Expression of the glucose transporter GLUT4 in the muscular dystrophic <i>mdx</i> mouse

Olichon-Berthe, C.; Gautier, Nadine; Obberghen, Emmanuel Van; Marchand-Brustel, Y. Le

doi:10.1042/bj2910257

Cited by 15 publications

(9 citation statements)

References 38 publications

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“…Total RNA and protein concentrations in the two groups were not different. This is not the first study to show discordance with respect to GLUT4 mRNA and protein concentrations2, 5, 17; however, we show that there is an inverse relationship between the two variables in patients with MD. Several studies have demonstrated that the relationship between GLUT4 transcription and translation is not always tightly coupled under conditions of metabolic stress.…”

Section: Discussioncontrasting

confidence: 60%

“…Two studies involving altered physiological states and GLUT4 expression in rats have shown no correlation between muscle GLUT4 mRNA and protein concentration 2, 5. Using the mdx murine model of Duchenne muscular dystrophy, investigators have reported discordant results with higher GLUT4 protein and lower GLUT4 mRNA levels when normalized to total RNA 17. The incongruence between the GLUT4 mRNA and protein results in the current study sends an important cautionary message to researchers in the area of physiology and medicine where there is a tendency to imply that changes in mRNA abundance lead to directionally similar changes in protein content, especially in gene array studies 22, 25…”

Section: Discussionmentioning

confidence: 99%

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Increased PFK activity and GLUT4 protein content in McArdle's disease

et al. 2008

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Inborn errors of metabolism represent an opportunity to conduct studies in order to understand compensatory adaptations to a defective metabolic pathway. We evaluated the molecular and biochemical adaptations in substrate metabolism (glycolysis, electron transport chain, tricarboxylic acid cycle, beta-oxidation) in response to myophosphorylase deficiency in skeletal muscle from 13 patients with McArdle's disease (MD) and 13 age-matched controls. MD muscle had higher phosphofructokinase protein content and activity as well as glucose transporter 4 (GLUT4) protein content and lower GLUT4 mRNA content than controls. At the protein level, skeletal muscle adaptations suggest an augmented glucose transport and glycolytic flux as a compensatory metabolic strategy to a chronic absence of muscle glycogen phosphorylase. These results support previous findings of increased glucose uptake during exercise and alleviation of symptoms with oral sucrose in patients with MD.

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Section: Discussioncontrasting

confidence: 60%

Section: Discussionmentioning

confidence: 99%

Increased PFK activity and GLUT4 protein content in McArdle's disease

et al. 2008

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“…In addition to being the voltage sensor for excitation-contraction coupling, the skeletal muscle Ca 2ϩ channel has a privileged connection to regulation of gene expression that bypasses the Ca 2ϩ signal generated by the sarcoplasmic reticulum and ryanodine-sensitive Ca 2ϩ release channels (5). Reduction in this Ca 2ϩ current may be partially responsible for the disruptions in gene expression observed in the mdx mouse and in individuals with Duchenne and Becker muscular dystrophies (52)(53)(54)(55)(56). Because trophic effects on gene expression are important in maintenance of muscle fiber function and structural integrity, alteration in the regulation of gene expression by voltage-gated L-type Ca 2ϩ currents may contribute significantly to the progressive muscle dysfunction and cell death associated with these diseases.…”

Section: Effects Of Pka On Voltage Dependence Of Ca 2؉ Channel Activimentioning

confidence: 99%

Convergent regulation of skeletal muscle Ca ²⁺ channels by dystrophin, the actin cytoskeleton, and cAMP-dependent protein kinase

Johnson

Scheuer

Catterall

2005

Proc. Natl. Acad. Sci. U.S.A.

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The skeletal muscle L-type Ca 2؉ channel (CaV1.1), which is responsible for initiating muscle contraction, is regulated by phosphorylation by cAMP-dependent protein kinase (PKA) in a voltagedependent manner that requires direct physical association between the channel and the kinase mediated through A-kinase anchoring proteins (AKAPs). The role of the actin cytoskeleton in channel regulation was investigated in skeletal myocytes cultured from wild-type mice, mdx mice that lack the cytoskeletal linkage protein dystrophin, and a skeletal muscle cell line, 129 CB 3. Voltage dependence of channel activation was shifted positively, and potentiation was greatly diminished in mdx myocytes and in 129 CB 3 cells treated with the microfilament stabilizer phalloidin. Voltage-dependent potentiation by strong depolarizing prepulses was reduced in mdx myocytes but could be restored by positively shifting the stimulus potentials to compensate for the positive shift in the voltage dependence of gating. Inclusion of PKA in the pipette caused a negative shift in the voltage dependence of activation and restored voltage-dependent potentiation in mdx myocytes. These results show that skeletal muscle Ca 2؉ channel activity and voltage-dependent potentiation are controlled by PKA and microfilaments in a convergent manner. Regulation of Ca 2؉ channel activity by hormones and neurotransmitters that use the PKA signal transduction pathway may interact in a critical way with the cytoskeleton and may be impaired by deletion of dystrophin, contributing to abnormal regulation of intracellular calcium concentrations in dystrophic muscle.calcium channel ͉ protein phosphorylation ͉ muscular dystrophy V oltage-gated Ca 2ϩ channels present in most cells play a critical role in converting cellular electrical activity into an intracellular Ca 2ϩ signal. Neurotransmitter and hormone release from neurons and endocrine cells, gene expression in many cell types, and contraction of cardiac, smooth, and skeletal muscle are all dependent on the activity of voltage-gated Ca 2ϩ channels. In skeletal muscle cells, the Ca V 1.1 channels in transverse tubules have two distinct functional roles. They serve as the voltage sensor for excitation-contraction coupling and transduce a voltage-dependent conformational change into activation of the ryanodine-sensitive Ca 2ϩ release channels in the sarcoplasmic reticulum (1, 2). Ca 2ϩ release from the sarcoplasmic reticulum rapidly initiates contraction. In addition, on a slower time scale, the L-type Ca 2ϩ current conducted by these channels is activated, and the resulting Ca 2ϩ influx increases contractile force in subsequent contractions (3, 4) and regulates gene expression and other muscle activities (5).Activation of skeletal muscle Ca 2ϩ channels is increased by cAMP-dependent phosphorylation in response to adrenergic stimulation (3, 6) and is further potentiated by strong depolarization (7-9), which requires cAMP-dependent protein kinase (PKA) phosphorylation (7). PKA is often anchored near substrates by A-kinas...

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“…Genotype/phenotype Mean weight, g Percentage of large animals mals of parental strain (C57Bl/10Sn), which was previously demonstrated for 6-7-month-old mutant and normal black females [10].…”

Section: Resultsmentioning

confidence: 95%

A New Genetic Variant of MDX Mice: Study of the Phenotype

et al. 2009

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Genetic selection in a colony of mdx mice (suffering from X-chromosome-linked muscular dystrophy) resulted in generation of their new genetic variant. In this new variant, the genetic, biochemical, and histological markers of muscular dystrophy are combined with signs of oculocutaneous albinism (skin and fur depigmentation), transillumination of the iris, sharply reduced pigmentation of the retinal epithelium, and increase of the eyeball refraction). Two sensorimotor tests (negative geotaxis and wire back down hanging) detected other phenotypical characteristics of albino mdx mice carrying, in addition to the mutation in the dystrophin gene exon 23 (intrinsic of the "classical" black mdx mice), an extra mutation responsible for pigmentation disorders. Slow geotaxis, despite longer wire back down hanging capacity, was regarded as aggravation of the neurological dysfunction in albino mdx mice in comparison with black mdx mice.

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Expression of the glucose transporter GLUT4 in the muscular dystrophic mdx mouse

Cited by 15 publications

References 38 publications

Increased PFK activity and GLUT4 protein content in McArdle's disease

Increased PFK activity and GLUT4 protein content in McArdle's disease

Convergent regulation of skeletal muscle Ca ²⁺ channels by dystrophin, the actin cytoskeleton, and cAMP-dependent protein kinase

A New Genetic Variant of MDX Mice: Study of the Phenotype

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Expression of the glucose transporter GLUT4 in the muscular dystrophic mdx mouse

Cited by 15 publications

References 38 publications

Increased PFK activity and GLUT4 protein content in McArdle's disease

Increased PFK activity and GLUT4 protein content in McArdle's disease

Convergent regulation of skeletal muscle Ca 2+ channels by dystrophin, the actin cytoskeleton, and cAMP-dependent protein kinase

A New Genetic Variant of MDX Mice: Study of the Phenotype

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Convergent regulation of skeletal muscle Ca ²⁺ channels by dystrophin, the actin cytoskeleton, and cAMP-dependent protein kinase