scholarly journals Oxidative damage and phospholipid fatty acyl composition in skeletal muscle mitochondria from mice underexpressing or overexpressing uncoupling protein 3

2002 ◽  
Vol 368 (2) ◽  
pp. 597-603 ◽  
Author(s):  
Martin D. BRAND ◽  
Reinald PAMPLONA ◽  
Manuel PORTERO-OTÍN ◽  
Jesús R. REQUENA ◽  
Stephen J. ROEBUCK ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Oxidative Damage ◽  
Uncoupling Protein ◽  
Fatty Acyl ◽  
Proton Conductance ◽  
Acyl Composition ◽  
Skeletal Muscle Mitochondria ◽  
Fatty Acyl Composition ◽  
Uncoupling Protein 3

Five markers of different kinds of oxidative damage to proteins [glutamic semialdehyde, aminoadipic semialdehyde, N∊-(carboxymethyl)lysine, N∊-(carboxyethyl)lysine and N∊-(malondialdehyde)lysine] and phospholipid fatty acyl composition were identified and measured in skeletal muscle mitochondria isolated from mice genetically engineered to underexpress or overexpress uncoupling protein 3 (UCP3). Mitochondria from UCP3-underexpressing mice had significantly higher levels of oxidative damage than wild-type controls, suggesting that UCP3 functions in vivo as part of the antioxidant defences of the cell, but mitochondria from UCP3-overexpressing mice had unaltered oxidative damage, suggesting that mild uncoupling in vivo beyond the normal basal uncoupling provides little protection against oxidative stress. Mitochondria from UCP3-underexpressing mice showed little change, but mitochondria from UCP3-overexpressing mice showed marked changes in mitochondrial phospholipid fatty acyl composition. These changes were very similar to those previously found to correlate with basal proton conductance in mitochondria from a range of species and treatments, suggesting that high protein expression, or some secondary result of uncoupling, may cause the observed correlation between basal proton conductance and phospholipid fatty acyl composition.

scholarly journals The Basal Proton Conductance of Skeletal Muscle Mitochondria from Transgenic Mice Overexpressing or Lacking Uncoupling Protein-3

2001 ◽  
Vol 277 (4) ◽  
pp. 2773-2778 ◽  
Author(s):  
Susana Cadenas ◽  
Karim S. Echtay ◽  
James A. Harper ◽  
Mika B. Jekabsons ◽  
Julie A. Buckingham ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Transgenic Mice ◽  
Uncoupling Protein ◽  
Proton Conductance ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Uncoupling Protein 3

Artifactual uncoupling by uncoupling protein 3 in yeast mitochondria at the concentrations found in mouse and rat skeletal-muscle mitochondria

2001 ◽  
Vol 361 (1) ◽  
pp. 49-56 ◽  
Author(s):  
James A. HARPER ◽  
Jeff A. STUART ◽  
Mika B. JEKABSONS ◽  
Damien ROUSSEL ◽  
Kevin M. BRINDLE ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Uncoupling Protein ◽  
Mitochondrial Protein ◽  
Yeast Mitochondria ◽  
Rat Skeletal Muscle ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Uncoupling Protein 3 ◽  
Brown Adipose

Western blots detected uncoupling protein 3 (UCP3) in skeletal-muscle mitochondria from wild-type but not UCP3 knock-out mice. Calibration with purified recombinant UCP3 showed that mouse and rat skeletal muscle contained 0.14μg of UCP3/mg of mitochondrial protein. This very low UCP3 content is 200–700-fold less than the concentration of UCP1 in brown-adipose-tissue mitochondria from warm-adapted hamster (24–84μg of UCP1/mg of mitochondrial protein). UCP3 was present in brown-adipose-tissue mitochondria from warm-adapted rats but was undetectable in rat heart mitochondria. We expressed human UCP3 in yeast mitochondria at levels similar to, double and 7-fold those found in rodent skeletal-muscle mitochondria. Yeast mitochondria containing UCP3 were more uncoupled than empty-vector controls, particularly at concentrations that were 7-fold physiological. However, uncoupling by UCP3 was not stimulated by the known activators palmitate and superoxide; neither were they inhibited by GDP, suggesting that the observed uncoupling was a property of non-native protein. As a control, UCP1 was expressed in yeast mitochondria at similar concentrations to that of UCP3 and at up to 50% of the physiological level of UCP1. Low levels of UCP1 gave palmitate-dependent and GDP-sensitive proton conductance but higher levels of UCP1 caused an additional GDP-insensitive uncoupling artifact. We conclude that the uncoupling of yeast mitochondria by high levels of UCP3 expression is entirely an artifact and provides no evidence for any native uncoupling activity of the protein.

Survival of rabbit and horse erythrocytes in vivo after changing the fatty acyl composition of their phosphatidylcholine

1985 ◽  
Vol 819 (2) ◽  
pp. 170-178 ◽  
Author(s):  
F.A. Kuypers ◽  
E.W. Easton ◽  
R. van den Hoven ◽  
T. Wensing ◽  
B. Roelofsen ◽  
...  
Keyword(s):  
Fatty Acyl ◽  
Acyl Composition ◽  
Fatty Acyl Composition

scholarly journals Thyroid hormones directly activate the expression of the human and mouse uncoupling protein-3 genes through a thyroid response element in the proximal promoter region

2005 ◽  
Vol 386 (3) ◽  
pp. 505-513 ◽  
Author(s):  
Gemma SOLANES ◽  
Neus PEDRAZA ◽  
Verónica CALVO ◽  
Antonio VIDAL-PUIG ◽  
Bradford B. LOWELL ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Uncoupling Protein ◽  
Gene Promoter ◽  
Proximal Promoter ◽  
Ucp3 Gene ◽  
Uncoupling Protein 3

The transcription of the human UCP3 (uncoupling protein-3) gene in skeletal muscle is tightly regulated by metabolic signals related to fatty acid availability. However, changes in thyroid status also modulate UCP3 gene expression, albeit by unknown mechanisms. We created transgenic mice bearing the entire human UCP3 gene to investigate the effect of thyroid hormones on human UCP3 gene expression. Treatment of human UCP3 transgenic mice with thyroid hormones induced the expression of the human gene in skeletal muscle. In addition, transient transfection experiments demonstrate that thyroid hormones activate the transcription of the human UCP3 gene promoter when MyoD and the TR (thyroid hormone receptor) were co-transfected. The action of thyroid hormones on UCP3 gene transcription is mediated by the binding of the TR to a proximal region in the UCP3 gene promoter that contains a direct repeat structure. An intact DNA sequence of this site is required for thyroid hormone responsiveness and TR binding. Chromatin immunoprecipitation assays revealed that the TR binds this element in vivo. The murine Ucp3 gene promoter was also dependent on MyoD and responsive to thyroid hormone in transient transfection assays. However, it was much less sensitive to thyroid hormone than the human UCP3 promoter. In summary, UCP3 gene transcription is activated by thyroid hormone treatment in vivo, and this activation is mediated by a TRE (thyroid hormone response element) in the proximal promoter region. Such regulation suggests a link between UCP3 gene expression and the effects of thyroid hormone on mitochondrial function in skeletal muscle.

scholarly journals AMP decreases the efficiency of skeletal-muscle mitochondria

2000 ◽  
Vol 351 (2) ◽  
pp. 307-311 ◽  
Author(s):  
Susana CADENAS ◽  
Julie A. BUCKINGHAM ◽  
Julie ST-PIERRE ◽  
Keith DICKINSON ◽  
Robert B. JONES ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Metabolic Rate ◽  
Rana Temporaria ◽  
Adenine Nucleotide ◽  
Uncoupling Protein ◽  
Metabolic Efficiency ◽  
Proton Conductance ◽  
Muscle Mitochondria ◽  
Rat Muscle ◽  
Skeletal Muscle Mitochondria

Mitochondrial proton leak in rat muscle is responsible for approx. 15% of the standard metabolic rate, so its modulation could be important in regulating metabolic efficiency. We report in the present paper that physiological concentrations of AMP (K0.5 = 80µM) increase the resting respiration rate and double the proton conductance of rat skeletal-muscle mitochondria. This effect is specific for AMP. AMP also doubles proton conductance in skeletal-muscle mitochondria from an ectotherm (the frog Rana temporaria), suggesting that AMP activation is not primarily for thermogenesis. AMP activation in rat muscle mitochondria is unchanged when uncoupling protein-3 is doubled by starvation, indicating that this protein is not involved in the AMP effect. AMP activation is, however, abolished by inhibitors and substrates of the adenine nucleotide translocase (ANT), suggesting that this carrier (possibly the ANT1 isoform) mediates AMP activation. AMP activation of ANT could be important for physiological regulation of metabolic rate.

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