Leukocyte activation induces surface redistribution of P-selectin glycoprotein Iigand-1

Abstract: Binding ofP-selectin on activated endothe-lium to P-selectin glycoprotein ligand-1 (PSGL-1) on neutrophils mediates the initial tethering and roll-ing of neutrophils on the vessel wall at inflammatory sites. Upon activation of rolling cells by locally ex-pressed signaling molecules, integrin-dependent ad-hesion mechanisms are engaged and transendothelial migration proceeds. P-selectin binding sites are uni-formly distributed on the surface of quiescent neutro-pMls, but are redistributed to the uropod of activated neutrophils. It is unclear whether this activation-induced change in the surface topography of P-selectin binding sites is due to surface redistribution of PSGL-1, shedding of PSGL-1 from the lamellapod, and/or movement of PSGL-1 from an intracellular compart