Figure 2

IGF-1 induced the phosphorylation of Akt in PC12 cells via the PI3 kinase pathway while MAPK and p38 MAPK pathways mediated the activation of CREB induced by IGF-1. Following treatment with different kinase inhibitors for 40 min, PC12 cells were exposed to 10 nM IGF-1 and the phosphorylation of Akt and CREB was determined by Western blots using anti-phospho- Akt/CREB antibodies. The PI3 kinase inhibitor LY294002 inhibited IGF-1-induced phosphorylation of Akt in PC12 cells while a MAPK pathway inhibitor PD98059, a p38 MAPK inhibitor PD169316 and a p70S6 pathway inhibitor rapamycin, did not have any significant effect. In contrast, the phosphorylation of CREB induced by IGF-1 was partially blocked by inhibitors of both MEK (PD98059) and p38 MAP kinase (PD169316). Blots represent prototypical example of experiments replicated at least 3 times.