scholarly journals 3D Images of Neuronal Adhesion Molecule Contactin-2 Reveal an Unanticipated Two-State Architecture

2018 ◽  
Author(s):  
Z. Lu ◽  
D. Lei ◽  
S. Seshadrinathan ◽  
A. Szwed ◽  
J. Liu ◽  
...  
Keyword(s):  
Structural Dynamics ◽  
Single Molecule ◽  
Adhesion Molecule ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Extracellular Domain ◽  
Imaging Method ◽  
Contact Points ◽  
Neural Adhesion Molecule ◽  
Terminal Domains

ABSTRACTContactins (CNTNs) are important cell adhesion molecules that mediate neuronal and axoglial contacts, and lesions in these molecules are linked to neuropsychiatric disorders. The extracellular domain of CNTNs contains six Ig domains and four FNIII domains. Crystal structures have shown that Ig1-Ig4 forms a horseshoe-shaped headpiece, in which the N-terminal domains might fold back on the C-terminal domains to form molecular super-U shaped architecture. The arrangement of these domains has been controversial, which may due to the structural dynamics and conformation heterogeneity of the protein. Here, we used a single-molecule 3D imaging method, individual-particle electron tomography (IPET), to study the extracellular domain of CNTN2 that forms monomers with a broad spectrum of conformations, and obtained 60 three-dimensional (3D) reconstructions. In addition to the known horseshoe-shaped headpiece, ~75% headpieces unexpectedly adopt an open (elongated) or a semi-open conformations contributed to our understanding about structural dynamics. The ectodomains formed curve but not double-back in any uniform way, with an averaged molecular dimension of ~255 Å. The first-time demonstration of the dynamic nature and conformational preferences of the full-length CNTN2 ectodomain suggest that the headpiece exists in equilibrium in the ‘closed’ or ‘not-closed’ states. The important architecture may provide a structural platform for protein partners to influence this balance regulating the function of CNTN2. Encoding the ability of this neural adhesion molecule to form both homomers with itself, as well as recruit different protein partner to neuronal and axoglial contact points play the key role in mediating cell-cell interactions.

A Novel Method for Automated Acquisition of Tilt Series for Electron Tomography Based on Pre-Calibration of the Specimen Stage

2000 ◽  
Vol 6 (S2) ◽  
pp. 1148-1149
Author(s):  
U. Ziese ◽  
A.H. Janssen ◽  
T.P. van der Krift ◽  
A.G. van Balen ◽  
W.J. de Ruijter ◽  
...  
Keyword(s):  
High Resolution ◽  
3D Reconstruction ◽  
Cell Biology ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Imaging Method ◽  
3D Images ◽  
Tilt Series ◽  
3D Information ◽  
Structural Arrangements

Electron tomography is a three-dimensional (3D) imaging method with transmission electron microscopy (TEM) that provides high-resolution 3D images of structural arrangements. Conventional TEM images are in first approximation mere 2D-projections of a 3D sample under investigation. With electron tomographya series of images is acquired of a sample that is tilted over a large angular range (±70°) with small angular tilt increments (so called tilt-series). For the subsequent 3D-reconstruction, the images of the tilt series are aligned relative to each other and the 3D-reconstruction is computed. Electron tomography is the only technique that can provide true 3D information with nm-scale resolution of individual and unique samples. For (cell) biology and material science applications the availability of high-resolution 3D images of structural arrangements within individual samples provides unique architectural information that cannot be obtained otherwise. Routine application of electron tomography will comprise a major revolutionary step forward in the characterization of complex materials and cellular arrangements.

Three-dimensional structural dynamics of myosin V by single-molecule fluorescence polarization

Nature ◽  
2003 ◽  
Vol 422 (6930) ◽  
pp. 399-404 ◽  
Author(s):  
Joseph N. Forkey ◽  
Margot E. Quinlan ◽  
M. Alexander Shaw ◽  
John E. T. Corrie ◽  
Yale E. Goldman
Keyword(s):  
Structural Dynamics ◽  
Single Molecule ◽  
Fluorescence Polarization ◽  
Three Dimensional ◽  
Myosin V ◽  
Single Molecule Fluorescence

Structure of cell–cell adhesion mediated by the Down syndrome cell adhesion molecule

2021 ◽  
Vol 118 (39) ◽  
pp. e2022442118
Author(s):  
Luqiang Guo ◽  
Yichun Wu ◽  
Haishuang Chang ◽  
Ze Zhang ◽  
Hua Tang ◽  
...  
Keyword(s):  
Neural Network ◽  
Down Syndrome ◽  
Cell Adhesion ◽  
Adhesion Molecule ◽  
Neural Development ◽  
Cell Adhesion Molecule ◽  
Network Formation ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Immunoglobulin Superfamily

The Down syndrome cell adhesion molecule (DSCAM) belongs to the immunoglobulin superfamily (IgSF) and plays important roles in neural development. It has a large ectodomain, including 10 Ig-like domains and 6 fibronectin III (FnIII) domains. Previous data have shown that DSCAM can mediate cell adhesion by forming homophilic dimers between cells and contributes to self-avoidance of neurites or neuronal tiling, which is important for neural network formation. However, the organization and assembly of DSCAM at cell adhesion interfaces has not been fully understood. Here we combine electron microscopy and other biophysical methods to characterize the structure of the DSCAM-mediated cell adhesion and generate three-dimensional views of the adhesion interfaces of DSCAM by electron tomography. The results show that mouse DSCAM forms a regular pattern at the adhesion interfaces. The Ig-like domains contribute to both trans homophilic interactions and cis assembly of the pattern, and the FnIII domains are crucial for the cis pattern formation as well as the interaction with the cell membrane. By contrast, no obvious assembly pattern is observed at the adhesion interfaces mediated by mouse DSCAML1 or Drosophila DSCAMs, suggesting the different structural roles and mechanisms of DSCAMs in mediating cell adhesion and neural network formation.

scholarly journals Three-dimensional structural dynamics and fluctuations of DNA-nanogold conjugates by individual-particle electron tomography

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Lei Zhang ◽  
Dongsheng Lei ◽  
Jessica M. Smith ◽  
Meng Zhang ◽  
Huimin Tong ◽  
...  
Keyword(s):  
Structural Dynamics ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Individual Particle

scholarly journals Three-dimensional structural dynamics of DNA origami Bennett linkages using individual-particle electron tomography

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Dongsheng Lei ◽  
Alexander E. Marras ◽  
Jianfang Liu ◽  
Chao-Min Huang ◽  
Lifeng Zhou ◽  
...  
Keyword(s):  
Structural Dynamics ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Dna Origami ◽  
Individual Particle

scholarly journals Awareness of Cryo Electro-Tomography among Dental Students

2020 ◽  
Vol 11 (SPL3) ◽  
pp. 1050-1053
Author(s):  
Nithyanandham Masilamani ◽  
Dhanraj Ganapathy
Keyword(s):  
College Students ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Image Data ◽  
Dental Students ◽  
Imaging Method ◽  
Cross Sectional ◽  
3D Images ◽  
Cryo Electron Tomography ◽  
Diagnostic Applications

CryoElectronomography (CryoET) is indeed an imaging method used to create high resolution (~1-4 nm) three-dimensional viewpoints of specimen, usually physiological macromolecules as well as cell lines. CryoET is really a highly specialized implementation of scanning electron microscopy cryomicroscopy whereby the specimen are scanned since they are tilted, triggering a series of Image data which can be processed to create a 3d image, analogous to 3D images, similar to a CT scan of the human body. This survey was done for assessing the awareness of Cryo electro tomography amongst dental students. This was a questionnaire oriented cross-sectional type of survey comprising 100 dental college students in Chennai. A self-designed questionnaire comprising ten questions based on the knowledge and awareness aboutCryo-electron tomography amongst dental college students. Questionnaires were circulated through an online website survey planet. The questions explored the awareness of using Cryo-electron tomography as a tool to study various biological applications. After the responses were received from 100 participants, data was collected and analyzed .7% are aware about Cryo Electro-tomography. 3% are aware of the mechanism of action of Cryo Electro-tomography. 5% are aware of the diagnostic applications of Cryo Electro-tomography. 3% are aware of the limitations Cryo Electro-tomography.91% are willing to learn about Cryo Electro-tomography. This study concluded that dental students showed less knowledge and awareness toward Cryo Electro-tomography. There are large gaps in the knowledge and attitudes requiring strong remedial measures.

Practical electron tomography

1995 ◽  
Vol 53 ◽  
pp. 742-743
Author(s):  
C.L. Woodcock
Keyword(s):  
Electron Tomography ◽  
Tomographic Reconstruction ◽  
Three Dimensional ◽  
3D Shape ◽  
Computational Resources ◽  
Shape Of Particles

Despite the potential of the technique, electron tomography has yet to be widely used by biologists. This is in part related to the rather daunting list of equipment and expertise that are required. Thanks to continuing advances in theory and instrumentation, tomography is now more feasible for the non-specialist. One barrier that has essentially disappeared is the expense of computational resources. In view of this progress, it is time to give more attention to practical issues that need to be considered when embarking on a tomographic project. The following recommendations and comments are derived from experience gained during two long-term collaborative projects.Tomographic reconstruction results in a three dimensional description of an individual EM specimen, most commonly a section, and is therefore applicable to problems in which ultrastructural details within the thickness of the specimen are obscured in single micrographs. Information that can be recovered using tomography includes the 3D shape of particles, and the arrangement and dispostion of overlapping fibrous and membranous structures.

Three-Dimensional reconstruction of isolated centrosomes by automated electron tomography

1994 ◽  
Vol 52 ◽  
pp. 310-311
Author(s):  
M.B. Braunfeld ◽  
M. Moritz ◽  
B.M. Alberts ◽  
J.W. Sedat ◽  
D.A. Agard
Keyword(s):  
Electron Tomography ◽  
Three Dimensional ◽  
Vital Role ◽  
Complex Nature ◽  
Animal Cells ◽  
Microtubule Organizing Center ◽  
Nucleation Sites ◽  
Dimensional Reconstruction ◽  
Organizing Center ◽  
Resolution Model

In animal cells, the centrosome functions as the primary microtubule organizing center (MTOC). As such the centrosome plays a vital role in determining a cell's shape, migration, and perhaps most importantly, its division. Despite the obvious importance of this organelle little is known about centrosomal regulation, duplication, or how it nucleates microtubules. Furthermore, no high resolution model for centrosomal structure exists.We have used automated electron tomography, and reconstruction techniques in an attempt to better understand the complex nature of the centrosome. Additionally we hope to identify nucleation sites for microtubule growth.Centrosomes were isolated from early Drosophila embryos. Briefly, after large organelles and debris from homogenized embryos were pelleted, the resulting supernatant was separated on a sucrose velocity gradient. Fractions were collected and assayed for centrosome-mediated microtubule -nucleating activity by incubating with fluorescently-labeled tubulin subunits. The resulting microtubule asters were then spun onto coverslips and viewed by fluorescence microscopy.

Structural dynamics of P-type ATPase ion pumps

2019 ◽  
Vol 47 (5) ◽  
pp. 1247-1257 ◽  
Author(s):  
Mateusz Dyla ◽  
Sara Basse Hansen ◽  
Poul Nissen ◽  
Magnus Kjaergaard
Keyword(s):  
Structural Dynamics ◽  
Single Molecule ◽  
New Technologies ◽  
Atp Hydrolysis ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Time Resolved ◽  
Dynamics Simulations ◽  
Types Of Information ◽  
P Type

Abstract P-type ATPases transport ions across biological membranes against concentration gradients and are essential for all cells. They use the energy from ATP hydrolysis to propel large intramolecular movements, which drive vectorial transport of ions. Tight coordination of the motions of the pump is required to couple the two spatially distant processes of ion binding and ATP hydrolysis. Here, we review our current understanding of the structural dynamics of P-type ATPases, focusing primarily on Ca2+ pumps. We integrate different types of information that report on structural dynamics, primarily time-resolved fluorescence experiments including single-molecule Förster resonance energy transfer and molecular dynamics simulations, and interpret them in the framework provided by the numerous crystal structures of sarco/endoplasmic reticulum Ca2+-ATPase. We discuss the challenges in characterizing the dynamics of membrane pumps, and the likely impact of new technologies on the field.

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