Transverse tubule remodeling enhances Orai1-dependent Ca2+ entry in skeletal muscle

• DOI: 10.7554/elife.47576
• Publication Date: 2019-10-28T13:00:21Z
• Authors: Antonio Michelucci; Simona Boncompagni; Laura Pietrangelo; Maricela García-C...; Takahiro Takano; Sundeep Malik; Robert T Dirksen; Feliciano Protasi
• Keywords: Orai1

Exercise promotes the formation of intracellular junctions in skeletal muscle between stacks sarcoplasmic reticulum (SR) cisternae and extensions transverse-tubules (TT) that increase co-localization proteins required for store-operated Ca2+ entry (SOCE). Here, we report SOCE, peak transient amplitude force production during repetitive stimulation are increased after exercise parallel with time course TT association SR-stacks. Unexpectedly, also activated constitutive coincident a modest decrease total releasable store content. Importantly, this content observed was reversed by high-frequency stimulation, consistent enhanced SOCE. The functional benefits on were lost mice muscle-specific loss Orai1 function. These results indicate SR-stacks enhances Orai1-dependent SOCE to optimize dynamics contractile function acute exercise.