Secreted extracellular domains of macrophage scavenger receptors form elongated trimers which specifically bind crocidolite asbestos.

摘要: Macrophage scavenger receptors, which have been implicated in the development of atherosclerosis and other macrophage-mediated events, are trimeric integral membrane glycoproteins whose extracellular domains predicted to include alpha-helical coiled-coil, collagenous globular structures. To elucidate further structural functional properties these we generated transfected Chinese hamster ovary cells express secreted type I II bovine receptors developed a solid-phase bead-binding assay assess their ligand-binding properties. The exhibited distinctive high-affinity, broad polyanionic specificity pH dependence binding characterize membrane-anchored cell-surface forms receptors. Both were comprising disulfide-linked dimers noncovalently associated monomers. Gel filtration glycerol-gradient centrifugation established that trimers highly elongated did not associate into higher order oligomers at low concentrations used experiments. Crocilodite asbestos, is phagocytosed by alveolar macrophages can cause asbestosis mesothelioma, bound efficiently less well This was specific it competed variety receptor ligands but negative controls. These studies identified new insoluble ligand, raised possibility may play role mediating physiological pathological interactions inspired particles with macrophages.