CD73 is a 70kD glycosyl-phosphatidylinositol (GPI)-anchored cell surface molecule that belongs to the 5'-nucleosidase family. It hydrolyzes extracellular nucleotides into membrane permeable nucleosides and is found as both a membrane-bound and soluble molecule. Because it is abundantly expressed on vascular endothelium and some lymphocyte subpopulations, CD73 is a useful lymphocyte differentiation marker. Like many other GPI-anchored molecules, it transmits T-cell activation signals upon ligand engagement.
