CD36: a class B scavenger receptor involved in angiogenesis, atherosclerosis, inflammation, and lipid metabolism

CD36, identified more than a quarter of a century ago as a platelet integra l membrane glycoprotein (glycoprotein IV), was until recently best known as a receptor for thrombospondin-1 (TSP-1). TSP-1 is found in ECMs and platel et a granules, and it participates in cell attachment, motility and prolife ration, as well as in modulation of protease activity, TGF-beta activation, neurite outgrowth, and angiogenesis (1). Initially, this receptor-ligand p air was shown to mediate interactions between platelets and monocytes, tumo r cells, and matrix. Since then, CD36 has been implicated in multiple biolo gical processes that define it as a multiligand scavenger receptor (see ref . 2 for review). These ligands appear remarkably diverse: In addition to TS P-1, they include long-chain fatty acids, modified LDL, retinal photorecept or outer segments, Plasmodium falciparum malaria-parasitized erythrocytes, sickle erythrocytes, anionic phospholipids, apoptotic cells, and collagens I and IV. The biology of CD36 can be broadly divided in terms of functions that it mediates with or without TSP-1, but it is probable that it acts in concert with other proteins, such as fatty acid-binding proteins, caveola-a ssociated proteins, integrins, cytoskeletal proteins, and signaling molecul es, to effect its diverse functions.