Electron Partitioning between the Two Branching Quinol-oxidizing Pathways in Acanthamoeba castellaniiMitochondria during Steady-state State 3 Respiration

Jarmuszkiewicz, Wiesława; Sluse-Goffart, Claudine M.; Hryniewiecka, L.; Michejda, J.; Sluse, Francis

doi:10.1074/jbc.273.17.10174

Cited by 46 publications

(41 citation statements)

References 42 publications

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“…The endogenous Q in A. castellanii mitochondria is Q 9 (Jarmuszkiewicz et al 1998). The redox state of Q in steady-state respiration was determined by an extraction technique followed by HPLC detection as previously described (Swida et al 2008).…”

Section: Measurements Of the Ubiquinone Reduction Levelmentioning

confidence: 99%

Hydroxynonenal, a lipid peroxidation end product, stimulates uncoupling protein activity in Acanthamoeba castellanii mitochondria; the sensitivity of the inducible activity to purine nucleotides depends on the membranous ubiquinone redox state

Woyda-Płoszczyca

Jarmuszkiewicz

2012

J Bioenerg Biomembr

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We studied the influence of exogenously generated superoxide and exogenous 4-hydroxy-2-nonenal (HNE), a lipid peroxidation end product, on the activity of the Acanthamoeba castellanii uncoupling protein (AcUCP). The superoxide-generating xanthine/xanthine oxidase system was insufficient to induce mitochondrial uncoupling. In contrast, exogenously added HNE induced GTP-sensitive AcUCP-mediated mitochondrial uncoupling. In nonphosphorylating mitochondria, AcUCP activation by HNE was demonstrated by increased oxygen consumption accompanied by a decreased membrane potential and ubiquinone (Q) reduction level. The HNE-induced GTP-sensitive proton conductance was similar to that observed with linoleic acid. In phosphorylating mitochondria, the HNEinduced AcUCP-mediated uncoupling decreased the yield of oxidative phosphorylation. We demonstrated that the efficiency of GTP to inhibit HNE-induced AcUCPmediated uncoupling was regulated by the endogenous Q redox state. A high Q reduction level activated AcUCP by relieving the inhibition caused by GTP while a low Q reduction level favoured the inhibition. We propose that the regulation of UCP activity involves a rapid response through the endogenous Q redox state that modulates the inhibition of UCP by purine nucleotides, followed by a late response through lipid peroxidation products resulting from an increase in the formation of reactive oxygen species that modulate the UCP activation.

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Section: Measurements Of the Ubiquinone Reduction Levelmentioning

confidence: 99%

Hydroxynonenal, a lipid peroxidation end product, stimulates uncoupling protein activity in Acanthamoeba castellanii mitochondria; the sensitivity of the inducible activity to purine nucleotides depends on the membranous ubiquinone redox state

Woyda-Płoszczyca

Jarmuszkiewicz

2012

J Bioenerg Biomembr

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“…In the absence of FFA (no PUMP activity), the AOX contribution and the cytochrome pathway contribution to state 3 respiration can be determined (1,22,23). Indeed, if V 3 = V cyt + V alt , and if…”

Section: True Contributions Of Aox Pump and Atp Synthesis To State 3mentioning

confidence: 99%

“…Indeed, the early parallel decrease in AOX activity and protein expression does not follow the late parallel decrease in PUMP activity and protein expression. The ADP/O method developed to determine the contribution of AOX and the cytochrome pathway to the overall state 3 respiration of Acanthamoeba castellanii (22) has permitted the description of the kinetics of the AOX and cytochrome pathway contributions when PUMP is inactive and the kinetics of V cyt cons (ATP synthase) and PUMP contributions when AOX is blocked. When state 3 respiration is decreased by substrate limitation, the contribution of AOX decreases sharply to zero (at 40% inhibition of V 3 ), in contrast to the contribution of PUMP that remains constant until 60% inhibition.…”

Section: Extrapolation To General Energy Partitioningmentioning

confidence: 99%

Activity and functional interaction of alternative oxidase and uncoupling protein in mitochondria from tomato fruit

Sluse

Jarmuszkiewicz

2000

Braz J Med Biol Res

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Cyanide-resistant alternative oxidase (AOX) is not limited to plant mitochondria and is widespread among several types of protists. The uncoupling protein (UCP) is much more widespread than previously believed, not only in tissues of higher animals but also in plants and in an amoeboid protozoan. The redox energy-dissipating pathway (AOX) and the proton electrochemical gradient energy-dissipating pathway (UCP) lead to the same final effect, i.e., a decrease in ATP synthesis and an increase in heat production. Studies with green tomato fruit mitochondria show that both proteins are present simultaneously in the membrane. This raises the question of a specific physiological role for each energy-dissipating system and of a possible functional connection between them (shared regulation). Linoleic acid, an abundant free fatty acid in plants which activates UCP, strongly inhibits cyanide-resistant respiration mediated by AOX. Moreover, studies of the evolution of AOX and UCP protein expression and of their activities during post-harvest ripening of tomato fruit show that AOX and plant UCP work sequentially: AOX activity decreases in early post-growing stages and UCP activity is decreased in late ripening stages. Electron partitioning between the alternative oxidase and the cytochrome pathway as well as H + gradient partitioning between ATP synthase and UCP can be evaluated by the ADP/O method. This method facilitates description of the kinetics of energy-dissipating pathways and of ATP synthase when state 3 respiration is decreased by limitation of oxidizable substrate.

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“…In animals, during respiration, electron transfer from NADH to molecular oxygen proceeds through sequential protein complexes within the inner mitochondrial membranes. In addition to this sequential cytochrome pathway, higher plants (27), algae (12), yeasts (34), filamentous fungi (20), dimorphic fungi (18), amoebae (17), and trypanosomes (8) possess a unique cyanide-resistant electron transport chain in their mitochondria (Fig. 1).…”

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Role of Alternative Oxidase Gene in Pathogenesis of Cryptococcus neoformans

et al. 2003

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We identified a homologue of the alternative oxidase gene in a screen to identify genes that are preferentially transcribed in response to a shift to 37°C in the human-pathogenic yeast Cryptococcus neoformans. Alternative oxidases are nucleus-encoded mitochondrial proteins that have two putative roles: they can function in parallel with the classic cytochrome oxidative pathway to produce ATP, and they may counter oxidative stress within the mitochondria. The C. neoformans alternative oxidase gene (AOX1) was found to exist as a single copy in the genome, and it encodes a putative protein of 401 amino acids. An aox1 mutant strain was created using targeted gene disruption, and the mutant strain was reconstituted to wild type using a full-length AOX1. Compared to both the wild-type and reconstituted strains, the aox1 mutant strain was not temperature sensitive but did have significant impairment of both respiration and growth when treated with inhibitors of the classic cytochrome oxidative pathway. The aox1 mutant strain was also found to be more sensitive to the oxidative stressor tert-butyl hydroperoxide. The aox1 mutant strain was significantly less virulent than both the wild type and the reconstituted strain in the murine inhalational model, and it also had significantly impaired growth within a macrophage-like cell line. These data demonstrate that the alternative oxidase of C. neoformans can make a significant contribution to metabolism, has a role in the yeast's defense against exogenous oxidative stress, and contributes to the virulence composite of this organism, possibly by improving survival within phagocytic cells.Cryptococcus neoformans is a basidiomycetous fungus and a major human pathogen. This pathogenic fungus has a wide human host range by producing infections in both immunocompromised and immunocompetent hosts (6). Understanding the mechanisms of how this encapsulated yeast can so effectively attack a susceptible host has received renewed attention as the infrastructure for molecular biology of this yeast has matured. Several phenotypic factors in the virulence composite, such as formation of a polysaccharide capsule (7), melanin production (45), urease synthesis (11), phospholipase secretion (10), mannose production (46), high-temperature growth (28), and several signaling molecules and pathways for these factors (44,28

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Electron Partitioning between the Two Branching Quinol-oxidizing Pathways in Acanthamoeba castellaniiMitochondria during Steady-state State 3 Respiration

Cited by 46 publications

References 42 publications

Hydroxynonenal, a lipid peroxidation end product, stimulates uncoupling protein activity in Acanthamoeba castellanii mitochondria; the sensitivity of the inducible activity to purine nucleotides depends on the membranous ubiquinone redox state

Hydroxynonenal, a lipid peroxidation end product, stimulates uncoupling protein activity in Acanthamoeba castellanii mitochondria; the sensitivity of the inducible activity to purine nucleotides depends on the membranous ubiquinone redox state

Activity and functional interaction of alternative oxidase and uncoupling protein in mitochondria from tomato fruit

Role of Alternative Oxidase Gene in Pathogenesis of Cryptococcus neoformans

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