Selective Binding of VEGF to One of the Three Vascular Endothelial Growth Factor Receptors of Vascular Endothelial Cells

doi:10.1074/jbc.271.10.5519

Selective Binding of VEGF to One of the Three Vascular Endothelial Growth Factor Receptors of Vascular Endothelial Cells (*)

From the (1)Department of Biology, Technion, Israel Institute of Technology, Haifa 32000, Israel, the
(2)Department of Food Engineering and Biotechnology, Technion, Israel Institute of Technology, Haifa 32000, Israel,
(3)ImClone Systems Inc., New York, New York 10014, and the
(4)Department of Biological Chemistry, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115

^¶ To whom correspondence should be addressed. Tel.: 972-4-829-4216; Fax: 972-4-822-5153; gera{at}techunix.technion.ac.il.

Abstract

VEGF and VEGF are vascular endothelial growth factor splice variants that promote the proliferation of endothelial cells and angiogenesis. VEGF contains the 44 additional amino acids encoded by exon 7 of the VEGF gene. These amino acids confer upon VEGF a heparin binding capability which VEGF lacks. I-VEGF bound to three vascular endothelial growth factor (VEGF) receptors on endothelial cells, while I-VEGF bound selectively only to the flk-1 VEGF receptor which corresponds to the larger of the three VEGF receptors. The binding of I-VEGF to flk-1 was not affected by the removal of cell surface heparan sulfates or by heparin. Both VEGF and VEGF inhibited the binding of I-VEGF to a soluble extracellular domain of the flk-1 VEGF receptor in the absence of heparin. However, heparin potentiated the inhibitory effect of VEGF by 2-3-fold. These results contrast with previous observations which have indicated that the binding of I-VEGF to the flk-1 receptor is strongly dependent on heparin-like molecules. Further experiments showed that the receptor binding ability of VEGF is susceptible to oxidative damage caused by oxidants such as HO or chloramine-T. VEGF was also damaged by oxidants but to a lesser extent. Heparin or cell surface heparan sulfates restored the flk-1 binding ability of damaged VEGF but not the receptor binding ability of damaged VEGF. These observations suggest that alternative splicing can generate a diversity in growth factor signaling by determining receptor recognition patterns. They also indicate that the heparin binding ability of VEGF may enable the restoration of damaged VEGF function in processes such as inflammation or wound healing.

Footnotes

↵^§ The first two authors contributed equally to this manuscript.
↵* This work was supported by a grant from the German-Israel Binational Foundation (GIF), by a grant from the Israel Cancer Research Fund, and by an angiogenesis research center grant from the Israel Academy of Sciences and Humanities (to G. N.). It was also supported by the Technion-Otto Meyerhof Biotechnology Laboratories (to B.-Z. L. and G. N.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

VEGF

vascular endothelial growth factor

VEGF

165-amino acid form of vascular endothelial growth factor

VEGF

121-amino acid form of vascular endothelial growth factor

aFGF

acidic fibroblast growth factor

bFGF

basic fibroblast growth factor

flk-1

mouse homologue of the human VEGF receptor KOR

HUE

human umbilical vein-derived endothelial cells

PAGE

polyacrylamide gel electrophoresis

ELISA

enzyme-linked immunosorbent assay.
- Received June 15, 1995.
- Revision received October 27, 1995.