Lectin and epidermal growth factor domains of P-selectin at physiologic density are the recognition unit for leukocyte binding.
Journal Article (Journal Article)
P-selectin is an integral membrane glycoprotein on stimulated platelets and endothelial cells that serves as a receptor for leukocytes. To estimate the density of P-selectin in membranes necessary to support adhesion, we incorporated purified P-selectin at varying concentrations into phospholipid bilayers that encapsulated glass microspheres. Maximal binding of these lipospheres to HL60 cells, a P-selectin ligand-expressing cell line, was approached at a P-selectin density of about 100 molecules per microns 2; half-maximal binding was observed at about 50 to 60 molecules per microns 2. Compatible results were obtained with P-selectin expressed on Chinese hamster ovary cells. The P-selectin density on stimulated platelets was estimated to be 150 to 200 molecules/microns 2. To identify the domains of P-selectin required for HL60 cell binding, chimeras of P-selectin and L-selectin were stably expressed in Chinese hamster ovary cells and clones that expressed the chimeras at the estimated physiologic density were selected. Chimeras containing the P-selectin lectin and epidermal growth factor (EGF) domains or the lectin, EGF, and short consensus repeats bound HL60 cells equivalently, but a chimera containing the P-selectin lectin domain alone bound HL60 cells much less well. These results indicate that at a physiologically relevant P-selectin density on membrane surfaces, the lectin, and EGF domains of P-selectin are together required for optimal leukocyte binding.
- Gibson, RM; Kansas, GS; Tedder, TF; Furie, B; Furie, BC
- January 1, 1995
Volume / Issue
- 85 / 1
Start / End Page
- 151 - 158
International Standard Serial Number (ISSN)
- United States