UCP3 protein regulation in human skeletal muscle fibre types I, IIa and IIx is dependent on exercise intensity

Russell, Aaron Paul; Somm, Emmanuel; Praz, Manu; Crettenand, Antoinette; Hartley, Oliver; Melotti, Astrid; Giacobino, Jean-Paul; Muzzin, Patrick; Gobelet, Charles; Dériaz, Olivier

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Title		UCP3 protein regulation in human skeletal muscle fibre types I, IIa and IIx is dependent on exercise intensity
Authors		Russell, Aaron Paul Somm, Emmanuel Praz, Manu Crettenand, Antoinette Hartley, Oliver Melotti, Astrid Giacobino, Jean-Paul Muzzin, Patrick Gobelet, Charles Dériaz, Olivier show all authors [1 - 10]
Published in		Journal of Physiology. 2003, vol. 550, no. Pt 3, p. 855-61
Abstract		It has been proposed that mitochondrial uncoupling protein 3 (UCP3) behaves as an uncoupler of oxidative phosphorylation. In a cross-sectional study, UCP3 protein levels were found to be lower in all fibre types of endurance-trained cyclists as compared to healthy controls. This decrease was greatest in the type I oxidative fibres, and it was hypothesised that this may be due to the preferential recruitment of these fibres during endurance training. To test this hypothesis, we compared the effects of 6 weeks of endurance (ETr) and sprint (STr) running training on UCP3 mRNA expression and fibre-type protein content using real-time PCR and immunofluorescence techniques, respectively. UCP3 mRNA and protein levels were downregulated similarly in ETr and STr (UCP3 mRNA: by 65 and 50%, respectively; protein: by 30 and 27%, respectively). ETr significantly reduced UCP3 protein content in type I, IIa and IIx muscle fibres by 54, 29 and 16%, respectively. STr significantly reduced UCP3 protein content in type I, IIa and IIx muscle fibres by 24, 31 and 26%, respectively. The fibre-type reductions in UCP3 due to ETr, but not STr, were significantly different from each other, with the effect being greater in type I than in type IIa, and in type IIa than in type IIx fibres. As a result, compared to STr, ETr reduced UCP3 expression significantly more in fibre type I and significantly less in fibre types IIx. This suggests that the more a fibre is recruited, the more it adapts to training by a decrease in its UCP3 expression. In addition, the more a fibre type depends on fatty acid beta oxidation and oxidative phosphorylation, the more it responds to ETr by a decrease in its UCP3 content.
Keywords		Adult — Anaerobic Threshold/physiology — Body Composition/physiology — Carrier Proteins/biosynthesis/genetics/metabolism — Exercise/physiology — Fluorescent Antibody Technique — Humans — Ion Channels — Isoenzymes/biosynthesis/genetics — Male — Mitochondrial Proteins — Muscle Fibers — Fast-Twitch/metabolism/physiology — Muscle Fibers — Slow-Twitch/metabolism/physiology — Muscle — Skeletal/cytology/metabolism — Myosin Heavy Chains/metabolism — Oxygen Consumption/physiology — Physical Endurance/physiology — Physical Fitness/physiology — RNA — Messenger/biosynthesis — Reverse Transcriptase Polymerase Chain Reaction
Identifiers		DOI: 10.1113/jphysiol.2003.040162 PMID: 12794174
Full text		Article (Published version) (163 Kb) - Limited access to UNIGE
Structures		Faculté de médecine / Section de médecine fondamentale / Département de pathologie et immunologie Faculté de médecine / Section de médecine clinique / Département de pédiatrie
Research group		HIV (835)
Citation (ISO format)		RUSSELL, Aaron Paul et al. UCP3 protein regulation in human skeletal muscle fibre types I, IIa and IIx is dependent on exercise intensity. In: Journal of Physiology, 2003, vol. 550, n° Pt 3, p. 855-61. https://archive-ouverte.unige.ch/unige:26071