Vitamin E (tocopherol) is the major fat-soluble antioxidant in humans. However, surprisingly little is known about the fate of this molecule once it enters target cells, or about the molecular events by which its storage, metabolism, and biological functions are regulated. As tocopherols are poorly soluble in water, it is believed that specific binding proteins are critical mediators of vitamin E function by virtue of their ability to solubilize and transport their ligand in the aqueous environment of the cell. Here, we propose to study the tocopherol transfer protein (aTTP) in order to gain insights into its biological role(s) and, in turn, into the mode of action of vitamin E. We will use our combined expertise in synthetic chemistry, stable-isotope analysis, protein biochemistry, and intra-cellular signaling to elucidate the functions of aTTP in mediating the biological activities of vitamin E. Specifically, we propose to address three specific aims: 1)- to characterize the structure/function relationship in aTTP in vitro. Using novel optical activity assays and site-directed mutagenesis, we will obtain molecular- level understanding of ligand binding and transfer activities of aTTP, and of the naturally occurring mutations in this protein. 2)- To characterize the structure/function relationship in aTTP in vivo. We will examine the effects of naturally occurring mutations in aTTP on tocopherol secretion from cultured hepatocytes. 3)- To identify proteins that interact with aTTP in a tocopherol dependent manner, and to determine the sub-cellular localization of the protein. Studies proposed in this application will provide critical information that is likely to improve our understanding of vitamin E function as a mediator of human health.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
7R01DK067494-04
Application #
7290700
Study Section
Nutrition Study Section (NTN)
Program Officer
May, Michael K
Project Start
2004-04-15
Project End
2009-03-31
Budget Start
2006-10-01
Budget End
2007-03-31
Support Year
4
Fiscal Year
2006
Total Cost
$179,171
Indirect Cost
Name
Case Western Reserve University
Department
Nutrition
Type
Schools of Medicine
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106
Ghelfi, Mikel; Ulatowski, Lynn; Manor, Danny et al. (2016) Synthesis and characterization of a fluorescent probe for ?-tocopherol suitable for fluorescence microscopy. Bioorg Med Chem 24:2754-61
Chung, Stacey; Ghelfi, Mikel; Atkinson, Jeffrey et al. (2016) Vitamin E and Phosphoinositides Regulate the Intracellular Localization of the Hepatic ?-Tocopherol Transfer Protein. J Biol Chem 291:17028-39
Baptist, Matilda; Panagabko, Candace; Nickels, Jonathan D et al. (2015) 2,2'-Bis(monoacylglycero) PO4 (BMP), but Not 3,1'-BMP, increases membrane curvature stress to enhance ?-tocopherol transfer protein binding to membranes. Lipids 50:323-8
Ulatowski, Lynn M; Manor, Danny (2015) Vitamin E and neurodegeneration. Neurobiol Dis 84:78-83
Ulatowski, L; Parker, R; Warrier, G et al. (2014) Vitamin E is essential for Purkinje neuron integrity. Neuroscience 260:120-9
Nicod, Nathalie; Parker, Robert S (2013) Vitamin E secretion by Caco-2 monolayers to APOA1, but not to HDL, is vitamer selective. J Nutr 143:1565-72
Ulatowski, Lynn; Manor, Danny (2013) Vitamin E trafficking in neurologic health and disease. Annu Rev Nutr 33:87-103
Ulatowski, Lynn; Dreussi, Cara; Noy, Noa et al. (2012) Expression of the ?-tocopherol transfer protein gene is regulated by oxidative stress and common single-nucleotide polymorphisms. Free Radic Biol Med 53:2318-26
Bardowell, Sabrina A; Duan, Faping; Manor, Danny et al. (2012) Disruption of mouse cytochrome p450 4f14 (Cyp4f14 gene) causes severe perturbations in vitamin E metabolism. J Biol Chem 287:26077-86
Bardowell, Sabrina A; Ding, Xinxin; Parker, Robert S (2012) Disruption of P450-mediated vitamin E hydroxylase activities alters vitamin E status in tocopherol supplemented mice and reveals extra-hepatic vitamin E metabolism. J Lipid Res 53:2667-76

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