Characterization of the VEGF binding site on the Flt-1 receptor.
The angiogenic growth factor VEGF binds to the receptor tyrosine kinases Flt-1 and KDR/Flk-1. Immunoglobulin (Ig)-like loop-2 of Flt-1 is involved in binding VEGF, but the contribution of other Flt-1 Ig-loops to VEGF binding remains unclear. We tested the ability of membrane-bound chimeras between the extracellular domain of Flt-1 and the cell adhesion molecule embigin to bind VEGF. VEGF bound as well to receptors containing Flt-1 loops 1-2 or 2-3 as it did to the entire Flt-1 extracellular domain. Chimeras containing only loop-2 of Flt-1 bound VEGF with 22-fold lower affinity. We conclude that high-affinity VEGF binding requires Ig-like loop-2 plus either loop-1 or loop-3. In addition, Flt-1 amino acid residues Arg-224 and Asp-231 were not essential for high-affinity binding of VEGF to membrane-bound Flt-1.
Herley
M T
MT
Biochemistry Department, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
Yu
Y
Y
Whitney
R G
RG
Sato
J D
JD
D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D017931:DNA Primers; D016228:Endothelial Growth Factors / Q000378:metabolism*; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008222:Lymphokines / Q000378:metabolism*; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D018832:Molecular Chaperones; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017433:Protein Structure, Secondary; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017978:Receptors, Growth Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D040262:Receptors, Vascular Endothelial Growth Factor; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D042442:Vascular Endothelial Growth Factors
D017931:DNA Primers; C069503:EMB protein, human; C504567:Emb protein, rat; D016228:Endothelial Growth Factors; D006023:Glycoproteins; D008222:Lymphokines; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D018832:Molecular Chaperones; D011518:Proto-Oncogene Proteins; D017978:Receptors, Growth Factor; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor; D040281:Vascular Endothelial Growth Factor Receptor-1