ◽  
Super Resolution ◽  
Snare Complex ◽  
Snare Proteins ◽  
Electrophysiological Recordings ◽  
Presynaptic Site ◽  
Presynaptic Nmda Receptors ◽  
And Function ◽  
Super Resolution Microscopy

The c-Jun N-terminal kinase (JNK) is part of a stress signalling pathway strongly activated by NMDA-stimulation and involved in synaptic plasticity. Many studies have been focused on the post-synaptic mechanism of JNK action, and less is known about JNK presynaptic localization and its physiological role at this site. Here we examined whether JNK is present at the presynaptic site and its activity after presynaptic NMDA receptors stimulation. By using N-SIM Structured Super Resolution Microscopy as well as biochemical approaches, we demonstrated that presynaptic fractions contained significant amount of JNK protein and its activated form. By means of modelling design, we found that JNK, via the JBD domain, acts as a physiological effector on T-SNARE proteins; then using biochemical approaches we demonstrated the interaction between Syntaxin-1-JNK, Syntaxin-2-JNK, and Snap25-JNK. In addition, taking advance of the specific JNK inhibitor peptide, D-JNKI1, we defined JNK action on the SNARE complex formation. Finally, electrophysiological recordings confirmed the role of JNK in the presynaptic modulation of vesicle release. These data suggest that JNK-dependent phosphorylation of T-SNARE proteins may have an important functional role in synaptic plasticity.

Super-Resolution Microscopy in Studying the Structure and Function of the Cell Nucleus

Acta Naturae ◽  
2017 ◽  
Vol 9 (4) ◽  
pp. 42-51
Author(s):  
S. S. Ryabichko ◽  
◽  
A. N. Ibragimov ◽  
L. A. Lebedeva ◽  
E. N. Kozlov ◽  
...  
Keyword(s):  
Cell Nucleus ◽  
Super Resolution ◽  
Structure And Function ◽  
And Function ◽  
Super Resolution Microscopy

scholarly journals Dynamics and nanoscale organization of the postsynaptic endocytic zone at excitatory synapses

2021 ◽  
Author(s):  
Lisa A.E. Catsburg ◽  
Manon Westra ◽  
Annemarie M. L. van Schaik ◽  
Harold D. MacGillavry
Keyword(s):  
Synaptic Plasticity ◽  
Actin Cytoskeleton ◽  
Glutamate Receptors ◽  
Super Resolution ◽  
Live Cell ◽  
Excitatory Synapses ◽  
Membrane Interactions ◽  
Synaptic Receptors ◽  
Microscopy Techniques ◽  
Super Resolution Microscopy

ABSTRACTAt postsynaptic sites of neurons, a prominent clathrin-coated structure, the endocytic zone (EZ), controls the trafficking of glutamate receptors and is essential for synaptic plasticity. Despite its importance, little is known about how this clathrin structure is organized to mediate endocytosis. We used live-cell and super-resolution microscopy techniques to reveal the dynamic organization of this poorly understood clathrin structure. We found that a subset of endocytic proteins only transiently appeared at postsynaptic sites. In contrast, other proteins, including Eps15, intersectin1L, and β2-adaptin, were persistently enriched and partitioned at the edge of the EZ. We found that uncoupling the EZ from the synapse led to the loss of most of these components, while disrupting the actin cytoskeleton or AP2-membrane interactions did not alter EZ positioning. We conclude that the EZ is a stable, highly organized molecular platform where components are differentially recruited and positioned to orchestrate the endocytosis of synaptic receptors.

scholarly journals Microscope-AOtools: A generalised adaptive optics implementation

2020 ◽  
Author(s):  
Nicholas Hall ◽  
Josh Titlow ◽  
Martin J. Booth ◽  
Ian M. Dobbie
Keyword(s):  
Image Quality ◽  
Adaptive Optics ◽  
Super Resolution ◽  
Biological Imaging ◽  
New Techniques ◽  
Reduce Image Quality ◽  
Set Up ◽  
And Function ◽  
Microscopy Techniques ◽  
Super Resolution Microscopy

AbstractMicroscope-AOtools is a software package which allows for a simple, robust and generalised implementation of adaptive optics (AO) elements. It contains all the necessary methods for set-up, calibration, and aberration correction which are simple to use and function in a robust manner. Aberrations arising from sources such as sample hetero-geneity and refractive index mismatches are constant problems in biological imaging. These aberrations reduce image quality and the achievable depth of imaging, particularly in super-resolution microscopy techniques. AO technology has been proven to be effective in correcting for these aberrations and thereby improving the image quality. However, it has not been widely adopted by the biological imaging community due, in part, to difficulty in set-up and operation of AO, particularly by non-specialist users. Microscope-AOtools offers a robust, easy-to-use implementation of the essential methods for set-up and use of AO techniques. These methods are constructed in a generalised manner that can utilise a range of adaptive optics elements, wavefront sensing techniques and sensorless AO correction methods. Furthermore, the methods are designed to be easily extensible as new techniques arise, leading to a streamlined pipeline for new AO technology and techniques to be adopted by the wider microscopy community.

scholarly journals Structural and Functional Modulation of Perineuronal Nets: In Search of Important Players with Highlight on Tenascins

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1345
Author(s):  
Ana Jakovljević ◽  
Milena Tucić ◽  
Michaela Blažiková ◽  
Andrej Korenić ◽  
Yannis Missirlis ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Brain Plasticity ◽  
Super Resolution ◽  
Perineuronal Nets ◽  
Optimal Conditions ◽  
Neuronal Function ◽  
Specialized Form ◽  
Functional Modulation ◽  
Super Resolution Microscopy ◽  
The Brain

The extracellular matrix (ECM) of the brain plays a crucial role in providing optimal conditions for neuronal function. Interactions between neurons and a specialized form of ECM, perineuronal nets (PNN), are considered a key mechanism for the regulation of brain plasticity. Such an assembly of interconnected structural and regulatory molecules has a prominent role in the control of synaptic plasticity. In this review, we discuss novel ways of studying the interplay between PNN and its regulatory components, particularly tenascins, in the processes of synaptic plasticity, mechanotransduction, and neurogenesis. Since enhanced neuronal activity promotes PNN degradation, it is possible to study PNN remodeling as a dynamical change in the expression and organization of its constituents that is reflected in its ultrastructure. The discovery of these subtle modifications is enabled by the development of super-resolution microscopy and advanced methods of image analysis.

scholarly journals Periodic actin structures in neuronal axons are required to maintain microtubules

2016 ◽  
Author(s):  
Yue Qu ◽  
Ines Hahn ◽  
Stephen Webb ◽  
Simon P. Pearce ◽  
Andreas Prokop
Keyword(s):  
Super Resolution ◽  
Close Correlation ◽  
Membrane Skeleton ◽  
Cortical Actin ◽  
Evolutionarily Conserved ◽  
Genes Encoding ◽  
Neuronal Processes ◽  
And Function ◽  
Super Resolution Microscopy ◽  
Actin Rings

SummaryAxons are the cable-like neuronal processes wiring the nervous system. They contain parallel bundles of microtubules as structural backbones, surrounded by regularly-spaced actin rings termed the periodic membrane skeleton (PMS). Despite being an evolutionarily-conserved, ubiquitous, highly-ordered feature of axons, the function of PMS is unknown. Here we studied PMS abundance, organisation and function, combining versatile Drosophila genetics with super-resolution microscopy and various functional readouts. Analyses with 11 different actin regulators and 3 actin-targeting drugs suggest PMS to contain short actin filaments which are depolymerisation resistant and sensitive to spectrin, adducin and nucleator deficiency - consistent with microscopy-derived models proposing PMS as specialised cortical actin. Upon actin removal we observed gaps in microtubule bundles, reduced microtubule polymerisation and reduced axon numbers suggesting a role of PMS in microtubule organisation. These effects become strongly enhanced when carried out in neurons lacking the microtubule-stabilising protein Short stop (Shot). Combining the aforementioned actin manipulations with Shot deficiency revealed a close correlation between PMS abundance and microtubule regulation, consistent with a model in which PMS-dependent microtubule polymerisation contributes to their maintenance in axons. We discuss potential implications of this novel PMS function along axon shafts for axon maintenance and regeneration.Significance statementAxons are cable-like neuronal processes that are up to a meter long in humans. These delicate structures often need to be maintained for an organism’s lifetime, i.e. up to a century in humans. Unsurprisingly, we gradually lose about 50% of axons as we age. Bundles of microtubules form the structural backbones and highways for life-sustaining transport within axons, and maintenance of these bundles is essential for axonal longevity. However, the mechanisms which actively maintain axonal microtubules are poorly understood. Here we identify cortical actin as an important factor maintaining microtubule polymerisation in axons. This finding provides potential explanations for the previously identified, but unexplained, links between mutations in genes encoding cortical actin regulators and neurodegeneration.

Tools and limitations to study the molecular composition of synapses by fluorescence microscopy

2016 ◽  
Vol 473 (20) ◽  
pp. 3385-3399 ◽  
Author(s):  
Manuel Maidorn ◽  
Silvio O. Rizzoli ◽  
Felipe Opazo
Keyword(s):  
Super Resolution ◽  
Molecular Composition ◽  
Synaptic Organization ◽  
Synaptic Physiology ◽  
Copy Numbers ◽  
Resolution Imaging ◽  
And Function ◽  
Microscopy Techniques ◽  
Super Resolution Microscopy ◽  
Affinity Probes

The synapse is densely packed with proteins involved in various highly regulated processes. Synaptic protein copy numbers and their stoichiometric distribution have a drastic influence on neuronal integrity and function. Therefore, the molecular analysis of synapses is a key element to understand their architecture and function. The overall structure of the synapse has been revealed with an exquisite amount of details by electron microscopy. However, the molecular composition and the localization of proteins are more easily addressed with fluorescence imaging, especially with the improved resolution achieved by super-resolution microscopy techniques. Notably, the fast improvement of imaging instruments has not been reflected in the optimization of biological sample preparation. During recent years, large efforts have been made to generate affinity probes smaller than conventional antibodies adapted for fluorescent super-resolution imaging. In this review, we briefly discuss the current views on synaptic organization and necessary key technologies to progress in the understanding of synaptic physiology. We also highlight the challenges faced by current fluorescent super-resolution methods, and we describe the prerequisites for an ideal study of synaptic organization.

Protein clustering and spatial organization in T-cells

2015 ◽  
Vol 43 (3) ◽  
pp. 315-321 ◽  
Author(s):  
Michael J. Shannon ◽  
Garth Burn ◽  
Andrew Cope ◽  
Georgina Cornish ◽  
Dylan M. Owen
Keyword(s):  
T Cell ◽  
Single Molecule ◽  
Spatial Organization ◽  
Super Resolution ◽  
Cell Protein ◽  
Single Molecule Level ◽  
Composition And Structure ◽  
Resolution Analysis ◽  
And Function ◽  
Super Resolution Microscopy

T-cell protein microclusters have until recently been investigable only as microscale entities with their composition and structure being discerned by biochemistry or diffraction-limited light microscopy. With the advent of super resolution microscopy comes the ability to interrogate the structure and function of these clusters at the single molecule level by producing highly accurate pointillist maps of single molecule locations at ~20nm resolution. Analysis tools have also been developed to provide rich descriptors of the pointillist data, allowing us to pose questions about the nanoscale organization which governs the local and cell wide responses required of a migratory T-cell.

scholarly journals CRISPR/Cas9-Based RGEN-ISL Allows the Simultaneous and Specific Visualization of Proteins, DNA Repeats, and Sites of DNA Replication

2019 ◽  
Vol 159 (1) ◽  
pp. 48-53 ◽  
Author(s):  
Alžběta Němečková ◽  
Christina Wäsch ◽  
Veit Schubert ◽  
Takayoshi Ishii ◽  
Eva Hřibová ◽  
...  
Keyword(s):  
Dna Replication ◽  
Chromatin Structure ◽  
Super Resolution ◽  
Dna Repeats ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Replication Sites ◽  
And Function ◽  
Super Resolution Microscopy

Visualizing the spatiotemporal organization of the genome will improve our understanding of how chromatin structure and function are intertwined. Here, we describe a further development of the CRISPR/Cas9-based RNA-guided endonuclease-in situ labeling (RGEN-ISL) method. RGEN-ISL allowed the differentiation between vertebrate-type (TTAGGG)n and Arabidopsis-type (TTTAGGG)n telomere repeats. Using maize as an example, we established a combination of RGEN-ISL, immunostaining, and EdU labeling to visualize in situ specific repeats, histone marks, and DNA replication sites, respectively. The effects of the non-denaturing RGEN-ISL and standard denaturing FISH on the chromatin structure were compared using super-resolution microscopy. 3D structured illumination microscopy revealed that denaturation and acetic acid fixation impaired and flattened the chromatin. The broad range of adaptability of RGEN-ISL to different combinations of methods has the potential to advance the field of chromosome biology.

Super-Resolution Microscopy in Studying the Structure and Function of the Cell Nucleus

Acta Naturae ◽  
2017 ◽  
Vol 9 (4) ◽  
pp. 42-51 ◽  
Author(s):  
S. S. Ryabichko ◽  
◽  
A. N. Ibragimov ◽  
L. A. Lebedeva ◽  
E. N. Kozlov ◽  
...  
Keyword(s):  
Cell Nucleus ◽  
Super Resolution ◽  
Structure And Function ◽  
And Function ◽  
Super Resolution Microscopy
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