Commentary on Fatty Acid Wars
The Diffusionists Versus the Translocatists
Cluster of Differentiation 36 (CD36) is an integral membrane protein and a member of the class B scavenger receptor family that binds many ligands—oxidized low-density lipoprotein,1,2 native lipoproteins,3 and oxidized phospholipids.4 In addition, CD36 has been shown to enhance the uptake of long-chain fatty acids,5 and CD36 null mice show a defect in fatty acid uptake6 as well as intestinal processing of dietary fat.7,8 CD36 has been implicated in fatty acid transport in heart,9 skeletal muscle,9 adipocytes,10 human pancreatic β-cells,11 and fibroblasts12; muscle-specific CD36 overexpression enhances fatty acid oxidation in contracting muscle, reduces plasma triglycerides and fatty acids, while increasing plasma glucose and insulin,13 thereby producing a diabetic phenotype. Based on these findings, CD36 has been postulated to be a fatty acid transporter; yet, many questions remain about the function of this promiscuous lipoprotein receptor. At the molecular level, what is the activity of CD36, what are the consequences of that activity, and what are the attendant mechanisms?
The existence of fatty acid translocators in cells has been somewhat controversial. Although there is a clear …