Daru Young Sharp

Microsomal Triglyceride Transfer Protein

The microsomal triglyceride transfer protein (MTP) is an intracellular lipid transfer protein that catalyzes the transport of triglyceride (TG), cholesteryl ester (CE), and phospholipid molecules between membranes. It is an unusual lipid transfer protein in that it is a complex of two proteins of molecular weight 55 kDa and 97 kDa. Intracellular lipid transfer proteins described to date are generally composed of a single polypeptide and have molecular weights in the range of 10,000 to 35,000. High levels of MTP activity are found in the lumen of microsomes isolated from liver and intestine (Wetterau and Zilversmit, 1986). The tissue and subcellular location of MTP, combined with its ability to promote neutral lipid (TG and CE) transfer, suggested that MTP plays a role in the assembly of the triglyceride rich, apolipoprotein B(apoB) containing lipoproteins, very low density lipoprotein (VLDL), and chylomicrons. This hypothesis has since been confirmed.