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The effects of endurance exercise on skeletal muscle intracellular signaling events
Author(s) -
Gaine P. Courtney,
Bolster Douglas R.,
Ferrando Arny A,
Wolfe Robert R.,
Vislocky Lisa M.,
Freake Hedley C.,
Rodriguez Nancy R.
Publication year - 2006
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.20.4.a169-b
Subject(s) - phosphorylation , p70 s6 kinase 1 , pi3k/akt/mtor pathway , protein kinase b , endurance training , intracellular , medicine , endocrinology , skeletal muscle , chemistry , signal transduction , biology , biochemistry
The influence of endurance exercise on proteins of the mTOR pathway is not clear. Furthermore, the relationship between the activity of these proteins and changes in muscle fractional synthetic rates (FSR) is not well characterized. Aims of this study were to: 1) determine total expression and phosphorylation states of proteins of the PI3K‐mTOR pathway (S6K1 and AKT) and 2) characterize the relationship between these signaling events and FSR following endurance exercise. Muscle biopsies were obtained at rest, immediately following, and 3h following a 75 min run @ 70%VO 2peak . FSR was determined using [ 2 H 5 ]‐phenylalanine and total expression and phosphorylation of proteins were determined via western blotting. During the recovery period post‐exercise, FSR was 53% lower than resting values. Total AKT expression and phosphorylation at Ser 473 were elevated post‐exercise and at 3h post‐exercise. Total S6K1 expression and phosphorylation at Thr 421 /Ser 424 were lower at 3h post‐exercise than at rest and post‐exercise. Phosphorylation of S6K1 at Thr 389 decreased from rest to post‐exercise and was lowest at 3h post‐exercise. Whether the decline in FSR was due to changes in rates of translation initiation is not clear. However, the decrease in expression and phosphorylation of S6K1 at 3h post‐exercise may be indicative of decreased mTOR signaling; which potentially resulted in slower rates of translation and decreased FSR. Supported in part by the Gatorade Sports Science Institute.