Sodium/Proton antiporter of rat liver mitochondria

Rosen, Barry P.; Futai, Masamitsu

doi:10.1016/0014-5793(80)80909-4

Cited by 28 publications

(5 citation statements)

References 20 publications

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“…The low rates of K+-dependent change in pH¡ do not show saturation kinetics under these conditions (Figure 4). These apparent Km values agree well with those previously reported for Na+/H+ antiport in mitochondria and SMP when estimated by other methods under similar conditions (Rosen & Futai, 1980;Nath & Garlid, 1988;Kapus et al, 1988).…”

Section: Resultssupporting

confidence: 92%

“…The respiration-dependent uptake of Na+ by SMP has also been attributed to this antiport (Douglas & Cockrell, 1973), as has respiration-dependent extrusion of accumulated Na+ from intact mitochondria (Brierley et al, 1977). These studies indicate that the Na+/H+ antiport is specific for Na+ and Li+ (Brierley et al, 1978;Rosen & Futai, 1980), has a pH0 optimum near 7.3 in acetate (Brierley et al, 1978), and is insensitive to quinine, divalent cations, and DCCD (Nakashima & Garlid, 1982;Garlid, 1988a). These properties permit the Na+/H+ antiport to be distinquished from the K+/H+ exchanger, an antiporter that becomes apparent in swollen or Mg2+-depleted mitochondria (Brierley & Jung, 1988a,b;Garlid, 1988a) and which appears capable of transporting Na+ and Li+, as well as K+.…”

mentioning

confidence: 87%

“…overt Na+/H+ antiport and a latent K+/H+ exchange component [see Brierley (1983), Jung (1988a,b), andGarlid (1988a,b) for recent reviews]. The activity of the Na+/H+ antiport has been followed by the passive osmotic swelling of mitochondria in acetate salts (Mitchell & Moyle, 1969b;Brierley et al, 1978;Nakashima & Garlid, 1982), by glass electrode records of Na+-dependent changes in the pH of the suspending medium of either mitochondria (Mitchell & Moyle, 1967; Crompton & Heid, 1978) or SMP (Papa et al, 1973), and by changes in quinacrine fluorescence in energized SMP (Rosen & Futai, 1980;Brierley et al, 1984).…”

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confidence: 99%

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Kinetic properties of the sodium/hydrogen ion antiport of heart mitochondria

Brierley¹,

Davis²,

Cragoe³

et al. 1989

Biochemistry

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The fluorescence of 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF) has been used to follow the Na+/H+ antiport activity of isolated heart mitochondria as a Na+-dependent extrusion of matrix H+. The antiport activity measured in this way shows a hyperbolic dependence on external Na+ or Li+ concentration when the external pH (pHo) is 7.2 or higher. The apparent Km for Na+ decreases with increasing pHo to a limit of 4.6 mM. The Ki for external H+ as a competitive inhibitor of Na+/H+ antiport averages 3.0 nM (pHo 8.6). The Vmax at 24 degrees C is 160 ng ion of H+ min-1 (mg of protein)-1 and does not vary with pHo. Li+ reacts with the antiporter with higher affinity, but much lower Vmax, and is a competitive inhibitor of Na+/H+ antiport. The rate of Na+/H+ antiport is optimal when the pHi is near 7.2. When pHo is maintained constant, Na+-dependent extrusion of matrix H+ shows a hyperbolic dependence on [H+]i with an apparent Km corresponding to a pHi of 6.8. The Na+/H+ antiport is inhibited by benzamil and by 5-N-substituted amiloride analogues with I50 values in the range from 50 to 100 microM. The pH profile for this inhibition seems consistent with the availability of a matrix binding site for the amiloride analogues. The mitochondrial Na+/H+ antiport resembles the antiport found in the plasma membrane of mammalian cells in that Na+, Li+, and external H+ appear to compete for a common external binding site and both exchanges are inhibited by amiloride analogues.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Resultssupporting

confidence: 92%

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confidence: 87%

mentioning

confidence: 99%

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Kinetic properties of the sodium/hydrogen ion antiport of heart mitochondria

Brierley¹,

Davis²,

Cragoe³

et al. 1989

Biochemistry

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“…At equilibrium in an ionic medium, the matrix volume reached reflects the net uptake of the cation as determined by the activities of its electrogenic influx and protogenic efflux (Brierley, 1976;Garlid, 1980). It is known that there are both influx and efflux pathways for K+, Na+, Li+ and choline (Mitchell & Moyle, 1969;Douglas & Cockerell, 1974;Rosen & Futai, 1980). Indeed, the Na+/H+ antiport is extremely active (Mitchell & Moyle, 1969;Douglas & Cockerell, 1974), and prevents energy-dependent swelling in NaCl media.…”

Section: Role Of Ca2+ In the Regulation Of Mitochondrial Volume In Hementioning

confidence: 99%

Regulation of the mitochondrial matrix volume in vivo and in vitro. The role of calcium

Halestrap¹,

Quinlan²,

Whipps³

et al. 1986

Biochemical Journal

100

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The ability of alpha-adrenergic agonists and vasopressin to increase the mitochondrial volume in hepatocytes is dependent on the presence of extracellular Ca2+. Addition of Ca2+ to hormone-treated cells incubated in the absence of Ca2+ initiates mitochondrial swelling. In the presence of extracellular Ca2+, A23187 (7.5 microM) induces mitochondrial swelling and stimulates gluconeogenesis from L-lactate. Isolated liver mitochondria incubated in KCl medium in the presence of 2.5 mM-phosphate undergo energy-dependent swelling, which is associated with electrogenic K+ uptake and reaches an equilibrium when the volume has increased to about 1.3-1.5 microliter/mg of protein. This K+-dependent swelling is stimulated by the presence of 0.3-1.0 microM-Ca2+, leading to an increase in matrix volume at equilibrium that is dependent on [Ca2+]. Ca2+-activated K+-dependent swelling requires phosphate and shows a strong preference for K+ over Na+, Li+ or choline. It is not associated with either uncoupling of mitochondria or any non-specific permeability changes and cannot be produced by Ba2+, Mn2+ or Sr2+. Ca2+-activated K+-dependent swelling is not prevented by any known inhibitors of plasma-membrane ion-transport systems, nor by inhibitors of mitochondrial phospholipase A2. Swelling is inhibited by 65% and 35% by 1 mM-ATP and 100 microM-quinine respectively. The effect of Ca2+ is blocked by Ruthenium Red (5 micrograms/ml) at low [Ca2+]. Spermine (0.25 mM) enhanced the swelling seen on addition of Ca2+, correlating with its ability to increase Ca2+ uptake into the mitochondria as measured by using Arsenazo-III. Mitochondria derived from rats treated with glucagon showed less swelling than did control mitochondria. In the presence of Ruthenium Red and higher [Ca2+], the mitochondria from hormone-treated animals showed greater swelling than did control mitochondria. These data imply that an increase in intramitochondrial [Ca2+] can increase the electrogenic flux of K+ into mitochondria by an unknown mechanism and thereby cause swelling. It is proposed that this is the mechanism by which alpha-agonists and vasopressin cause an increase in mitochondrial volume in situ.

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“…Respiration was initiated by addition of Trizma‐succinate to a final concentration of 2.5 mM. The chloride content of the buffer was high enough to ensure that the pmf established upon addition of an electron donor was entirely due to a ΔpH, acidic inside the inverted membrane vesicles (Rosen and Futai, 1980). Establishment of the ΔpH was monitored by quenching of the fluorescence of acridine orange.…”

Section: Methodsmentioning

confidence: 99%

The halophilic alkalithermophile Natranaerobius thermophilus adapts to multiple environmental extremes using a large repertoire of Na⁺(K⁺)/H⁺ antiporters

Mesbah

Cook

Wiegel

2009

Molecular Microbiology

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Natranaerobius thermophilus is an unusual extremophile because it is halophilic, alkaliphilic and thermophilic, growing optimally at 3.5 M Na+, pH55°C 9.5 and 53°C. Mechanisms enabling this tripartite lifestyle are essential for understanding how microorganisms grow under inhospitable conditions, but remain unknown, particularly in extremophiles growing under multiple extremes. We report on the response of N. thermophilus to external pH at high salt and elevated temperature and identify mechanisms responsible for this adaptation. N. thermophilus exhibited cytoplasm acidification, maintaining an unanticipated transmembrane pH gradient of 1 unit over the entire extracellular pH range for growth. N. thermophilus uses two distinct mechanisms for cytoplasm acidification. At extracellular pH values at and below the optimum, N. thermophilus utilizes at least eight electrogenic Na+(K+)/H+ antiporters for cytoplasm acidification. Characterization of these antiporters in antiporter-deficient Escherichia coli KNabc showed overlapping pH profiles (pH 7.8–10.0) and Na+ concentrations for activity (K0.5 values 1.0–4.4 mM), properties that correlate with intracellular conditions of N. thermophilus. As the extracellular pH increases beyond the optimum, electrogenic antiport activity ceases, and cytoplasm acidification is achieved by energy-independent physiochemical effects (cytoplasmic buffering) potentially mediated by an acidic proteome. The combination of these strategies allows N. thermophilus to grow over a range of extracellular pH and Na+ concentrations and protect biomolecules under multiple extreme conditions.

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Sodium/Proton antiporter of rat liver mitochondria

Cited by 28 publications

References 20 publications

Kinetic properties of the sodium/hydrogen ion antiport of heart mitochondria

Kinetic properties of the sodium/hydrogen ion antiport of heart mitochondria

Regulation of the mitochondrial matrix volume in vivo and in vitro. The role of calcium

The halophilic alkalithermophile Natranaerobius thermophilus adapts to multiple environmental extremes using a large repertoire of Na⁺(K⁺)/H⁺ antiporters

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Sodium/Proton antiporter of rat liver mitochondria

Cited by 28 publications

References 20 publications

Kinetic properties of the sodium/hydrogen ion antiport of heart mitochondria

Kinetic properties of the sodium/hydrogen ion antiport of heart mitochondria

Regulation of the mitochondrial matrix volume in vivo and in vitro. The role of calcium

The halophilic alkalithermophile Natranaerobius thermophilus adapts to multiple environmental extremes using a large repertoire of Na+(K+)/H+ antiporters

Contact Info

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The halophilic alkalithermophile Natranaerobius thermophilus adapts to multiple environmental extremes using a large repertoire of Na⁺(K⁺)/H⁺ antiporters