The glycoprotein Ib-IX-V complex is a platelet counterreceptor for P-selectin.
We have identified platelet glycoprotein (GP) Ibalpha as a counterreceptor for P-selectin. GP Ibalpha is a component of the GP Ib-IX-V complex, which mediates platelet adhesion to subendothelium at sites of injury. Cells expressing P-selectin adhered to immobilized GP Ibalpha, and GP Ibalpha-expressing cells adhered to and rolled on P-selectin and on histamine-stimulated endothelium in a P-selectin-dependent manner. In like manner, platelets rolled on activated endothelium, a phenomenon inhibited by antibodies to both P-selectin and GP Ibalpha. Unlike the P-selectin interaction with its leukocyte ligand, PSGL-1 (P-selectin glycoprotein ligand 1), the interaction with GP Ibalpha required neither calcium nor carbohydrate core-2 branching or alpha(1,3)-fucosylation. The interaction was inhibited by sulfated proteoglycans and by antibodies against GP Ibalpha, including one directed at a tyrosine-sulfated region of the polypeptide. Thus, the GP Ib-IX-V complex mediates platelet attachment to both subendothelium and activated endothelium.
Romo
G M
GM
Department of Medicine, Baylor College of Medicine and Veterans Affairs Medical Center, Houston, Texas 77030, USA.
Dong
J F
JF
Schade
A J
AJ
Gardiner
E E
EE
Kansas
G S
GS
Li
C Q
CQ
McIntire
L V
LV
Berndt
M C
MC
López
J A
JA
D000818:Animals; D001792:Blood Platelets / Q000378:metabolism* / Q000473:pathology; D016466:CHO Cells; D006224:Cricetinae; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008024:Ligands; D008562:Membrane Glycoproteins / Q000378:metabolism; D019007:P-Selectin / Q000378:metabolism*; D010973:Platelet Adhesiveness; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000378:metabolism*
D008024:Ligands; D008562:Membrane Glycoproteins; D019007:P-Selectin; C084882:P-selectin ligand protein; D019038:Platelet Glycoprotein GPIb-IX Complex