Molecular mechanism of vitamin E transport in the body

Vitamin E occurs in nature in eight different forms, but animal body is enriched in alpha-tocopherol compared with other forms. alpha-Tocopherol transfer protein (alpha-TTP) is a liver cytosolic protein, which specifically binds alpha-tocopherol, and plays an important role in the discrimination of various tocopherols in the body. Furthermore, alpha-TTP is a product of the causative gene for familial isolated vitamin E deficiency. Using cell culture system, it was shown that alpha-TTP functions to enhance secretion of alpha-tocopherol from liver cells and that the reaction utilizes a novel non-Golgi mediated pathway which may be linked to cellular cholesterol metabolism and/or transport.