TBC1D4: Proteins and Enzymes

AS160, also known as TBC1D4, is a 160 kDa Akt substrate that plays a critical role in regulating insulin-stimulated exocytosis of glucose transporter GLUT4. AS-160 contains a Rab GTPase-activating protein domain (GAP), suggesting its potential role in membrane trafficking. Insulin-stimulated phosphorylation of AS160 on threonine 642 is critical for mediating GLUT4 translocation in fat and muscle cells, via inactivation of Rab GAP function. Phosphorylation of Thr642 is also important in mediating TBC1D4 redistribution from low density microsomes to the cytosol in adipocytes.