Ion transport in heart mitochondria. XIII. The effect of ethylenediaminetetraacetate on monovalent ion uptake

Settlemire, C. T.; Hunter, George R.; Brierley, Gerald P.

doi:10.1016/0005-2728(68)90055-8

Cited by 89 publications

(8 citation statements)

References 20 publications

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“…As a consequence, attempts made so far at the direct measurements of Ca++ or K + permeability did not yield unambiguous results. Settlemire, Hunter, and Brierley (1968) observed that the permeability of beef heart mitochondria was altered by EDTA under conditions which are somewhat different from those found with microsomes. The swelling of mitochondria is induced by EDTA only during respiration and in the presence of high concentration of Na++ and a permeant anion (acetate).…”

Section: Discussionmentioning

confidence: 74%

Sarcoplasmic Reticulum

Duggan

Martonosi

1970

The Journal of General Physiology

283

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Fragmented sarcoplasmic reticulum (FSR) membranes isolated from rabbit skeletal muscle are impermeable to inulin-' 4 C (mol wt 5,000), and dextran-' 4 C (mol wt 15,000-90,000) at pH 7.0-9.0, yielding an excluded space of 4-5 ul/mg microsomal protein. In the same pH range urea and sucrose readily penetrate the FSR membrane. EDTA or EGTA (1 m) increased the permeability of microsomes to inulin-14C or dextran-' 4 C at pH 8-9, parallel with the lowering of the FSR-bound Ca + + content from initial levels of 20 nmoles/mg protein to 1-3 nmoles/mg protein. EGTA was as effective as EDTA, although causing little change in the Mg++ content of FSR. The permeability increase caused by chelating agents results from the combined effects of high pH and cation depletion. As inulin began to penetrate the membrane there was an abrupt fall in the rate of Ca + + uptake and a simultaneous rise in ATPase activity. At 40°C inulin penetration occurred at pH 7.0 with I m. EDTA and at pH 9.0 without EDTA, suggesting increased permeability of FSR membranes. This accords with the higher rate of Ca++ release from FSR at temperatures over 30 0 C. The penetration of microsomal membranes by anions is markedly influenced by charge effects. At low ionic strength and alkaline pH acetate and C1 are partially excluded from microsomes when applied in concentrations not exceeding I mM, presumably due to the Donnan effect. Penetration of microsomal water space by acetate and Cl occurs at ionic strengths sufficiently high to minimize charge repulsions.

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Section: Discussionmentioning

confidence: 74%

Sarcoplasmic Reticulum

Duggan

Martonosi

1970

The Journal of General Physiology

283

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“…Addition of EDTA to respiring mitochondria is followed by swelling in NaCl and LiCl but not KCl media, suggesting the existence of a Mg 2ϩ -modulated inner membrane channel with selectivity for Na ϩ and Li ϩ (12,55,314,356). We have provided unambiguous evidence that Na ϩ and Li ϩ uptake after treatment of mitochondria with EDTA occurs via an electrophoretic mechanism (37).…”

Section: Na ϩ Channelmentioning

confidence: 68%

Mitochondrial Transport of Cations: Channels, Exchangers, and Permeability Transition

Bernardi

1999

Physiological Reviews

1,423

1,241

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This review provides a selective history of how studies of mitochondrial cation transport (K+, Na+, Ca2+) developed in relation to the major themes of research in bioenergetics. It then covers in some detail specific transport pathways for these cations, and it introduces and discusses open problems about their nature and physiological function, particularly in relation to volume regulation and Ca2+ homeostasis. The review should provide the basic elements needed to understand both earlier mitochondrial literature and current problems associated with mitochondrial transport of cations and hopefully will foster new interest in the molecular definition of mitochondrial cation channels and exchangers as well as their roles in cell physiology.

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“…5 indicates that the antibiotic does not require alkali metal cations to stimulate ATP hydrolysis in mitochondria. Settlemire et al, 1968). This clearly indicates that alkali ions are not involved in the uncoupling action of the antibiotic.…”

Section: The Ionic Selectivity Of X-537a To Uncouple Oxidative Phosphmentioning

confidence: 92%

“…In some experiments, mitochondria were substantially depleted of more than 90 % of the endogenous K + and Mg z+ content by the modification made by Gdmez-Puyou, Sandoval, Tuena, Pefia and Chfivez (1969) to the method of Settlemire, Hunter and Brierley (1968).…”

Section: Methodsmentioning

confidence: 99%

Model translocators for divalent and monovalent ion transport in phospholipid membranes

Estrada

Célis

et al. 1974

J. Membrain Biol.

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The antibiotic X-537A, already characterized as an ionophore for mono-, di-and trivalent cations across lipid membranes, inhibits ATP hydrolysis and glutamate oxidation stimulated in mitochondria by ion translocators such as monazomycin and beauvericin with the selectivity pattern: Cs + > Rb + > K + > Na + > Li+. The ionophoremediated inhibition of both ATPase and respiration is fully reversed by concentration gradients of K + and H + imposed between intra-extra mitochondrial compartments. It is not reversed by modifying the concentrations of divalent or trivalent cations in the medium. These data as well as the substrate dependance of the respiratory inhibition indicate that X-537A inhibits energy transduction primarily by mediating the translocation of protons in exchange for K + rather than by complexing divalent cations. Because of its ability to catalyze net proton transfer, concentrations of X-537A above 5 x 10 -6 M uncouple the respiratory control of intact mitochondria. At concentrations below 10-6 M, the antibiotic releases the oligomycin-induced respiratory control of submitochondrial sonic particles with an alkali ion and proton-dependent selectivity as that shown to transport ions across lipid bilayers. It also stimulates a lanthanide-sensitive, ruthenium red-insensitive uptake of Ca 2+ in submitochondrial sonic particles apparently occurring through an antiport type of electroneutral exchange diffusion of Ca 2+ out/2H + in.The antibiotic X-537A is an ion-transporting membrane carrier of the widest ionic selectivity properties known. Not only is it able to transport alkali metal, divalent and trivalent cations through natural and model membranes but protons as well (Lardy,

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Ion transport in heart mitochondria. XIII. The effect of ethylenediaminetetraacetate on monovalent ion uptake

Cited by 89 publications

References 20 publications

Sarcoplasmic Reticulum

Sarcoplasmic Reticulum

Mitochondrial Transport of Cations: Channels, Exchangers, and Permeability Transition

Model translocators for divalent and monovalent ion transport in phospholipid membranes

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