Figure 3

Schematic presentation of suggested pathways of PTEN involvement in neuronal survival. PTEN regulates the conversion of Phosphatidylinositol (3,4,5) triphosphate into Phosphatidylinositol (4,5) bis phosphate (PIP2). PTEN activation leads to cell spreading and growth by inhibition or dephosphorylation of FAK1 (protein tyrosine kinase 2) and SHC transforming protein 1 in cytoplasm and by inhibiting cyclin D1 in the nucleus. PTEN depletion activate Akt signaling pathway which in turn regulate all downstream cellular effects such as cell growth, proliferation and cell survival. PTEN depletion is sufficient to trigger mammalian target of rapamycin (mTOR) that alters downstream signaling pathways for local protein synthesis by increasing P70s6 kinase activity. This pathway also influences many apoptosis factors either by transcriptional regulation or by direct phosphorylation.