Wilson, Rebecca JLyons, Scott PKoves, Timothy RBryson, Victoria GZhang, HengtaoLi, TianYuCrown, Scott BDing, Jin-DongGrimsrud, Paul ARosenberg, Paul BMuoio, Deborah M2024-02-022024-02-022022-032212-87782212-8778https://hdl.handle.net/10161/30114<h4>Objective</h4>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.<h4>Methods</h4>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.<h4>Results</h4>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.<h4>Conclusion</h4>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.Muscle, SkeletalAnimalsMiceCalciumEnergy MetabolismExercise ToleranceStromal Interaction Molecule 1ProteostasisJournal article