Plasmodium falciparum-infected erythrocytes and oxidized low-density lipoprotein bind to separate domains of CD36.
The cytoadherence of erythrocytes (red blood cells) infected with Plasmodium falciparum (pRBCs) to endothelial cells and the uptake of oxidized low-density lipoprotein (oxLDL) by macrophages are both mediated, in part, by the glycoprotein receptor CD36. The interaction of lipoproteins and pRBCs competing for the human CD36 receptor was examined by use of Chinese hamster ovary cells expressing human CD36. OxLDL competitively inhibits the adherence of pRBCs to CD36, but native LDL and high-density lipoprotein do not. Modification of Lys residues in CD36 inhibits both oxLDL and pRBC binding; however, only oxLDL binding is inhibited by receptor iodination, and only pRBC binding is influenced by pH variations and receptor reduction. Furthermore, peptide inhibitors of the pRBC/CD36 interaction do not influence oxLDL binding. These results suggest that, although oxLDL competitively inhibits the adherence of pRBCs, these ligands interact with distinct domains on the CD36 receptor.
Tropical Disease Unit, The Toronto Hospital, and Department of Medicine, University of Toronto, Toronto, Ontario, Canada. iancrandall@utoronto.ca
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Maguire
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Connelly
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D000818:Animals; D018955:CD36 Antigens / Q000737:chemistry / Q000378:metabolism*; D016466:CHO Cells; D002448:Cell Adhesion / Q000187:drug effects; D006224:Cricetinae; D004912:Erythrocytes / Q000378:metabolism* / Q000469:parasitology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008075:Lipoproteins, HDL / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism*; D010084:Oxidation-Reduction; D010455:Peptides / Q000494:pharmacology; D010963:Plasmodium falciparum / Q000254:growth & development*
D018955:CD36 Antigens; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D010455:Peptides; C099252:oxidized low density lipoprotein