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Mitochondrial fusion is frequent in skeletal muscle and supports excitation-contraction coupling.

Authors: Eisner, Verónica  Lenaers, Guy  Hajnóczky, György 
Citation: Eisner V, etal., J Cell Biol. 2014 Apr 28;205(2):179-95. doi: 10.1083/jcb.201312066. Epub 2014 Apr 21.
Pubmed: (View Article at PubMed) PMID:24751540
DOI: Full-text: DOI:10.1083/jcb.201312066

Genetic targeting experiments indicate a fundamental role for mitochondrial fusion proteins in mammalian physiology. However, owing to the multiple functions of fusion proteins, their related phenotypes are not necessarily caused by altered mitochondrial fusion. Perhaps the biggest mystery is presented by skeletal muscle, where mostly globular-shaped mitochondria are densely packed into the narrow intermyofilamental space, limiting the interorganellar interactions. We show here that mitochondria form local networks and regularly undergo fusion events to share matrix content in skeletal muscle fibers. However, fusion events are less frequent and more stable in the fibers than in nondifferentiated myoblasts. Complementation among muscle mitochondria was suppressed by both in vivo genetic perturbations and chronic alcohol consumption that cause myopathy. An Mfn1-dependent pathway is revealed whereby fusion inhibition weakens the metabolic reserve of mitochondria to cause dysregulation of calcium oscillations during prolonged stimulation. Thus, fusion dynamically connects skeletal muscle mitochondria and its prolonged loss jeopardizes bioenergetics and excitation-contraction coupling, providing a potential pathomechanism contributing to myopathies.

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CRRD Object Information
CRRD ID: 13204834
Created: 2017-07-21
Species: All species
Last Modified: 2017-07-21
Status: ACTIVE



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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.