Figure 8.

A schematic diagram for the anti-autophagic action of insulin. The anti-autophagic activity of insulin is mediated by upregulation of mTnfaip8, which is followed by the specific accommodation of PE in its hydrophobic cavity. The mTnfaip8 triple mutant defective for PE binding has lost intrinsic anti-autophagic capability, whereas the wild-type mTnfaip8 maintains anti-autophagic activity. PTX treatment also disrupted anti-autophagic activity of mTnfaip8 by accumulating the inactive GDP form of Gαi3, which has lost the coupling with mTnfaip8. The loss of anti-autophagic activity of the mTnfaip8 mutant is very likely due to impairment in coupling with the active GTP form of Gαi3.