Reactome | TTPA transports alpha-TOH from lysosomal membrane to plasma membrane

TTPA transports alpha-TOH from lysosomal membrane to plasma membrane

Stable Identifier

R-HSA-8874705

Type

Reaction [transition]

Species

Homo sapiens

Compartment

cytosol, lysosomal membrane, plasma membrane

ReviewStatus

5/5

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TTPA transports alpha-TOH from lysosomal membrane to plasma membrane

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Alpha-tocopherol (alpha-TOH) is the major form of fat-soluble vitamin E in humans. It functions as an antioxidant to protect plasma lipoproteins and cell membranes. It is secreted from the liver into the bloodstream, a process mediated by 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 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 Qian, J, Morley, S, Wilson, K, Nava, P, Atkinson, J, Manor, D	J. Lipid Res.	2005
26981194	Complexity of vitamin E metabolism Schmölz, L, Birringer, M, Lorkowski, S, Wallert, M	World J Biol Chem	2016
7832785	Human plasma phospholipid transfer protein accelerates exchange/transfer of alpha-tocopherol between lipoproteins and cells Kostner, GM, Oettl, K, Jauhiainen, M, Ehnholm, C, Esterbauer, H, Dieplinger, H	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 Arita, M, Sato, Y, Miyata, A, Tanabe, T, Takahashi, E, Kayden, HJ, Arai, H, Inoue, K	Biochem. J.	1995
7937827	Human plasma vitamin E kinetics demonstrate rapid recycling of plasma RRR-alpha-tocopherol Traber, MG, Ramakrishnan, R, Kayden, HJ	Proc. Natl. Acad. Sci. U.S.A.	1994