Binding of urokinase plasminogen activator to gp130 via a putative urokinase-binding consensus sequence.
Urokinase-type plasminogen activator (uPA) and its receptor (uPAR) are instrumental in cellular activities during inflammation, angiogenesis and tumor metastasis. Recent studies suggest that uPA might exert its function on cell proliferation and migration in a uPAR-independent manner or through an adaptor to the uPA-uPAR system. By applying phage display technology, we have identified a putative uPA-binding consensus sequence BXXSSXXB (where B represents a basic amino acid and X represents any amino acid), which has no apparent sequence correlation to uPAR. This uPA-binding motif apparently recognizes the kringle domain of the protease and has an agonistic effect on uPA binding to immobilized uPAR, thereby possibly serving as part of an adaptor component for uPAR signaling. As a result of protein database searches, this motif was found in the extracellular domain of several cell surface proteins, some of which were proposed to be associated with the uPA-uPAR system. Among these, gp130, a common signal transducer for cytokines, was identified as a uPA-binding protein. The specificity of this interaction was demonstrated by inhibition of uPA binding to immobilized gp130 with soluble gp130. Furthermore, the binding could be partially inhibited by a uPA-binding consensus sequence-containing fusion protein in a dose-dependent manner, with an IC50 of approximately 1 microM, indicating that the uPA-binding motif is apparently involved in the uPA-gp130 interaction. The association of gp130 with uPA may link the uPA-uPAR system to various signal transduction pathways.
Liang
Olin D
OD
Institut für Biochemie, Fachbereich Humanmedizin, Justus-Liebig-Universität, Friedrichstr. 24, D-35392 Giessen, Germany.
Chavakis
Triantafyllos
T
Linder
Monica
M
Bdeir
Khalil
K
Kuo
Alice
A
Preissner
Klaus T
KT
D020816:Amino Acid Motifs / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D001435:Bacteriophages / Q000276:immunology; D001667:Binding, Competitive; D016384:Consensus Sequence; D050822:Cytokine Receptor gp130; D004305:Dose-Response Relationship, Drug; D000939:Epitopes / Q000276:immunology; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D020128:Inhibitory Concentration 50; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D019151:Peptide Library; D011485:Protein Binding; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D016415:Sequence Alignment; D015398:Signal Transduction; D013379:Substrate Specificity; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics* / Q000378:metabolism* / Q000494:pharmacology
D015703:Antigens, CD; D000939:Epitopes; C494199:IL6ST protein, human; C494200:Il6st protein, mouse; C494201:Il6st protein, rat; D008562:Membrane Glycoproteins; D019151:Peptide Library; D011993:Recombinant Fusion Proteins; D050822:Cytokine Receptor gp130; D005982:Glutathione Transferase; D014568:Urokinase-Type Plasminogen Activator