Modulation of signal transduction and gene expression by vitamin E via PI3Kγ/PKB and hTAP1/SEC14L2-mediated lipid exchange

Abstract

The ability of vitamin E to modulate signal transduction and gene expression has been observed in numerous cell culture and animal studies. These cellular signalling effects of vitamin E have been mainly explained as result of protection of lipids and signal transduction enzymes from random modification by free radicals or by specifically influencing their redox state. Alternatively, the observed signalling may reflect specific interactions of vitamin E with enzymes, structural proteins, and transcription factors and/or result from vitamin E-induced alterations of physical and structural properties of membrane lipid domains in which it is embedded. A novel signal transduction mechanism of vitamin E is proposed in which lipid transfer proteins (LTP) facilitate phosphorylation of phosphatidyl-inositol by exchanging it with vitamin E and presenting it to phosphatidylinositol-3-kinase (PI3K).