scholarly journals Structure and Function of Mitochondria-Associated Endoplasmic Reticulum Membranes (MAMs) and Their Role in Cardiovascular Diseases

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Yi Luan ◽  
Ying Luan ◽  
Rui-Xia Yuan ◽  
Qi Feng ◽  
Xing Chen ◽  
...  

Abnormal function of suborganelles such as mitochondria and endoplasmic reticulum often leads to abnormal function of cardiomyocytes or vascular endothelial cells and cardiovascular disease (CVD). Mitochondria-associated membrane (MAM) is involved in several important cellular functions. Increasing evidence shows that MAM is involved in the pathogenesis of CVD. MAM mediates multiple cellular processes, including calcium homeostasis regulation, lipid metabolism, unfolded protein response, ROS, mitochondrial dynamics, autophagy, apoptosis, and inflammation, which are key risk factors for CVD. In this review, we discuss the structure of MAM and MAM-associated proteins, their role in CVD progression, and the potential use of MAM as the therapeutic targets for CVD treatment.

2019 ◽  
Vol 20 (7) ◽  
pp. 1792 ◽  
Author(s):  
Kyeorda Kemp ◽  
Cody Poe

The unfolded protein response (UPR) is a highly conserved pathway that allows cells to respond to stress in the endoplasmic reticulum caused by an accumulation of misfolded and unfolded protein. This is of great importance to secretory cells because, in order for proteins to traffic from the endoplasmic reticulum (ER), they need to be folded appropriately. While a wealth of literature has implicated UPR in immune responses, less attention has been given to the role of UPR in T cell development and function. This review discusses the importance of UPR in T cell development, homeostasis, activation, and effector functions. We also speculate about how UPR may be manipulated in T cells to ameliorate pathologies.


2021 ◽  
Vol 12 ◽  
Author(s):  
Emily M. Nakada ◽  
Rui Sun ◽  
Utako Fujii ◽  
James G. Martin

The accumulation of unfolded/misfolded proteins in the endoplasmic reticulum (ER) causes ER stress and induces the unfolded protein response (UPR) and other mechanisms to restore ER homeostasis, including translational shutdown, increased targeting of mRNAs for degradation by the IRE1-dependent decay pathway, selective translation of proteins that contribute to the protein folding capacity of the ER, and activation of the ER-associated degradation machinery. When ER stress is excessive or prolonged and these mechanisms fail to restore proteostasis, the UPR triggers the cell to undergo apoptosis. This review also examines the overlooked role of post-translational modifications and their roles in protein processing and effects on ER stress and the UPR. Finally, these effects are examined in the context of lung structure, function, and disease.


2020 ◽  
Vol 219 (6) ◽  
Author(s):  
Yasmine J. Liu ◽  
Rebecca L. McIntyre ◽  
Georges E. Janssens ◽  
Evan G. Williams ◽  
Jiayi Lan ◽  
...  

Mitochondrial form and function are closely interlinked in homeostasis and aging. Inhibiting mitochondrial translation is known to increase lifespan in C. elegans, and is accompanied by a fragmented mitochondrial network. However, whether this link between mitochondrial translation and morphology is causal in longevity remains uncharacterized. Here, we show in C. elegans that disrupting mitochondrial network homeostasis by blocking fission or fusion synergizes with reduced mitochondrial translation to prolong lifespan and stimulate stress response such as the mitochondrial unfolded protein response, UPRMT. Conversely, immobilizing the mitochondrial network through a simultaneous disruption of fission and fusion abrogates the lifespan increase induced by mitochondrial translation inhibition. Furthermore, we find that the synergistic effect of inhibiting both mitochondrial translation and dynamics on lifespan, despite stimulating UPRMT, does not require it. Instead, this lifespan-extending synergy is exclusively dependent on the lysosome biogenesis and autophagy transcription factor HLH-30/TFEB. Altogether, our study reveals the mechanistic crosstalk between mitochondrial translation, mitochondrial dynamics, and lysosomal signaling in regulating longevity.


Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 640
Author(s):  
Nataša Pavlović ◽  
Femke Heindryckx

Endoplasmic reticulum (ER) stress and actors of unfolded protein response (UPR) have emerged as key hallmarks of hepatocarcinogenesis. Numerous reports have shown that the main actors in the UPR pathways are upregulated in HCC and contribute to the different facets of tumor initiation and disease progression. Furthermore, ER-stress inducers and inhibitors have shown success in preclinical HCC models. Despite the mounting evidence of the UPR’s involvement in HCC pathogenesis, it remains unclear how ER-stress components can be used safely and effectively as therapeutic targets or predictive biomarkers for HCC patients. In an effort to add a clinical context to these findings and explore the translational potential of ER-stress in HCC, we performed a systematic overview of UPR-associated proteins as predictive biomarkers in HCC by mining the Human Protein Atlas database. Aside from evaluating the prognostic value of these markers in HCC, we discussed their expression in relation to patient age, sex, ethnicity, disease stage, and tissue localization. We thereby identified 44 UPR-associated proteins as unfavorable prognostic markers in HCC. The expression of these markers was found to be higher in tumors compared to the stroma of the hepatic HCC patient tissues.


2021 ◽  
Vol 13 ◽  
Author(s):  
Haigang Ren ◽  
Wanqing Zhai ◽  
Xiaojun Lu ◽  
Guanghui Wang

Parkinson’s disease (PD) is the most common neurodegenerative movement disorder, and it is characterized by the selective loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc), as well as the presence of intracellular inclusions with α-synuclein as the main component in surviving DA neurons. Emerging evidence suggests that the imbalance of proteostasis is a key pathogenic factor for PD. Endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR) and autophagy, two major pathways for maintaining proteostasis, play important roles in PD pathology and are considered as attractive therapeutic targets for PD treatment. However, although ER stress/UPR and autophagy appear to be independent cellular processes, they are closely related to each other. In this review, we focused on the roles and molecular cross-links between ER stress/UPR and autophagy in PD pathology. We systematically reviewed and summarized the most recent advances in regulation of ER stress/UPR and autophagy, and their cross-linking mechanisms. We also reviewed and discussed the mechanisms of the coexisting ER stress/UPR activation and dysregulated autophagy in the lesion regions of PD patients, and the underlying roles and molecular crosslinks between ER stress/UPR activation and the dysregulated autophagy in DA neurodegeneration induced by PD-associated genetic factors and PD-related neurotoxins. Finally, we indicate that the combined regulation of ER stress/UPR and autophagy would be a more effective treatment for PD rather than regulating one of these conditions alone.


Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1960
Author(s):  
K. Tanuj Sapra ◽  
Ohad Medalia

The cytoskeleton of the eukaryotic cell provides a structural and functional scaffold enabling biochemical and cellular functions. While actin and microtubules form the main framework of the cell, intermediate filament networks provide unique mechanical properties that increase the resilience of both the cytoplasm and the nucleus, thereby maintaining cellular function while under mechanical pressure. Intermediate filaments (IFs) are imperative to a plethora of regulatory and signaling functions in mechanotransduction. Mutations in all types of IF proteins are known to affect the architectural integrity and function of cellular processes, leading to debilitating diseases. The basic building block of all IFs are elongated α-helical coiled-coils that assemble hierarchically into complex meshworks. A remarkable mechanical feature of IFs is the capability of coiled-coils to metamorphize into β-sheets under stress, making them one of the strongest and most resilient mechanical entities in nature. Here, we discuss structural and mechanical aspects of IFs with a focus on nuclear lamins and vimentin.


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