scholarly journals The disulfide relay system of mitochondria is connected to the respiratory chain

2007 ◽  
Vol 179 (3) ◽  
pp. 389-395 ◽  
Author(s):  
Karl Bihlmaier ◽  
Nikola Mesecke ◽  
Nadia Terziyska ◽  
Melanie Bien ◽  
Kai Hell ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transport ◽  
Cytochrome C ◽  
Respiratory Chain ◽  
Disulfide Bonds ◽  
Electron Transport Chain ◽  
Intermembrane Space ◽  
Sulfhydryl Oxidase ◽  
Relay System ◽  
Transport Chain

All proteins of the intermembrane space of mitochondria are encoded by nuclear genes and synthesized in the cytosol. Many of these proteins lack presequences but are imported into mitochondria in an oxidation-driven process that relies on the activity of Mia40 and Erv1. Both factors form a disulfide relay system in which Mia40 functions as a receptor that transiently interacts with incoming polypeptides via disulfide bonds. Erv1 is a sulfhydryl oxidase that oxidizes and activates Mia40, but it has remained unclear how Erv1 itself is oxidized. Here, we show that Erv1 passes its electrons on to molecular oxygen via interaction with cytochrome c and cytochrome c oxidase. This connection to the respiratory chain increases the efficient oxidation of the relay system in mitochondria and prevents the formation of toxic hydrogen peroxide. Thus, analogous to the system in the bacterial periplasm, the disulfide relay in the intermembrane space is connected to the electron transport chain of the inner membrane.

scholarly journals Regulation of COX Assembly and Function by Twin CX9C Proteins—Implications for Human Disease

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 197
Author(s):  
Stephanie Gladyck ◽  
Siddhesh Aras ◽  
Maik Hüttemann ◽  
Lawrence I. Grossman
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Atp Synthase ◽  
Protein Interactions ◽  
Human Disease ◽  
Electron Transport Chain ◽  
Intermembrane Space ◽  
Protein Protein Interactions ◽  
Inner Mitochondrial Membrane ◽  
Transport Chain

Oxidative phosphorylation is a tightly regulated process in mammals that takes place in and across the inner mitochondrial membrane and consists of the electron transport chain and ATP synthase. Complex IV, or cytochrome c oxidase (COX), is the terminal enzyme of the electron transport chain, responsible for accepting electrons from cytochrome c, pumping protons to contribute to the gradient utilized by ATP synthase to produce ATP, and reducing oxygen to water. As such, COX is tightly regulated through numerous mechanisms including protein–protein interactions. The twin CX9C family of proteins has recently been shown to be involved in COX regulation by assisting with complex assembly, biogenesis, and activity. The twin CX9C motif allows for the import of these proteins into the intermembrane space of the mitochondria using the redox import machinery of Mia40/CHCHD4. Studies have shown that knockdown of the proteins discussed in this review results in decreased or completely deficient aerobic respiration in experimental models ranging from yeast to human cells, as the proteins are conserved across species. This article highlights and discusses the importance of COX regulation by twin CX9C proteins in the mitochondria via COX assembly and control of its activity through protein–protein interactions, which is further modulated by cell signaling pathways. Interestingly, select members of the CX9C protein family, including MNRR1 and CHCHD10, show a novel feature in that they not only localize to the mitochondria but also to the nucleus, where they mediate oxygen- and stress-induced transcriptional regulation, opening a new view of mitochondrial-nuclear crosstalk and its involvement in human disease.

scholarly journals Complex I-Associated Hydrogen Peroxide Production Is Decreased and Electron Transport Chain Enzyme Activities Are Altered in n-3 Enriched fat-1 Mice

PLoS ONE ◽  
2010 ◽  
Vol 5 (9) ◽  
pp. e12696 ◽  
Author(s):  
Kevork Hagopian ◽  
Kristina L. Weber ◽  
Darren T. Hwee ◽  
Alison L. Van Eenennaam ◽  
Guillermo López-Lluch ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transport ◽  
Enzyme Activities ◽  
Complex I ◽  
Electron Transport Chain ◽  
Hydrogen Peroxide Production ◽  
Transport Chain

scholarly journals Effects of L-Malate on Mitochondrial Oxidoreductases in Liver of Aged Rats

2011 ◽  
pp. 329-336 ◽  
Author(s):  
J.-L. WU ◽  
Q.-P. WU ◽  
Y.-P. PENG ◽  
J.-M. ZHANG
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Electron Transport Chain ◽  
Nadh Dehydrogenase ◽  
Tricarboxylic Acid Cycle ◽  
Radical Scavenger ◽  
Aged Rats ◽  
Transport Chain ◽  
Nadh Cytochrome

Accumulation of oxidative damage has been implicated to be a major causative factor in the decline in physiological functions that occur during the aging process. The mitochondrial respiratory chain is a powerful source of reactive oxygen species (ROS), considered as the pathogenic agent of many diseases and aging. L-malate, a tricarboxylic acid cycle intermediate, plays an important role in transporting NADH from cytosol to mitochondria for energy production. Previous studies in our laboratory reported L-malate as a free radical scavenger in aged rats. In the present study we focused on the effect of L-malate on the activities of electron transport chain in young and aged rats. We found that mitochondrial membrane potential (MMP) and the activities of succinate dehydrogenase, NADH-cytochrome c oxidoreductase and cytochrome c oxidase in liver of aged rats were significantly decreased when compared to young control rats. Supplementation of L-malate to aged rats for 30 days slightly increased MMP and improved the activities of NADH-dehydrogenase, NADH-cytochrome c oxidoreductase and cytochrome c oxidase in liver of aged rats when compared with aged control rats. In young rats, L-malate administration increased only the activity of NADH-dehydrogenase. Our result suggested that L-malate could improve the activities of electron transport chain enzymes in aged rats

Formation mechanisms of superoxide radical and hydrogen peroxide in chloroplasts, and factors determining the signalling by hydrogen peroxide

2018 ◽  
Vol 45 (2) ◽  
pp. 102 ◽  
Author(s):  
Boris N. Ivanov ◽  
Maria M. Borisova-Mubarakshina ◽  
Marina A. Kozuleva
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transport ◽  
Thylakoid Membrane ◽  
Electron Transport Chain ◽  
Superoxide Radical ◽  
Photosynthetic Electron Transport ◽  
Formation Mechanisms ◽  
H2o2 Production ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

Reduction of O2 molecule to superoxide radical, O2•−, in the photosynthetic electron transport chain is the first step of hydrogen peroxide, H2O2, production in chloroplasts in the light. The mechanisms of O2 reduction by ferredoxin, by the components of the plastoquinone pool, and by the electron transfer cofactors in PSI are analysed. The data indicating that O2•− and H2O2 can be produced both outside and within thylakoid membrane are presented. The H2O2 production in the chloroplast stroma is described as a result of either dismutation of O2•− or its reduction by stromal reductants. Formation of H2O2 within thylakoid membrane in the reaction of O2•− with plastohydroquinone is examined. The significance of both ways of H2O2 formation for specificity of the signal being sent by photosynthetic electron transport chain to cell adaptation systems is discussed.

THE EFFECT OF LETHAL DOSES OF X-IRRADIATION ON THE ENZYMATIC ACTIVITY OF MITOCHONDRIAL CYTOCHROME c

1966 ◽  
Vol 44 (4) ◽  
pp. 433-448 ◽  
Author(s):  
J. F. Scaife
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Electron Transport Chain ◽  
Reductase Activity ◽  
Ehrlich Ascites Carcinoma ◽  
Whole Body ◽  
Triphenyltetrazolium Chloride ◽  
Transport Chain ◽  
Ehrlich Ascites ◽  
X Irradiation

The coupling of the tetrazolium salts triphenyltetrazolium chloride and nitro-blue tetrazolium to the electron transport chain in mitochondria of thymus, spleen, liver, kidney, and Ehrlich ascites carcinoma cells has been studied with several substrates. In experiments on succinate–triphenyltetrazolium chloride reductase activity it has been possible to demonstrate a radiation lesion in the electron transport chain of mitochondria from thymus and spleen, but not in those from other tissues. This lesion is evident 4 hours after 25 rad of whole-body irradiation, or earlier with higher doses. It is not prevented by the prior administration of aminoethylisothiouronium bromide, serotonin, vitamin K1, or vitamin E, but is reduced by anoxic conditions.Lower levels of cytochrome c are found in irradiated mitochondria isolated from thymus, and the radiation lesion is believed to be produced by loosening the binding of cytochrome c to the mitochondrial membrane after X-irradiation. Decreased levels of ATP occur in thymus, spleen, and ascites cells following irradiation.

Choline and dimethylglycine produce superoxide/hydrogen peroxide from the electron transport chain in liver mitochondria

FEBS Letters ◽  
2016 ◽  
Vol 590 (23) ◽  
pp. 4318-4328 ◽  
Author(s):  
Ryan J. Mailloux ◽  
Adrian Young ◽  
Julia Chalker ◽  
Danielle Gardiner ◽  
Marisa O'Brien ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Liver Mitochondria ◽  
Transport Chain
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