Downregulation of uncoupling protein 2 mRNA in white adipose tissue and uncoupling protein 3 mRNA in skeletal muscle during the early stages of leptin treatment

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.

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Uncoupling Protein-2 and -3 Messenger Ribonucleic Acids in Adipose Tissue and Skeletal Muscle of Healthy Males: Variability, Factors Affecting Expression, and Relation to Measures of Metabolic Rate

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.85.5.1975 ◽

2000 ◽

Vol 85 (5) ◽

pp. 1975-1983 ◽

Cited By ~ 7

Author(s):

M. Boivin

Keyword(s):

Skeletal Muscle ◽

Adipose Tissue ◽

Metabolic Rate ◽

Uncoupling Protein ◽

Uncoupling Protein 2 ◽

Ribonucleic Acids ◽

Factors Affecting ◽

Healthy Males

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Mutation yellow in agouti loci prevents age-related increase of skeletal muscle genes regulating free fatty acids oxidation

Vavilov Journal of Genetics and Breeding ◽

10.18699/vj18.358 ◽

2018 ◽

Vol 22 (2) ◽

pp. 265-272 ◽

Cited By ~ 1

Author(s):

Y. V. Piskunova ◽

A. Y. Kazantceva ◽

A. V. Baklanov ◽

N. M. Bazhan

Keyword(s):

Skeletal Muscle ◽

Fatty Acids ◽

Adipose Tissue ◽

Free Fatty Acids ◽

Glucose Uptake ◽

White Adipose Tissue ◽

Uncoupling Protein ◽

Age Related ◽

Brown Adipose ◽

Ay Mice

The lethal yellow mutation in agouti loci (Ay mutation) reduces the activity of melanocortin (MC) receptors and causes hyperphagia, obesity and type two diabetes mellitus in aging mice (Ay mice). It is unknown if changes in distinct elements of the metabolic system such as white adipose tissue (WAT) and brown adipose tissue (BAT), and skeletal muscle will manifest before the development of obesity. The aim of this work was to measure the relative gene expression of key proteins that regulate carbohydrate-lipid metabolism in WAT, BAT and skeletal muscle in Ay mice before the development of obesity. C57Bl/6J mice bearing a dominant autosomal mutation Ay (Ay /a mice) and mice of the standard genotype (a/a mice, control) have been studied in three age groups: 10, 15 and 30 weeks. The relative mRNA level of genes was measured by real-time PCR in skeletal muscles (uncoupling protein 3 (Ucp3) and carnitine palmitoyl transferase 1b (Cpt1b) (free fatty acids oxidation), solute carrier family 2 (facilitated glucose transporter), member 4 (Slc2a4) (glucose uptake)), in WAT lipoprotein lipase (Lpl) (triglyceride deposition), hormone-sensitive lipase (Lipe) (lipid mobilization), and Slc2a4 (glucose uptake)), and in BAT: uncoupling protein 1 (Ucp1) (energy expenditure). The expression of Cpt1b was reduced in young Ay mice (10 weeks), there was no transient peak of transcription of Cpt1b, Ucp3 in skeletal muscle tissue and Lipe, Slc2a4 in WAT in early adult Ay mice (15 weeks), which was noted in а/а mice. Reduction of the transcriptional activity of the studied genes in skeletal muscle and white adipose tissue can initiate the development of melanocortin obesity in Ay mice.

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Differential Regulation of Uncoupling Protein-2 and Uncoupling Protein-3 Gene Expression in Brown Adipose Tissue during Development and Cold Exposure

Biochemical and Biophysical Research Communications ◽

10.1006/bbrc.1998.8088 ◽

1998 ◽

Vol 243 (1) ◽

pp. 224-228 ◽

Cited By ~ 39

Author(s):

M.Carmen Carmona ◽

Angel Valmaseda ◽

Sonia Brun ◽

Octavi Viñas ◽

Teresa Mampel ◽

...

Keyword(s):

Gene Expression ◽

Adipose Tissue ◽

Brown Adipose Tissue ◽

Cold Exposure ◽

Uncoupling Protein ◽

Differential Regulation ◽

Uncoupling Protein 2 ◽

Uncoupling Protein 3 ◽

Brown Adipose

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Uncoupling protein 2 and 3 in marsupials: identification, phylogeny, and gene expression in response to cold and fasting in Antechinus flavipes

Physiological Genomics ◽

10.1152/physiolgenomics.00165.2003 ◽

2004 ◽

Vol 17 (2) ◽

pp. 130-139 ◽

Cited By ~ 23

Author(s):

Martin Jastroch ◽

Kerry Withers ◽

Martin Klingenspor

Keyword(s):

Gene Expression ◽

Skeletal Muscle ◽

Adipose Tissue ◽

Tissue Specificity ◽

Striated Muscle ◽

Uncoupling Protein ◽

Uncoupling Protein 2 ◽

Reading Frame ◽

Amino Acid Peptide ◽

Ucp3 Gene

We searched for the presence of uncoupling protein genes so far unknown in marsupials and monotremes and identified uncoupling protein 2 (UCP2) and UCP3 full-length cDNAs in libraries constructed from the marsupials Antechinus flavipes and Sminthopsis macroura. Marsupial UCP2 is 89–90% identical to rodent UCP2, whereas UCP3 exhibits 80% identity to mouse UCP3. A phylogenetic tree including all known UCPs positions the novel marsupial UCP2 and UCP3 at the base of the mammalian orthologs. In the 5′-untranslated region of UCP2 a second open reading frame encoding for a 36-amino acid peptide was identified which is highly conserved in all vertebrate UCP2 transcripts. Analysis of tissue specificity in A. flavipes with homologous cDNA probes revealed ubiquitous presence of UCP2 mRNA and striated muscle specificity of UCP3 mRNA resembling the known expression pattern in rodents. Neither UCP2 nor UCP3 gene expression was stimulated in adipose tissue and skeletal muscle of cold exposed A. flavipes. However, UCP3 mRNA expression was upregulated 6-fold in heart and 2.5-fold in skeletal muscle as reported for rodents in response to fasting. Furthermore, UCP3 mRNA seems to be coregulated with PDK4 mRNA, indicating a relation to enhanced lipid metabolism. In contrast, UCP2 gene expression was not regulated in response to fasting in adipose tissue and skeletal muscle but was diminished in the lung and increased in adipose tissue. Taken together, the sequence analysis, tissue specificity and physiological regulation suggest a conserved function of UCP2 and UCP3 during 130 million years of mammalian evolution.

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