Endocytosis of oxidized low density lipoprotein through scavenger receptor CD36 utilizes a lipid raft pathway that does not require caveolin-1.

摘要: The scavenger receptor CD36 binds a diverse array of ligands, including thrombospondin-1, oxidized low density lipoprotein (OxLDL), fatty acids, anionic phospholipids, and apoptotic cells. has been reported to be present in lipid rafts/caveolae, but little is known about the membrane trafficking this protein at baseline or following ligand binding. Here, we determined that expression Chinese hamster ovary (CHO) cells endogenous C32 led homogeneous distribution on plasma membrane, as judged by confocal fluorescence microscopy. This pattern was observed both anti-CD36 antibody staining live cell imaging CHO expressing chimeric CD36-green fluorescent construct. In contrast, caveolin-1 displayed its usual punctate surface distribution. Correspondingly, dual labeling showed essentially no overlap, neither immunofluorescence light microscopy nor immunogold electron Furthermore, isolation rafts sucrose gradient ultracentrifugation cold Triton X-100 lysates yielded caveolin-1, immunoprecipitates did not contain CD36. Binding Ox-LDL internalization OxLDL into endosomal structures transferrin co-internalized glycosyl-phosphatidylinositol-anchored decay accelerating factor, raft protein. caveolin-1-negative KB line sufficient for OxLDL-induced CD36, indicating required endocytic process. Taken together, these data demonstrate steady state, localized caveolae, binding leads endocytosis through pathway distinct from clathrin-mediated caveolin pathways.