scholarly journals New insights into protein secretion: TANGO1 runs rings around the COPII coat

2017 ◽  
Vol 216 (4) ◽  
pp. 859-861 ◽  
Author(s):  
Benjamin S. Glick
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Secretion ◽  
Super Resolution ◽  
Cell Biol ◽  
Er Exit Sites ◽  
Er Export ◽  
Super Resolution Microscopy

In this issue, Liu et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201611088) and Raote et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201608080) use super-resolution microscopy to visualize large COPII-coated endoplasmic reticulum (ER) export carriers. Rings of TANGO1 surround COPII, implicating TANGO1 in organizing ER exit sites and in regulating COPII coat dynamics and geometry.

Cubic spline-based depth-dependent localization of mitochondria–endoplasmic reticulum contacts by three-dimensional light-sheet super-resolution microscopy

The Analyst ◽  
2021 ◽  
Author(s):  
Yucheng Sun ◽  
Seungah Lee ◽  
Seong Ho Kang
Keyword(s):  
Endoplasmic Reticulum ◽  
Calcium Homeostasis ◽  
Three Dimensional ◽  
Super Resolution ◽  
Light Sheet ◽  
Cubic Spline ◽  
Contact Distance ◽  
Super Resolution Microscopy

The contact distance between mitochondria (Mito) and endoplasmic reticulum (ER) has received considerable attention owing to their crucial function in maintaining lipid and calcium homeostasis. Herein, cubic spline algorithm-based depth-dependent...

scholarly journals Super Resolution Microscopy and Deep Learning Identify Zika Virus Reorganization of the Endoplasmic Reticulum

2020 ◽  
Author(s):  
Rory K. M. Long ◽  
Kathleen P. Moriarty ◽  
Ben Cardoen ◽  
Guang Gao ◽  
A. Wayne Vogl ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Deep Learning ◽  
Viral Replication ◽  
Zika Virus ◽  
Deep Neural Networks ◽  
Super Resolution ◽  
Zikv Infection ◽  
Subcellular Organelle ◽  
Infected Cells ◽  
Super Resolution Microscopy

AbstractThe endoplasmic reticulum (ER) is a complex subcellular organelle composed of diverse structures such as tubules, sheets and tubular matrices. Flaviviruses such as Zika virus (ZIKV) induce reorganization of endoplasmic reticulum (ER) membranes to facilitate viral replication. Here, using 3D super resolution microscopy, ZIKV infection is shown to induce the formation of dense tubular matrices associated with viral replication in the central ER. Viral non-structural proteins NS4B and NS2B associate with replication complexes within the ZIKV-induced tubular matrix and exhibit distinct ER distributions outside this central ER region. Deep neural networks trained to identify ZIKV-infected versus mock-infected cells successfully identified ZIKV-induced central ER tubular matrices as a determinant of viral infection. Super resolution microscopy and deep learning are therefore able to identify and localize morphological features of the ER and may be of use to screen for inhibitors of infection by ER-reorganizing viruses.

scholarly journals Polysulfide-triggered fluorescent indicator suitable for super-resolution microscopy and application in imaging

2018 ◽  
Vol 54 (30) ◽  
pp. 3735-3738 ◽  
Author(s):  
Anila Hoskere A. ◽  
Sreejesh Sreedharan ◽  
Firoj Ali ◽  
Carl G. Smythe ◽  
Jim A. Thomas ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Membrane ◽  
Super Resolution ◽  
Molecular Probe ◽  
Fluorescent Indicator ◽  
Super Resolution Microscopy

A new physiologically benign and cell membrane permeable BODIPY based molecular probe, MB-Sn, specifically senses intracellular hydrogen polysulfides (H2Sn, n > 1) localized in the endoplasmic reticulum.

scholarly journals Super resolution microscopy and deep learning identify Zika virus reorganization of the endoplasmic reticulum

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rory K. M. Long ◽  
Kathleen P. Moriarty ◽  
Ben Cardoen ◽  
Guang Gao ◽  
A. Wayne Vogl ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Deep Learning ◽  
Viral Replication ◽  
Viral Infection ◽  
Zika Virus ◽  
Deep Neural Networks ◽  
Super Resolution ◽  
Zikv Infection ◽  
Infected Cells ◽  
Super Resolution Microscopy

AbstractThe endoplasmic reticulum (ER) is a complex subcellular organelle composed of diverse structures such as tubules, sheets and tubular matrices. Flaviviruses such as Zika virus (ZIKV) induce reorganization of ER membranes to facilitate viral replication. Here, using 3D super resolution microscopy, ZIKV infection is shown to induce the formation of dense tubular matrices associated with viral replication in the central ER. Viral non-structural proteins NS4B and NS2B associate with replication complexes within the ZIKV-induced tubular matrix and exhibit distinct ER distributions outside this central ER region. Deep neural networks trained to distinguish ZIKV-infected versus mock-infected cells successfully identified ZIKV-induced central ER tubular matrices as a determinant of viral infection. Super resolution microscopy and deep learning are therefore able to identify and localize morphological features of the ER and allow for better understanding of how ER morphology changes due to viral infection.

scholarly journals Assay for dual cargo sorting into endoplasmic reticulum exit sites imaged by 3D Super-resolution Confocal Live Imaging Microscopy (SCLIM)

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258111
Author(s):  
Sofia Rodriguez-Gallardo ◽  
Kazuo Kurokawa ◽  
Susana Sabido-Bozo ◽  
Alejandro Cortes-Gomez ◽  
Ana Maria Perez-Linero ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Chain Length ◽  
Cell Biology ◽  
Super Resolution ◽  
Live Imaging ◽  
Live Cell ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Er Export ◽  
Cargo Sorting

Understanding how in eukaryotic cells thousands of proteins are sorted from each other through the secretory pathway and delivered to their correct destinations is a central issue of cell biology. We have further investigated in yeast how two distinct types of cargo proteins are sorted into different endoplasmic reticulum (ER) exit sites (ERES) for their differential ER export to the Golgi apparatus. We used an optimized protocol that combines a live cell dual-cargo ER export system with a 3D simultaneous multi-color high-resolution live cell microscopy called Super-resolution Confocal Live Imaging Microscopy (SCLIM). Here, we describe this protocol, which is based on the reversible ER retention of two de novo co-expressed cargos by blocking COPII function upon incubation of the thermo-sensitive COPII allele sec31-1 at restrictive temperature (37°C). ER export is restored by shifting down to permissive temperature (24°C) and progressive incorporation of the two different types of cargos into the fluorescently labelled ERES can be then simultaneously captured at 3D high spatial resolution by SCLIM microscopy. By using this protocol, we have shown that newly synthesized glycosylphosphatidylinositol (GPI)-anchored proteins having a very long chain ceramide lipid moiety are clustered and sorted into specialized ERES that are distinct from those used by transmembrane secretory proteins. Furthermore, we showed that the chain length of the ceramide present in the ER membrane is critical for this sorting selectivity. Therefore, thanks to the presented method we could obtain the first direct in vivo evidence for lipid chain length-based protein cargo sorting into selective ERES.

scholarly journals Super-resolution microscopy unveils FIP200-scaffolded, cup-shaped organization of mammalian autophagic initiation machinery

2019 ◽  
Author(s):  
Samuel J Kenny ◽  
Xuyan (Shirley) Chen ◽  
Liang Ge ◽  
Ke Xu
Keyword(s):  
Three Dimensional ◽  
Super Resolution ◽  
Subcellular Location ◽  
Outer Face ◽  
Structural Protein ◽  
Er Exit Sites ◽  
Autophagy Pathway ◽  
20 Nm ◽  
Yeast Homolog ◽  
Super Resolution Microscopy

AbstractAutophagy is an essential physiological process by which eukaryotic cells degrade and recycle cellular materials. Although the biochemical hierarchies of the mammalian autophagy pathway have been identified, questions remain regarding the sequence, subcellular location, and structural requirements of autophagosome formation. Here, we characterize the structural organization of key components of the mammalian autophagic initiation machinery at ∼20 nm spatial resolution via three-color, three-dimensional super-resolution fluorescence microscopy. We thus show that upon cell starvation, FIP200, a large structural protein of the ULK1 complex with no direct yeast homolog, scaffolds the formation of cup-like structures located at SEC12-enriched remodeled ER-exit sites prior to LC3 lipidation. This cup scaffold, then, provides a structural asymmetry to enforce the directional recruitment of downstream components, including the Atg12-Atg5-Atg16 complex, WIPI2, and LC3, to the cup inside. Moreover, we provide evidence that the early autophagic machinery is recruited in its entirety to these cup structures prior to LC3 lipidation, and gradually disperses and dissociates on the outer face of the phagophore membrane during elongation. We thus shed new light on the physical process of mammalian autophagic initiation and development at the nanometer-scale.

scholarly journals Shedding light on paraspeckle structure by super-resolution microscopy

2016 ◽  
Vol 214 (7) ◽  
pp. 789-791 ◽  
Author(s):  
Shi-Bin Hu ◽  
Run-Wen Yao ◽  
Ling-Ling Chen
Keyword(s):  
Gene Regulation ◽  
Super Resolution ◽  
Nuclear Body ◽  
Core Shell ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Cell Biol ◽  
Super Resolution Microscopy ◽  
Lncrna Neat1

The nuclear body paraspeckle is built on the lncRNA Neat1 and plays important roles in gene regulation. In this issue, West et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201601071) use super-resolution structured illumination microscopy to show that paraspeckles are organized in a core-shell spheroidal structure composed of Neat1 and seven proteins.

scholarly journals The endoplasmic reticulum adopts two distinct forms of tubules

2021 ◽  
Author(s):  
Ke Xu ◽  
Bowen Wang ◽  
Zhiheng Zhao ◽  
Michael Xiong ◽  
Rui Yan
Keyword(s):  
Endoplasmic Reticulum ◽  
Lipid Synthesis ◽  
Super Resolution ◽  
Cell Types ◽  
Membrane Curvature ◽  
Calcium Storage ◽  
Complex Membrane ◽  
Functional Implications ◽  
Different Cell Types ◽  
Super Resolution Microscopy

Abstract Being the largest and most expansive organelle in the cell, the endoplasmic reticulum (ER) carries diverse key functions from protein and lipid synthesis, protein folding and modification, transport, calcium storage, to organelle interactions1-6. The shaping mechanism of this complex, membrane-bounded organelle is thus of fundamental significance7-21. Using super-resolution microscopy, we uncover the coexistence of two distinct, well-defined forms of ER tubules in the mammalian cell. Whereas an ultrathin form, R1, is consistently covered by the membrane curvature-promoting protein Rtn4, in the second form, R2, Rtn4 curiously appears as two parallel lines at a conserved separation of ~105 nm over long ranges. The two tubule forms together account for ~90% of the total tubule lengths, with either one being dominant in different cell types. The R1-R2 dichotomy and the final tubule geometry are both co-regulated by Rtn4 and the ER sheet-maintaining protein Climp63, which respectively define the edge curvature and lumen height of the R2 tubules to generate a ribbon-like structure of well-defined width. The R1 and R2 tubules undergo active remodeling in the cell as they differently accommodate proteins, with the former effectively excluding ER-luminal proteins and ER-membrane proteins with large intraluminal domains. We thus unveil a dynamic ER-tubule structural dichotomy with intriguing functional implications.

scholarly journals LTK is an ER-resident receptor tyrosine kinase that regulates secretion

2019 ◽  
Author(s):  
Federica G. Centonze ◽  
Veronika Reiterer ◽  
Karsten Nalbach ◽  
Kota Saito ◽  
Krzysztof Pawlowski ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Tyrosine Kinase ◽  
Signaling Pathways ◽  
Receptor Tyrosine Kinase ◽  
Secretory Proteins ◽  
Golgi Transport ◽  
Er Exit Sites ◽  
Local Signaling ◽  
Er Export ◽  
Pharmacologic Inhibition

AbstractThe endoplasmic reticulum (ER) is a key regulator of cellular proteostasis because it controls folding, sorting and degradation of secretory proteins. Much has been learned about how environmentally triggered signaling pathways regulate ER function, but only little is known about local signaling at the ER. The identification of ER-resident signaling molecules will help gain a deeper understanding of the regulation of ER function and thus of proteostasis. Here, we show that leukocyte tyrosine kinase (LTK) is an ER-resident receptor tyrosine kinase. Depletion of LTK as well as its pharmacologic inhibition reduces the number of ER exit sites and slows ER-to-Golgi transport. Furthermore, we show that LTK interacts with and phosphorylates Sec12. Expression of a phosphoablating mutant of Sec12 reduces the efficiency of ER export. Thus, LTK-to-Sec12 signaling represents the first example of an ER-resident signaling module the potential to regulate proteostasis.

scholarly journals The endoplasmic reticulum adopts two distinct tubule forms

2021 ◽  
Author(s):  
Bowen Wang ◽  
Zhiheng Zhao ◽  
Michael Xiong ◽  
Rui Yan ◽  
Ke Xu
Keyword(s):  
Endoplasmic Reticulum ◽  
Super Resolution ◽  
Cell Types ◽  
Membrane Curvature ◽  
Parallel Lines ◽  
Native Cell ◽  
Functional Implications ◽  
Different Cell Types ◽  
Super Resolution Microscopy ◽  
Er Membrane

The endoplasmic reticulum (ER) is a versatile organelle with diverse functions. Through super-resolution microscopy, we show that the peripheral ER in the mammalian cell adopts two distinct forms of tubules. Whereas an ultrathin form, R1, is consistently covered by ER-membrane curvature-promoting proteins, e.g., Rtn4 in the native cell, in the second form, R2, Rtn4 and analogs are arranged into two parallel lines at a conserved separation of ~105 nm over long ranges. The two tubule forms together account for ~90% of the total tubule length in the cell, with either one being dominant in different cell types. The R1-R2 dichotomy and the final tubule geometry are both co-regulated by Rtn4 (and analogs) and the ER sheet-maintaining protein Climp63, which respectively define the edge curvature and lumen height of the R2 tubules to generate a ribbon-like structure of well-defined width. Accordingly, the R2 tubule width correlates positively with the Climp63 intralumenal size. The R1 and R2 tubules undergo active remodeling at the second/sub-second time scales as they differently accommodate proteins, with the former effectively excluding ER-luminal proteins and ER-membrane proteins with large intraluminal domains. We thus uncover a dynamic structural dichotomy for ER tubules with intriguing functional implications.

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