title: Over-expressing mitofusin-2 in healthy mature mammalian skeletal muscle does not alter mitochondrial bioenergetics.
abstract: The role of mitofusin-2 (MFN-2) in regulating mitochondrial dynamics has been well-characterized in lower order eukaryotic cell lines through the complete ablation of MFN-2 protein. However, to support the contractile function of mature skeletal muscle, the subcellular architecture and constituent proteins of this tissue differ substantially from simpler cellular organisms. Such differences may also impact the role of MFN-2 in mature mammalian muscle, and it is unclear if minor fluctuations in MFN-2, as observed in response to physiological perturbations, has a functional consequence. Therefore, we have transiently transfected MFN-2 cDNA into rat tibialis anterior muscle to determine the effect of physiolgically relevant increases in MFN-2 protein on mitochondrial bioenergetics. Permeabilized muscle fibres generated from muscle following MFN-2-transfection were used for functional assessments of mitochondrial bioenergetics. In addition, we have further established a novel method for selecting fibre bundles that are positively transfected, and using this approach transient transfection increased MFN-2 protein ∼2.3 fold in selected muscle fibres. However, this did not alter maximal rates of oxygen consumption or the sensitivity for ADP-stimulated respiration. In addition, MFN-2 over-expression did not alter rates of H(2)O(2) emission. Altogether, and contrary to evidence from lower order cell lines, our results indicate that over-expressing MFN-2 in healthy muscle does not influence mitochondrial bioenergetics in mature mammalian skeletal muscle.
authors: Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
authors: James S V
authors: JS
authors: Lally
authors: Eric A F
authors: EA
authors: Herbst
authors: Sarthak
authors: S
authors: Matravadia
authors: Amy C
authors: AC
authors: Maher
authors: Christopher G R
authors: CG
authors: Perry
authors: Renée
authors: R
authors: Ventura-Clapier
authors: Graham P
authors: GP
authors: Holloway
mesh_terms: D000818:Animals; D019069:Cell Respiration; D004734:Energy Metabolism; D005260:Female; D020558:GTP Phosphohydrolases; D015870:Gene Expression; D006861:Hydrogen Peroxide / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008931:Mitochondria, Muscle / Q000235:genetics* / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics* / Q000378:metabolism; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D051381:Rats; D014162:Transfection
chemical_list: D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D006861:Hydrogen Peroxide; D020558:GTP Phosphohydrolases; C489710:Mfn2 protein, rat
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