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Preferential stimulation of myofibrillar proteins by amino acids in absence of increased mTORC1 signaling
Author(s) -
Haegens Astrid,
Schols Annemie M,
Essen A LM,
Loon Luc JC,
Langen Ramon CJ
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.233.4
Subject(s) - leucine , mtorc1 , myofibril , glutamine , amino acid , valine , c2c12 , biochemistry , pi3k/akt/mtor pathway , stimulation , chemistry , p70 s6 kinase 1 , myostatin , myocyte , biology , signal transduction , endocrinology , skeletal muscle , myogenesis
An important goal of nutritional intervention in muscle wasting disorders is to stimulate protein synthesis. Branched chain amino acids (AA) have been suggested to promote protein synthesis via mammalian target of rapamycin (mTOR) signaling. We previously demonstrated a preferential stimulation of myofibrillar protein expression by leucine in skeletal muscle. The aim of this study was to investigate in a high through put tissue culture and analysis system, whether the preferential stimulation of myofibrillar proteins is unique for leucine and involves mTORC1 signaling. C2C12 myoblasts were differentiated in DMEM containing 1g/L glucose, 1% FBS and physiological AA levels. Supplementation consisted of 2 or 5mM of a single AA. Absolute creatine kinase activity and total protein accretion were not significantly altered in cells that had differentiated in medium supplemented with a single AA. Myosin Heavy Chain fast and slow, measured by western blot, were however increased after supplementation with Leucine, Isoleucine, Valine, Alanine, Asparagine, Phenylalanine, Serine, Glutamine, or Threonine. Single AA stimulation did however not always increase mTOR signaling. These findings suggest that the previously described anabolic effect is not unique to leucine and that the stimulating effect of these AA might be mTOR independent.