Mitochondrial Biogenesis in Skeletal Muscle.

Mitochondrial biogenesis refers to the synthesis of nuclear- and mitochondrially encoded proteins, along with phospholipids, that aid in the expansion of the mitochondrial network. In skeletal muscle, mitochondria are organized as a reticulum, as this ideal morphology complements the elongated shape of a myofibre. This allows for efficient substrate diffusion and supports the vigorously dynamic metabolic capabilities of this tissue type. Mitochondria are central responders to deviations in metabolic homeostasis and are thus required to support acute or chronic bouts of endurance exercise, cold exposure, starvation, or other externally imposed stimuli. This chapter marks the introduction to skeletal muscle mitochondrial adaptability as we discuss the subcellular events that contribute to mitochondrial biogenesis. Topics range from mitochondrial content and subpopulations in different muscle fibre types to signaling cascades and regulatory elements that support this mechanism. The characterization of mitochondrial biogenesis was made possible through clever models of both exercise and muscle disuse, at times with genetic modifications to important regulators, and is incorporated in this discussion. The chapter concludes with reviews on changes to signaling towards biogenesis with age. Altogether, our review attempts to highlight the vast revelations on the targeting, contribution, and significance of mitochondrial biogenesis in skeletal muscle.