extracellular domain (ECD) found in glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPI-HBP1) and similar proteins
GPI-HBP1 (also called GPI-anchored HDL-binding protein 1, or high density lipoprotein-binding protein 1) is an endothelial cell transporter for lipoprotein lipase. It mediates the transport of lipoprotein lipase LPL from the basolateral to the apical surface of endothelial cells in capillaries and anchors LPL on the surface of endothelial cells in the lumen of blood capillaries. GPI-HBP1 protects LPL against loss of activity, and against ANGPTL4-mediated unfolding. Thereby, it plays an important role in lipolytic processing of chylomicrons by LPL, triglyceride metabolism and lipid homeostasis. GPI-HBP1 binds chylomicrons and phospholipid particles that contain APOA5. It also binds high-density lipoprotein (HDL) and plays a role in the uptake of lipids from HDL. GPI-HBP1 contains an extracellular domain (ECD), which belongs to Ly-6 antigen/uPA receptor-like (LU) superfamily and exhibits a snake toxin-like fold (also known as three-finger toxin/3FTx fold or three-fingered protein/TFP domain fold).
Jiyao W et al.(2023). "The conserved domain database in 2023.",