Carrier protein. Binds to some hydrophobic molecules and promotes their transfer between the different cellular sites. Binds with high affinity to alpha-tocopherol. Also binds with a weaker affinity to other tocopherols and to tocotrienols. May have a transcriptional activatory activity via its association with alpha-tocopherol (By similarity). Probably recognizes and binds some squalene structure, suggesting that it may regulate cholesterol biosynthesis by increasing the transfer of squalene to a metabolic active pool in the cell. Monomer. Cytoplasmic in absence of alpha-tocopherol, and nuclear in presence of alpha-tocopherol. Experimental confirmation may be lacking for some isoforms. Widely expressed. High expression in liver and small intestine.