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.
Última actualización: 23/03/2018