Enterocyte Fatty Acid Handling Proteins and Chylomicron Formation

Intestinal lipid absorption is an efficient and highly complex process. Here we review the main pathways involved in intestinal processing of dietary lipid. We discuss the regulation of enterocyte fatty acid transport and the functions in absorption of lipid transporters, scavenger receptor B1 (SR-B1), CD36 or SR-B2, and fatty acid transport protein 4 (FATP4). We describe recent findings highlighting importance of the remodeling of membrane phospholipids in particular by lysophosphatidylcholine acyltransferase 3 (LPCAT3), in facilitating passive diffusion of fatty acid and promoting triacylglycerol (TAG) assembly into lipoproteins. We review what we currently know about the most prominent intestinal enzymes involved in TAG synthesis in the endoplasmic reticulum including long-chain acyl-CoA synthetase (ACSL), monoacylglycerol acyltransferase (MGAT), and diacylglycerol acyltransferase (DGAT). We also provide a detailed and updated review on the mechanisms and regulation of prechylomicron formation, assembly, and transport from the endoplasmic reticulum to the Golgi for chylomicron generation, with special reference to the role of CD36 and liver fatty acid-binding protein (LFABP).