Fig. 1.

Rb1 and Rb2 enhance Akt/mTOR signaling–mediated myotube hypertrophy. (A) C2C12 cells were induced to differentiate for 2 days and then treated with indicated concentrations of Rb1 or Rb2 for the additional 2 days. The myotube formation was analyzed by MHC immunostaining. 4′,6-diamidino-2-phenylindole (DAPI) was used to visualize nuclei. (B) Average myotube diameter shown in panel (A) was measured using NIS-Elements F software. Data are presented as means determination of 6 fields± 1 SD. *P < 0.05 and **P < 0.01 compared with the control group. (C) Muscle-specific proteins from panel (A) were analyzed by immunoblotting. pan-Cadherin had been used as a loading control. (D) Total and phosphorylated forms of Akt, mTOR, p70S6K, and 4E-BP1 from panel (A) were analyzed by immunoblotting. α-Tubulin was used as a loading control.

MHC, myosin heavy chain; mTOR, mammalian target of rapamycin; SD, standard deviation.