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Ellard JP, McCudden CR, Tanega C, James KA, Ratkovic S, Staples JF, Wagner GF. The respiratory effects of stanniocalcin-1 (STC-1) on intact mitochondria and cells: STC-1 uncouples oxidative phosphorylation and its actions are modulated by nucleotide triphosphates. Mol Cell Endocrinol 2007; 264:90-101. [PMID: 17092635 DOI: 10.1016/j.mce.2006.10.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 10/10/2006] [Accepted: 10/11/2006] [Indexed: 12/27/2022]
Abstract
Stanniocalcin-1 (STC-1) is one of only a handful of hormones that are targeted to mitochondria. High affinity receptors for STC-1 are present on cytoplasmic membranes and both the outer and inner mitochondrial membranes of nephron cells and hepatocytes. In both cell types, STC-1 is also present within the mitochondrial matrix and receptors presumably enable its sequestration. Furthermore, studies in bovine heart sub-mitochondrial particles have shown that STC-1 has concentration-dependent stimulatory effects on electron transport chain activity. The aim of the present study was to determine if the same effects could be demonstrated in intact, respiring mitochondria. At the same time, we also sought to demonstrate the functionality, if any, of an ATP binding cassette that has only recently been identified within the N-terminus of STC-1 by Prosite analysis. Intact, respiring mitochondria were isolated from rat muscle and liver and exposed to increasing concentrations of recombinant human STC-1 (STC-1). Following a 1h exposure to 500 nM STC-1, mitochondria from both organs displayed significant increases in respiration rate as compared to controls. Moreover, STC-1 uncoupled oxidative phosphorylation as ADP:O ratios were significantly reduced in mitochondria from both tissues. The resulting uncoupling was correlated with enhanced mitochondrial (45)Ca uptake in the presence of hormone. Respiratory studies were also conducted on a mouse inner medullary collecting cell line, where STC-1 had time and concentration-dependent stimulatory effects within the physiological range. In the presence of nucleotide triphosphates such as ATP and GTP (5mM) the respiratory effects of STC-1 were attenuated or abolished. Receptor binding studies revealed that this was due to a four-fold decrease in binding affinity (KD) between ligand and receptor. The results suggest that STC-1 stimulates mitochondrial electron transport chain activity and calcium transport, and that these effects are negatively modulated by nucleotide triphosphates.
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Affiliation(s)
- Joseph P Ellard
- Department of Physiology and Pharmacology, Faculty of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1
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Stolz B, Bereiter-Hahn J. Sequestration of iontophoretically injected calcium by living endothelial cells. Cell Calcium 1987; 8:103-21. [PMID: 3594554 DOI: 10.1016/0143-4160(87)90049-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Sequestration of iontophoretically injected Ca2+ by monolayer culture cells (primary Xenopus laevis Tadpole Heart cells, XTH P, and an established cell line, XTH 2) is investigated. Injections are made at different velocities by changing the influx current. On Ca2+ injection the entire ER desintegrates, and near to the tip of the injecting pipette microtubules depolymerize. The time required to attain cell death is taken as the parameter indicating an overload of cellular Ca2+ sequestration capability. Three different Ca2+ transport kinetics are found: at Ca2+ flux rates of up to 20 X 10(-15) mol X s-1 (condition I) cells can tolerate long injection periods before they die; at flux rates from 20 to 40 X 10(-15) mol X s-1 (condition II) the injection time before cell death remains constant. Flux rates exceeding 40 X 10(-15) mol X s-1 decrease cellular Ca2+ sequestration capability to a minimum. These observations support the assumption of two Ca2+ sequestrating mechanisms: one of high affinity, but with low capacity (less than = 5 X 10(-15) mol X s-1) the other with low affinity for Ca2+ and a high capacity (10 to 40 X 10(-15) mol X s-1) for Ca2+ accumulation. Both mechanisms are saturable. As the Ca2+ sequestration velocity remains approximately constant in condition II, the capacity of the second mechanism seems to grow with increasing Ca2+ influx. The highly affin Ca2+ compartment is the ER, mitochondria form the less affin system. XTH 2 differ from primary cells by possessing a 5 to 8 fold higher Ca2+ sequestration capacity, whereas sequestration velocity is equal in both cell types.
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Arshad JH, Holdsworth ES. Calcium uptake and release by rat liver mitochondria in the presence of rat liver cytosol or the components of cytosol. J Membr Biol 1980; 57:195-205. [PMID: 7205946 DOI: 10.1007/bf01869587] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A study has been made of factors present in rat liver cytosol that might regulate the calcium content of mitochondria. A cytosol preparation containing all the components of molecular weight greater than 10,000 prevented uptake and caused early release of accumulated calcium. These effects were due to free long-chain fatty acids and their coenzyme A derivatives present in the cytosol, and these inhibitory effects were controlled by inclusion of Mg2+, carnitine, and adenosine triphosphate at physiological levels in the incubation medium. Palmitoyl carnitine was a good substrate for calcium uptake and did not cause release of calcium from mitochondria. A specific fatty acid-binding protein was found in cytosol which may be the intracellular transport protein for fatty acids.
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Gómez-Puyou A, Tuena de Gómez-Puyou M, Klapp M, Carafoli E. The effect of calcium on the translocation of adenine nucleotides in rat liver mitochondria. Arch Biochem Biophys 1979; 194:399-404. [PMID: 443811 DOI: 10.1016/0003-9861(79)90633-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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7
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Lee NH, Shapiro IM. Ca2+ transport by chondrocyte mitochondria of the epiphyseal growth plate. J Membr Biol 1978; 41:349-60. [PMID: 357726 DOI: 10.1007/bf01871999] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In a study of the Ca2+ kinetics of mitochondria of chick epiphyseal chondrocytes, the rate of Ca2+ uptake was linear up to a medium Ca2+ concentration of 30 mum. The half maximal transport rate occurred at 34 mum Ca2+. The Ca2+ uptake rate, expressed as a function of time, was 35 nmoles/mg protein/min; the presence of Mg2+ had little effect on Ca2+ accumulation. While these kinetic parameters did not differ significantly from mitochondria of cells of nonmineralizing tissues, the respiratory characteristics of the chondrocyte organelles exhibited functional differences. Thus, up to 350 nmoles Ca2+/mg protein, chondrocyte mitochondria performed coupled oxidative phosphorylation. Calcium uptake was energy supported, while Ca2+ binding was low. Addition of respiratory inhibitors and uncouplers to these mitochondria resulted in a rapid loss of more than 80% of the total Ca2+. The Ca/Pi ratio of the extrudate was very similar to the ratio of the ions in cartilage septum fluid. In the most mineralized zones of the epiphyseal plate, there was little change in the state 4 respiratory rate, but nonspecific Ca2+ binding was elevated and a high percentage of the total Ca2+ was in a nonextrudable form. The results indicate that in cells preparing for mineralization, much of the total mitochondrial Ca2+ is in a form that can be transported to the calcification front. In cells close to the calcification front, nonextrudable Ca2+ may form calcium phosphate granules described by other investigators.
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Bikle D, Rasmussen H. A biochemical model for the ionic control of 25-hydroxyvitamin D3 1alpha-hydroxylase. J Biol Chem 1978. [DOI: 10.1016/s0021-9258(17)40800-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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9
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Carafoli E, Crompton M. The Regulation of Intracellular Calcium. CURRENT TOPICS IN MEMBRANES AND TRANSPORT 1978. [DOI: 10.1016/s0070-2161(08)60835-7] [Citation(s) in RCA: 241] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Dirks JH, Quamme GA. Renal handling of magnesium. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1978; 103:51-64. [PMID: 362854 DOI: 10.1007/978-1-4684-7758-0_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In summary, magnesium reabsorption occurs throughout the proximal and distal segments of the nephron. The proximal tubule is less permeable to magnesium than calcium and sodium with most of the filtered load being reclaimed in the ascending loop of Henle. In contrast to calcium and sodium a tubular reabsorptive maximum has been demonstrated for magnesium and under certain circumstances secretion has been demonstrated in the terminal nephron segments. Although many factors are known to affect magnesium reabsorption the mechanism of the renal homeostasis remains to be determined.
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Noack EA, Heinen EM. A kinetic study of calcium transort by heart mitochondria. EUROPEAN JOURNAL OF BIOCHEMISTRY 1977; 79:245-50. [PMID: 410642 DOI: 10.1111/j.1432-1033.1977.tb11802.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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12
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Tsokos J, Sans R, Bloom S. Ca2+ uptake by hyperpermeable mouse heart cells: effects of inhibitors of mitochondrial function. Life Sci 1977; 20:1913-21. [PMID: 875628 DOI: 10.1016/0024-3205(77)90228-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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13
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Condeelis JS. The isolation of microquantities of myosin from Amoeba proteus and Chaos carolinensis. Anal Biochem 1977; 78:374-94. [PMID: 851213 DOI: 10.1016/0003-2697(77)90099-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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14
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Shapiro IM, Burke AC, Lee NH. Effect of tetracycline on chondrocyte mitochondria--an explanation of tetracycline-induced defects of mineralized tissues. Biochem Pharmacol 1977; 26:595-600. [PMID: 856189 DOI: 10.1016/0006-2952(77)90030-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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15
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Mason M, Tobes MC. Opposing actions of Ca++ and ATP plus Mg++ in controlling the kynurenine aminotransferase activity of isolated rat kidney mitochondria. Biochem Biophys Res Commun 1977; 75:434-41. [PMID: 15565 DOI: 10.1016/0006-291x(77)91061-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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16
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Akerman KE. Effect of Mg2+ and spermine on the kinetics of Ca2+ transport in rat-liver mitochondria. J Bioenerg Biomembr 1977; 9:65-72. [PMID: 881424 DOI: 10.1007/bf00745043] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Plots relating the initial rate of mitochondrial Ca2+ transport to the Ca2+ concentration (kinetic plots) have a hyperbolic shape in a Ca2+ concentration range of 2.5-100 muM as measured in sucrose or KCl media. In the presence of Mg2+ or a polyamine spermine, which both are competitive inhibitors of Ca2+ binding to low affinity sites at the membrane surface, the shape of the plots becomes sigmoidal. At higher concentrations of these agents linear kinetic plots are obtained as measured in a sucrose medium. In a KCl medium the sigmoidality of the kinetic plots is enhanced by an increase in the Mg2+ or spermine concentration. It is suggested that Mg2+ and spermine affect the kinetics of Ca2+ transport by interfering with Ca2+ binding to low affinity sites of the membrane surface and that the binding of Ca2+ to these sites is the first step of the mitochondrial Ca2+ transport.
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17
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Moyle J, Mitchell P. Electric charge stoicheiometry of calcium translocation in rat liver mitochondria. FEBS Lett 1977; 73:131-6. [PMID: 14023 DOI: 10.1016/0014-5793(77)80964-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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18
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Farber JL, El-Mofty SK, Schanne FA, Aleo JJ, Serroni A. Intracellular calcium homeostasis in galactosamine-intoxicated rat liver cells. Active sequestration of calcium by microsomes and mitochondria. Arch Biochem Biophys 1977; 178:617-24. [PMID: 836048 DOI: 10.1016/0003-9861(77)90233-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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19
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Akerman KE, Wikström MK, Saris NE. Effect of inhibitors on the sigmoidicity of the calcium ion transport kinetics in rat liver mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA 1977; 464:287-94. [PMID: 831799 DOI: 10.1016/0005-2736(77)90004-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The kinetic plot (initial rate of Ca2+ transport versus concentration) of mitochondrial Ca2+ transport is hyperbolic in a sucrose medium. The plot becomes sigmoidal in the presence of competitive inhibitors of Ca2+ binding to low affinity sites of the membrane surface such as Mg2+ and K+. The plot also becomes sigmoidal in the presence of Ba2+. Ba2+ is a competitive inhibitor of both Ca2+ transport and Ca2+ binding to the low affinity sites. The 5i for the inhibition of Ca2+ transport by Ba2+ increases in the presence of K+ and Mg2+, which suggests a competition for the low affinity sites between the cations. The plot is still hyperbolic in the presence of La3+, which inhibits Ca2+ transport competitively. Ruthenium red which is a pure non-competitive inhibitor of mitochondrial Ca2+ transport, does not affect the shape of the kinetic plot. These results indicate that the surface potential, which depends on the ions bound to the low affinity sites, determines whether the kinetics of Ca2+ uptake in mitochondria is sigmoidal or hyperbolic.
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Luthra R, Olson MS. Studies of mitochondrial calcium movements using chlorotetracycline. BIOCHIMICA ET BIOPHYSICA ACTA 1976; 440:744-58. [PMID: 822874 DOI: 10.1016/0005-2728(76)90056-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
1. The association of calcium with isolated rat liver mitochondrial membranes under various metabolic conditions was monitored using the fluorescent chelate probe, chlorotetracycline. Chlorotetracycline fluorescence increased markedly during energized calcium uptake in the absence of a permeant anion. Uncoupler and a respiratory chain inhibitor caused a rapid decrease in chlorotetracycline fluorescence when added either before or after calcium. During calcium uptake experiments concentrations of calcium exceeding 100 muM caused a transient fluorescence increase followed by an extensive decrease in fluorescence. 2. Changes in the chlorotetracycline-associated fluorescence of the mitochondrial suspensions were correlated with the uptake of exogenous 45Ca. A positive correlation was observed between fluorescence and energized 45Ca uptake in the absence of permeant anions. Addition of the permeant anion, phosphate, caused an extensive decrease in chloretetracycline fluorescence but an enhanced uptake of exogenous 45Ca. 3. The interaction of endogenous mitochondrial calcium with the fluorescent chelate probe was studied under a number of experimental conditions using mitochondria labeled during preparation with 45Ca. Endogenous 45Ca was lost rapidly from the mitochondria upon treatment with uncoupler, antimycin A, and A23187. Potassium phosphate and EGTA had no effect on the endogenous calcium as measured by either the 45Ca content of the mitochondria or the fluorescence of the probe. 4. Mitochondria treated with antimycin A lost most of their endogenous 45Ca within 3 min; subsequent energization of the mitochondria resulted in a partial uptake of the released 45Ca but caused nearly a complete return of the chlorotetracycline fluorescence to the original level. Addition of phosphate did not change the fluorescence level but resulted in an almost complete accumulation of the 45Ca previously released. 5. Following this energized uptake of 45Ca, EGTA, p-trifluoromethoxyphenyl hydrazone of carbonyl cyanide, A23187 and calcium chloride all caused a nearly complete loss of the 45Ca from the mitochondria and, with the exception of calcium chloride, caused an extensive decrease in the fluorescence level. Hence, the apparent location and/or properties of the endogenous calcium in this rat liver mitochondrial system were altered significantly by manipulation of the energetic state of the mitochondrial membrane.
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22
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Heaton GM, Nicholls DG. The calcium conductance of the inner membrane of rat liver mitochondria and the determination of the calcium electrochemical gradient. Biochem J 1976; 156:635-46. [PMID: 949345 PMCID: PMC1163798 DOI: 10.1042/bj1560635] [Citation(s) in RCA: 126] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
1. A method is described for establishing steady-state conditions of calcium transport across the inner membrane of rat liver mitochondria and for determining the current of Ca2+ flowing across the membrane, together with the Ca2+ electrochemical gradient across the native Ca2+ carrier. These parameters were used to quantify the apparent Ca2+ conductance of the native carrier. 2. At 23 degrees C and pH7.0, the apparent Ca2+ conductance of the carrier is close to 1 nmol of Ca2+-min-1-mg of protein-1 mV-1. Proton extrusion by the respiratory chain, rather than the Ca2+ carrier itself, may often be rate-limiting in studies of initial rates of Ca2+ uptake. 3. Under parallel conditions, the endogenous H+ conductance of the membrane is 0.3 nmol of H+-min-1-mg of protein-1-mV-1. 4. Ruthenium Red and La3+ both strongly inhibit the Ca2+ conductance of the carrier, but are without effect on the H+ conductance of the membrane. 5. The apparent Ca2+ conductance of the carrier shows a sigmoidal dependence on the activity of Ca2+ in the medium. At 23 degrees C and pH7.2, half-maximum conductance is obtained at a Ca2+ activity of 4.7 muM. 6. The apparent Ca2+ conductance and the H+ conductance of the inner membrane increase fourfold from 23 degrees to 38 degrees C. The apparent Arrhenius activation energy for Ca2+ transport is 69kJ/mol. The H+ electrochemical gradient maintained in the absence of Ca2+ transport does not vary significantly with temperature. 7. The apparent Ca2+ conductance increases fivefold on increasing the pH of the medium from 6.8 to 8.0. The H+ conductance of the membrane does not vary significantly with pH over this range. 8. Mg2+ has no effect on the apparent Ca2+ conductance when added at concentration up to 1 mM. 9. Results are compared with classical methods of studying Ca2+ transport across the mitochondrial inner membrane.
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Schechter JE. Cations in the rat pars distalis ultrastructural localization. THE AMERICAN JOURNAL OF ANATOMY 1976; 146:189-205. [PMID: 941849 DOI: 10.1002/aja.1001460207] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Pituitary glands of female Sprague Dawley rats were fixed using the potassium pyroantimonate-osmium tetroxide technique by immersion or vascular perfusion. Both fixation procedures resulted in similar patterns of cation localization visualized as electron-dense precipitate within cells of the pars distalis. Nuclei were prominent sites of localization. Cytoplasmic precipitate occurred in association with the endoplasmic reticulum, typically within the cisternal spaces, and also was localized within the mitochondrial matrix and cristae, as well as Golgi membranes, small Golgi-associated vesicles, and multivesicular bodies. Immature secretory granules often contained precipitate between the core material of the granule and the enclosing smooth membrane. Frequently small antimonate-containing vesicles bordered the immature secretory granules. Precipitate was variable in secretory granules of more mature appearance although precipitate was apparent occasionally just within a granule's enclosing membrane. Granules closest to the plasma membrane often contained increased amounts of precipitate and small vesicles containing precipitate were observed fusing with them. Instances of granule release by emiocytosis often revealed a clustering of precipitate behind the core material away from the emiocytotic stoma, as well as at the stoma, and frequently an increased electron density of filamentous material radiating from the granules' enclosing membranes or from the adjacent plasma membrane. Exposure of section material to the chelating agents EGTA and EDTA indicate that calcium is the primary cation localized within the cytoplasm of these secretory cells. These findings are consistent with a role for calcium as a facilitator in the processes of transport and release of secretory granules.
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24
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Mikkelsen RB, Wallach DF. Binding of fluorescent lanthanides to rat liver mitochondrial membranes and calcium ion-binding proteins. BIOCHIMICA ET BIOPHYSICA ACTA 1976; 433:674-83. [PMID: 6061 DOI: 10.1016/0005-2736(76)90290-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
(1) Tb3+ binding to mitochondrial membranes can be monitored by enhanced ion fluorescence at 545 nm with excitation at 285 nm. At low protein concentrations (less than 30 mug/ml) no inner filter effects are observed. (2) This binding is localized at the external surface of the inner membrane and is unaffected by inhibitors of respiration or oxidative phosphorylation. (3) A soluble Ca2+ binding protein isolated according to Lehninger, A.L. ((1971) Biochem. Biophys. Res. Commun. 42, 312-317) also binds Tb3+ with enhanced ion fluorescence upon excitation at 285 nm. The excitation spectrum of the isolated protein and of the intact mitochondria are indicative of an aromatic amino acid at the cation binding site. (4) Further characterization of the Tb3+-protein interaction revealed that there is more than one binding site per protein molecule and that these sites are clustered (less than 20 A). Neuraminidase treatment or organic solvent extraction of the protein did not affect fluorescent Tb3+ binding. (5) pH dependency studies of Tb3+ binding to the isolated protein or intact mitochondria demonstrated the importance of an ionizable group of pK greater than 6. At pH less than 7.5 the amount of Tb3+ bound to the isolated protein decreased with increase in pH as monitored by Tb3+ fluorescence. With intact mitochondria the opposite occurred with a large increase in Tb3+ fluorescence at higher pH. This increase was not observed when the mitochondria were preincubated with antimycin A and rotenone.
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25
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Spencer TL, See JK, Bygrave FL. Translocation and binding of adenine nucleotides by rat liver mitochondria partially depleted of phospholipids. BIOCHIMICA ET BIOPHYSICA ACTA 1976; 423:365-73. [PMID: 1259954 DOI: 10.1016/0005-2728(76)90193-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
1. Rat liver mitochondria were partially depleted of their phospholipids using phospholipase A prepared from porcine pancreas (substrate specificity, cardiolipin greater than phosphatidylethanolamine greater than phosphatidylcholine) or from Crotalus adamanteus venom (substrate specificity, phosphatidylethanolamine = phosphatidylcholine greater than cardiolipin). 2. Removal of only about 1% of the mitochondrial phospholipid with the pancreatic enzyme leads to 50% and 25% losses in ADP and ATP translocation, respectively. Concomitant with the loss in translocation is a decline in the ability of both carbonylcyanide m-chlorophenylhydrazone and Ca2+ to stimulate ATP translocation. 3. To achieve comparable losses in ADP and ATP translocation with the venom enzyme, it is necessary to remove about 8% of the total mitochondrial phospholipid. Following such treatment, carbonylcyanide m-chlorophenylhydrazone and Ca2+ are still capable of stimulating ATP translocation. 4. Control experiments involving treatment of the mitochondria with the products of phospholipase digestion indicate that the effects observed on the translocase reflect a loss of phospholipid from the membrane. 5. Binding studies indicate that the loss in adenine nucleotide translocation following phospholipase treatment cannot be accoundted for by an altered ability to bind adenine nucleotides to atractyloside-sensitive sites. 6. The data are interpreted in terms of a mechanism of adenine nucleotide translocation involving a lipoprotein carrier system, consisting of the translocator protein and phospholipids, possibly cardiolipin and phosphatidylethanolamine.
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Jacobus WE, Tiozzo R, Lugli G, Lehninger AL, Carafoli E. Aspects of energy-linked calcium accumulation by rat heart mitochondria. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)40895-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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28
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Binet A, Volfin P. Regulation by Mg2+ and Ca2+ of mitochondrial membrane integrity: study of the effects of a cytosolic molecule and Ca2+ antagonists. Arch Biochem Biophys 1975; 170:576-86. [PMID: 1190780 DOI: 10.1016/0003-9861(75)90153-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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29
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Shapiro IM, Lee NH. Effects of Ca2+ on the respiratory activity of chondrocyte mitochondria. Arch Biochem Biophys 1975; 170:627-33. [PMID: 172017 DOI: 10.1016/0003-9861(75)90158-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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30
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Carafoli E. The interaction of Ca2+ with mitochondria, with special reference to the structural role of Ca2+ in mitochondrial and other membranes. Mol Cell Biochem 1975; 8:133-40. [PMID: 1102955 DOI: 10.1007/bf01792764] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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31
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Dorman DM, Barritt GJ, Bygrave FL. Stimulation of hepatic mitochondrial calcium transport by elevated plasma insulin concentrations. Biochem J 1975; 150:389-95. [PMID: 1212198 PMCID: PMC1165753 DOI: 10.1042/bj1500389] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The effect of insulin (injected intraperitoneally) on the transport of Ca2+ by hepatic mitochondria from rats was investigated. 2. Elevated concentrations of plasma insulin within the physiological range (10-100muunits/ml) stimulate the initial rate of Ca2+ transport into mitochondria at 4 degrees C by about 75% and prolong by approx. tenfold the time for which the mitochondria retain the accumulated Ca2+. 3. The prolonged retention of Ca2+ is observed under the conditions where hypoglycaemia is significantly decreased by the simultaneous injection of glucose and insulin. 4. A good correlation is observed between the effects on Ca2+ transport and the decrease in blood glucose concentration when the amount of insulin injected was varied. 5. The effects of insulin on mitochondrial Ca2+ transport are apparent at about 30 min after the injection, and are inhibited by cycloheximide. 6. There is little change in mitochondrial energy transduction after the administration of insulin. 7. The results are briefly discussed in relation to the mechanisms of Ca2+ transport across the inner mitochondrial membrane and the role of mitochondria in modifying intracellular Ca2+ concentrations with reference to the mechanism(s) by which insulin affects cellular metabolism.
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32
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Thorne RF, Bygrave FL. Kinetic evidence for calcium-ion and phosphate-ion transport systems in mitochondria from Ehrlich ascites tumour cells. FEBS Lett 1975; 56:185-8. [PMID: 1157937 DOI: 10.1016/0014-5793(75)81087-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Flatmark T, Romslo I. Energy-dependent accumulation of iron by isolated rat liver mitochondria. Requirement of reducing equivalents and evidence for a unidirectional flux of Fe(II) across the inner membrane. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)41082-x] [Citation(s) in RCA: 77] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Reed KC, Bygrave FL. A kinetic study of mitochondrial calcium transport. EUROPEAN JOURNAL OF BIOCHEMISTRY 1975; 55:497-504. [PMID: 240699 DOI: 10.1111/j.1432-1033.1975.tb02187.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This report describes a kinetic analysis of energy-linked Ca2+ transport in rat liver mitochondria, in which a ruthenium red/EGTA [ethanedioxy-bis(ethylamine)-tetraacetic acid] quenching technique has been used to measure rates of 45Ca2+ transport. Accurately known concentrations of free 45Ca2+ were generated with Ca2+/nitrilotriacetic acids buffers for the determination of substrate/velocity relationships. The results show that the initial velocity of transport is a sigmoidal function of Ca2+ concentration (Hill coefficient = 1.7), the Km being 4 muM Ca4 at 0 degrees C and pH 7.4. These values for the Hill coefficient and the Km remain constant in the presence of up to 2 mM phosphate, but with 10 mM acetate both parameters are increased slightly. Both permeant acids increase the maximum velocity to an extent dependent on their concentration. The Ca2+-binding site(s) of the carrier contains a group ionizing at pH approximately 7.5 at 0 degrees C, which is functional in the dissociated state. The stimulatory effect of permeant acids is ascribed to their facilitating the release of Ca2+ from the carrier to the internal phase, an interpretation which is strengthened by the lack of effect of the permeant anion SCN- on Ca2+ transport. Studies on the time-course of Ca2+ uptake and of EFTA-induced Ca2+ efflux from pre-loaded mitochondria demonstrate the reversibility of the carrier in respiring mitochondria and the extent to which this property is influenced by permeant acids. These data are accommodated in a carrier mechanism based on electrophoretic transport of Ca2+ bound to pairs of interacting acidic sites.
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Romslo I. Energy-dependent accumulation of iron by isolated rat liver mitochondria. IV. Relationship to the energy state of the mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA 1975; 387:69-79. [PMID: 1125288 DOI: 10.1016/0005-2728(75)90052-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
1. The energy-dependent accumulation of iron by isolated rat liver mitochondria, respiring on endogenous substrates, is strongly dependent on the efficiency of energy coupling in the respiratory chain as measured by respiratory control with ADP and the endogenous energy dissipation. The accumulation reached a saturation level at respiratory control with ADP values (with succinate as the substrate) of approx. 4.0. 2. In the presence of exogenous substrate, the energy-dependent accumulation of iron was markedly reduced, primarily due to binding of iron as carboxylate complexes having less favourable constants than the iron (III)-sucrose complex(es). 3. The effect of added ATP was at least 2-fold, i.e. that of providing energy and that of chelating iron. When the mitochondria respired on endogenous substrate, the energy-dependent accumulation of iron increased at low concentrations of ATP, whereas higher concentrations (greater than 50 mu M) gradually inhibited the uptake. 4. Energization of the mitochondria by the generation of an artificial K-+ gradient across the inner membrane with valinomycin in a K-+-free medium increased the energy-dependent accumulation iron.
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Bygrave FL, Daday AA, Doy FA. Evidence of a calcium-ion-transport system in mitochondria isolated from flight muscle of the developing sheep blowfly Lucilia cuprina. Biochem J 1975; 146:601-8. [PMID: 807204 PMCID: PMC1165349 DOI: 10.1042/bj1460601] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The EGTA (ethanedioxybis(ethylamine)tetra-acetic acid)-Ruthenium Red-quench technique (Reed & Bygrave, 1974a) was used to measure initial rates of Ca-2+ transport in mitochondria from flight muscle of the blowfly Lucilia cuprina. Evidence is provided for the existence in these mitochondria of a Ca-2+-transport system that has many features in common with that known to exist in rat liver mitochondria. These include requirement for energy, saturation at high concentrations of Ca-2+, a sigmoidal relation between initial rates of Ca-2+ transport and Ca-2+ concentration, a high affinity for free Ca-2+ (Km approx. 5 muM) and high affinity for the Ca-2+-transport inhibitoy, Ruthenium Red (approx. 0.03 nmol of carrier-specific binding-sites/mg of protein; Ki approx. 1.6 x 10- minus 8 M). Controlled respiration can be stimulated by Ca-2+ after a short lag-period provided the incubation medium contains KCl and not sucrose. The ability of Lucilia mitochondria to transport Ca-2+ critically depends on the stage of mitochondrial development; Ca-2+ transport is minimal in mitochondria from pharate adults, is maximal between 0 and 2h post-emergence and thereafter rapidly declines to reach less than 20% of the maximum value by about 2-3 days post-emergence. Respiration in mitochondria from newly emerged flies does not respond to added Ca-2+; that from 3-5-day-old flies is stimulated approx. 50%. Whereas very low concentrations of Ca-2+ inhibit ADP-stimulated respiration and oxidative phosphorylation in mitochondria from newly emerged flies (Ki approx. 60 ng-ions of Ca-2+/mg of protein); much higher concentrations (approx. 200 ng-ion/mg of protein) are needed to inhibit these processes in those from older flies. The potential of this system for studying the function and development of metabolite transport systems in mitochondria is discussed.
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McIntyre HJ, Bygrave FL. Retention of calcium by mitochondria isolated from Ehrlich ascites tumor cells. Arch Biochem Biophys 1974; 165:744-8. [PMID: 4474839 DOI: 10.1016/0003-9861(74)90303-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Thorne RF, Bygrave FL. The role of mitochondria in modifying the cellular ionic environment. Calcium-induced respiratory activities in mitochondria isolated from various tumour cells. Biochem J 1974; 144:551-8. [PMID: 4377656 PMCID: PMC1168533 DOI: 10.1042/bj1440551] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Cyclic stimulation by Ca(2+) of respiration in mitochondria isolated from Ehrlich ascites-tumour cells occurs only when low phosphate concentrations (approx. 0.5mm) are also included in the incubation system. Under these circumstances the extra oxygen consumed is related stoicheiometrically to the amount of Ca(2+) taken up by the mitochondria; the values are similar to those obtained with mitochondria from rat liver in the absence of added phosphate. In contrast with liver mitochondria, up to 280nmol of Ca(2+)/mg of protein can be added to ascites mitochondria without causing any deleterious effect. Respiration in mitochondria isolated from the Yoshida ascites hepatoma (HA 130) and from the Morris hepatomas 5123C and 9618A is also stimulated by Ca(2+) in a cyclic manner. However, that in mitochondria from regenerating rat liver responds to Ca(2+) in the same way as those from normal rat liver. ADP-stimulated respiration in mitochondria from Ehrlich ascites tumour cells, but not from rat liver, is inhibited by low amounts of Ca(2+).
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Reed KC, Bygrave FL. A re-evaluation of energy-independent calcium-ion binding by rat liver mitochondria. Biochem J 1974; 142:555-66. [PMID: 4219276 PMCID: PMC1168319 DOI: 10.1042/bj1420555] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The impermeability of the mitochondrial inner membrane to the chelator ethanedioxybis(ethylamine)tetra-acetic acid permits discrimination between Ca(2+) which has been transported to the internal (matrix) phase and Ca(2+) which binds to the external surfaces of the mitochondrion. With this technique, it is shown that ;energy-independent high-affinity' binding is a measure of carrier-mediated active Ca(2+) transport in respiration-inhibited mitochondria; the carrier also transports Ca(2+) to the internal phase after treatment with carbonyl cyanide m-chlorophenylhydrazone, but in this case the active-transport component is inhibited. The Ca(2+)-binding sites associated with the external membrane surfaces are similar in concentration and affinity for both inhibited and uncoupled mitochondria; it was not possible to measure external Ca(2+) binding which could be identified as carrier specific. The results are discussed in relation to the mechanism of mitochondrial Ca(2+) transport, and to previous studies of energy-independent Ca(2+) binding.
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Romslo I. Energy-dependent accumulation of iron by isolated rabbit reticulocyte mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA 1974; 357:34-42. [PMID: 4413242 DOI: 10.1016/0005-2728(74)90109-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Spencer TL, Bygrave FL. Inhibition by local anaesthetics of adenine nucleotide translocation in rat liver mitochondria. Biochem J 1974; 140:413-22. [PMID: 4280910 PMCID: PMC1168018 DOI: 10.1042/bj1400413] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
1. The mechanism of adenine nucleotide translocation in mitochondria isolated from rat liver was further examined by using the local anaesthetics procaine, butacaine, nupercaine and tetracaine as perturbators of lipid-protein interactions. Each of these compounds inhibited translocation of ADP and of ATP; butacaine was the most effective with 50% inhibition occurring at 30mum for 200mum-ATP and at 10mum for 200mum-ADP. The degree of inhibition by butacaine of both adenine nucleotides was dependent on the concentration of adenine nucleotide present; with low concentrations of adenine nucleotide, low concentrations of butacaine-stimulated translocation, but at high concentrations (greater than 50mum) low concentrations of butacaine inhibited translocation. Butacaine increased the affinity of the translocase for ATP to a value which approached that of ADP. 2. Higher concentrations of nupercaine and of tetracaine were required to inhibit translocation of both nucleotides; 50% inhibition of ATP translocation occurred at concentrations of 0.5mm and 0.8mm of these compounds respectively. The pattern of inhibition of ADP translocation by nupercaine and tetracaine was more complex than that of ATP; at very low concentrations (less than 250mum) inhibition ensued, followed by a return to almost original rates at 1mm. At higher concentrations inhibition of ADP translocation resulted. 3. That portion of ATP translocation stimulated by Ca(2+) was preferentially inhibited by each of the local anaesthetics tested. In contrast, inhibition by the anaesthetics of ADP translocation was prevented by low concentrations of Ca(2+). 4. The data provide further support for our hypothesis that lipid-protein interactions are important determinants in the activity of the adenine nucleotide translocase in mitochondria.
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Rao KN, de Smet M, Howells AJ, Bygrave FL. Inhibition by calcium of tRNA aminoacylation in preparations from rat liver. FEBS Lett 1974; 41:185-8. [PMID: 4852464 DOI: 10.1016/0014-5793(74)81207-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Thorne RF, Bygrave FL. Inhibition by calcium of adenine nucleotide translocation in mitochondria isolated from Ehrlich ascites tumour cells. FEBS Lett 1974; 41:118-21. [PMID: 4852463 DOI: 10.1016/0014-5793(74)80968-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Thorne RF, Bygrave FL. Calcium does not uncouple oxidative phosphorylation in tightly-coupled mitochondria from Ehrlich ascites tumour cells. Nature 1974; 248:348-51. [PMID: 4274304 DOI: 10.1038/248348a0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Roberts JB, Bygrave FL. Influence of mitochondria on phospholipid synthesis in preparations from rat liver. Biochem J 1973; 136:467-75. [PMID: 4360711 PMCID: PMC1165981 DOI: 10.1042/bj1360467] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
1. The addition of mitochondria to an incubation system containing the soluble and microsomal fractions of rat liver enhances severalfold the incorporation of each of ethanolamine, phosphorylethanolamine and CDP-ethanolamine into phosphatidylethanolamine. 2. In the presence of microsomal, mitochondrial and soluble fractions, CDP-ethanolamine exhibits the greatest initial rate of incorporation (approx. 6nmol/h per mg of protein), being slightly faster than that of phosphorylethanolamine (approx. 5nmol/h per mg of protein). Incorporation of ethanolamine proceeds very slowly for the first 20min and only after 30min gives rates approaching those of the other two precursors. 3. By using a substrate ;dilution' technique it was shown that in the reconstituted system the affinity of each of the enzymes for their respective substrates is very high: 10mum for ethanolamine, 25mum for phosphorylethanolamine and 5mum for CDP-ethanolamine. 4. Isolation of the mitochondrial and microsomal fractions from the medium after incubation together with phosphorylethanolamine showed that about 70% of the total radioactivity was present in the microsomal fraction and about 30% in the mitochondria after only 20min. Similar experiments with ethanolamine as precursor revealed that after 20min only about 15% of the total radioactivity was present in the mitochondria but that after 40min about 30% was present in this fraction. 5. Heating and phospholipase treatment of mitochondria, but not freeze-thawing, eliminated the stimulatory effect of mitochondria on phospholipid synthesis. 6. The reconstituted system exhibits an absolute requirement for Mg(2+) (2mm gave maximal rates) and is inhibited by very low concentrations of Ca(2+) (100mum-Ca(2+) produced half-maximal inhibition with 3mm-Mg(2+)). Further addition of Mg(2+) overcame the Ca(2+) inhibition, suggesting that the inhibitory effect is readily reversible. 7. The concept that modification of the Mg(2+)/Ca(2+) ratio is a means of controlling the rate of cellular phospholipid synthesis is introduced.
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