Glycoprotein Ic-IIa Functions as an Activation-Independent Fibronectin Receptor on Human Platelets

• Published in: The Journal of cell biology 1988-04, Vol.106 (4), p.1359-1364
• Main Authors: Piotrowicz, Randolph S., Orchekowski, Randal P., Nugent, Diane J., Yamada, Kenneth Y., Kunicki, Thomas J.
• Format: Article
• Language: English
• Subjects: Adhesion; Antibodies; Biological and medical sciences; Blood Platelet Disorders - blood; Blood Platelets - metabolism; cell adhesion; Cell receptors; Cell structures and functions; Electrophoresis, Polyacrylamide Gel; fibronectin; Fibronectin receptors; Fibronectins - metabolism; Fibrosis; Fundamental and applied biological sciences. Psychology; Gels; Glycoproteins; Humans; Immunoassay; membrane glycoproteins; Mice; Molecular and cellular biology; Monoclonal antibodies; Platelet Adhesiveness; Platelet Membrane Glycoproteins - physiology; Platelets; Receptors; Receptors, Fibronectin; Receptors, Immunologic - physiology; Thrombasthenia - blood
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.106.4.1359

Soluble fibronectin binds specifically to glycoprotein (GP) IIb-IIIa on thrombin-activated platelets, and this binding is not observed with platelets of patients with Glanzmann's thrombasthenia (GT) which lack GPIIb-IIIa. Here we report that GT platelets retain the ability to interact with fibronectin-coated surfaces. Adhesion to fibronectin does not require platelet activation and is inhibited by soluble fibronectin, antibodies specific for fibronectin, peptides containing the sequence Arg-Gly-Asp and polyclonal antibodies specific for band 3 of the chicken embryo fibroblast fibronectin receptor (anti-band 3). Using anti-band 3, we have purified a second fibronectin receptor from human platelets, a heterodimer composed of glycoproteins previously designated GPIc and GPIIa. The GPIc-IIa complex is found on both GT and normal platelets and appears to be identical to the GP138 kD-GP160 kD complex recently immunopurified by Giancotti et al. and by Sonnenberg et al. In this report, we provide the first evidence that GPIc-IIa actually mediates adhesion of platelets to fibronectin-coated surfaces. GPIc-IIa thus represents a second functional fibronectin receptor, distinct from GPIIb-IIIa, that is largely responsible for the adhesion of nonactivated platelets to fibronectin-coated surfaces.