Molecular Metabolism (Mar 2022)

Disruption of STIM1-mediated Ca2+ sensing and energy metabolism in adult skeletal muscle compromises exercise tolerance, proteostasis, and lean mass

  • Rebecca J. Wilson,
  • Scott P. Lyons,
  • Timothy R. Koves,
  • Victoria G. Bryson,
  • Hengtao Zhang,
  • TianYu Li,
  • Scott B. Crown,
  • Jin-Dong Ding,
  • Paul A. Grimsrud,
  • Paul B. Rosenberg,
  • Deborah M. Muoio

Journal volume & issue
Vol. 57
p. 101429

Abstract

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Objective: Stromal interaction molecule 1 (STIM1) is a single-pass transmembrane endoplasmic/sarcoplasmic reticulum (E/SR) protein recognized for its role in a store operated Ca2+ entry (SOCE), an ancient and ubiquitous signaling pathway. Whereas STIM1 is known to be indispensable during development, its biological and metabolic functions in mature muscles remain unclear. Methods: Conditional and tamoxifen inducible muscle STIM1 knock-out mouse models were coupled with multi-omics tools and comprehensive physiology to understand the role of STIM1 in regulating SOCE, mitochondrial quality and bioenergetics, and whole-body energy homeostasis. Results: This study shows that STIM1 is abundant in adult skeletal muscle, upregulated by exercise, and is present at SR-mitochondria interfaces. Inducible tissue-specific deletion of STIM1 (iSTIM1 KO) in adult muscle led to diminished lean mass, reduced exercise capacity, and perturbed fuel selection in the settings of energetic stress, without affecting whole-body glucose tolerance. Proteomics and phospho-proteomics analyses of iSTIM1 KO muscles revealed molecular signatures of low-grade E/SR stress and broad activation of processes and signaling networks involved in proteostasis. Conclusion: These results show that STIM1 regulates cellular and mitochondrial Ca2+ dynamics, energy metabolism and proteostasis in adult skeletal muscles. Furthermore, these findings provide insight into the pathophysiology of muscle diseases linked to disturbances in STIM1-dependent Ca2+ handling.

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