scholarly journals Oncogenic pathways and the electron transport chain: a dangeROS liaison

2019 ◽  
Vol 122 (2) ◽  
pp. 168-181 ◽  
Author(s):  
Vittoria Raimondi ◽  
Francesco Ciccarese ◽  
Vincenzo Ciminale
Keyword(s):  
Electron Transport ◽  
Electron Transport Chain ◽  
Electron Flow ◽  
Second Messengers ◽  
Driver Mutations ◽  
Cell Phenotype ◽  
Oxygen Species ◽  
Hallmarks Of Cancer ◽  
Oncogenic Pathways ◽  
Transport Chain

AbstractDriver mutations in oncogenic pathways, rewiring of cellular metabolism and altered ROS homoeostasis are intimately connected hallmarks of cancer. Electrons derived from different metabolic processes are channelled into the mitochondrial electron transport chain (ETC) to fuel the oxidative phosphorylation process. Electrons leaking from the ETC can prematurely react with oxygen, resulting in the generation of reactive oxygen species (ROS). Several signalling pathways are affected by ROS, which act as second messengers controlling cell proliferation and survival. On the other hand, oncogenic pathways hijack the ETC, enhancing its ROS-producing capacity by increasing electron flow or by impinging on the structure and organisation of the ETC. In this review, we focus on the ETC as a source of ROS and its modulation by oncogenic pathways, which generates a vicious cycle that resets ROS levels to a higher homoeostatic set point, sustaining the cancer cell phenotype.

Rewiring photosynthesis: a photosystem I-hydrogenase chimera that makes H2in vivo

2020 ◽  
Vol 13 (9) ◽  
pp. 2903-2914 ◽  
Author(s):  
Andrey Kanygin ◽  
Yuval Milrad ◽  
Chandrasekhar Thummala ◽  
Kiera Reifschneider ◽  
Patricia Baker ◽  
...  
Keyword(s):  
Electron Transport ◽  
Hydrogen Production ◽  
Photosystem I ◽  
Electron Transport Chain ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

Photosystem I-hydrogenase chimera intercepts electron flow directly from the photosynthetic electron transport chain and directs it to hydrogen production.

Possible role of free oxidation processes in the regulation of reactive oxygen species production in plant mitochondria

2003 ◽  
Vol 31 (6) ◽  
pp. 1316-1317 ◽  
Author(s):  
V.N. Popov
Keyword(s):  
Reactive Oxygen Species ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Plant Mitochondria ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Oxidation Processes ◽  
Transport Chain ◽  
Electron Reduction ◽  
Species Production

The non-coupled substrate oxidation mediated by components of the electron transport chain that are not coupled to energy accumulation (such as plant alternative oxidase and rotenone-insensitive NADH dehydrogenases) and uncoupled respiration are peculiar features of plant mitochondria. The physiological significance of such energy-wasting oxidation processes is still debated. It is proposed that non-coupled oxidation could regulate the level of reduction of components of the electron transport chain and the rate of one-electron reduction of oxygen, thereby affecting the rate of formation of reactive oxygen species.

scholarly journals Purification of Helicobacter pylori NCTC 11637 Cytochrome bc1 and Respiration with d-Proline as a Substrate

2009 ◽  
Vol 192 (5) ◽  
pp. 1410-1415 ◽  
Author(s):  
Minoru Tanigawa ◽  
Tomomitsu Shinohara ◽  
Katsushi Nishimura ◽  
Kumiko Nagata ◽  
Morio Ishizuka ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Amino Acid ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Electron Flow ◽  
Gene Clusters ◽  
Acid Dehydrogenase ◽  
Amino Acid Dehydrogenase ◽  
Transport Chain ◽  
H Pylori

ABSTRACT Helicobacter pylori is a microaerophilic bacterium associated with gastric inflammation and peptic ulcers. Knowledge of how pathogenic organisms produce energy is important from a therapeutic point of view. We found d-amino acid dehydrogenase-mediated electron transport from d-proline or d-alanine to oxygen via the respiratory chain in H. pylori. Coupling of the electron transport to ATP synthesis was confirmed by using uncoupler reagents. We reconstituted the electron transport chain to demonstrate the electron flow from the d-amino acids to oxygen using the recombinant cytochrome bc 1 complex, cytochrome c-553, and the terminal oxidase cytochrome cbb 3 complex. Upon addition of the recombinant d-amino acid dehydrogenase and d-proline or d-alanine to the reconstituted electron transport system, reduction of cytochrome cbb 3 and oxygen consumption was revealed spectrophotometrically and polarographically, respectively. Among the constituents of H. pylori's electron transport chain, only the cytochrome bc 1 complex had been remained unpurified. Therefore, we cloned and sequenced the H. pylori NCTC 11637 cytochrome bc 1 gene clusters encoding Rieske Fe-S protein, cytochrome b, and cytochrome c 1, with calculated molecular masses of 18 kDa, 47 kDa, and 32 kDa, respectively, and purified the recombinant monomeric protein complex with a molecular mass of 110 kDa by gel filtration. The absorption spectrum of the recombinant cytochrome bc 1 complex showed an α peak at 561 nm with a shoulder at 552 nm.

scholarly journals Impact of High Light on Reactive Oxygen Species Production within Photosynthetic Biological Membranes

2015 ◽  
Vol 6 (2) ◽  
pp. 50 ◽  
Author(s):  
Vetoshkina D. V. ◽  
Borisova-Mubarakshina M. M. ◽  
Naydov I. A. ◽  
Kozuleva M. A. ◽  
Ivanov B. N.
Keyword(s):  
Reactive Oxygen Species ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Reactive Oxygen ◽  
Photosynthetic Electron Transport ◽  
Lipid Phase ◽  
H2o2 Production ◽  
Oxygen Species ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

In this study we describe the mechanisms of reactive oxygen species (ROS) production in the photosynthetic electron transport chain of higher plants chloroplasts under illumination. We implement an improved method for the measurement of hydrogen peroxide (H2O2) production in lipid phase of photosynthetic membranes of chloroplasts. Total rate of H2O2 production and the production within the thylakoid membrane under operation of photosynthetic electron transport chain is evaluated. Obtained data show that even in the presence of an efficient electron acceptor, methyl viologen, an increase in light intensity leads to an increase in H2O2 production mainly within the thylakoid membranes. The role of H2O2 produced within the photosynthetic biological membrane is discussed.

scholarly journals A Chemogenomic Screen in Saccharomyces cerevisiae Uncovers a Primary Role for the Mitochondria in Farnesol Toxicity and Its Regulation by the Pkc1 Pathway

2006 ◽  
Vol 282 (7) ◽  
pp. 4868-4874 ◽  
Author(s):  
Gregory D. Fairn ◽  
Kendra MacDonald ◽  
Christopher R. McMaster
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Reactive Oxygen Species ◽  
Cell Death ◽  
Electron Transport ◽  
Signaling Pathway ◽  
Electron Transport Chain ◽  
Reactive Oxygen ◽  
Complex Iii ◽  
Oxygen Species ◽  
Transport Chain

The isoprenoid farnesol has been shown to preferentially induce apoptosis in cancerous cells; however, the mode of action of farnesol-induced death is not established. We used chemogenomic profiling using Saccharomyces cerevisiae to probe the core cellular processes targeted by farnesol. This screen revealed 48 genes whose inactivation increased sensitivity to farnesol. The gene set indicated a role for the generation of oxygen radicals by the Rieske iron-sulfur component of complex III of the electron transport chain as a major mediator of farnesol-induced cell death. Consistent with this, loss of mitochondrial DNA, which abolishes electron transport, resulted in robust resistance to farnesol. A genomic interaction map predicted interconnectedness between the Pkc1 signaling pathway and farnesol sensitivity via regulation of the generation of reactive oxygen species. Consistent with this prediction (i) Pkc1, Bck1, and Mkk1 relocalized to the mitochondria upon farnesol addition, (ii) inactivation of the only non-essential and non-redundant member of the Pkc1 signaling pathway, BCK1, resulted in farnesol sensitivity, and (iii) expression of activated alleles of PKC1, BCK1, and MKK1 increased resistance to farnesol and hydrogen peroxide. Sensitivity to farnesol was not affected by the presence of the osmostabilizer sorbitol nor did farnesol affect phosphorylation of the ultimate Pkc1-responsive kinase responsible for controlling the cell wall integrity pathway, Slt2. The data indicate that the generation of reactive oxygen species by the electron transport chain is a primary mechanism by which farnesol kills cells. The Pkc1 signaling pathway regulates farnesol-mediated cell death through management of the generation of reactive oxygen species.

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