Fig. 4

A breakdown of cell surface GRP78 (csGRP78) roles in AKT/P13K/ mTOR pathway. AKT and phosphoinositide-dependent kinase-1 (PDK1) are both drawn to the membrane after PI3K produces the second messenger PIP3. Due to proximity, PDK1 can phosphorylate AKT at position T308 of the activation loop (T-loop). The rapamycin-resistant mTOR complex 2 then phosphorylates AKT at residue S473 of the hydrophobic motif (mTORC2), a key step in the complete activation of AKT's kinase activity. TSC2, a negative regulator of mTORC1 activity, is one of several additional substrates that AKT itself has the ability to phosphorylate