Figure 2: Insulin receptor (IR) activation and glucose uptake. Insulin binding to α subunits induces the phosphorylation (P) of transmembrane β subunits generating insulin receptor signal transduction (IRS). Glucose transporter (GLUT4) vesicle translocation to the cell membrane allows intramembranous incorporation of GLUT4 and it enables the facilitated diffusion of glucose into the cell. Estrogen receptor signal (ERS) regulates the phosphorylation of IR protein (ERS1), participates in GLUT4 expression (ERS2) and translocation (ERS3), as well as in the intramembranous incorporation of GLUT4 (ERS4).