A urokinase receptor-associated protein with specific collagen binding properties
Research output: Contribution to journal › Journal article › Research › peer-review
The plasminogen activation cascade system, directed by urokinase and the urokinase receptor, plays a key role in extracellular proteolysis during tissue remodeling. To identify molecular interaction partners of these trigger proteins on the cell, we combined covalent protein cross-linking with mass spectrometry based methods for peptide mapping and primary structure analysis of electrophoretically isolated protein conjugates. A specific tri-molecular complex was observed upon addition of pro-urokinase to human U937 cells. This complex included the urokinase receptor, pro-urokinase, and an unknown, high molecular weight urokinase receptor-associated protein. The tryptic peptide mixture derived from a cross-linked complex of pro-urokinase and the latter protein was analyzed by nanoelectrospray tandem mass spectrometric sequencing. This analysis identified the novel protein as the human homologue of a murine membrane-bound lectin with hitherto unknown function. The human cDNA was cloned and sequenced. The protein, designated uPARAP, is a member of the macrophage mannose receptor protein family and contains a putative collagen-binding (fibronectin type II) domain in addition to 8 C-type carbohydrate recognition domains. It proved capable of binding strongly to a single type of collagen, collagen V. This collagen binding reaction at the exact site of plasminogen activation on the cell may lead to adhesive functions as well as a contribution to cellular degradation of collagen matrices.
|Journal||The Journal of Biological Chemistry|
|Number of pages||10|
|Publication status||Published - 2000|
- Amino Acid Sequence, Animals, Cloning, Molecular, Collagen, Cross-Linking Reagents, Dose-Response Relationship, Drug, Glycosylation, Humans, Mannose-Binding Lectins, Mass Spectrometry, Membrane Glycoproteins, Mice, Molecular Sequence Data, Muscle, Smooth, Vascular, Plasminogen Activators, Protein Binding, Protein Structure, Tertiary, Receptors, Cell Surface, Receptors, Urokinase Plasminogen Activator, Sequence Homology, Amino Acid, U937 Cells, Journal Article, Research Support, Non-U.S. Gov't