Sarcoplasmic Reticulum-Mitochondrial Symbiosis: Bidirectional Signaling in Skeletal Muscle

In mammalian skeletal muscle, an intimate association between the sarcoplasmic reticulum (SR) and mitochondria results in a symbiotic and privileged bidirectional communication between these organelles. Orthograde signaling reflects SR calcium release stimulating mitochondrial adenosine triphosphate (ATP) production via excitation-metabolism coupling. Retrograde signaling involves mitochondrial inhibition of local SR calcium release by controlling the redox environment of the calcium release unit.