scholarly journals Induction of the Endoplasmic-Reticulum-Stress Response: MicroRNA-34a Targeting of the IRE1α-Branch

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1442
Author(s):  
Lena Krammes ◽  
Martin Hart ◽  
Stefanie Rheinheimer ◽  
Caroline Diener ◽  
Jennifer Menegatti ◽  
...  

Neurodegenerative disorders such as Alzheimer’s disease (AD) and Parkinson’s disease (PD) are characterized by the accumulation of misfolded proteins in the endoplasmic reticulum (ER) and the unfolded protein response (UPR). Modulating the UPR is one of the major challenges to counteract the development of neurodegenerative disorders and other diseases with affected UPR. Here, we show that miR-34a-5p directly targets the IRE1α branch of the UPR, including the genes BIP, IRE1α, and XBP1. Upon induction of ER stress in neuronal cells, miR-34a-5p overexpression impacts the resulting UPR via a significant reduction in IRE1α and XBP1s that in turn leads to decreased viability, increased cytotoxicity and caspase activity. The possibility to modify the UPR signaling pathway by a single miRNA that targets central genes of the IRE1α branch offers new perspectives for future therapeutic approaches against neurodegeneration.

Author(s):  
Kashi Raj Bhattarai ◽  
Thoufiqul Alam Riaz ◽  
Hyung-Ryong Kim ◽  
Han-Jung Chae

AbstractThe endoplasmic reticulum (ER) is an essential organelle of eukaryotic cells. Its main functions include protein synthesis, proper protein folding, protein modification, and the transportation of synthesized proteins. Any perturbations in ER function, such as increased demand for protein folding or the accumulation of unfolded or misfolded proteins in the ER lumen, lead to a stress response called the unfolded protein response (UPR). The primary aim of the UPR is to restore cellular homeostasis; however, it triggers apoptotic signaling during prolonged stress. The core mechanisms of the ER stress response, the failure to respond to cellular stress, and the final fate of the cell are not yet clear. Here, we discuss cellular fate during ER stress, cross talk between the ER and mitochondria and its significance, and conditions that can trigger ER stress response failure. We also describe how the redox environment affects the ER stress response, and vice versa, and the aftermath of the ER stress response, integrating a discussion on redox imbalance-induced ER stress response failure progressing to cell death and dynamic pathophysiological changes.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yang Yu ◽  
Dan-yang Liu ◽  
Xue-shen Chen ◽  
Ling Zhu ◽  
Li-hong Wan

The mesencephalic astrocyte-derived neurotrophic factor (MANF), also named as arginine-rich protein (ARP) or arginine-rich mutated in early-stage tumors (ARMET), is a novel evolutionary conserved protein related to unfolded protein response. Growing evidence suggests that MANF critically involves in many ER stress-related diseases with a protective effect. Here, we review the function of MANF based on its structure in neurological and metabolic disorders and summarize its potential applications in disease diagnosis and therapies.


2005 ◽  
Vol 391 (1) ◽  
pp. 135-142 ◽  
Author(s):  
Daisuke Oikawa ◽  
Yukio Kimata ◽  
Masato Takeuchi ◽  
Kenji Kohno

The luminal domain of the type I transmembrane protein Ire1 senses endoplasmic reticulum stress by an undefined mechanism to up-regulate the signalling pathway for the unfolded protein response. Previously, we proposed that the luminal domain of yeast Ire1 is divided into five subregions, termed subregions I–V sequentially from the N-terminus. Ire1 lost activity when internal deletions of subregion II or IV were made. In the present paper, we show that partial proteolysis of a recombinant protein consisting of the Ire1 luminal domain suggests that subregions II–IV are tightly folded. We also show that a recombinant protein of subregions II–IV formed homodimers, and that this homodimer formation was impaired by an internal deletion of subregion IV. Furthermore, recombinant fragments of subregion IV exhibited a self-binding ability. Therefore, although its sequence is little conserved evolutionarily, subregion IV plays an essential role to promote Ire1 dimer formation.


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