High-frequency electrically stimulated skeletal muscle contractions increase p70s6k phosphorylation independent of known IGF-I sensitive signaling pathways.
Insulin-like growth factor (IGF-I) is hypothesized to be a critical upstream regulator of mammalian target of rapamycin (mTOR)-regulated protein synthesis with muscle contraction. We utilized a mouse model that expresses a skeletal muscle specific dominant-negative IGF-I receptor to investigate the role of IGF-I signaling of protein synthesis in response to unilateral lengthening contractions (10 sets, 6 repetitions, 100 Hz) at 0 and 3 h following the stimulus. Our results indicate that one session of high frequency muscle contractions can activate mTOR signaling independent of signaling components directly downstream of the receptor.
Witkowski
Sarah
S
Department of Kinesiology, University of Maryland School of Public Health, College Park, MD 20742, USA.
Lovering
Richard M
RM
Spangenburg
Espen E
EE
D000818:Animals; D015153:Blotting, Western; D004560:Electricity; D004591:Electrophoresis, Polyacrylamide Gel; D047468:Immunoprecipitation; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D017526:Receptor, IGF Type 1 / Q000235:genetics / Q000378:metabolism; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*
D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1; D038762:Ribosomal Protein S6 Kinases, 70-kDa
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