Specific ATPases drive compartmentalized glycogen utilization in rat skeletal muscle

Joachim Nielsen*, Peter Dubillot, Marie Louise H. Stausholm, Niels Ørtenblad

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Glycogen is a key energy substrate in excitable tissue, including in skeletal muscle fibers where it also contributes to local energy production. Transmission electron microscopy imaging has revealed the existence of a heterogenic subcellular distribution of three distinct glycogen pools in skeletal muscle, which are thought to reflect the requirements for local energy stores at the subcellular level. Here, we show that the three main energy-consuming ATPases in skeletal muscles (Ca2+, Na+,K+, and myosin ATPases) utilize different local pools of glycogen. These results clearly demonstrate compartmentalized glycogen metabolism and emphasize that spatially distinct pools of glycogen particles act as energy substrate for separated energy requiring processes, suggesting a new model for understanding glycogen metabolism in working muscles, muscle fatigue, and metabolic disorders. These observations suggest that the distinct glycogen pools can regulate the functional state of mammalian muscle cells and have important implications for the understanding of how the balance between ATP utilization and ATP production is regulated at the cellular level in general and in skeletal muscle fibers in particular.

Original languageEnglish
Article numbere202113071
JournalJournal of General Physiology
Volume154
Issue number9
ISSN0022-1295
DOIs
Publication statusPublished - 5. Sept 2022

Keywords

  • Adenosine Triphosphatases/metabolism
  • Adenosine Triphosphate/metabolism
  • Animals
  • Glycogen/metabolism
  • Mammals/metabolism
  • Muscle Fatigue/physiology
  • Muscle, Skeletal/metabolism
  • Rats

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