Figure 2.
Structure and function of scavenger receptor family members, CD36, SR-BI, and LOX-1 in atherosclerosis. The scavenger receptors belong to a large family of pattern recognition receptors, which can interact with a wide range of ligands. Interacting with the circulating native or modified lipoproteins, such as oxLDL, these receptors modulate vascular inflammation, lipid accumulation, and plaque formation. Both CD36 and SR-BI have two short N- and C-terminal cytoplasmic tails, two transmembrane domains, and a large extracellular domain that binds to the ligands. CD36, through binding to modified lipoproteins and lipids, plays a major role in atherogenesis, by promoting endothelial dysfunction, macrophage foam cell formation, vascular inflammation, and atherothrombosis. Hepatic SR-BI protects against atherosclerosis by facilitating the reverse cholesterol transport and maintaining anti-atherogenic characteristics of HDL in the vascular cells; however, recent findings indicate that the receptor has a key pro-atherogenic function in endothelium by mediating transport of LDL into the artery wall. LOX-1 contains a short N-terminal cytoplasmic domain, a single transmembrane domain, a NECK or stalk domain, and a C-terminal extracellular domain that binds to oxLDL. In a variety of vascular cells, LOX-1 mediates a majority of pro-atherogenic actions of oxLDL, contributing inflammation, smooth muscle cell proliferation, and platelet activation.