GPIHBP1, a GPI-anchored protein required for the lipolytic processing of triglyceride-rich lipoproteins.

GPIHBP1, a small glycosylphosphatidylinositol-anchored glycoprotein, is required for the lipolytic processing of triglyceride-rich lipoproteins. GPIHBP1 knockout mice exhibit chylomicronemia, even on a low-fat diet, with plasma triglyceride levels of 3,500-5,000 mg/dl. GPIHBP1 is expressed highly in heart, adipose tissue, and skeletal muscle, the same tissues that express high levels of lipoprotein lipase (LPL). In each of these tissues, GPIHBP1 is located in capillary endothelial cells. Chinese hamster ovary (CHO) cells transfected with a GPIHBP1 expression vector bind LPL and chylomicrons avidly. The expression of GPIHBP1 in mice is modulated by fasting and refeeding and is also regulated by peroxisome proliferator-activated receptor (PPAR)gamma agonists. Here, we review recent progress in understanding GPIHBP1 and discuss its role in lipolysis.