Fig. 2. Brain insulin resistance causes Alzheimer's disease. (A) Insulin signaling maintains normal neuronal functions through IRS, ERK/MAPK, PI3K/AKT, and GSK3 signals. (B) Brain insulin resistance blunts insulin signal transduction, leading to neuronal cell death and Alzheimer's disease. IRS, insulin receptor substrate; ERK/MAPK, extracellular signal-related kinase/mitogen activated protein kinase; PI3K/AKT, PI3 kinase/Akt pathways; GSK3, glycogen synthase kinase-3; IDE, insulin-degrading enzyme; Aβ, amyloid beta.
