Cultured human endothelial cells synthesize a plasma membrane protein
complex immunologically related to the platelet glycoprotein IIb/IIIa
complex
OC Leeksma, J Zandbergen-Spaargaren, JC Giltay and JA van Mourik
We have previously demonstrated that endothelial cells synthesize a plasma
membrane protein indistinguishable from platelet glycoprotein (GP) IIa. The
present study provides evidence for a further analogy between the platelet
and the endothelial cell membrane by showing that cultured endothelial
cells also synthesize a membrane protein complex immunologically related to
the platelet GP IIb/GP IIIa complex. This evidence is based on the
following observations: (1) C17, a murine monoclonal antiplatelet GP IIIa
antibody, consistently precipitates two proteins, apparent molecular
weights, respectively, 115,000 and 125,000 reduced and 95,000 and 135,000
nonreduced, from metabolically (35S- methionine) as well as surface
125I-labeled cultured human endothelial cells; (2) upon crossed
immunoelectrophoresis of solubilized endothelial cells against a polyclonal
rabbit antiplatelet antiserum and 125I-labeled C17 IgG, a single
precipitate of the protein(s) recognized by C17 is observed. As judged by
their mobility in 9% polyacrylamide gels, both endothelial proteins appear
to have a somewhat larger molecular weight than their platelet
counterparts. Patterns obtained by crossed immunoelectrophoresis are also
indicative of a difference in electrophoretic behavior of the platelet GP
IIb/IIIa complex and the endothelial cell protein complex.
Volume 67,
Issue 4,
pp. 1176-1180,
04/01/1986
Copyright © 1986 by The American Society of Hematology