S-protein/vitronectin interaction with the C5b and the C8 of the complement membrane attack complex.
S-protein/vitronectin participates in the regulation of complement-mediated lysis by incorporating into the membrane attack complex C5b-9. Subsequently, soluble SC5b-7 and SC5b-9 macromolecules are not inserted into the membrane lipid bilayer nor induce lytic pore formation. Using a dot blot binding assay, it was determined that soluble S-protein/vitronectin interacted with immobilized C5b and C8 among the five separately immobilized components (C5b, C6, C7, C8, C9) of the membrane attack complex. Those interactions imply a new model of the formation of the complement membrane attack complex and its regulation by S-protein/vitronectin.
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Department of Stomatology, Medical University of South Carolina, Charleston, USA.
D000818:Animals; D003182:Complement C5 / Q000378:metabolism* / Q000494:pharmacology; D050776:Complement C5b; D003185:Complement C8 / Q000378:metabolism* / Q000494:pharmacology; D015938:Complement Membrane Attack Complex / Q000378:metabolism*; D006493:Heparin / Q000494:pharmacology; D012995:Solubility; D019096:Vitronectin / Q000037:antagonists & inhibitors / Q000378:metabolism*
D003182:Complement C5; D003185:Complement C8; D015938:Complement Membrane Attack Complex; D019096:Vitronectin; D050776:Complement C5b; D006493:Heparin