Deficiency in ethanolamine plasmalogen leads to altered cholesterol transport.

Abstract

Plasmalogens are a major sub-class of ethanolamine and choline phospholipids in which the sn-1 position has a long chain fatty alcohol attached through a vinyl ether bond. These phospholipids are proposed to play a role in membrane fusion-mediated events. In this study, we investigated the role of the ethanolamine plasmalogen plasmenylethanolamine (PlsEtn) in intracellular cholesterol transport in Chinese hamster ovary cell mutants NRel-4 and NZel-1, which have single gene defects in PlsEtn biosynthesis. We found that PlsEtn was essential for specific cholesterol transport pathways, those from the cell surface or endocytic compartments to acyl-CoA/cholesterol acyltransferase in the endoplasmic reticulum. The movement of cholesterol from the endoplasmic reticulum or endocytic compartments to the cell surface was normal in PlsEtn-deficient cells. Also, vesicle trafficking was normal in PlsEtn-deficient cells, as measured by fluid phase endocytosis and exocytosis, as was the movement of newly-synthesized proteins to the cell surface. The mutant cholesterol transport phenotype was due to the lack of PlsEtn, since it was corrected when NRel-4 cells were transfected with a cDNA encoding the missing enzyme or supplied with a metabolic intermediate that enters the PlsEtn biosynthetic pathway downstream of the defect. Future work must determine the precise role that plasmalogens have on cholesterol transport to the endoplasmic reticulum.

• Authors: Natalie J Munn, Emily Arnio, Dailan Liu, Raphael A Zoeller, Laura Liscum
• Journal: Journal of lipid research (J Lipid Res) Vol. 44 Issue 1 Pg. 182-92 (Jan 2003) ISSN: 0022-2275 [Print] United States
• PMID: 12518037 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Plasmalogens
• phosphatidal ethanolamines
• Filipin
• Cholesterol

Topics

• Biological Transport
• Cell Membrane (metabolism)
• Cells, Cultured
• Cholesterol (metabolism)
• Endocytosis
• Endoplasmic Reticulum (metabolism)
• Esterification
• Exocytosis
• Filipin
• Lysosomes (metabolism)
• Microscopy, Fluorescence
• Molecular Structure
• Plasmalogens (biosynthesis, metabolism)