Vascular endothelial growth factor receptor-2 and neuropilin-1 form a receptor complex that is responsible for the differential signaling potency of VEGF(165) and VEGF(121)

J Biol Chem. 2001 Jul 6;276(27):25520-31. doi: 10.1074/jbc.M102315200. Epub 2001 May 1.

Abstract

The two most abundant secreted isoforms of vascular endothelial growth factor A (VEGF(165) and VEGF(121)) are formed as a result of differential splicing of the VEGF-A gene. VEGF(165) and VEGF(121) share similar affinities at the isolated VEGF receptor (VEGFR)-2 but have been previously demonstrated to have differential ability to activate VEGFR-2-mediated effects on endothelial cells. Herein we investigate whether the recently described VEGF(165) isoform-specific receptor neuropilin-1 (Npn-1) is responsible for the difference in potency observed for these ligands. We demonstrate that although VEGFR-2 and Npn-1 form a complex, this complex does not result in an increase in VEGF(165) binding affinity. Therefore, the differential activity of VEGF(165) and VEGF(121) cannot be explained by a differential binding affinity for the complex. Using an antagonist that competes for VEGF(165) binding at the VEGFR-2.Npn-1 complex, we observe specific antagonism of VEGF(165)-meditated phosphorylation of VEGFR-2 without affecting the VEGF(121) response. These data indicate that the formation of the complex is responsible for the increased potency of VEGF(165) versus VEGF(121). Taken together, these data suggest a receptor-clustering role for Npn-1, as opposed to Npn-1 behaving as an affinity-converting subunit.

MeSH terms

  • Affinity Labels
  • Animals
  • Binding, Competitive
  • COS Cells
  • Cells, Cultured
  • Electrophoresis, Polyacrylamide Gel
  • Endothelial Growth Factors / metabolism*
  • Endothelium, Vascular / metabolism
  • Humans
  • Lymphokines / metabolism*
  • Macromolecular Substances
  • Nerve Tissue Proteins / metabolism*
  • Neuropilin-1
  • Phosphorylation
  • Placenta Growth Factor
  • Pregnancy Proteins / metabolism
  • Protein Binding
  • Protein Conformation
  • Receptor Protein-Tyrosine Kinases / metabolism*
  • Receptors, Growth Factor / metabolism*
  • Receptors, Vascular Endothelial Growth Factor
  • Signal Transduction*
  • Vascular Endothelial Growth Factor A
  • Vascular Endothelial Growth Factors

Substances

  • Affinity Labels
  • Endothelial Growth Factors
  • Lymphokines
  • Macromolecular Substances
  • Nerve Tissue Proteins
  • PGF protein, human
  • Pregnancy Proteins
  • Receptors, Growth Factor
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Vascular Endothelial Growth Factors
  • Placenta Growth Factor
  • Neuropilin-1
  • Receptor Protein-Tyrosine Kinases
  • Receptors, Vascular Endothelial Growth Factor