Microsomal triacylglycerol transfer protein is required for lumenal accretion of triacylglycerol not associated with ApoB, as well as for ApoB lipidation.

The assembly of very low density lipoproteins in hepatocytes requires the microsomal triacylglycerol transfer protein (MTP). This microsomal lumenal protein transfers lipids, particularly triacylglycerols (TG), between membranes in vitro and has been proposed to transfer TG to nascent apolipoprotein (apo) B in vivo. We examined the role of MTP in the assembly of apoB-containing lipoproteins in cultured murine primary hepatocytes using an inhibitor of MTP.