ABSTRACT

Selective fatty acid-targeting mechanisms allow human cells to incorporate specic fatty acids into specic membranes, thus maximizing benets and avoiding risks. The biochemical basis of fatty acid targeting is poorly understood, but it is clear from compositional analysis that powerful mechanisms are at work to shuttle fatty acids to specic membranes or membrane domains. One of the best known examples is the targeting of docosahexaenoic acid (DHA) to the tail membrane domain of sperm (Chapter 12), which not only is enriched with DHA, but also houses a set of proteins specic for the tail domain. We suggest that DHA targeting has several advantages for sperm, including enhancing biochemical efciency of motility and avoiding oxidative damage to germ-line DNA packaged in the head (Valentine and Valentine, 2009). In addition to sperm, humans target DHA to neurons of the brain and nervous system, with the highest levels found in the retina. In contrast, membranes of most human cells and mitochondria contain only traces of DHA and relatively low levels of other highly unsaturated fatty acids (HUFAs).