Crystal structure of the urokinase receptor in a ligand-free form

Xiang Xu; Henrik Gårdsvoll; Cai Yuan; Lin Lin; Michael Ploug; Mingdong Huang

doi:10.1016/j.jmb.2011.12.058

Crystal structure of the urokinase receptor in a ligand-free form

Xiang Xu, Henrik Gårdsvoll, Cai Yuan, Lin Lin, Michael Ploug, Mingdong Huang

37 Citations (Scopus)

Abstract

The urokinase receptor urokinase-type plasminogen activator receptor (uPAR) is a surface receptor capable of not only focalizing urokinase-type plasminogen activator (uPA)-mediated fibrinolysis to the pericellular micro-environment but also promoting cell migration and chemotaxis. Consistent with this multifunctional role, uPAR binds several extracellular ligands, including uPA and vitronectin. Structural studies suggest that uPAR possesses structural flexibility. It is, however, not clear whether this flexibility is an inherent property of the uPAR structure per se or whether it is induced upon ligand binding. The crystal structure of human uPAR in its ligand-free state would clarify this issue, but such information remains unfortunately elusive. We now report the crystal structures of a stabilized, human uPAR (H47C/N259C) in its ligand-free form to 2.4 Å and in complex with amino-terminal fragment (ATF) to 3.2 Å. The structure of uPAR(H47C/N259C) in complex with ATF resembles the wild-type uPAR·ATF complex, demonstrating that these mutations do not perturb the uPA binding properties of uPAR. The present structure of uPAR(H47C/N259C) provides the first structural definition of uPAR in its ligand-free form, which represents one of the biologically active conformations of uPAR as defined by extensive biochemical studies. The domain boundary between uPAR DI-DII domains is more flexible than the DII-DIII domain boundary. Two important structural features are highlighted by the present uPAR structure. First, the DI-DIII domain boundary may face the cell membrane. Second, loop 130-140 of uPAR plays a dynamic role during ligand loading/unloading. Together, these studies provide new insights into uPAR structure-function relationships, emphasizing the importance of the inter-domain dynamics of this modular receptor.

Original language	English
Journal	Journal of Molecular Biology
Volume	416
Issue number	5
Pages (from-to)	629-41
Number of pages	13
ISSN	0022-2836
DOIs	https://doi.org/10.1016/j.jmb.2011.12.058
Publication status	Published - 9 Mar 2012

Keywords

Binding Sites
Cell Membrane
Crystallization
Crystallography, X-Ray
Humans
Ligands
Mannose-Binding Lectins
Membrane Glycoproteins
Models, Molecular
Mutation
Protein Binding
Protein Structure, Secondary
Protein Structure, Tertiary
Receptors, Cell Surface
Recombinant Proteins
Structure-Activity Relationship
Urokinase-Type Plasminogen Activator
Vitronectin

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10.1016/j.jmb.2011.12.058

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@article{86f1cca48ed84ea8af0007685b126a50,

title = "Crystal structure of the urokinase receptor in a ligand-free form",

abstract = "The urokinase receptor urokinase-type plasminogen activator receptor (uPAR) is a surface receptor capable of not only focalizing urokinase-type plasminogen activator (uPA)-mediated fibrinolysis to the pericellular micro-environment but also promoting cell migration and chemotaxis. Consistent with this multifunctional role, uPAR binds several extracellular ligands, including uPA and vitronectin. Structural studies suggest that uPAR possesses structural flexibility. It is, however, not clear whether this flexibility is an inherent property of the uPAR structure per se or whether it is induced upon ligand binding. The crystal structure of human uPAR in its ligand-free state would clarify this issue, but such information remains unfortunately elusive. We now report the crystal structures of a stabilized, human uPAR (H47C/N259C) in its ligand-free form to 2.4 {\AA} and in complex with amino-terminal fragment (ATF) to 3.2 {\AA}. The structure of uPAR(H47C/N259C) in complex with ATF resembles the wild-type uPAR·ATF complex, demonstrating that these mutations do not perturb the uPA binding properties of uPAR. The present structure of uPAR(H47C/N259C) provides the first structural definition of uPAR in its ligand-free form, which represents one of the biologically active conformations of uPAR as defined by extensive biochemical studies. The domain boundary between uPAR DI-DII domains is more flexible than the DII-DIII domain boundary. Two important structural features are highlighted by the present uPAR structure. First, the DI-DIII domain boundary may face the cell membrane. Second, loop 130-140 of uPAR plays a dynamic role during ligand loading/unloading. Together, these studies provide new insights into uPAR structure-function relationships, emphasizing the importance of the inter-domain dynamics of this modular receptor.",

keywords = "Binding Sites, Cell Membrane, Crystallization, Crystallography, X-Ray, Humans, Ligands, Mannose-Binding Lectins, Membrane Glycoproteins, Models, Molecular, Mutation, Protein Binding, Protein Structure, Secondary, Protein Structure, Tertiary, Receptors, Cell Surface, Recombinant Proteins, Structure-Activity Relationship, Urokinase-Type Plasminogen Activator, Vitronectin",

author = "Xiang Xu and Henrik G{\aa}rdsvoll and Cai Yuan and Lin Lin and Michael Ploug and Mingdong Huang",

year = "2012",

month = mar,

day = "9",

doi = "10.1016/j.jmb.2011.12.058",

language = "English",

volume = "416",

pages = "629--41",

journal = "Journal of Molecular Biology",

issn = "0022-2836",

publisher = "Academic Press",

number = "5",

}

TY - JOUR

T1 - Crystal structure of the urokinase receptor in a ligand-free form

AU - Xu, Xiang

AU - Gårdsvoll, Henrik

AU - Yuan, Cai

AU - Lin, Lin

AU - Ploug, Michael

AU - Huang, Mingdong

PY - 2012/3/9

Y1 - 2012/3/9

N2 - The urokinase receptor urokinase-type plasminogen activator receptor (uPAR) is a surface receptor capable of not only focalizing urokinase-type plasminogen activator (uPA)-mediated fibrinolysis to the pericellular micro-environment but also promoting cell migration and chemotaxis. Consistent with this multifunctional role, uPAR binds several extracellular ligands, including uPA and vitronectin. Structural studies suggest that uPAR possesses structural flexibility. It is, however, not clear whether this flexibility is an inherent property of the uPAR structure per se or whether it is induced upon ligand binding. The crystal structure of human uPAR in its ligand-free state would clarify this issue, but such information remains unfortunately elusive. We now report the crystal structures of a stabilized, human uPAR (H47C/N259C) in its ligand-free form to 2.4 Å and in complex with amino-terminal fragment (ATF) to 3.2 Å. The structure of uPAR(H47C/N259C) in complex with ATF resembles the wild-type uPAR·ATF complex, demonstrating that these mutations do not perturb the uPA binding properties of uPAR. The present structure of uPAR(H47C/N259C) provides the first structural definition of uPAR in its ligand-free form, which represents one of the biologically active conformations of uPAR as defined by extensive biochemical studies. The domain boundary between uPAR DI-DII domains is more flexible than the DII-DIII domain boundary. Two important structural features are highlighted by the present uPAR structure. First, the DI-DIII domain boundary may face the cell membrane. Second, loop 130-140 of uPAR plays a dynamic role during ligand loading/unloading. Together, these studies provide new insights into uPAR structure-function relationships, emphasizing the importance of the inter-domain dynamics of this modular receptor.

AB - The urokinase receptor urokinase-type plasminogen activator receptor (uPAR) is a surface receptor capable of not only focalizing urokinase-type plasminogen activator (uPA)-mediated fibrinolysis to the pericellular micro-environment but also promoting cell migration and chemotaxis. Consistent with this multifunctional role, uPAR binds several extracellular ligands, including uPA and vitronectin. Structural studies suggest that uPAR possesses structural flexibility. It is, however, not clear whether this flexibility is an inherent property of the uPAR structure per se or whether it is induced upon ligand binding. The crystal structure of human uPAR in its ligand-free state would clarify this issue, but such information remains unfortunately elusive. We now report the crystal structures of a stabilized, human uPAR (H47C/N259C) in its ligand-free form to 2.4 Å and in complex with amino-terminal fragment (ATF) to 3.2 Å. The structure of uPAR(H47C/N259C) in complex with ATF resembles the wild-type uPAR·ATF complex, demonstrating that these mutations do not perturb the uPA binding properties of uPAR. The present structure of uPAR(H47C/N259C) provides the first structural definition of uPAR in its ligand-free form, which represents one of the biologically active conformations of uPAR as defined by extensive biochemical studies. The domain boundary between uPAR DI-DII domains is more flexible than the DII-DIII domain boundary. Two important structural features are highlighted by the present uPAR structure. First, the DI-DIII domain boundary may face the cell membrane. Second, loop 130-140 of uPAR plays a dynamic role during ligand loading/unloading. Together, these studies provide new insights into uPAR structure-function relationships, emphasizing the importance of the inter-domain dynamics of this modular receptor.

KW - Binding Sites

KW - Cell Membrane

KW - Crystallization

KW - Crystallography, X-Ray

KW - Humans

KW - Ligands

KW - Mannose-Binding Lectins

KW - Membrane Glycoproteins

KW - Models, Molecular

KW - Mutation

KW - Protein Binding

KW - Protein Structure, Secondary

KW - Protein Structure, Tertiary

KW - Receptors, Cell Surface

KW - Recombinant Proteins

KW - Structure-Activity Relationship

KW - Urokinase-Type Plasminogen Activator

KW - Vitronectin

U2 - 10.1016/j.jmb.2011.12.058

DO - 10.1016/j.jmb.2011.12.058

M3 - Journal article

C2 - 22285761

SN - 0022-2836

VL - 416

SP - 629

EP - 641

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

IS - 5

ER -

Crystal structure of the urokinase receptor in a ligand-free form

Abstract

Keywords

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