Regulation of lipid metabolism via angiopoietin-like proteins

Regulation of mammalian energy metabolism is an intricate process involving numerous hormones, transcription factors and signal transduction cascades. Much of the regulation occurs via secreted factors that relay information from one organ to another. One group of secreted factors that recently emerged as having a major impact on lipid and possibly glucose metabolism are the ANGPTLs (angiopoietin-like proteins). This includes ANGPTL3, ANGPTL4/FIAF (fasting-induced adipose factor), and ANGPTL6/AGF (angiopoietin-related growth factor). Although the receptors for these proteins have yet to be identified, it is nevertheless increasingly clear that these proteins have important effects on plasma triacylglycerol clearance, adipose tissue lipolysis, and adiposity. This review summarizes contemporary data on ANGPTLs with emphasis on the connection with energy metabolism.