Requirements for Binding and Signaling of the Kinase Domain Receptor for Vascular Endothelial Growth Factor*
- From the §Departments of Protein Engineering and¶Molecular Biology, Genentech, Inc., South San Francisco, California 94080
Abstract
Vascular endothelial growth factor (VEGF) is a dimeric hormone that controls much of vascular development through binding and activation of its kinase domain receptor (KDR). We produced analogs of VEGF that show it has two receptor-binding sites which are located near the poles of the dimer and straddle the interface between subunits. Deletion experiments in KDR indicate that of the seven IgG-like domains in the extracellular domain, only domains 2–3 are needed for tight binding of VEGF. Monomeric forms of the extracellular domain of KDR bind ∼100 times weaker than dimeric forms showing a strong avidity component for binding of VEGF to predimerized forms of the receptor. Based upon these structure-function studies and a mechanism in which receptor dimerization is critical for signaling, we constructed a receptor antagonist in the form of a heterodimer of VEGF that contained one functional and one non-functional site. These studies establish a functional foundation for the design of VEGF analogs, mimics, and antagonists.
Footnotes
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↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵‡ Contributed equally to the results of this work.
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↵‖ To whom correspondence should be addressed.
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↵1 The abbreviations used are: VEGF, vascular endothelial growth factor; KDR, kinase domain receptor; Flt-1, fms-like tyrosine kinase-1; PLGF, placenta growth factor; PDGF, platelet-derived growth factor; HuVEC, human umbilical vein endothelial cells; mAb, monoclonal antibody; PAGE, polyacrylamide gel electrophoresis.
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↵2 B. Li, unpublished data.
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- Received November 7, 1997.
- Revision received February 9, 1998.
- The American Society for Biochemistry and Molecular Biology, Inc.
