Coupling of oxidative phosphorylation by monovalent cations

Gómez‐Puyou, Armando; Sandoval, F.; Gómez-Puyou, de; Peña, Antonio; Chávez, Edmundo

doi:10.1021/bi00751a017

Cited by 28 publications

(6 citation statements)

References 20 publications

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“…It is known that under certain conditions, internal acidification, and K+ loss in mitochondria interfere with anionic substrate permeability (8)(9)(10). This interference is more significantly demonstrated using DPN-linked substrates than it is using f3-hydroxybutyrate or succinate (5,6,11,31 a The reaction mixture was the same as described in Table 1 ATPase activity in Li+, Na+, or Cs+ medium (Fig.…”

Section: Discussionmentioning

confidence: 99%

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Salinomycin Effects on Mitochondrial Ion Translocation and Respiration

Mitani

Yamanishi

Miyazaki

et al. 1976

Antimicrob Agents Chemother

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The effects of salinomycin on alkali cation transport and membrane functions in rat liver mitochondria have been investigated. After potassium uptake, stimulated by valinomycin or monazomycin in the presence of adenosine 5'-triphosphate, salinomycin caused rapid release of K+ from mitochondria. Salinomycin reversed valinomycin-or monazomycin-induced oscillatory swelling of mitochondria preloaded with K+, Rb+, and Na+ but was without effect on Li+ or Cs+ preloaded mitochondria. Salinomycin blocked the retention of K+ more effectively than the retention of Rb+ or Na+. Salinomycin inhibited both coupled and uncoupled respiration with strict substrate specificity in medium of low but not in high K+ concentration. The oxidation of glutamate, a-ketoglutarate, and malate plus pyruvate was inhibited by salinomycin, but that of 3-hydroxybutyrate or succinate was not significantly affected. Salinomycin inhibited adenosine triphosphatase activity of mitochondria induced by valinomycin or monazomycin in K+ and Rb+ medium without significantly affecting adenosine triphosphatase activity in Li+, Na+, or Cs+ medium. Oxidative phosphorylation in mitochondria was inhibited by sklinomycin but the inhibitory effect of salinomycin lacked the substrate specificity observed for respiration. It is proposed that salinomycin perturbs mitochondrial functions by acting as a mobile carrier for alkali cations through membranes.

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Section: Discussionmentioning

confidence: 99%

“…The stimulatory effect of monovalent cations, especially of K+, on oxidative phosphorylation has been well described (9,10). It is sug- 4); temperature, 30 C. Mitochondria were preincubated for 1 min with or without 1.3 nmol of salinomycin before 2.5 mM ADP and 2.5 mM potassium phosphate (pH 7.4) labeled with 32p were added.…”

Section: Discussionmentioning

confidence: 99%

Salinomycin Effects on Mitochondrial Ion Translocation and Respiration

Mitani

Yamanishi

Miyazaki

et al. 1976

Antimicrob Agents Chemother

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“…It has been reported previously that isolated mitochondria can polarize and respire normally in the absence of an ETC substrate (e.g., succinate) as long as a “permeant ion” such as K + is present in the buffer. 24–26 Furthermore, the presence of this ion facilitates valinomycin (a K + ionophore) mediated depolarization of mitochondria. Of note, we found JC-9 dye to be incompatible with CCCP (or FCCP) because treatment with this depolarizing agent appeared to dramatically affect the amount of JC-1 in solution, which ultimately could alter the red/green ratio of mitochondria.…”

Section: Methodsmentioning

confidence: 99%

Identification and Characterization of Mitochondrial Subtypes in Caenorhabditis elegans via Analysis of Individual Mitochondria by Flow Cytometry

et al. 2016

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Mitochondrial bioenergetics has been implicated in a number of vital cellular and physiological phenomena, including aging, metabolism, and stress resistance. Heterogeneity of the mitochondrial membrane potential (Δψ), which is central to organismal bioenergetics, has been successfully measured via flow cytometry in whole cells but rarely in isolated mitochondria from large animal models. Similar studies in small animal models, such as Caenorhabditis elegans (C. elegans), are critical to our understanding of human health and disease but lack analytical methodologies. Here we report on new methodological developments that make it possible to investigate the heterogeneity of Δψ in C. elegans during development and in tissue-specific studies. The flow cytometry methodology described here required an improved collagenase-3-based mitochondrial isolation procedure and labeling of mitochondria with the ratiometric fluorescent probe JC-9. To demonstrate feasibility of tissue-specific studies, we used C. elegans strains expressing blue-fluorescent muscle-specific proteins, which enabled identification of muscle mitochondria among mitochondria from other tissues. This methodology made it possible to observe, for the first time, critical changes in Δψ during C. elegans larval development and provided direct evidence of the elevated bioenergetic status of muscle mitochondria relative to their counterparts in the rest of the organism. Further application of these methodologies can help tease apart bioenergetics and other biological complexities in C. elegans and other small animal models used to investigate human disease and aging.

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“…(mMl between decreased respiratory rates and sucrose impermeable spaces [7]. Increasing concentrations of sucrose have also been associated with decreased glutamate/malate induced NADH fluorescence [12], which has been taken as evidence that substrate transport into the matrix has been inhibited. Alternatively, it is possible that the activity of the oxidative enzymes of the matrix has decreased, due to dehydration of the matrix space.…”

Section: ;0 300mentioning

confidence: 99%