High-affinity binding of plasminogen-activator inhibitor 1 complexes to LDL receptor-related protein 1 requires lysines 80, 88, and 207
JournalThe Journal of biological chemistry
PublisherAmerican Society for Biochemistry and Molecular Biology
MetadataShow full item record
AbstractIt is well-established that complexes of plasminogen-activator inhibitor 1 (PAI-1) with its target enzymes bind tightly to low-density lipoprotein (LDL) receptor-related protein 1 (LRP1), but the molecular details of this interaction are not well-defined. Furthermore, considerable controversy exists in the literature regarding the nature of the interaction of free PAI-1 with LRP1. In this study, we examined the binding of free PAI-1 and complexes of PAI-1 with low-molecular-weight urokinase-type plasminogen activator to LRP1. Our results confirmed that uPA:PAI-1 complexes bind LRP1 with ?100-fold increased affinity over PAI-1 alone. Chemical modification of PAI-1 confirmed an essential requirement of lysine residues in PAI-1 for the interactions of both PAI-1 and uPA:PAI-1 complexes with LRP1. Results of surface plasmon resonance measurements supported a bivalent binding model in which multiple sites on PAI-1 and uPA:PAI-1 complexes interact with complementary sites on LRP1. An ionic-strength dependence of binding suggested the critical involvement of two charged residues for the interaction of PAI-1 with LRP1 and three charged residues for the interaction of uPA:PAI-1 complexes with LRP1. An enhanced affinity resulting from the interaction of three regions of the uPA:PAI-1 complex with LDLa repeats on LRP1 provided an explanation for the increased affinity of uPA:PAI-1 complexes for LRP1. Mutational analysis revealed an overlap between LRP1 binding and binding of a small-molecule inhibitor of PAI-1, CDE-096, confirming an important role for Lys-207 in the interaction of PAI-1 with LRP1 and of the orientations of Lys-207, -88, and -80 for the interaction of uPA:PAI-1 complexes with LRP1. Copyright 2020 Migliorini et al.
lipoprotein receptor-related protein (LRP)
surface plasmon resonance (SPR)
Identifier to cite or link to this itemhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-85077477063&doi=10.1074%2fjbc.RA119.010449&partnerID=40&md5=e82a8d9b0d8be09753bf6f6dd9e9c710; http://hdl.handle.net/10713/11624