4JYO image
Entry Detail
PDB ID:
4JYO
Title:
Structural basis for angiopoietin-1 mediated signaling initiation
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2013-03-31
Release Date:
2013-05-08
Method Details:
Experimental Method:
Resolution:
2.50 Å
R-Value Free:
0.24
R-Value Work:
0.18
R-Value Observed:
0.18
Space Group:
P 64 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Angiopoietin-1
Chain IDs:A (auth: X)
Chain Length:230
Number of Molecules:1
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
Structural basis for angiopoietin-1-mediated signaling initiation.
Proc.Natl.Acad.Sci.USA 110 7205 7210 (2013)
PMID: 23592718 DOI: 10.1073/pnas.1216890110

Abstact

Angiogenesis is a complex cellular process involving multiple regulatory growth factors and growth factor receptors. Among them, the ligands for the endothelial-specific tunica intima endothelial receptor tyrosine kinase 2 (Tie2) receptor kinase, angiopoietin-1 (Ang1) and Ang2, play essential roles in balancing vessel stability and regression during both developmental and tumor-induced angiogenesis. Despite possessing a high degree of sequence identity, Ang1 and Ang2 have distinct functional roles and cell-signaling characteristics. Here, we present the crystal structures of Ang1 both unbound and in complex with the Tie2 ectodomain. Comparison of the Ang1-containing structures with their Ang2-containing counterparts provide insight into the mechanism of receptor activation and reveal molecular surfaces important for interactions with Tie2 coreceptors and associated signaling proteins. Using structure-based mutagenesis, we identify a loop within the angiopoietin P domain, adjacent to the receptor-binding interface, which confers the specific agonist/antagonist properties of the molecule. We demonstrate using cell-based assays that an Ang2 chimera containing the Ang1 loop sequence behaves functionally similarly to Ang1 as a constitutive Tie2 agonist, able to efficiently dissociate the inhibitory Tie1/Tie2 complex and elicit Tie2 clustering and downstream signaling.

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