Testoni 2017 Cell Metab
|Testoni G, Duran J, García-Rocha M, Vilaplana F, Serrano AL, Sebastián D, López-Soldado I, Sullivan MA6, Slebe F, Vilaseca M, Muñoz-Cánoves P, Guinovart JJ (2017) Lack of glycogenin causes glycogen accumulation and muscle function impairment. Cell Metab 26:256-66.|
Abstract: Glycogenin is considered essential for glycogen synthesis, as it acts as a primer for the initiation of the polysaccharide chain. Against expectations, glycogenin-deficient mice (Gyg KO) accumulate high amounts of glycogen in striated muscle. Furthermore, this glycogen contains no covalently bound protein, thereby demonstrating that a protein primer is not strictly necessary for the synthesis of the polysaccharide in vivo. Strikingly, in spite of the higher glycogen content, Gyg KO mice showed lower resting energy expenditure and less resistance than control animals when subjected to endurance exercise. These observations can be attributed to a switch of oxidative myofibers toward glycolytic metabolism. Mice overexpressing glycogen synthase in the muscle showed similar alterations, thus indicating that this switch is caused by the excess of glycogen. These results may explain the muscular defects of GSD XV patients, who lack glycogenin-1 and show high glycogen accumulation in muscle.
Copyright © 2017 Elsevier Inc. All rights reserved.
• Keywords: GSD XV, Glycogenin, Exercise, Glycogen, Glycogen storage disease XV, Glycogenosis, Mitochondrial respiration, Muscle performance, Oxidative metabolism, Priming protein • Bioblast editor: Kandolf G • O2k-Network Lab: ES Barcelona Zorzano A
Labels: MiParea: Respiration
Organism: Mouse Tissue;cell: Skeletal muscle Preparation: Permeabilized tissue
Coupling state: LEAK, OXPHOS, ET Pathway: N, NS HRR: Oxygraph-2k