Connecting the dots for mechanochemical transduction in muscle

Abstract

One of the most impressive adaptive physiological responses is that of muscle to high intensity exercise, as espoused by power athletes and body builders, which results in increases in muscle mass. Athletics and vanity aside, there are many reasons for wishing to know more about the mechanisms underlying this hypertrophy, not least being the possibility of pharmacologically enhancing it in sarcopenia. The work of Bolster and colleagues in this issue of The Journal of Physiology brings us nearer to a complete understanding of the relevant subcellular events occurring in response to resistance exercise by providing a time course of activities of signalling proteins involved in regulating the translational phase of muscle protein synthesis.

Figure 1. Scheme of the pathways investigated

Contraction may induce a transient activation of the translational machinery via the proteins shown and others. Since contraction also leads to an increase in the expression of IGF-1 variants, these may trigger a late sustained response. All activations should lead to increased muscle protein synthesis and hypertrophy.