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European Journal of Applied Physiology

, Volume 102, Issue 3, pp 253–263 | Cite as

Mechanical stimuli of skeletal muscle: implications on mTOR/p70s6k and protein synthesis

  • Nelo Eidy ZanchiEmail author
  • Antonio Herbert LanchaJr
Invited Review

Abstract

The skeletal muscle is a tissue with adaptive properties which are essential to the survival of many species. When mechanically stimulated it is liable to undergo remodeling, namely, changes in its mass/volume resulting mainly from myofibrillar protein accumulation. The mTOR pathway (mammalian target of rapamycin) via its effector p70s6k (ribosomal protein kinase S6) has been reported to be of importance to the control of skeletal muscle mass, particularly under mechanical stimulation. However, not all mechanical stimuli are capable of activating this pathway, and among those who are, there are differences in the activation magnitude. Likewise, not all skeletal muscle fibers respond to the same extent to mechanical stimulation. Such evidences suggest specific mechanical stimuli through appropriate cellular signaling to be responsible for the final physiological response, namely, the accumulation of myofibrillar protein. Lately, after the mTOR signaling pathway has been acknowledged as of importance for remodeling, the interest for the mechanical/chemical mediators capable of activating it has increased. Apart from the already known MGF (mechano growth factor), some other mediators such as phosphatidic acid (PA) have been identified. This review article comprises and discusses relevant information on the mechano-chemical transduction of the pathway mTOR, with especial emphasis on the muscle protein synthesis.

Keywords

mTOR p70s6k Mechanical stimulation Hypertrophy Protein synthesis 

Notes

Acknowledgments

We thank Dr. Érico Chagas Caperuto for his critical reading of the manuscript and Maria Cristina Fioratti Florez for the careful specialized language revision of the present review article.

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© Springer-Verlag 2007

Authors and Affiliations

  1. 1.Laboratory of Applied Nutrition and Metabolism, Physical Education and Sport SchoolUniversity of São PauloSão Paulo, SPBrazil

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