Figure 3.

ATP-induced activation of mTOR is mediated by the P2Y₂ receptor and its downstream PLC/IP₃R pathway in C2C12 myotubes. (A–E) Representative Western blots showing the effects of BAPTA-AM or EGTA (A), siRNA for the P2Y₂ receptor (B), suramin (C), U73122 (D), XeC (E) on ATP- or UTP-induced phosphorylation of p70S6K and Akt (n = 4). (F) ATP- or UTP-induced phosphorylation of p70S6K and Akt in the IP₃-sponge-overexpressed C2C12 myotubes (n = 4). The concentration of ATP and UTP was 100 µM and the duration of treatment in all experiments shown in this figure was 30 min.