scholarly journals MNRR1, a Biorganellar Regulator of Mitochondria

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Lawrence I. Grossman ◽  
Neeraja Purandare ◽  
Rooshan Arshad ◽  
Stephanie Gladyck ◽  
Mallika Somayajulu ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Neurodegenerative Diseases ◽  
Family Members ◽  
Unusual Property ◽  
Promoter Element ◽  
Low Oxygen ◽  
Oxidative Stresses ◽  
Graded Response ◽  
Oxygen Tensions

The central role of energy metabolism in cellular activities is becoming widely recognized. However, there are many gaps in our knowledge of the mechanisms by which mitochondria evaluate their status and call upon the nucleus to make adjustments. Recently, a protein family consisting of twin CX9C proteins has been shown to play a role in human pathophysiology. We focus here on two family members, the isoforms CHCHD2 (renamed MNRR1) and CHCHD10. The better studied isoform, MNRR1, has the unusual property of functioning in both the mitochondria and the nucleus and of having a different function in each. In the mitochondria, it functions by binding to cytochromecoxidase (COX), which stimulates respiration. Its binding to COX is promoted by tyrosine-99 phosphorylation, carried out by ABL2 kinase (ARG). In the nucleus, MNRR1 binds to a novel promoter element inCOX4I2and itself, increasing transcription at 4% oxygen. We discuss mutations in both MNRR1 and CHCHD10 found in a number of chronic, mostly neurodegenerative, diseases. Finally, we propose a model of a graded response to hypoxic and oxidative stresses, mediated under different oxygen tensions by CHCHD10, MNRR1, and HIF1, which operate at intermediate and very low oxygen concentrations, respectively.

scholarly journals The Role of Ethylene in the Inhibition of Rooting under Low Oxygen Tensions

1989 ◽  
Vol 89 (1) ◽  
pp. 165-168 ◽  
Author(s):  
Hillel Soffer ◽  
Shimon Mayak ◽  
David W. Burger ◽  
Michael S. Reid
Keyword(s):  
Low Oxygen ◽  
Oxygen Tensions

scholarly journals ER-mitochondria cross-talk is regulated by the Ca2+ sensor NCS1 and is impaired in Wolfram syndrome

2018 ◽  
Vol 11 (553) ◽  
pp. eaaq1380 ◽  
Author(s):  
Claire Angebault ◽  
Jérémy Fauconnier ◽  
Simone Patergnani ◽  
Jennifer Rieusset ◽  
Alberto Danese ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Energy Metabolism ◽  
Neurodegenerative Diseases ◽  
Cell Survival ◽  
Cross Talk ◽  
Wolfram Syndrome ◽  
Calcium Sensor ◽  
Inositol 1,4,5 Trisphosphate ◽  
Trisphosphate Receptor

Communication between the endoplasmic reticulum (ER) and mitochondria plays a pivotal role in Ca2+ signaling, energy metabolism, and cell survival. Dysfunction in this cross-talk leads to metabolic and neurodegenerative diseases. Wolfram syndrome is a fatal neurodegenerative disease caused by mutations in the ER-resident protein WFS1. Here, we showed that WFS1 formed a complex with neuronal calcium sensor 1 (NCS1) and inositol 1,4,5-trisphosphate receptor (IP3R) to promote Ca2+ transfer between the ER and mitochondria. In addition, we found that NCS1 abundance was reduced in WFS1-null patient fibroblasts, which showed reduced ER-mitochondria interactions and Ca2+ exchange. Moreover, in WFS1-deficient cells, NCS1 overexpression not only restored ER-mitochondria interactions and Ca2+ transfer but also rescued mitochondrial dysfunction. Our results describe a key role of NCS1 in ER-mitochondria cross-talk, uncover a pathogenic mechanism for Wolfram syndrome, and potentially reveal insights into the pathogenesis of other neurodegenerative diseases.

Vasoactivity of S-nitrosohemoglobin: role of oxygen, heme, and NO oxidation states

Blood ◽  
2003 ◽  
Vol 101 (11) ◽  
pp. 4408-4415 ◽  
Author(s):  
Jack H. Crawford ◽  
C. Roger White ◽  
Rakesh P. Patel
Keyword(s):  
Nitrogen Monoxide ◽  
No Oxidation ◽  
Oxidation States ◽  
Low Oxygen ◽  
Independent Manner ◽  
No Donor ◽  
Oxygen Tensions ◽  
Isolated Rat

Abstract The mechanisms by which S-nitrosohemoglobin (SNOHb) stimulates vasodilation are unclear and underlie the controversies surrounding the proposal that this S-nitrosothiol modulates blood flow in vivo. Among the mechanistic complexities are the nature of vasoactive species released from SNOHb and the role heme and oxygen play in this process. This is important to address since hemoglobin inhibits NO-dependent vasodilation. We compared the vasodilatory properties of distinct oxidation and ligation states of SNOHb at different oxygen tensions. The results show that SNOHb in the oxygenated state (SNOoxyHb) is significantly less efficient than SNOHb in the ferric or met oxidation state (SNOmetHb) at stimulating relaxation of isolated rat aortic rings. Using pharmacologic approaches to modulate nitrogen monoxide radical (·NO)–dependent relaxation, our data suggest that SNOoxyHb promotes vasodilation in a ·NO-independent manner. In contrast, both SNOmetHb and S-nitrosoglutathione (GSNO), a putative intermediate in SNOHb reactivity, elicit vasodilation in a ·NO-dependent process. Consistent with previous observations, an increase in sensitivity of SNOHb vasodilation at low oxygen tensions also was observed. However, this was not exclusive for this protein but applied to a range of nitrosovasodilators (including a ·NO donor [DeaNonoate], an S-nitrosothiol [GSNO], and the nitroxyl anion donor, Angelis salt). This suggests that oxygen-dependent modulation of SNOHb vasoactivity does not occur by controlling the allosteric state of Hb but is a property of vessel responsiveness to nitrosovasodilators at low oxygen tensions.

Mitochondrial matrix calcium ions regulate energy production in myocardium: A cytochemical study

1990 ◽  
Vol 48 (2) ◽  
pp. 166-167
Author(s):  
W.A. Jacob ◽  
R. Hertsens ◽  
A. Van Bogaert ◽  
M. De Smet
Keyword(s):  
Energy Metabolism ◽  
Calcium Ions ◽  
Energy Production ◽  
Regulation Of Respiration ◽  
Free Calcium ◽  
Mitochondrial Matrix ◽  
Cytochemical Study ◽  
Nmr Techniques

In the past most studies of the control of energy metabolism focus on the role of the phosphorylation potential ATP/ADP.Pi on the regulation of respiration. Studies using NMR techniques have demonstrated that the concentrations of these compounds for oxidation phosphorylation do not change appreciably throughout the cardiac cycle and during increases in cardiac work. Hence regulation of energy production by calcium ions, present in the mitochondrial matrix, has been the object of a number of recent studies.Three exclusively intramitochondnal dehydrogenases are key enzymes for the regulation of oxidative metabolism. They are activated by calcium ions in the low micromolar range. Since, however, earlier estimates of the intramitochondnal calcium, based on equilibrium thermodynamic considerations, were in the millimolar range, a physiological correlation was not evident. The introduction of calcium-sensitive probes fura-2 and indo-1 made monitoring of free calcium during changing energy metabolism possible. These studies were performed on isolated mitochondria and extrapolation to the in vivo situation is more or less speculative.

The Role of Family Members in Safer/Unsafe Injection Drug Use Practices

2011 ◽  
Author(s):  
L. Jackson ◽  
M. Dykeman ◽  
J. Gahagan ◽  
J. Karabanow ◽  
J. Parker
Keyword(s):  
Drug Use ◽  
Injection Drug Use ◽  
Family Members ◽  
Injection Drug ◽  
Unsafe Injection

Role of the Structural Characteristics of Dendrimers in the Manifestation of the Antiamyloid Properties

INEOS OPEN ◽  
2020 ◽  
Vol 3 ◽  
Author(s):  
S. A. Sorokina ◽  
◽  
Yu. Yu. Stroilova ◽  
V. I. Muronets ◽  
Z. B. Shifrina ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Structural Characteristics ◽  
Short Review ◽  
External Factors ◽  
Amyloid Aggregation ◽  
Amyloid Proteins ◽  
Molecular Parameters ◽  
Amyloid Aggregates ◽  
Aggregation Processes

Among the compounds able to efficiently inhibit the amyloid aggregation of proteins and decompose the amyloid aggregates that cause neurodegenerative diseases, of particular interest are dendrimers, which represent individual macromolecules with the hypercrosslinked architectures and given molecular parameters. This short review outlines the peculiarities of the antiamyloid activity of dendrimers and discusses the effect of dendrimer structures and external factors on their antiamyloid properties. The potential of application of dendrimers in further investigations on the aggregation processes of amyloid proteins as the compounds that exhibit the remarkable antiamyloid activity is evaluated.

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