Recent progress in understanding protein and lipid factors affecting hepatic VLDL assembly and secretion

Excess lipid induced metabolic disorders are one of the major existing challenges for the society. Among many different causes of lipid disorders, overproduction and compromised catabolism of triacylglycerol-rich very low density lipoproteins (VLDL) have become increasingly prevalent leading to hyperlipidemia worldwide. This review provides the latest understanding in different aspects of VLDL assembly process, including structure-function relationships within apoB, mutations in APOB causing hypobetalipoproteinemia, significance of modulating microsomal triglyceride-transfer protein activity in VLDL assembly, alterations of VLDL assembly by different fatty acid species, and hepatic proteins involved in vesicular trafficking, and cytosolic lipid droplet metabolism that contribute to VLDL assembly. The role of lipoprotein receptors and exchangeable apolipoproteins that promote or diminish VLDL assembly and secretion is discussed. New understanding on dysregulated insulin signaling as a consequence of excessive triacylglycerol-rich VLDL in the plasma is also presented. It is hoped that a comprehensive view of protein and lipid factors that contribute to molecular and cellular events associated with VLDL assembly and secretion will assist in the identification of pharmaceutical targets to reduce disease complications related to hyperlipidemia.