A 28-kDa glycoprotein functions as a platelet ligand for P-selectin (CD62P).
P-selectin (CD62P) is expressed on activated platelets and on stimulated endothelial cells. It interacts with P-selectin glycoprotein ligand-1 (PSGL-1; CD162) for adhesion of activated platelets on leukocytes and for rolling of leukocytes on stimulated endothelial cells. Recently, resting and activated platelets have been shown to roll on endothelial P-selectin, indicating that platelets express (a) ligand(s) for P-selectin. Here we show that P-selectin specifically precipitated one 28-kDa glycoprotein from the whole cell lysates and the membrane lysates of human platelets in a Ca2+-dependent manner. Further, the purified 28-kDa molecule could inhibit the binding of P-selectin to human resting and activated platelets. In contrast, KPLI (a leukocyte adhesion blocking MoAb to PSGL-1) did not neutralize the binding of P-selectin to human platelets, even though it abolished the binding of P-selectin to human promyeloid HL-60 cells. Our results thus indicate that the 28-kDa glycoprotein may function as an important platelet ligand for P-selectin.
Li
Ling
L
Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.
Qian
Kai-Xian
KX
Geng
Jian-Guo
JG
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001792:Blood Platelets / Q000378:metabolism*; D011232:Chemical Precipitation; D002846:Chromatography, Affinity; D019040:E-Selectin / Q000378:metabolism; D006023:Glycoproteins / Q000302:isolation & purification / Q000494:pharmacology / Q000502:physiology; D018922:HL-60 Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008024:Ligands; D008562:Membrane Glycoproteins / Q000276:immunology; D008970:Molecular Weight; D019007:P-Selectin / Q000378:metabolism*; D015539:Platelet Activation; D010973:Platelet Adhesiveness / Q000502:physiology; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D000911:Antibodies, Monoclonal; D019040:E-Selectin; D006023:Glycoproteins; D008024:Ligands; D008562:Membrane Glycoproteins; D019007:P-Selectin; C084882:P-selectin ligand protein; D011993:Recombinant Fusion Proteins