In Vitro Analysis of the Very-Low Density Lipoprotein Export from the Trans-Golgi Network

The movement of mature VLDL particles from the TGN to the plasma membrane (PM) is a complex physiological process that plays a critical role in hepatic lipid homeostasis. However, the molecular mechanisms regulating these intracellular transport events had not been studied until recently because of the lack of appropriate molecular assays and techniques. This unit provides a detailed description of cell-free approaches and techniques to study the TGN-to-PM transport of the mature VLDL at the molecular level. A major emphasis is placed on the preparation and purification of sub-cellular organelles because the success of in vitro assays for the vesicle formation and fusion depends on the quality of the isolated TGN, hepatic PM and hepatic cytosol. A number of critical factors that control the formation of mature VLDL-containing vesicle, the PG-VTV, from the TGN and their subsequent targeting to and fusion with the hepatic PM have been discussed.