Structural requirements for dimerization, glycosylation, secretion, and biological function of VPF/VEGF

Biochim Biophys Acta. 1995 Jan 5;1246(1):1-9. doi: 10.1016/0167-4838(94)00144-6.


Vascular permeability factor (VPF) also known as vascular endothelial growth factor (VEGF), is a dimeric protein that affects endothelial cell (EC) and vascular functions including enhancement of microvascular permeability and stimulation of EC growth. To investigate the structural features of VPF/VEGF necessary for efficient dimerization, secretion, and biological activities, we employed site-directed mutagenesis with a Cos-1 cell expression system. Several cysteine residues essential for VPF dimerization were identified by mutation analysis of the Cys-25, Cys-56, and Cys-67 residues. Mutant VPF isoforms lacking either of these cysteines were secreted as monomers and were completely inactive in both vascular permeability and endothelial cell mitotic assays. VPF Cys-145 mutant protein was efficiently secreted as a glycosylated, dimeric polypeptide, but had a reduction in biological activities. The site of N-linked glycosylation was directly identified as Asn-74, which, when mutated produced an inefficiently secreted dimeric protein without post-translational glycosylation, yet maintained full vascular permeability activity. Finally, we found that one VPF mutant isoform Cys-101 was not secreted and this mutant functioned as a dominant-negative suppressor of wild-type VPF secretion as demonstrated by co-expression assays in Cos-1 cells.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Aorta
  • Base Sequence
  • Capillary Permeability
  • Cattle
  • Cell Division
  • Cell Line, Transformed
  • Chlorocebus aethiops
  • Culture Media, Conditioned
  • Endothelial Growth Factors / chemistry*
  • Endothelial Growth Factors / genetics
  • Endothelial Growth Factors / pharmacology*
  • Endothelium, Vascular / cytology
  • Gene Expression
  • Glycosylation
  • Guinea Pigs
  • Kidney
  • Lymphokines / chemistry*
  • Lymphokines / genetics
  • Lymphokines / pharmacology*
  • Macromolecular Substances
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Recombinant Proteins / pharmacology
  • Structure-Activity Relationship
  • Vascular Endothelial Growth Factor A
  • Vascular Endothelial Growth Factors


  • Culture Media, Conditioned
  • Endothelial Growth Factors
  • Lymphokines
  • Macromolecular Substances
  • Recombinant Proteins
  • Vascular Endothelial Growth Factor A
  • Vascular Endothelial Growth Factors