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Identification and characterization of the murine cell surface receptor for the urokinase-type plasminogen activator

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  1. Cell-surface acceleration of urokinase-catalyzed receptor cleavage

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  1. Unfolding of monomeric lipoprotein lipase by ANGPTL4: Insight into the regulation of plasma triglyceride metabolism

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  2. The PCNA interaction motifs revisited: thinking outside the PIP-box

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  3. Peptide disc mediated control of membrane protein orientation in supported lipid bilayers for surface-sensitive investigations

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  4. TAFI deficiency causes maladaptive vascular remodeling after hemophilic joint bleeding

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Cell-binding experiments have indicated that murine cells on their surface have specific binding sites for mouse urokinase-type plasminogen activator (u-PA). In contrast to the human system, chemical cross-linking studies with an iodinated ligand did not yield any covalent adducts in the murine system, but in ligand-blotting analysis, two mouse u-PA-binding proteins could be visualized. To confirm that these proteins are the murine counterpart of the human u-PA receptor (u-PAR), a peptide was derived from the murine cDNA clone assigned to represent the murine u-PAR due to cross-hybridization and pronounced sequence similarity with human u-PAR cDNA [Kristensen, P., Eriksen, J., Blasi, F. & Danø, K. (1991) J. Cell Biol. 115, 1763-1771]. A rabbit antiserum raised against this peptide specifically recognized two polypeptide bands with electrophoretic mobilities identical to those identified by ligand-blotting analysis. Binding of mouse u-PA to its receptor showed species specificity in ligand-blotting analysis, since mouse u-PA did not bind to human u-PAR and human u-PA did not bind to mouse u-PAR. The apparent M(r) of mouse u-PAR varied between different mouse cell lines and ranged over M(r) 45,000-60,000. In four of the cell lines, mouse u-PA bound to two mouse u-PAR variant proteins, whereas in the other two cell lines studied, there was only one mouse u-PA-binding protein. In the monocyte macrophage cell line P388D.1, trypsin-treatment of intact cells could remove only the large mouse u-PAR variant (M(r) 60,000) indicating that only this type was a cell-surface-exposed molecule. The smaller mouse u-PAR variant (M(r) 45,000), was deglycosylated by the enzyme endo-beta-N-acetylglucosaminidase H and is probably an intracellular precursor form carrying only high-mannose carbohydrate. Deglycosylation of this variant yielded a polypeptide with an apparent M(r) of about 30,000, which corresponds to the Mr calculated from the cDNA derived protein sequence of mouse u-PAR. Receptor-bound mouse u-PA could be released by phosphatidylinositol-specific phospholipase C treatment, indicating that mouse u-PAR is attached to the cell surface by glycosylphosphatidylinositol. Purification of the two mouse u-PAR variant proteins by diisopropylfluorophosphate-inactivated mouse u-PA-Sepharose affinity chromatography yielded two silver-stained bands when analysed by SDS/PAGE, corresponding in electrophoretic mobility to those seen by ligand-blotting analysis.(ABSTRACT TRUNCATED AT 400 WORDS)

Original languageEnglish
JournalEuropean Journal of Biochemistry
Volume205
Issue number2
Pages (from-to)451-8
Number of pages8
ISSN0014-2956
Publication statusPublished - 15 Apr 1992

    Research areas

  • Amino Acid Sequence, Animals, Antibodies, Blotting, Northern, Cell Line, Cloning, Molecular, Enzyme-Linked Immunosorbent Assay, Humans, Iodine Radioisotopes, Kinetics, Ligands, Macrophages, Mice, Molecular Sequence Data, Molecular Weight, Peptides, RNA, Receptors, Cell Surface, Receptors, Urokinase Plasminogen Activator, Species Specificity, Tetradecanoylphorbol Acetate, Urokinase-Type Plasminogen Activator

ID: 46434763