TTPA transports alpha-TOH from lysosomal membrane to plasma membrane

Stable Identifier
Reaction [transition]
Homo sapiens
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Alpha-tocopherol (alpha-TOH) belongs to the fat-soluble vitamin E family and is the major form used by humans as an important antioxidant of plasma lipoproteins and cell membranes. It is secreted from the liver into the blood stream but as it is a lipophilic compound, it requires intracellular binding proteins to bind and transport it to exert its actions. One such protein is alpha-tocopherol transfer protein (TTPA, TPP1), a cytosolic protein highly expressed in liver and placenta (Arita et al. 1995, Kostner et al. 1995). The main function of TTPA is to maintain normal alpha-TOH concentrations in the plasma and extrahepatic tissues by binding to, and facilitating the transport of, alpha-TOH from lysosomes to the plasma membrane followed by the continuous export of alpha-TOH from the liver to the plasma (Traber et al. 1994, Qian et al. 2005; reviews Kono & Arai 2015, Schmolz et al. 2016).

Literature References
PubMed ID Title Journal Year
16024914 Intracellular trafficking of vitamin E in hepatocytes: the role of tocopherol transfer protein

Manor, D, Qian, J, Atkinson, J, Nava, P, Wilson, K, Morley, S

J. Lipid Res. 2005
26981194 Complexity of vitamin E metabolism

Birringer, M, Lorkowski, S, Wallert, M, Schmölz, L

World J Biol Chem 2016
7832785 Human plasma phospholipid transfer protein accelerates exchange/transfer of alpha-tocopherol between lipoproteins and cells

Dieplinger, H, Kostner, GM, Jauhiainen, M, Ehnholm, C, Esterbauer, H, Oettl, K

Biochem. J. 1995
25262571 Intracellular transport of fat-soluble vitamins A and E

Kono, N, Arai, H

Traffic 2015
7887897 Human alpha-tocopherol transfer protein: cDNA cloning, expression and chromosomal localization

Sato, Y, Arai, H, Arita, M, Takahashi, E, Miyata, A, Kayden, HJ, Inoue, K, Tanabe, T

Biochem. J. 1995
7937827 Human plasma vitamin E kinetics demonstrate rapid recycling of plasma RRR-alpha-tocopherol

Traber, MG, Kayden, HJ, Ramakrishnan, R

Proc. Natl. Acad. Sci. U.S.A. 1994
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