scholarly journals GRIM-19, a Cell Death Regulatory Protein, Is Essential for Assembly and Function of Mitochondrial Complex I

2004 ◽  
Vol 24 (19) ◽  
pp. 8447-8456 ◽  
Author(s):  
Guochang Huang ◽  
Hao Lu ◽  
Aijun Hao ◽  
Dominic C. H. Ng ◽  
Sathivel Ponniah ◽  
...  
Keyword(s):  
Cell Death ◽  
Electron Transfer ◽  
Complex I ◽  
Cellular Localization ◽  
Regulatory Protein ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Native Form

ABSTRACT Mitochondria play essential roles in cellular energy production via the oxidative phosphorylation system (OXPHOS) consisting of five multiprotein complexes and also in the initiation of apoptosis. NADH:ubiquinone oxidoreductase (complex I) is the largest complex that catalyzes the first step of electron transfer in the OXPHOS system. GRIM-19 was originally identified as a nuclear protein with apoptotic nature in interferon (IFN)- and all-trans-retinoic acid (RA)-induced tumor cells. To reveal its biological role, we generated mice deficient in GRIM-19 by gene targeting. Homologous deletion of GRIM-19 causes embryonic lethality at embryonic day 9.5. GRIM-19−/− blastocysts show retarded growth in vitro and, strikingly, display abnormal mitochondrial structure, morphology, and cellular distribution. We reexamined the cellular localization of GRIM-19 in various cell types and found its primary localization in the mitochondria. Furthermore, GRIM-19 is detected in the native form of mitochondrial complex I. Finally, we show that elimination of GRIM-19 destroys the assembly and electron transfer activity of complex I and also influences the other complexes in the mitochondrial respiratory chain. Our result demonstrates that GRIM-19, a gene product with a specific role in IFN-RA-induced cell death, is a functional component of mitochondrial complex I and is essential for early embryonic development.

scholarly journals Cell death induced by mitochondrial complex I inhibition is mediated by Iron Regulatory Protein 1

2017 ◽  
Vol 1863 (9) ◽  
pp. 2202-2209 ◽  
Author(s):  
Pamela J. Urrutia ◽  
Pabla Aguirre ◽  
Victoria Tapia ◽  
Carlos M. Carrasco ◽  
Natalia P. Mena ◽  
...  
Keyword(s):  
Cell Death ◽  
Complex I ◽  
Regulatory Protein ◽  
Mitochondrial Complex I ◽  
Iron Regulatory Protein ◽  
Mitochondrial Complex ◽  
Iron Regulatory Protein 1

scholarly journals Paracoccus denitrificans: a genetically tractable model system for studying respiratory complex I

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Owen D. Jarman ◽  
Olivier Biner ◽  
John J. Wright ◽  
Judy Hirst
Keyword(s):  
Complex I ◽  
Paracoccus Denitrificans ◽  
Model System ◽  
Proton Pumping ◽  
Model Systems ◽  
Metabolic Enzyme ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Inner Mitochondrial Membrane

AbstractMitochondrial complex I (NADH:ubiquinone oxidoreductase) is a crucial metabolic enzyme that couples the free energy released from NADH oxidation and ubiquinone reduction to the translocation of four protons across the inner mitochondrial membrane, creating the proton motive force for ATP synthesis. The mechanism by which the energy is captured, and the mechanism and pathways of proton pumping, remain elusive despite recent advances in structural knowledge. Progress has been limited by a lack of model systems able to combine functional and structural analyses with targeted mutagenic interrogation throughout the entire complex. Here, we develop and present the α-proteobacterium Paracoccus denitrificans as a suitable bacterial model system for mitochondrial complex I. First, we develop a robust purification protocol to isolate highly active complex I by introducing a His6-tag on the Nqo5 subunit. Then, we optimize the reconstitution of the enzyme into liposomes, demonstrating its proton pumping activity. Finally, we develop a strain of P. denitrificans that is amenable to complex I mutagenesis and create a catalytically inactive variant of the enzyme. Our model provides new opportunities to disentangle the mechanism of complex I by combining mutagenesis in every subunit with established interrogative biophysical measurements on both the soluble and membrane bound enzymes.

Abstract 404: High-throughput Screening Reveals the Mitochondrial Complex I Inhibitor Nornicotine is Cardioprotective in Ischemia-reperfusion Injury When Delivered at Reperfusion

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Jimmy Zhang ◽  
Marcin K Karcz ◽  
Sergiy M Nadtochiy ◽  
Paul S Brookes
Keyword(s):  
Infarct Size ◽  
Reperfusion Injury ◽  
Functional Recovery ◽  
Complex I ◽  
Ischemia Reperfusion ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Early Reperfusion ◽  
Perfused Hearts

Background: To date, there are no FDA-approved therapies for the reduction of infarct size in acute myocardial infarction. Previously, we developed a cell-based phenotypic assay of ischemia-reperfusion (IR) injury, which was used to identify novel cytoprotective agents delivered prior to ischemia. Herein, we sought to identify cytoprotective agents in a more clinically relevant model: drug delivery at reperfusion, and to investigate possible underlying mechanisms of protection. Methods: Primary adult mouse cardiomyocytes were subjected to simulated IR injury using a modified Seahorse XF24 apparatus with drug addition at the onset of reperfusion. Cell death was estimated using LDH release. Drugs which protected cardiomyocytes in vitro were tested in a Langendorff model of IR injury, measuring functional recovery and infarct size. In separate experiments, metabolites extracted from perfused hearts were resolved by HPLC. Results: Nornicotine was identified as a cardioprotective agent in the screen. In perfused hearts, 10 nM nornicotine injected at the onset of reperfusion improved functional recovery and decreased in infarct size (13.1% ± 2.4 vs 49.2% ± 2.5 in non-treated hearts, p<0.05, n=16-20). Nornicotine also exhibited profound inhibitory effects on mitochondrial complex I activity. Succinate is known to accumulate in ischemia, and its rapid consumption during early reperfusion exacerbates reperfusion injury via ROS generation from electron backflow through complex I [PMID: 25383517]. In non-treated hearts, we confirmed that high post ischemic levels of succinate rapidly declined during the first 2 min of reperfusion. In contrast, nornicotine slowed post-ischemic succinate consumption, suggesting that electron backflow through complex I is the major pathway driving succinate consumption. Conclusions: Herein, we demonstrated that nornicotine was cardioprotective when delivered at early reperfusion in vitro and ex vivo. The mechanism of cardioprotection may be due to inhibition of rapid succinate consumption during early reperfusion via reverse electron flow back through complex I.

scholarly journals Inhibition of the ER stress IRE1α inflammatory pathway protects against cell death in mitochondrial complex I mutant cells

2018 ◽  
Vol 9 (6) ◽  
Author(s):  
Meghan S. Soustek ◽  
Eduardo Balsa ◽  
Joeva J. Barrow ◽  
Mark Jedrychowski ◽  
Rutger Vogel ◽  
...  
Keyword(s):  
Cell Death ◽  
Er Stress ◽  
Complex I ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Inflammatory Pathway ◽  
Mutant Cells

scholarly journals Mitochondrial Complex I Inhibitors and Forced Oxidative Phosphorylation Synergize in Inducing Cancer Cell Death

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Roberta Palorini ◽  
Tiziana Simonetto ◽  
Claudia Cirulli ◽  
Ferdinando Chiaradonna
Keyword(s):  
Cell Death ◽  
Oxidative Phosphorylation ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Complex I ◽  
Mitochondrial Complex I ◽  
Low Doses ◽  
Mitochondrial Complex ◽  
Cancer Cell Death ◽  
Glucose Depletion

Cancer cells generally rely mostly on glycolysis rather than oxidative phosphorylation (OXPHOS) for ATP production. In fact, they are particularly sensitive to glycolysis inhibition and glucose depletion. On the other hand mitochondrial dysfunctions, involved in the onset of the Warburg effect, are sometimes also associated with the resistance to apoptosis that characterizes cancer cells. Therefore, combined treatments targeting both glycolysis and mitochondria function, exploiting peculiar tumor features, might be lethal for cancer cells. In this study, we show that glucose deprivation and mitochondrial Complex I inhibitors synergize in inducing cancer cell death. In particular, our results reveal that low doses of Complex I inhibitors, ineffective on immortalized cells and in high glucose growth, become specifically cytotoxic on cancer cells deprived of glucose. Importantly, the cytotoxic effect of the inhibitors on cancer cells is strongly enhanced by forskolin, a PKA pathway activator, that we have previously shown to stimulate OXPHOS. Taken together, we demonstrate that induction in cancer cells of a switch from a glycolytic to a more respirative metabolism, obtained by glucose depletion or mitochondrial activity stimulation, strongly increases their sensitivity to low doses of mitochondrial Complex I inhibitors. Our findings might be a valuable approach to eradicate cancer cells.

scholarly journals Molecular mechanism and physiological role of active–deactive transition of mitochondrial complex I

2013 ◽  
Vol 41 (5) ◽  
pp. 1325-1330 ◽  
Author(s):  
Marion Babot ◽  
Alexander Galkin
Keyword(s):  
Complex I ◽  
Physiological Role ◽  
Protective Mechanism ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
The Status ◽  
Nitric Oxide Metabolites

The unique feature of mitochondrial complex I is the so-called A/D transition (active–deactive transition). The A-form catalyses rapid oxidation of NADH by ubiquinone (k ~104 min−1) and spontaneously converts into the D-form if the enzyme is idle at physiological temperatures. Such deactivation occurs in vitro in the absence of substrates or in vivo during ischaemia, when the ubiquinone pool is reduced. The D-form can undergo reactivation given both NADH and ubiquinone availability during slow (k ~1–10 min−1) catalytic turnover(s). We examined known conformational differences between the two forms and suggested a mechanism exerting A/D transition of the enzyme. In addition, we discuss the physiological role of maintaining the enzyme in the D-form during the ischaemic period. Accumulation of the D-form of the enzyme would prevent reverse electron transfer from ubiquinol to FMN which could lead to superoxide anion generation. Deactivation would also decrease the initial burst of respiration after oxygen reintroduction. Therefore the A/D transition could be an intrinsic protective mechanism for lessening oxidative damage during the early phase of reoxygenation. Exposure of Cys39 of mitochondrially encoded subunit ND3 makes the D-form susceptible for modification by reactive oxygen species and nitric oxide metabolites which arrests the reactivation of the D-form and inhibits the enzyme. The nature of thiol modification defines deactivation reversibility, the reactivation timescale, the status of mitochondrial bioenergetics and therefore the degree of recovery of the ischaemic tissues after reoxygenation.

Mitochondrial complex I inhibitors, acetogenins, induce HepG2 cell death through the induction of the complete apoptotic mitochondrial pathway

2012 ◽  
Vol 45 (1-2) ◽  
pp. 153-164 ◽  
Author(s):  
Nuria de Pedro ◽  
Bastien Cautain ◽  
Angeles Melguizo ◽  
Francisca Vicente ◽  
Olga Genilloud ◽  
...  
Keyword(s):  
Cell Death ◽  
Hepg2 Cell ◽  
Complex I ◽  
Mitochondrial Pathway ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex
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