title: Secreted protein acidic and rich in cysteine (SPARC/osteonectin/BM-40) binds to fibrinogen fragments D and E, but not to native fibrinogen.
abstract: Secreted protein acidic and rich in cysteine (SPARC/osteonectin/BM-40) is a matricellular protein that functions in wound healing. Fibrinogen is a plasma protein involved in many aspects of wound healing, such as inflammation, fibrosis and thrombosis. In this study, the binding of SPARC to both native and plasmin-cleaved fibrinogen under physiological conditions was examined by the use of a surface plasmon resonance (SPR) biosensor. We show that SPARC binds to plasmin-cleaved fibrinogen, but not to native fibrinogen. SPARC binds to both fibrinogen fragments D and E fg D and fg E with similar dissociation constants (8.67 x 10(-8) M for Fg D and 1.61 x 10(-7) M for Fg E). Results from endothelial cell proliferation assays show that the binding of SPARC to Fg E suppressed the inhibition of proliferation by SPARC, whereas the binding of SPARC to Fg D did not influence the activity of SPARC on the cell cycle. The interaction of SPARC with fibrinogen fragments D and E, which are produced as a result of proteolytic activation of fibrinolysis, reveals potential storage sites in provisional extracellular matrix for SPARC during the wound healing process and indicates a regulatory role of SPARC in fibrinolysis and angiogenesis.
authors.affiliation: Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA.
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.forename: Gail
authors.initials: G
authors.lastname: Workman
authors.forename: Shengfu
authors.initials: S
authors.lastname: Chen
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Barker
authors.forename: Buddy D
authors.initials: BD
authors.lastname: Ratner
authors.forename: E Helene
authors.initials: EH
authors.lastname: Sage
authors.forename: Shaoyi
authors.initials: S
authors.lastname: Jiang
mesh_terms: D000818:Animals; D002364:Caseins / Q000378:metabolism; D002417:Cattle; D049109:Cell Proliferation; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D005340:Fibrinogen / Q000737:chemistry / Q000378:metabolism*; D005341:Fibrinolysin / Q000378:metabolism; D006801:Humans; D015676:Osteonectin / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D020349:Surface Plasmon Resonance
chemical_list: D002364:Caseins; D024042:Collagen Type I; D015676:Osteonectin; D010446:Peptide Fragments; D005340:Fibrinogen; D005341:Fibrinolysin