Scavenger receptor class B type I as a receptor for oxidized low density lipoprotein

J Lipid Res. 2001 Sep;42(9):1474-82.


Scavenger receptor class B type I (SR-BI) has been established as the primary mediator of the selective transfer of lipids from HDL to mammalian cells. In addition to its role in cholesterol metabolism, SR-BI has been shown to bind apoptotic cells and thus could in theory also function as a scavenger receptor. We now show that SR-BI binds oxidized LDL (OxLDL) with high affinity (K(d) of 4.0 +/- 0.5 microg/ml) and mediates internalization and degradation to an extent comparable to that of other scavenger receptors, when normalized to binding activity. The best competitors for OxLDL binding to SR-BI were oxidized lipoproteins, whereas native or acetylated lipoproteins only competed for a small fraction of OxLDL binding. Both the isolated lipids and the isolated protein from OxLDL bound with high affinity to SR-BI and showed partial reciprocal competition. Monoclonal antibody EO6, an antibody against oxidized phospholipids, and 1-palmitoyl-2-(5-oxovaleroyl) phosphatidylcholine (POVPC) both competed effectively with intact OxLDL and with isolated lipids from OxLDL for SR-BI binding.Together, these results demonstrate a potential function of SR-BI, in addition to its role in selective uptake of lipids, to mediate internalization of OxLDL by macrophages and suggest a central role for oxidized phospholipids in this process.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies, Monoclonal / metabolism
  • Apolipoproteins B / metabolism
  • Apoptosis
  • Binding, Competitive
  • CD36 Antigens / metabolism*
  • Cholesterol / metabolism
  • Cholesterol Esters / metabolism
  • Humans
  • Iodine Radioisotopes
  • Lipoproteins, LDL / metabolism*
  • Macrophages / metabolism
  • Membrane Proteins*
  • Oxidation-Reduction
  • Phospholipid Ethers / metabolism
  • Receptors, Immunologic*
  • Receptors, Lipoprotein*
  • Receptors, Scavenger
  • Scavenger Receptors, Class B


  • 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphorylcholine
  • Antibodies, Monoclonal
  • Apolipoproteins B
  • CD36 Antigens
  • Cholesterol Esters
  • Iodine Radioisotopes
  • Lipoproteins, LDL
  • Membrane Proteins
  • Phospholipid Ethers
  • Receptors, Immunologic
  • Receptors, Lipoprotein
  • Receptors, Scavenger
  • SCARB1 protein, human
  • Scarb1 protein, mouse
  • Scavenger Receptors, Class B
  • oxidized low density lipoprotein
  • Cholesterol