Cellular receptor for urokinase plasminogen activator. Carboxyl-terminal processing and membrane anchoring by glycosyl-phosphatidylinositol
Research output: Contribution to journal › Journal article › Research › peer-review
The cellular receptor for human urokinase-type plasminogen activator (u-PAR) is shown by several independent criteria to be a true member of a family of integral membrane proteins, anchored to the plasma membrane exclusively by a COOH-terminal glycosyl-phosphatidylinositol moiety. 1) Amino acid analysis of u-PAR after micropurification by affinity chromatography and N-[2-hydroxy-1,1-bis(hydroxymethyl)-ethyl]glycine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of 2-3 mol of ethanolamine/mol protein. 2) Membrane-bound u-PAR is efficiently released from the surface of human U937 cells by trace amounts of purified bacterial phosphatidylinositol-specific phospholipase C. This soluble form of u-PAR retains the binding specificity toward both u-PA and its amino-terminal fragment holding the receptor-binding domain. 3) Treatment of purified u-PAR with phosphatidylinositol-specific phospholipase C or mild alkali completely alters the hydrophobic properties of the receptor as judged by temperature-induced detergent-phase separation and charge-shift electrophoresis. 4) Biosynthetic labeling of u-PAR was obtained with [3H]ethanolamine and myo-[3H]inositol. 5) Finally, comparison of amino acid compositions derived from cDNA sequence and amino acid analysis shows that a polypeptide of medium hydrophobicity is excised from the COOH terminus of the nascent u-PAR. A similar proteolytic processing has been reported for other proteins that are linked to the plasma membrane by a glycosyl-phosphatidylinositol membrane anchor.
Original language | English |
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Journal | The Journal of Biological Chemistry |
Volume | 266 |
Issue number | 3 |
Pages (from-to) | 1926-33 |
Number of pages | 8 |
ISSN | 0021-9258 |
Publication status | Published - 25 Jan 1991 |
Externally published | Yes |
- Amino Acids, Ethanolamine, Ethanolamines, Glycolipids, Glycosylphosphatidylinositols, Humans, In Vitro Techniques, Membrane Glycoproteins, Molecular Weight, Phosphatidylinositol Diacylglycerol-Lyase, Phosphatidylinositols, Phosphoinositide Phospholipase C, Phosphoric Diester Hydrolases, Polysaccharides, Protein Processing, Post-Translational, Receptors, Cell Surface, Receptors, Urokinase Plasminogen Activator, Solubility, Tumor Cells, Cultured, Urokinase-Type Plasminogen Activator, Journal Article, Research Support, Non-U.S. Gov't
Research areas
ID: 178214984