CHAPTER 5. α-Tocopherol Transfer Protein

α-Tocopherol transfer protein (α-TTP) is an α-tocopherol-selective vitamin E-binding protein expressed predominantly in hepatocytes. By stimulating the secretion of endocytosed α-tocopherol to the systemic circulation in hepatocytes, α-TTP plays a critical role in maintaining the α-tocopherol level in the body. Heritable mutations in the α-TTP gene are the cause of familial vitamin E deficiency, termed ataxia with vitamin E deficiency (AVED). Recent studies on missense mutations found in AVED patients highlight the molecular mechanism underlying the intracellular α-tocopherol transport by α-TTP. In this review, we will discuss the molecular mechanism and physiological roles of α-TTP-mediated α-tocopherol transport in the hepatocytes.