To identify the HDL3-binding proteins on human macrophages, we examined the involvement of GPI-anchored protein in the binding of HDL3, and tried to purify HDL3-binding protein. From membrane fractions of macrophages, we obtained 80- and 130-kDa HDL3-binding proteins by ligand blotting. Treatment of macrophages with phosphatidylinositol-specific phospholipase C (PI-PLC) significantly decreased the specific HDL3-binding in a dose-dependent manner. Furthermore, treatment with mannosamine, which blocks GPI-anchor formation, decreased specific HDL3-binding in a dose-dependent manner. PI-PLC treatment released from the cells the proteins with an M(r) of 80 kDa, which could also bind HDL3. PI-PLC as well as mannosamine treatment markedly reduced cholesterol efflux from macrophages in association with the decreased HDL-binding. Using HDL3-affinity chromatography, we purified 80-kDa GPI-anchored type HDL3-binding protein. In summary, we demonstrate the implication of 80-kDa GPI-anchored protein in the binding of HDL3 to human macrophages, which might have some role in reverse cholesterol transport. (C) 2000 Academic Press.
|Number of pages||8|
|Journal||Biochemical and Biophysical Research Communications|
|Publication status||Published - 16-06-2000|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology