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Aguilar-Gaytán, R; Mas-Oliva, J (2002)


Gac. Med. Mex. 138(5):445-460
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The scavenger receptor (SRA or RPA) belongs to a wide family of receptor proteins. The classification is based on sequence homologies and structural similarities; nevertheless, it has been useful to group them on the basis ofligand specificity. The SRA was first identified as a receptor for modified low-density lipoproteins, where such modification permits to regulate the uptake of modified LDL by macrophages leading to a massive cholesterol accumulation. Moreover, SRA facilitates the clearance by phagocytic cells of microbial pathogens and senescent cells. SRA is a transmembrane glycoprotein that exists as a trimer comprised of a cystein-linker dimer and a non-covalently bound monomer. SRA has an a-helical coiled coil domain, which is essential for both trimerformation and acid-dependent ligand dissociation. It also contains a collagenous domain, essential for ligand binding. The majority of these ligands are polyanionic molecules, such as the A ?-peptide, important in the development of Alzheimer's disease. Present findings including our own consider that binding of these peptides to SRA activates an inflammatory response with the production of oxidative stress.