Regulation of Protein Synthesis in Inactivated Skeletal Muscle: Signal Inputs, Protein Kinase Cascades, and Ribosome Biogenesis

Disuse atrophy of skeletal muscles is characterized by a significant decrease in the mass and size of muscle fibers. Disuse atrophy develops as a result of prolonged reduction in the muscle functional activity caused by bed rest, limb immobilization, and real or simulated microgravity. Disuse atrophy is associated with the downregulation of protein biosynthesis and simultaneous activation of protein degradation. This review is focused on the key molecular mechanisms regulating the rate of protein synthesis in mammalian skeletal muscles during functional unloading.