title: Functional duplication of ligand-binding domains within low-density lipoprotein receptor-related protein for interaction with receptor associated protein, alpha2-macroglobulin, factor IXa and factor VIII.
abstract: The low-density lipoprotein receptor-related protein (LRP) binds a range of proteins including receptor associated protein (RAP), activated alpha2-macroglobulin (alpha2M*), factor IXa (FIXa), and factor VIII (FVIII) light chain. The binding is mediated by the complement-type repeats, which are clustered in four distinct regions within LRP. Cluster II of 8 repeats (CR3-10) and cluster IV of 11 repeats (CR21-31) have been implicated in ligand-binding. Previous studies have aimed to identify the cluster II repeats involved in binding alpha2M* and RAP. We now evaluated the binding to RAP, alpha2M*, FIXa and FVIII light chain of triplicate repeat-fragments of not only clusters II but also of cluster IV. Employing surface plasmon resonance analysis, we found that most efficient ligand-binding was displayed by the repeats within region CR4-8 of cluster II and within region CR24-28 of cluster IV. Whereas the binding to RAP could be attributed to two consecutive repeats (CR5-6, CR26-27), combinations of three repeats showed most efficient binding to FIXa (CR6-8, CR26-28), FVIII light chain (CR5-7, CR6-8, CR24-26), and alpha2M* (CR4-6, CR24-26). The results imply that there is an internal functional duplication of complement-type repeats within LRP resulting in two clusters that bind the same ligands.
authors.affiliation: Sanquin Research, Department of Plasma Proteins, 1066 CX Amsterdam, The Netherlands. s.meijer@sanquin.nl
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Meijer
authors.forename: Jakub
authors.initials: J
authors.lastname: Rohlena
authors.forename: Carmen
authors.initials: C
authors.lastname: van der Zwaan
authors.forename: Anton-Jan
authors.initials: AJ
authors.lastname: van Zonneveld
authors.forename: Ria C
authors.initials: RC
authors.lastname: Boertjes
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Lenting
authors.forename: Koen
authors.initials: K
authors.lastname: Mertens
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D006224:Cricetinae; D015949:Factor IXa / Q000378:metabolism*; D005169:Factor VIII / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D026563:LDL-Receptor Related Protein-Associated Protein / Q000378:metabolism*; D026502:LDL-Receptor Related Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008024:Ligands; D008969:Molecular Sequence Data; D005810:Multigene Family; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D020349:Surface Plasmon Resonance; D000511:alpha-Macroglobulins / Q000378:metabolism*
chemical_list: D026563:LDL-Receptor Related Protein-Associated Protein; D026502:LDL-Receptor Related Proteins; D008024:Ligands; D010446:Peptide Fragments; D000511:alpha-Macroglobulins; D005169:Factor VIII; D015949:Factor IXa