Binding of anionic phospholipids to retinal pigment epithelium may be mediated by the scavenger receptor CD36. J Biol Chem 1996 Aug 23;271(34):20536-9
Date
08/23/1996Pubmed ID
8702796DOI
10.1074/jbc.271.34.20536Scopus ID
2-s2.0-0029786328 (requires institutional sign-in at Scopus site) 129 CitationsAbstract
The specific recognition of negatively charged phospholipids in cell membranes has been suggested to play an important role in a variety of physiological and pathophysiological processes. Recent work (Rigotti, A., Acton, S. L., and Krieger, M. (1995) J. Biol. Chem. 270, 16221-16224) has described specific and tight binding of anionic phospholipids, such as phosphatidylserine (PS) and phosphatidylinositol (PI), to the class B scavenger receptors, CD36 and SR-B1. We have previously reported that CD36 is present on retinal pigment epithelium (RPE) and plays a role in the phagocytosis of photoreceptor outer segments (ROS), a function critical to the normal visual process (Ryeom, S. W., Sparrow, J. R., and Silverstein, R. L. (1996) J. Cell Sci. 109, 387-395). We now report that phospholipid liposomes PS and PI, but not phosphatidylethanolamine, bind specifically to RPE. Cross-competition experiments suggest that PS and PI recognize the same receptor on RPE, while immunoinhibition studies indicate that the receptor is CD36. RPE cells isolated from a mutant rat strain, the RPE of which does not express CD36 ( Sparrow, J. R., Ryeom, S. W. , Abumrad, N., Ibrahimi, A., and Silverstein, R. L. (1996) Exp. Eye Res., in press), did not bind PS or PI, further confirming the role of CD36. We also showed that purified ROS blocked binding and uptake of anionic phospholipid liposomes by RPE and that PS and PI liposomes blocked ROS uptake by RPE, suggesting that PS and PI on the ROS membrane may be the ligands on ROS recognized by CD36. This is the first demonstration that CD36-phospholipid interactions may play a role in normal physiology.
Author List
Ryeom SW, Silverstein RL, Scotto A, Sparrow JRAuthor
Roy L. Silverstein MD Professor in the Medicine department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsCD36 Antigens
Cells, Cultured
Endocytosis
Liposomes
Membrane Lipids
Phosphatidylcholines
Phosphatidylinositols
Phosphatidylserines
Pigment Epithelium of Eye
Rats
