Docosahexaenoic acid and membrane lipid domains

Docosahexaenoic acid (DHA, 22:6(Delta4,7,10,13,16,19)) is the longest chain and most unsaturated fatty acid commonly found in biological systems [1]. It represents the extreme example of the important class of fatty acids kno wn as omega-3s. Primarily through dietary studies, this fatty acid has been linked to an enormous variety of human afflictions including cancer [2, 3] , heart disease [4], rheumatoid arthritis [5], lupus [6], alcoholism [7], b lindness [8], respiratory diseases [9], peroxisomal disorders [10], cystic fibrosis [11], schizophrenia [12], depression [13], malaria [14], multiple sclerosis [15] and even migrane headaches. In order for one simple molecule to affect so many seemingly unrelated processes it must function at a fund amental level, common to most cells. It has been suggested that this level is in controlling membrane structure and function [16]. Due to its extreme chain length and unsaturation it should be easier to demonstrate a unique r ole for DHA in membrane structure/function than it will be for other shorte r, less unsaturated fatty acids commonly found in membranes. Reviewed here is the possible involvement of DHA in membrane lipid domains.