Phosphatidylserine (PS) is asymmetrically distributed in mammalian cell membrane, being preferentially localized in the inner leaflet. Some studies have suggested that a disturbance in the normal asymmetric distribution of PS - e.g., PS exposure in the outer leaflet of the cell membrane, which can occur upon platelet activation as well as in certain pathologic red cells - serves as a potent procoagulant surface and as a single for triggering their recognition by macrophages. These studies suggest that the regulation of PS distribution in cell membranes may be critical in controlling coagulation and in determining the survival of pathologic cells in the circulation. In this paper we describe a sensitive technique, based on PS-dependent prothrombinase complex activity, for assessing the amount of PS on the external leaflet of intact viable cells. Our results indicate that tumorigenic, undifferentiated murine erythroleukemic cells express 7- to 8-fold more PS in their outer leaflet than do their differentiated, nontumorigenic counterparts. Increased expression of PS in the tumorigenic cells directly correlated with their ability to be recognized and bound by macrophages.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jan 1 1989|
ASJC Scopus subject areas