Journal
JOURNAL OF CELLULAR BIOCHEMISTRY
Volume 97, Issue 6, Pages 1207-1216Publisher
WILEY
DOI: 10.1002/jcb.20671
Keywords
amino acids; growth; mTOR; p70S6k; stretch
Categories
Funding
- NHLBI NIH HHS [5T32HL07089, R01HL19454, R01HL64382] Funding Source: Medline
Ask authors/readers for more resources
The mammalian target of rapamycin (mTOR) has been identified as a growth factor and nutrient-sensitive molecule that controls the translational machinery and cell growth. Rapamycin-sensitive (RS) signaling events have also been shown to be necessary for mechanical load-induced growth of skeletal muscle, but the mechanisms involved in the mechanical activation of RS signaling are not known. The finding that mechanical stimuli induce nutrient uptake in skeletal muscle raises the possibility that mechanically induced RS signaling is mediated via a nutrient-dependent mechanism. To investigate this hypothesis, skeletal muscles (ex vivo) were stimulated with nutrients or intermittent mechanical stretch and the phoshorylation of p70S6k [P-p70(389)], PKB [P-PKB], mTOR [P-mTOR(2481)], and p38 [P-p38] was assessed. In comparison to vehicle-treated controls, both nutrient and mechanical stimuli induced P-p70(389), neither stimulus altered P-PKB or P-mTOR(2481), and only mechanical stimuli-induces P-p38. The nutrient and mechanically induced increase in P-p70(389) was blocked by rapamycin, but only nutrient-induced signaling to P-p70(389) was blocked by wortmannin. Furthermore, the mechanically induced increase in P-p70(389) was not impaired by the removal of exogenous nutrients. Taken together, these results indicate that exogenous nutrients are not required for mechanically induced RS signaling and that nutrient and mechanical stimuli activate RS signaling through distinct upstream mechanisms.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available