UCP3 protein expression is lower in type I, IIa and IIx muscle fiber types of endurance-trained compared to untrained subjects.

Full Abstract

Uncoupling protein 3 (UCP3) is a muscle mitochondrial protein believed to uncouple the respiratory chain, producing heat and reducing aerobic ATP production. Our aim was to quantify and compare the UCP3 protein levels in type I, IIa and IIx skeletal muscle fibers of endurance-trained (Tr) and healthy untrained (UTr) individuals. UCP3 protein content was quantified using Western blot and immunofluorescence. Skeletal muscle fiber type was determined by both an enzymatic ATPase stain and immunofluorescence. UCP3 protein expression measured in skeletal muscle biopsies was 46% lower ( P=0.01) in the Tr compared to the UTr group. UCP3 protein expression in the different muscle fibers was expressed as follows; IIx>IIa>I in the fibers for both groups ( P<0.0167) but was lower in all fiber types of the Tr when compared to the UTr subjects ( P<0.001). Our results show that training status did not change the skeletal muscle fiber hierarchical UCP3 protein expression in the different fiber types. However, it affected UCP3 content more in type I and type IIa than in the type IIx muscle fibers. We suggest that this decrease may be in relation to the relative improvement in the antioxidant defense systems of the skeletal muscle fibers and that it might, as a consequence, participate in the training induced improvement in mechanical efficiency.

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Author information

Author/s: Russell, A P (AP); Wadley, G (G); Hesselink, M K C (MK); Schaart, G (G); Lo, S (S); Léger, B (B); Garnham, A (A); Kornips, E (E); Cameron-Smith, D (D); Giacobino, J P (JP); Muzzin, P (P); Snow, R (R); Schrauwen, P (P);

Affiliation: Department of Medical Biochemistry, University of Geneva, CMU, Switzerland. aaron.russell(-atsign-)crr-suva.ch

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Pflügers Archiv : European journal of physiology (Pflugers Arch), published in Germany. (Language: eng)

Reference: 2003-Feb; vol 445 (issue 5) : pp 563-9

Dates: Created 2003/03/13; Completed 2003/10/14; Revised 2006/11/15;

PMID: 12634927, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Ion Channels
Male
Mitochondrial Proteins
Muscle Fibers, Fast-Twitch - metabolism
Muscle Fibers, Slow-Twitch - metabolism
Physical Education and Training
Physical Endurance - physiology

Associated Chemicals: Carrier Proteins (0) ; Ion Channels (0) ; Mitochondrial Proteins (0) ; mitochondrial uncoupling protein 3 (0)

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