scholarly journals Mixed-Disulfide Folding Intermediates between Thyroglobulin and Endoplasmic Reticulum Resident Oxidoreductases ERp57 and Protein Disulfide Isomerase

2005 ◽  
Vol 25 (22) ◽  
pp. 9793-9805 ◽  
Author(s):  
Bruno Di Jeso ◽  
Young-nam Park ◽  
Luca Ulianich ◽  
A. Sonia Treglia ◽  
Malene L. Urbanas ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Disulfide Isomerase ◽  
Er Quality Control ◽  
Disulfide Isomerase ◽  
Folding Intermediates ◽  
Unfolded Protein ◽  
Mixed Disulfide ◽  
Mixed Disulfides ◽  
The Unfolded Protein Response ◽  
Protein Disulfide

ABSTRACT We present the first identification of transient folding intermediates of endogenous thyroglobulin (Tg; a large homodimeric secretory glycoprotein of thyrocytes), which include mixed disulfides with endogenous oxidoreductases servicing Tg folding needs. Formation of disulfide-linked Tg adducts with endoplasmic reticulum (ER) oxidoreductases begins cotranslationally. Inhibition of ER glucosidase activity blocked formation of a subgroup of Tg adducts containing ERp57 while causing increased Tg adduct formation with protein disulfide isomerase (PDI), delayed adduct resolution, perturbed oxidative folding of Tg monomers, impaired Tg dimerization, increased Tg association with BiP/GRP78 and GRP94, activation of the unfolded protein response, increased ER-associated degradation of a subpopulation of Tg, partial Tg escape from ER quality control with increased secretion of free monomers, and decreased overall Tg secretion. These data point towards mixed disulfides with the ERp57 oxidoreductase in conjunction with calreticulin/calnexin chaperones acting as normal early Tg folding intermediates that can be “substituted” by PDI adducts only at the expense of lower folding efficiency with resultant ER stress.

scholarly journals Aging and Hypercholesterolemia Differentially Affect the Unfolded Protein Response in the Vasculature of ApoE −/− Mice

2021 ◽  
Author(s):  
Yuxiang Zhou ◽  
Xueping Wan ◽  
Kerstin Seidel ◽  
Mo Zhang ◽  
Jena B. Goodman ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Transcription Factor ◽  
Endoplasmic Reticulum Stress ◽  
Protein Disulfide Isomerase ◽  
Disulfide Isomerase ◽  
Unfolded Protein ◽  
Activating Transcription Factor ◽  
The Unfolded Protein Response ◽  
Protein Response ◽  
Protein Disulfide

Background Persistent activation of endoplasmic reticulum stress and the unfolded protein response (UPR) induces vascular cell apoptosis, contributing to atherogenesis. Aging and hypercholesterolemia are 2 independent proatherogenic factors. How they affect vascular UPR signaling remains unclear. Methods and Results Transcriptome analysis of aortic tissues from high fat diet–fed and aged ApoE −/− mice revealed 50 overlapping genes enriched for endoplasmic reticulum stress‐ and UPR‐related pathways. Aortae from control, Western diet (WD)–fed, and aged ApoE −/− mice were assayed for (1) 3 branches of UPR signaling (pancreatic ER eIF2‐alpha kinase /alpha subunit of the eukaryotic translation initiation factor 1/activating transcription factor 4, inositol‐requiring enzyme 1 alpha/XBP1s, activating transcription factor 6); (2) UPR‐mediated protective adaptation (upregulation of immunoglobulin heavy chain‐binding protein and protein disulfide isomerase); and (3) UPR‐mediated apoptosis (induction of C/EBP homologous transcription factor, p‐JNK, and cleaved caspase‐3). Aortic UPR signaling was differentially regulated in the aged and WD‐fed groups. Consumption of WD activated all 3 UPR branches; in the aged aorta, only the ATF6α arm was activated, but it was 10 times higher than that in the WD group. BiP and protein disulfide isomerase protein levels were significantly decreased only in the aged aorta despite a 5‐fold increase in their mRNA levels. Importantly, the aortae of aged mice exhibited a substantially enhanced proapoptotic UPR compared with that of WD‐fed mice. In lung tissues, UPR activation and the resultant adaptive/apoptotic responses were not significantly different between the 2 groups. Conclusions Using a mouse model of atherosclerosis, this study provides the first in vivo evidence that aging and an atherogenic diet activate differential aortic UPR pathways, leading to distinct vascular responses. Compared with dietary intervention, aging is associated with impaired endoplasmic reticulum protein folding and increased aortic apoptosis.

scholarly journals S-Glutathionylation of Protein Disulfide Isomerase Regulates Estrogen ReceptorαStability and Function

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Ying Xiong ◽  
Yefim Manevich ◽  
Kenneth D. Tew ◽  
Danyelle M. Townsend
Keyword(s):  
Protein Disulfide Isomerase ◽  
Estrogen Receptor Alpha ◽  
Redox Regulation ◽  
Gene Products ◽  
Disulfide Isomerase ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
And Function ◽  
Protein Response ◽  
Protein Disulfide

S-Glutathionylation of cysteine residues within target proteins is a posttranslational modification that alters structure and function. We have shown that S-glutathionylation of protein disulfide isomerase (PDI) disrupts protein folding and leads to the activation of the unfolded protein response (UPR). PDI is a molecular chaperone for estrogen receptor alpha(ERα). Our present data show in breast cancer cells that S-glutathionylation of PDI interferes with its chaperone activity and abolishes its capacity to form a complex withERα. Such drug treatment also reverses estradiol-induced upregulation of c-Myc, cyclinD1, andP21Cip, gene products involved in cell proliferation. Expression of an S-glutathionylation refractory PDI mutant diminishes the toxic effects of PABA/NO. Thus, redox regulation of PDI causes its S-glutathionylation, thereby mediating cell death through activation of the UPR and abrogation ofERαstability and signaling.

scholarly journals Structure-Function Analysis of the Endoplasmic Reticulum Oxidoreductase TMX3 Reveals Interdomain Stabilization of the N-terminal Redox-active Domain

2007 ◽  
Vol 282 (46) ◽  
pp. 33859-33867 ◽  
Author(s):  
Johannes Haugstetter ◽  
Michael Andreas Maurer ◽  
Thomas Blicher ◽  
Martin Pagac ◽  
Gerhard Wider ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Disulfide Isomerase ◽  
Function Analysis ◽  
Transmembrane Protein ◽  
Reduced Form ◽  
Disulfide Isomerase ◽  
Binding Domains ◽  
Redox Active ◽  
Protein Disulfide ◽  
Protein Disulfide Isomerase Family

Disulfide bond formation in the endoplasmic reticulum is catalyzed by enzymes of the protein disulfide-isomerase family that harbor one or more thioredoxin-like domains. We recently discovered the transmembrane protein TMX3, a thiol-disulfide oxidoreductase of the protein disulfide-isomerase family. Here, we show that the endoplasmic reticulum-luminal region of TMX3 contains three thioredoxin-like domains, an N-terminal redox-active domain (named a) followed by two enzymatically inactive domains (b and b′). Using the recombinantly expressed TMX3 domain constructs a, ab, and abb′, we compared structural stability and enzymatic properties. By structural and biophysical methods, we demonstrate that the reduced a domain has features typical of a globular folded domain that is, however, greatly destabilized upon oxidization. Importantly, interdomain stabilization by the b domain renders the a domain more resistant toward chemical denaturation and proteolysis in both the oxidized and reduced form. In combination with molecular modeling studies of TMX3 abb′, the experimental results provide a new understanding of the relationship between the multidomain structure of TMX3 and its function as a redox enzyme. Overall, the data indicate that in addition to their role as substrate and co-factor binding domains, redox-inactive thioredoxin-like domains also function in stabilizing neighboring redox-active domains.

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