[HTML][HTML] The mitochondrial calcium uniporter underlies metabolic fuel preference in skeletal muscle

JQ Kwong, J Huo, MJ Bround, JG Boyer… - JCI insight, 2018 - ncbi.nlm.nih.gov
JQ Kwong, J Huo, MJ Bround, JG Boyer, JA Schwanekamp, N Ghazal, JT Maxwell, YC Jang
JCI insight, 2018ncbi.nlm.nih.gov
The mitochondrial Ca 2+ uniporter (MCU) complex mediates acute mitochondrial Ca 2+
influx. In skeletal muscle, MCU links Ca 2+ signaling to energy production by directly
enhancing the activity of key metabolic enzymes in the mitochondria. Here, we examined the
role of MCU in skeletal muscle development and metabolic function by generating mouse
models for the targeted deletion of Mcu in embryonic, postnatal, and adult skeletal muscle.
Loss of Mcu did not affect muscle growth and maturation or otherwise cause pathology …
Abstract
The mitochondrial Ca 2+ uniporter (MCU) complex mediates acute mitochondrial Ca 2+ influx. In skeletal muscle, MCU links Ca 2+ signaling to energy production by directly enhancing the activity of key metabolic enzymes in the mitochondria. Here, we examined the role of MCU in skeletal muscle development and metabolic function by generating mouse models for the targeted deletion of Mcu in embryonic, postnatal, and adult skeletal muscle. Loss of Mcu did not affect muscle growth and maturation or otherwise cause pathology. Skeletal muscle–specific deletion of Mcu in mice also did not affect myofiber intracellular Ca 2+ handling, but it did inhibit acute mitochondrial Ca 2+ influx and mitochondrial respiration stimulated by Ca 2+, resulting in reduced acute exercise performance in mice. However, loss of Mcu also resulted in enhanced muscle performance under conditions of fatigue, with a preferential shift toward fatty acid metabolism, resulting in reduced body fat with aging. Together, these results demonstrate that MCU-mediated mitochondrial Ca 2+ regulation underlies skeletal muscle fuel selection at baseline and under enhanced physiological demands, which affects total homeostatic metabolism.
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