Figure 6.

AMPK/mTOR signalling mediates the effect of calcineurin on autophagy and cell survival after H₂O₂ treatment. (a) Inhibition of calcineurin by FK506 enhances AMPK phosphorylation and attenuates the phosphorylation of mTOR. Cells were treated as described in Figure 3, and whole-cell lysates were subjected to western blot analysis. (b) Overexpression of calcineurin attenuates the phosphorylation of AMPK and enhances mTOR phosphorylation. Cells were treated as described in Figure 5, and whole-cell lysates were subjected to western blot analysis. (c) Calcineurin attenuates Akt signalling under normal conditions but not under oxidative stress conditions. Cells were treated as previously described. (d) FK506 showed no effect on autophagy regulation, cell protection and mTOR inhibition in DN-AMPK-expressing cells. Cells were transfected with the control vector (CV) and the DN-AMPK vector for 24 h and subsequently incubated with 150 μM H₂O₂ in the presence or absence of FK506 (1 μM) for 12 h. Representative images are from three or more independent experiments