mTOR is the rapamycin-sensitive kinase that confers mechanically-induced phosphorylation of the hydrophobic motif site Thr(389) in p70(S6k).
Mechanical stretch induces phosphorylation of the hydrophobic motif site Thr(389) in p70(S6k) through a rapamycin-sensitive (RS) pathway that involves a unique PI3K-independent mechanism. Rapamycin is considered to be a highly specific inhibitor of the protein kinase mTOR; however, mTOR is also considered to be a PI3K-dependent signaling molecule. Thus, questions remain as to whether mTOR is the RS element that confers mechanically-induced signaling to p70(S6k)(389). In this study, rapamycin-resistant mutants of mTOR along with mechanical stretch were used to address this question. The results indicate that mTOR is the RS element and reveal that mTOR signaling can be activated through a PI3K-independent mechanism.
Hornberger
Troy Alan
TA
Department of Bioengineering, University of California San Diego, 9500 Gilman Drive., La Jolla, CA 92093-0412, USA. thornb1@bioeng.ucsd.edu
Sukhija
Kunal Balu
KB
Wang
Xiao-Rong
XR
Chien
Shu
S
D000818:Animals; D002460:Cell Line; D057927:Hydrophobic and Hydrophilic Interactions; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects; D011494:Protein Kinases / Q000378:metabolism*; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D020123:Sirolimus / Q000494:pharmacology*; D058570:TOR Serine-Threonine Kinases; D013912:Threonine / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors