scholarly journals Inter-dependent apical microtubule and actin dynamics orchestrate centrosome retention and neuronal delamination

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Ioannis Kasioulis ◽  
Raman M Das ◽  
Kate G Storey
Keyword(s):  
Adherens Junctions ◽  
Adherens Junction ◽  
Super Resolution ◽  
Actin Dynamics ◽  
Actin Cable ◽  
Neuroepithelial Cells ◽  
Cytoskeletal Dynamics ◽  
Resolution Imaging ◽  
Newborn Neurons ◽  
Functional Circuitry

Detachment of newborn neurons from the neuroepithelium is required for correct neuronal architecture and functional circuitry. This process, also known as delamination, involves adherens-junction disassembly and acto-myosin-mediated abscission, during which the centrosome is retained while apical/ciliary membranes are shed. Cell-biological mechanisms mediating delamination are, however, poorly understood. Using live-tissue and super-resolution imaging, we uncover a centrosome-nucleated wheel-like microtubule configuration, aligned with the apical actin cable and adherens-junctions within chick and mouse neuroepithelial cells. These microtubules maintain adherens-junctions while actin maintains microtubules, adherens-junctions and apical end-foot dimensions. During neuronal delamination, acto-myosin constriction generates a tunnel-like actin-microtubule configuration through which the centrosome translocates. This movement requires inter-dependent actin and microtubule activity, and we identify drebrin as a potential coordinator of these cytoskeletal dynamics. Furthermore, centrosome compromise revealed that this organelle is required for delamination. These findings identify new cytoskeletal configurations and regulatory relationships that orchestrate neuronal delamination and may inform mechanisms underlying pathological epithelial cell detachment.

scholarly journals Abelson kinase regulates epithelial morphogenesis in Drosophila

2001 ◽  
Vol 155 (7) ◽  
pp. 1185-1198 ◽  
Author(s):  
Elizabeth E. Grevengoed ◽  
Joseph J. Loureiro ◽  
Traci L. Jesse ◽  
Mark Peifer
Keyword(s):  
Epithelial Cells ◽  
Adherens Junctions ◽  
Adherens Junction ◽  
Epithelial Morphogenesis ◽  
Actin Dynamics ◽  
Nonreceptor Tyrosine Kinase ◽  
Abelson Kinase ◽  
Adherens Junction Protein ◽  
Junction Protein ◽  
Guidance Receptors

Activation of the nonreceptor tyrosine kinase Abelson (Abl) contributes to the development of leukemia, but the complex roles of Abl in normal development are not fully understood. Drosophila Abl links neural axon guidance receptors to the cytoskeleton. Here we report a novel role for Drosophila Abl in epithelial cells, where it is critical for morphogenesis. Embryos completely lacking both maternal and zygotic Abl die with defects in several morphogenetic processes requiring cell shape changes and cell migration. We describe the cellular defects that underlie these problems, focusing on dorsal closure as an example. Further, we show that the Abl target Enabled (Ena), a modulator of actin dynamics, is involved with Abl in morphogenesis. We find that Ena localizes to adherens junctions of most epithelial cells, and that it genetically interacts with the adherens junction protein Armadillo (Arm) during morphogenesis. The defects of abl mutants are strongly enhanced by heterozygosity for shotgun, which encodes DE-cadherin. Finally, loss of Abl reduces Arm and α-catenin accumulation in adherens junctions, while having little or no effect on other components of the cytoskeleton or cell polarity machinery. We discuss possible models for Abl function during epithelial morphogenesis in light of these data.

scholarly journals PSGL-1 inhibits HIV-1 infection by restricting actin dynamics and sequestering HIV envelope proteins

2020 ◽  
Author(s):  
Ying Liu ◽  
Yutong Song ◽  
Siyu Zhang ◽  
Min Diao ◽  
Shanjin Huang ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Viral Entry ◽  
Super Resolution ◽  
Actin Dynamics ◽  
Hiv Dna ◽  
Cryo Electron Microscopy ◽  
Resolution Imaging ◽  
Underlying Mechanisms ◽  
Hiv Envelope ◽  
Anti Hiv

AbstractPSGL-1 has recently been identified as an HIV restriction factor that inhibits HIV DNA synthesis and more potently, virion infectivity. But the underlying mechanisms of these inhibitions are unknown. Here we show that PSGL-1 directly binds to cellular actin filaments (F-actin) and restricts actin dynamics, which leads to inhibition of HIV DNA synthesis. PSGL-1 is incorporated into nascent virions and restricts actin dynamics in the virions, which partially accounts for the inhibition of virion infectivity. More potently, PSGL-1 inhibits incorporation of Env proteins into nascent virions, leading to loss of envelope spikes on the virions as shown by Cryo-electron microscopy and super-resolution imaging. This loss is associated with a profound defect in viral entry. Mechanistically, PSGL-1 binds gp41 and sequesters gp41 at the plasma membrane, explaining the inhibition of Env incorporation in nascent virions. PSGL-1’s dual anti-HIV mechanisms represent novel strategies of human cells to defend against HIV infection.

scholarly journals Fast Target Localization Method for FMCW MIMO Radar via VDSR Neural Network

2021 ◽  
Vol 13 (10) ◽  
pp. 1956
Author(s):  
Jingyu Cong ◽  
Xianpeng Wang ◽  
Xiang Lan ◽  
Mengxing Huang ◽  
Liangtian Wan
Keyword(s):  
Neural Network ◽  
Continuous Wave ◽  
Super Resolution ◽  
Mimo Radar ◽  
Target Localization ◽  
Estimation Accuracy ◽  
Low Resolution ◽  
Range Estimation ◽  
Resolution Image ◽  
Resolution Imaging

The traditional frequency-modulated continuous wave (FMCW) multiple-input multiple-output (MIMO) radar two-dimensional (2D) super-resolution (SR) estimation algorithm for target localization has high computational complexity, which runs counter to the increasing demand for real-time radar imaging. In this paper, a fast joint direction-of-arrival (DOA) and range estimation framework for target localization is proposed; it utilizes a very deep super-resolution (VDSR) neural network (NN) framework to accelerate the imaging process while ensuring estimation accuracy. Firstly, we propose a fast low-resolution imaging algorithm based on the Nystrom method. The approximate signal subspace matrix is obtained from partial data, and low-resolution imaging is performed on a low-density grid. Then, the bicubic interpolation algorithm is used to expand the low-resolution image to the desired dimensions. Next, the deep SR network is used to obtain the high-resolution image, and the final joint DOA and range estimation is achieved based on the reconstructed image. Simulations and experiments were carried out to validate the computational efficiency and effectiveness of the proposed framework.

scholarly journals 3D super-resolved imaging in live cells using sub-diffractive plasmonic localization of hybrid nanopillar arrays

Nanophotonics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 2847-2859
Author(s):  
Soojung Kim ◽  
Hyerin Song ◽  
Heesang Ahn ◽  
Seung Won Jun ◽  
Seungchul Kim ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Imaging Techniques ◽  
Optical Loss ◽  
Super Resolution ◽  
Living Cells ◽  
Live Cells ◽  
Complex Biological System ◽  
Observation Volume ◽  
Resolution Imaging ◽  
Nanopillar Arrays

AbstractAnalysing dynamics of a single biomolecule using high-resolution imaging techniques has been had significant attentions to understand complex biological system. Among the many approaches, vertical nanopillar arrays in contact with the inside of cells have been reported as a one of useful imaging applications since an observation volume can be confined down to few-tens nanometre theoretically. However, the nanopillars experimentally are not able to obtain super-resolution imaging because their evanescent waves generate a high optical loss and a low signal-to-noise ratio. Also, conventional nanopillars have a limitation to yield 3D information because they do not concern field localization in z-axis. Here, we developed novel hybrid nanopillar arrays (HNPs) that consist of SiO2 nanopillars terminated with gold nanodisks, allowing extreme light localization. The electromagnetic field profiles of HNPs are obtained through simulations and imaging resolution of cell membrane and biomolecules in living cells are tested using one-photon and 3D multiphoton fluorescence microscopy, respectively. Consequently, HNPs present approximately 25 times enhanced intensity compared to controls and obtained an axial and lateral resolution of 110 and 210 nm of the intensities of fluorophores conjugated with biomolecules transported in living cells. These structures can be a great platform to analyse complex intracellular environment.

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