Loss of Tsc1/Tsc2 activates mTOR and disrupts PI3K-Akt signaling through downregulation of PDGFR
J. Clin. Invest. Hongbing Zhang, et al. 112:1223 doi:10.1172/JCI17222 [
Go to this article.]
Figure 3Effects of inhibitors on S6K/S6 phosphorylation and growth of
TP53–/–Tsc2–/– and control
TP53–/– MEFs. (
a) Immunoblot analysis of a serum-starved (2 days) then stimulated
TP53–/–Tsc2+/+ cell line (top) and a serum-starved
TP53–/–Tsc2–/– cell line (bottom). Cells were treated with 10 μM LY294002, 0.1 μM wortmannin, 10 nM rapamycin, 0.1 μM calyculin A, 5 μM TPCK, 10 μM U0126, or 20 μM PD98059 for 30 minutes. (
b) Growth effects in two
TP53–/–Tsc2–/– (open squares) and two
TP53–/–Tsc2+/+ (filled triangles) cell lines of treatment with rapamycin. Each symbol reflects a consecutive day in culture. Rapamycin selectively reduces the growth of the
TP53–/–Tsc2–/– cell lines in 0% serum. (
c) Immunoblot analysis of effects of 1- and 2-butanol treatment on S6K/S6 phosphorylation in
TP53–/–Tsc2–/– and control
TP53–/– cell lines. 1- or 2-butanol (0.3%) were applied to the cell lines for 30 minutes, and the cells were serum stimulated for 5 minutes. (
d) Immunoblot analysis of effects of AA deprivation and stimulation on S6K/S6 phosphorylation in two
TP53–/–Tsc2–/– cell lines. All treatments were for 2 hours. Note that with either the EBSS or HBSS buffers, AAs are required to maintain pS6K and pS6 phosphorylation.
