Posttranslational Modifications Limit High Level Expression of Functionally Active Chimeric P-Selectin Glycoprotein Ligand-1 in rCHO Cells

Abstract

P-Selectin Glycoprotein Ligand-1 (PSGL-1) is a dimeric mucin-like transmembrane glycoprotein identified as a functional ligand for P-Selectin (1). Functional activity of PSGL-1 is dependent upon at least two key posttranslational modifications made to the amino terminus. Core 2 O-linked oligosaccharide structures at Thr¹⁶ bearing the sialyl-Lewis^x (SLe^x) antigen and sulfation of one or more of the NH2-terminal tyrosine it has been shown that a polypeptide containing the NH₂-terminal 47 amino acid sequence of human PSGL-1 is sufficient for high-affinity binding to P-Selectin (2).