Gimme shelter: three-dimensional architecture of the endoplasmic reticulum, the replication site of grapevine Pinot gris virus

2021 ◽  
Author(s):  
Laura Pagliari ◽  
Giulia Tarquini ◽  
Alberto Loschi ◽  
Sara Buoso ◽  
Gregor Kapun ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Three Dimensional ◽  
Grapevine Pinot Gris Virus ◽  
Replication Site

scholarly journals Structure of the Lectin Mannose 6-Phosphate Receptor Homology (MRH) Domain of Glucosidase II, an Enzyme That Regulates Glycoprotein Folding Quality Control in the Endoplasmic Reticulum

2013 ◽  
Vol 288 (23) ◽  
pp. 16460-16475 ◽  
Author(s):  
Linda J. Olson ◽  
Ramiro Orsi ◽  
Solana G. Alculumbre ◽  
Francis C. Peterson ◽  
Ivan D. Stigliano ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Three Dimensional ◽  
Binding Pocket ◽  
Dimensional Structure ◽  
Mannose Residue ◽  
Glucosidase Ii ◽  
Mannose 6 Phosphate ◽  
First Time ◽  
Conserved Residue

Here we report for the first time the three-dimensional structure of a mannose 6-phosphate receptor homology (MRH) domain present in a protein with enzymatic activity, glucosidase II (GII). GII is involved in glycoprotein folding in the endoplasmic reticulum. GII removes the two innermost glucose residues from the Glc3Man9GlcNAc2 transferred to nascent proteins and the glucose added by UDP-Glc:glycoprotein glucosyltransferase. GII is composed of a catalytic GIIα subunit and a regulatory GIIβ subunit. GIIβ participates in the endoplasmic reticulum localization of GIIα and mediates in vivo enhancement of N-glycan trimming by GII through its C-terminal MRH domain. We determined the structure of a functional GIIβ MRH domain by NMR spectroscopy. It adopts a β-barrel fold similar to that of other MRH domains, but its binding pocket is the most shallow known to date as it accommodates a single mannose residue. In addition, we identified a conserved residue outside the binding pocket (Trp-409) present in GIIβ but not in other MRHs that influences GII glucose trimming activity.

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...

Three-dimensional organization of endoplasmic reticulum in the ventral photoreceptors ofLimulus

1994 ◽  
Vol 341 (2) ◽  
pp. 172-183 ◽  
Author(s):  
Jane J. Feng ◽  
John H. Carson ◽  
Frank Morgan ◽  
Bernd Walz ◽  
Alan Fein
Keyword(s):  
Endoplasmic Reticulum ◽  
Three Dimensional

scholarly journals Endoplasmic reticulum–associated degradation regulates mitochondrial dynamics in brown adipocytes

Science ◽  
2020 ◽  
Vol 368 (6486) ◽  
pp. 54-60 ◽  
Author(s):  
Zhangsen Zhou ◽  
Mauricio Torres ◽  
Haibo Sha ◽  
Christopher J. Halbrook ◽  
Françoise Van den Bergh ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Mitochondrial Dynamics ◽  
Three Dimensional ◽  
Sigma Receptor ◽  
High Resolution Imaging ◽  
Brown Adipocytes ◽  
Physiological Importance ◽  
Endoplasmic Reticulum Associated Degradation ◽  
Cold Sensitive ◽  
Resolution Imaging

The endoplasmic reticulum (ER) engages mitochondria at specialized ER domains known as mitochondria-associated membranes (MAMs). Here, we used three-dimensional high-resolution imaging to investigate the formation of pleomorphic “megamitochondria” with altered MAMs in brown adipocytes lacking the Sel1L-Hrd1 protein complex of ER-associated protein degradation (ERAD). Mice with ERAD deficiency in brown adipocytes were cold sensitive and exhibited mitochondrial dysfunction. ERAD deficiency affected ER-mitochondria contacts and mitochondrial dynamics, at least in part, by regulating the turnover of the MAM protein, sigma receptor 1 (SigmaR1). Thus, our study provides molecular insights into ER-mitochondrial cross-talk and expands our understanding of the physiological importance of Sel1L-Hrd1 ERAD.

scholarly journals Morphogenesis of Endoplasmic Reticulum Membrane-Invaginated Vesicles during Beet Black Scorch Virus Infection: Role of Auxiliary Replication Protein and New Implications of Three-Dimensional Architecture

2015 ◽  
Vol 89 (12) ◽  
pp. 6184-6195 ◽  
Author(s):  
Xiuling Cao ◽  
Xuejiao Jin ◽  
Xiaofeng Zhang ◽  
Ying Li ◽  
Chunyan Wang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Rna Viruses ◽  
Rna Virus ◽  
Three Dimensional ◽  
Replication Protein ◽  
Positive Strand ◽  
Content Type ◽  
Positive Strand Rna ◽  
Tomographic Analysis ◽  
Beet Black Scorch Virus

ABSTRACTAll well-characterized positive-strand RNA viruses[(+)RNA viruses] induce the formation of host membrane-bound viral replication complexes (VRCs), yet the underlying mechanism and machinery for VRC formation remain elusive. We report here the biogenesis and topology of theBeet black scorch virus(BBSV) replication complex. Distinct cytopathological changes typical of endoplasmic reticulum (ER) aggregation and vesiculation were observed in BBSV-infectedNicotiana benthamianacells. Immunogold labeling of the auxiliary replication protein p23 and double-stranded RNA (dsRNA) revealed that the ER-derived membranous spherules provide the site for BBSV replication. Further studies indicated that p23 plays a crucial role in mediating the ER rearrangement. Three-dimensional electron tomographic analysis revealed the formation of multiple ER-originated vesicle packets. Each vesicle packet enclosed a few to hundreds of independent spherules that were invaginations of the ER membranes into the lumen. Strikingly, these vesicle packets were connected to each other via tubules, a rearrangement event that is rare among other virus-induced membrane reorganizations. Fibrillar contents within the spherules were also reconstructed by electron tomography, which showed diverse structures. Our results provide the first, to our knowledge, three-dimensional ultrastructural analysis of membrane-bound VRCs of a plant (+)RNA virus and should help to achieve a better mechanistic understanding of the organization and microenvironment of plant (+)RNA virus replication complexes.IMPORTANCEAssembly of virus replication complexes for all known positive-strand RNA viruses depends on the extensive remodeling of host intracellular membranes.Beet black scorch virus, a necrovirus in the familyTombusviridae, invaginates the endoplasmic reticulum (ER) membranes to form spherules in infected cells. Double-stranded RNAs, the viral replication intermediate, and the viral auxiliary replication protein p23 are all localized within such viral spherules, indicating that these are the sites for generating progeny viral RNAs. Furthermore, the BBSV p23 protein could to some extent reorganize the ER when transiently expressed inN. benthamiana. Electron tomographic analysis resolves the three-dimensional (3D) architecture of such spherules, which are connected to the cytoplasm via a neck-like structure. Strikingly, different numbers of spherules are enclosed in ER-originated vesicle packets that are connected to each other via tubule-like structures. Our results have significant implications for further understanding the mechanisms underlying the replication of positive-strand RNA viruses.

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