Fatty acid uptake in : Host resources and possible mechanisms.

spp. causes African Sleeping Sickness in humans and nagana, a wasting disease, in cattle. As goes through its life cycle in its mammalian and insect vector hosts, it is exposed to distinct environments that differ in their nutrient resources. One such nutrient resource is fatty acids, which uses to build complex lipids or as a potential carbon source for oxidative metabolism. Of note, fatty acids are the membrane anchoring moiety of the glycosylphosphatidylinositol (GPI)-anchors of the major surface proteins, Variant Surface Glycoprotein (VSG) and the Procyclins, which are implicated in parasite survival in the host. While can synthesize fatty acids , it also readily acquires fatty acids from its surroundings. The relative contribution of parasite-derived vs. host-derived fatty acids to growth and survival is not known, nor have the molecular mechanisms of fatty acid uptake been defined. To facilitate experimental inquiry into these important aspects of biology, we addressed two questions in this review: (1) What is known about the availability of fatty acids in different host tissues where can live? (2) What is known about the molecular mechanisms mediating fatty acid uptake in ? Finally, based on existing biochemical and genomic data, we suggest a model for fatty acid uptake that proposes two major routes of fatty acid uptake: diffusion across membranes followed by intracellular trapping, and endocytosis of host lipoproteins.