Dead Zone Measurement Of The P-Selectin/PSGL-1 Interaction

PEI 10 nm INTRODUCTION Induced on activated endothelial cells and platelets, P-selectin is a cell adhesion molecule that plays a critical role in the inflammatory and thrombotic processes. P-selectin glycoprotein ligand 1 (PSGL-1) is expressed on leukocytes, and its interaction with P-selectin mediates the flowing cells tethering to and rolling on the blood vessel wall [1]. In this dynamic environment, the adhesive bonds are subject to a wide range of forces. As such, not only the kinetic rates but also how these molecules respond to mechanical stress is important to the function of this interaction. We measured the dead zone or zero force extension of P-selectin interacting with two different ligands and an antibody. These include a dimeric P-selectin/PSGL-1 interaction [2], a monomeric sPselectin/PSGL-1 interaction, and a P-selectin/G1 antigen/antibody interaction. The dimension of the dead zone is related to the interaction distance of the molecular pair and provides insight into the proper force versus molecular extension model for the interaction.