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Ligand binding regions in the receptor for urokinase-type plasminogen activator.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2001 Aug 03; Vol. 276 (31), pp. 28946-53. - Publication Year :
- 2001
-
Abstract
- The interaction between urokinase plasminogen activator (uPA) and its cellular receptor (uPAR) is a key event in cell surface-associated plasminogen activation, relevant for cell migration and invasion. In order to define receptor recognition sites for uPA, we have expressed uPAR fragments as fusion products with the minor coat protein on the surface of M13 bacteriophages. Sequence analysis of cDNA fragments encoding uPA-binding peptides indicated the existence of a composite uPA-binding structure including all three uPAR domains. This finding was confirmed by experiments using an overlapping 15-mer peptide array covering the entire uPAR molecule. Four regions within the uPAR sequence were found to directly bind to uPA: two distinct regions containing amino acids 13--20 and amino acids 74--84 of the uPAR domain I, and regions in the putative loop 3 of the domains II and III. All the uPA-binding fragments from the three domains were shown to have an agonistic effect on uPA binding to immobilized uPAR. Furthermore, uPAR-(154--176) increased uPAR-transfected BAF3-cell adhesion on vitronectin in the presence of uPA, whereas uPAR-(247--276) stimulated the cell adhesion both in the absence or presence of uPA. The latter fragment was also able to augment the binding of vitronectin to uPAR in a purified system, thereby mimicking the effect of uPA on this interaction. These results indicate that uPA binding can take place to particular part(s) on several uPAR molecules and that direct uPAR-uPAR contacts may contribute to receptor activation and ligand binding.
- Subjects :
- Amino Acid Sequence
Binding Sites
Binding, Competitive
Chromatography, Affinity
DNA, Complementary
Humans
Kinetics
Ligands
Models, Molecular
Molecular Sequence Data
Peptide Fragments chemistry
Peptide Fragments isolation & purification
Peptide Fragments metabolism
Protein Conformation
Receptors, Cell Surface genetics
Receptors, Urokinase Plasminogen Activator
Recombinant Fusion Proteins chemistry
Recombinant Fusion Proteins metabolism
Recombinant Proteins chemistry
Recombinant Proteins metabolism
Sequence Alignment
Vitronectin blood
Vitronectin metabolism
Receptors, Cell Surface chemistry
Receptors, Cell Surface metabolism
Urokinase-Type Plasminogen Activator chemistry
Urokinase-Type Plasminogen Activator metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 276
- Issue :
- 31
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 11501527
- Full Text :
- https://doi.org/10.1074/jbc.m011347200