Protein Turnover in Skeletal Muscle: Looking at Molecular Regulation towards an Active Lifestyle

Abstract

Skeletal muscle is a highly plastic tissue, able to change its mass and functional properties in response to several stimuli. Skeletal muscle mass is influenced by the balance between protein synthesis and breakdown, which is regulated by several signaling pathways. The relative contribution of Akt/mTOR signaling, ubiquitin-proteasome pathway, autophagy among other signaling pathways to protein turnover and, therefore, to skeletal muscle mass differs depending on the wasting or loading condition and muscle type. By modulating mitochondria biogenesis, PGC-1α has a major role in cell’s bioenergetic status and, thus, on protein turnover. In fact, rates of protein turnover regulate differently the levels of distinct protein classes in response to atrophic or hypertrophic stimuli. Mitochondrial protein turnover rates may be enhanced in wasting conditions whereas the increased turnover of myofibrillar proteins triggers muscle mass gain. The present review aims to update the knowledge on the molecular pathways implicated in the regulation of protein turnover in skeletal muscle, focusing on how distinct muscle proteins may be modulated by lifestyle interventions with emphasis on exercise training. The comprehensive analysis of the anabolic effects of exercise programs will pave the way to the tailored management of muscle wasting conditions.

Exercise and Caloric Restriction Exert Different Benefits on Skeletal Muscle Metabolism in Aging Condition

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Selenium supplementation via modulation of selenoproteins ameliorates binge drinking-induced oxidative, energetic, metabolic, and endocrine imbalance in adolescent rats’ skeletal muscle

“…SKM is a highly plastic organ, able to modify its mass and functional properties in response to several stimuli, such as energetic imbalance and OS. 56 SKM mass is influenced by the balance between protein synthesis and breakdown: the protein turnover. Protein synthesis relies on Akt/mTOR signaling, which is usually activated by the hormones insulin and IGF-1; whereas protein breakdown hinges on the UPS, autophagy and mitophagy processes.…”

Taurine activates the AKT–mTOR axis to restore muscle mass and contractile strength in human 3D in vitro models of steroid myopathy

“…Skeletal muscles are the largest and most adaptable protein reservoirs with a capacity to regulate their mass, protein turnover and fiber cross-sectional area in response to a variety of external and internal stimuli ( Ferreira and Duarte, 2023 ). A well-regulated balance between proteolytic and proteogenic pathways is essential to maintain healthy muscular function ( Vélez et al, 2017 ).…”