Fig. 2. Schematic depicting the pathways that incorporate fatty acids entering the cell. (A) When detergent-like fatty acid levels get too high, they emulsify cellular membranes. The lysis occurs over 3 stages: fatty acid penetration into the bilayer; their equilibration into both faces of the bilayer; and the transition of the bilayer into a micelle. (B) To prevent lysis, fatty acids entering the cell are quickly coupled to CoA and then incorporated into backbones to produce acylcarnitines, glycerolipids, and sphingolipids. Acylcarnitines are formed as fatty acids translocate into mitochondria. Glycerolipids that are produced make up the bulk of membrane bilayers and create the triglyceride stores that form the majority of the lipid droplet. Sphingolipids are signals of lipid excess that signal to upregulate the other 2 pathways under conditions of lipid excess.

CoA, coenzyme A.