Identification of a sequence in the matricellular protein SPARC that interacts with the scavenger receptor stabilin-1

SPARC (osteonectin/BM-40), a secreted matricellular protein that promotes cellular deadhesion and motility in wound healing, carcinogenesis, and inflammation, binds to the scavenger receptor stabilin-1 in alternatively activated macrophages and undergoes endocytosis and clearance from the extracellular space. Both SPARC and stabilin-1 are expressed by endothelial cells during inflammation, but their interaction in this context is unknown. We have identified a binding site on SPARC for stabilin-1 by a solid-state peptide array coupled with a modified enzyme-linked immunosorbent assay. A monoclonal antibody that recognizes the identified binding site was also characterized that could be an inhibitor for the SPARC-stabilin-1 interaction in macrophages or endothelial cells.