title: Structure of uPAR, plasminogen, and sugar-binding sites of the 300 kDa mannose 6-phosphate receptor.
abstract: The 300 kDa cation-independent mannose 6-phosphate receptor (CI-MPR) mediates the intracellular transport of newly synthesized lysosomal enzymes containing mannose 6-phosphate on their N-linked oligosaccharides. In addition to its role in lysosome biogenesis, the CI-MPR interacts with a number of different extracellular ligands at the cell surface, including latent transforming growth factor-beta, insulin-like growth factor-II, plasminogen, and urokinase-type plasminogen activator receptor (uPAR), to regulate cell growth and motility. We have solved the crystal structure of the N-terminal 432 residues of the CI-MPR at 1.8 A resolution, which encompass three out of the 15 repetitive domains of its extracytoplasmic region. The three domains, which exhibit similar topology to each other and to the 46 kDa cation-dependent mannose 6-phosphate receptor, assemble into a compact structure with the uPAR/plasminogen and the carbohydrate-binding sites situated on opposite faces of the molecule. Knowledge of the arrangement of these three domains has allowed us to propose a model of the entire extracytoplasmic region of the CI-MPR that provides a context with which to envision the numerous binding interactions carried out by this multi-faceted receptor.
authors.affiliation: Department of Biochemistry, Medical College of Wisconsin, Watertown Plank Road, Milwaukee, WI 53226, USA.
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Olson
authors.forename: Rama D
authors.initials: RD
authors.lastname: Yammani
authors.forename: Nancy M
authors.initials: NM
authors.lastname: Dahms
authors.forename: Jung-Ja P
authors.initials: JJ
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001692:Biological Transport / Q000502:physiology; D002417:Cattle; D018360:Crystallography, X-Ray; D008247:Lysosomes / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009844:Oligosaccharides / Q000378:metabolism*; D010958:Plasminogen / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017527:Receptor, IGF Type 2 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D016415:Sequence Alignment
chemical_list: D009844:Oligosaccharides; D017527:Receptor, IGF Type 2; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D010958:Plasminogen