AS160 also known as NIDDM5, TBC1D4 is a member of the Tre-2/BUB2/CDC16 domain family. AS160 is a Rab-GTPase-activating protein, and contains two phopshotyrosine-binding domains (PTB1 and PTB2), a calmodulin-binding domain (CBD), a Rab-GTPase domain, and multiple AKT phosphomotifs. AS160 protein is thought to play an important role in glucose homeostasis by regulating the insulin-dependent trafficking of the glucose transporter 4 (GLUT4), important for removing glucose from the bloodstream into skeletal muscle and fat tissues. Reduced expression of AS160 results in an increase in GLUT4 levels at the plasma membrane, suggesting that AS160 protein is important in intracellular retention of GLUT4 under basal conditions. When exposed to insulin, AS160 protein is phosphorylated, dissociates from GLUT4 vesicles, resulting in increased GLUT4 at the cell surface, and enhanced glucose transport.