PTEN Protein, Human (GST)

PTEN is a dual-specificity protein phosphatase that dephosphorylates tyrosine-, serine-, and threonine-phosphorylated proteins. It also functions as a lipid phosphatase, preferentially acting on PtdIns(3,4,5)P3/phosphatidylinositol 3,4,5-trisphosphate to remove the phosphate group at the D3 position of the inositol ring. Additionally, PTEN acts as a cytosolic inositol 3-phosphatase, targeting Ins(1,3,4,5,6)P5/inositol 1,3,4,5,6 pentakisphosphate and possibly Ins(1,3,4,5)P4/1D-myo-inositol 1,3,4,5-tetrakisphosphate. By dephosphorylating phosphoinositides, PTEN antagonizes the PI3K-AKT/PKB signaling pathway, modulating cell cycle progression and survival. In motile cells, it suppresses lateral pseudopod formation, promoting polarization and directed movement. PTEN also dephosphorylates tyrosine-phosphorylated focal adhesion kinase, inhibiting migration, integrin-mediated spreading, and focal adhesion formation. It plays a key role in growth factor-induced epithelial cell migration, interacting with DLC1 or p85 to regulate RHOA and RAC1 activation. Furthermore, PTEN is a critical modulator of the AKT-mTOR pathway, influencing neuronal integration during adult neurogenesis (by similar). In excitatory hippocampal synapses, PTEN regulates synaptic function and plasticity, with its lipid phosphatase activity driving AMPA receptor-mediated synaptic depression, essential for NMDA receptor-dependent long-term depression (LTD) (by similar). PTEN may negatively regulate insulin signaling and glucose metabolism in adipose tissue. The nuclear monoubiquitinated form exhibits stronger pro-apoptotic potential, while the cytoplasmic nonubiquitinated form has weaker tumor-suppressive activity.