Differentiation-enhanced binding of the amino-terminal fragment of human urokinase plasminogen activator to a specific receptor on U937 monocytes.
The purified amino-terminal fragment (ATF) of human urokinase plasminogen activator (residues 1-135), which is not required for activation of plasminogen, binds with high affinity to specific plasma membrane receptors on U937 monocytes. Intact urokinase efficiently competes for 125I-labeled ATF binding; 50% competition occurs with 1 nM urokinase. A large part of receptor-bound urokinase remains on the cell surface for at least 2 hr at 37 degrees C. Differentiation of U937 monocytes into macrophage-like cells specifically increases ATF binding 10- to 20-fold. These results suggest an important role for urokinase in monocyte/macrophage biology: the native enzyme binds to the cells with the amino-terminal domain; the catalytic, carboxyl-terminal domain remains exposed on the cell surface to stimulate localized proteolysis and facilitate cell migration.
Stoppelli
M P
MP
Corti
A
A
Soffientini
A
A
Cassani
G
G
Blasi
F
F
Assoian
R K
RK
D000595:Amino Acid Sequence; D001667:Binding, Competitive; D002454:Cell Differentiation / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D008264:Macrophages / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*
C524898:PLAUR protein, human; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator; D013755:Tetradecanoylphorbol Acetate