The localization of a platelet GpIIb-IIIa-related protein in endothelial
cell adhesion structures
E Dejana, LR Languino, S Colella, GC Corbascio, E Plow, M Ginsberg and PC Marchisio
Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy.
Previous studies have shown that human endothelial cells (ECs) adhere to
fibrinogen (fg) and fibronectin (fn) and organize their cytoskeleton on
these substrata. However, the mechanism governing this chain of events is
poorly known. In ECs glycoproteins immunologically and biochemically
similar to the platelet membrane GpIIb-IIIa complex have been described.
The functional role of this complex in ECs remains to be established. In
this study we show that the antigens recognized by polyclonal antibodies
raised against human platelet GpIIb-IIIa and crossreacting with the EC form
have a discrete and well-organized distribution at cell adhesion
structures. Indeed these antigens are located at vinculin-rich focal
contacts found at the membrane insertion of microfilament bundles of the
stress fiber type. They are also found at cell-to-cell contacts and, with a
diffuse pattern, at the dorsal surface of ECs. GpIIb-IIIa antibodies, added
to EC suspensions prior to plating, inhibit EC spreading on fg and
vitronectin (vn) substrata in a concentration-dependent way. In contrast,
the antibodies are very poorly active when the cells are seeded on
fn-coated glass. The same antibodies, added to adherent cells, disrupt
cell-to-cell contacts and cause their rounding and detachment. Overall
these results indicate that EC GpIIb-IIIa complex is involved in
controlling the adhesion mechanism of these cells to extracellular matrix
proteins.
Volume 71,
Issue 3,
pp. 566-572,
03/01/1988
Copyright © 1988 by The American Society of Hematology
