SCAVENGER RECEPTOR FAMILY PROTEINS - ROLES FOR ATHEROSCLEROSIS, HOST-DEFENSE AND DISORDERS OF THE CENTRAL-NERVOUS-SYSTEM

In this review, we summarize the structure and function of the scaveng er receptor family of proteins including class A (type I and II macrop hage scavenger receptors, MARCO), class B (CD36, scavenger receptor cl ass BI), mucinlike (CD68/macrosialin. dSR-CI) and endothelial (LOX-1) receptors. Two motifs have been identified as ligand-binding domains: a charged collagen structure of type I and II receptors, and an immuno dominant domain of CD36. These structures can recognize a wide range o f negatively charged macromolecules, including oxidized low-density li poproteins, damaged or apoptotic cells, and pathogenic microorganisms. After binding, these ligands can be either internalized by endocytosi s or phagocytosis, or remain at the cell surface and mediate adhesion or lipid transfer through caveolae. Under physiological conditions, sc avenger receptors serve to scavenge or clean up cellular debris and ot her related materials, and they play a role in host defence. In pathol ogical states, they mediate the recruitment, activation and transforma tion of macrophages and other cells which may be related to the develo pment of atherosclerosis and to disorders caused by the accumulation o f denatured materials, such as Alzheimer's disease.