The molecular regulation of skeletal muscle mass

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Clin Exp Pharmacol Physiol. 2009 Jul 24.

The molecular regulation of skeletal muscle mass.

AP.

Centre for Physical Activity and Nutrition, School of Exercise and Nutrition

Sciences, Deakin University, Burwood, VIC 3125, Australia.

1. The maintenance of skeletal muscle mass is determined by a fine balance

between protein synthesis and protein degradation. Skeletal mass is increased

when there is a net gain in protein synthesis which can occur following

progressive exercise training. In contrast, skeletal muscle mass is lost when

degradation occurs more rapidly than synthesis and is observed in numerous

conditions including neuromuscular disease, chronic disease, ageing, as well as

following limb immobilization, or prolonged bed rest due to injury or trauma.

2. Understanding the molecular pathways that regulate skeletal muscle

protein synthesis and protein degradation is vital for identifying potential

therapeutic targets that can attenuate muscle atrophy during disease and disuse.

3. The regulation of skeletal mass is complex and involves the precise

co-ordination of several intracellular signalling pathways. This review will

focus on the role and regulation of pathways involving Akt, atrogin-1 and MuRF1

(atrogenes), PGC-1alpha and STARS, with exercise and disease.