A deletion mutant of vitronectin lacking the somatomedin B domain exhibits residual plasminogen activator inhibitor-1-binding activity
| Autor: | Cynthia B. Peterson, Kenneth H. Minor, Grant E. Blouse, Christine R. Schar |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Plasma protein binding
Biology Spodoptera Biochemistry chemistry.chemical_compound Somatomedin B Somatomedins Plasminogen Activator Inhibitor 1 Cell Adhesion Animals Humans Vitronectin Binding site Cell adhesion Molecular Biology Binding Sites Heparin Cell Biology U937 Cells Recombinant Proteins Cell biology Protein Structure Tertiary Urokinase receptor chemistry Plasminogen activator inhibitor-1 Mutation Protein Structure and Folding biology.protein Plasminogen activator Ultracentrifugation Gene Deletion Protein Binding |
| Zdroj: | The Journal of biological chemistry. 283(16) |
| ISSN: | 0021-9258 |
| Popis: | Vitronectin and plasminogen activator inhibitor-1 (PAI-1) are important physiological binding partners that work in concert to regulate cellular adhesion, migration, and fibrinolysis. The high affinity binding site for PAI-1 is located within the N-terminal somatomedin B domain of vitronectin; however, several studies have suggested a second PAI-1-binding site within vitronectin. To investigate this secondary site, a vitronectin mutant lacking the somatomedin B domain (rΔsBVN) was engineered. The short deletion had no effect on heparin-binding, integrin-binding, or cellular adhesion. Binding to the urokinase receptor was completely abolished while PAI-1 binding was still observed, albeit with a lower affinity. Analytical ultracentrifugation on the PAI-1-vitronectin complex demonstrated that increasing NaCl concentration favors 1:1 versus 2:1 PAI-1-vitronectin complexes and hampers formation of higher order complexes, pointing to the contribution of charge-charge interactions for PAI-1 binding to the second site. Furthermore, fluorescence resonance energy transfer between differentially labeled PAI-1 molecules confirmed that two independent molecules of PAI-1 are capable of binding to vitronectin. These results support a model for the assembly of higher order PAI-1-vitronectin complexes via two distinct binding sites in both proteins. |
| Databáze: | OpenAIRE |
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