Dual regulation of vascular endothelial growth factor bioavailability by genetic and proteolytic mechanisms.
The vascular endothelial growth factor (VEGF) family encompasses four polypeptides that result from alternative splicing of mRNA. We have previously demonstrated differences in the secretion pattern of these polypeptides. Stable cell lines expressing VEGFs were established in human embryonic kidney CEN4 cells. VEGF121, the shortest form, was secreted and freely soluble in tissue culture medium. VEGF189 was secreted, but was almost entirely bound to the cell surface or extracellular matrix. VEGF165 displayed an intermediary behavior. Suramin induced the release of VEGF189, permitting its characterization as a more basic protein with higher affinity for heparin than VEGF165 or VEGF121, but with similar endothelial cell mitogenic activity. Heparin, heparan sulfate, and heparinase all induced the release of VEGF165 and VEGF189, suggesting heparin-containing proteoglycans as candidate VEGF-binding sites. Finally, VEGF165 and VEGF189 were released from their bound states by treatment with plasmin. The released 34-kDa dimeric species are active as endothelial cell mitogens and as vascular permeability agents. We conclude that the bioavailability of VEGF may be regulated at the genetic level by alternative splicing that determines whether VEGF will be soluble or incorporated into a biological reservoir and also through proteolysis following plasminogen activation.
Houck
K A
KA
Department of Molecular Biology, Genetech, Inc., South San Francisco, California 94080.
Leung
D W
DW
Rowland
A M
AM
Winer
J
J
Ferrara
N
N
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001681:Biological Assay; D002460:Cell Line; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D003545:Cysteine / Q000378:metabolism; D004622:Embryo, Mammalian; D016228:Endothelial Growth Factors / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D005822:Genetic Vectors; D006493:Heparin / Q000494:pharmacology; D006497:Heparan Sulfate / Q000494:pharmacology; D006801:Humans; D007668:Kidney; D008222:Lymphokines / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D008715:Methionine / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D011975:Receptors, Mitogen / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor; D013498:Suramin / Q000494:pharmacology; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D003545:Cysteine; D016228:Endothelial Growth Factors; D006493:Heparin; D006497:Heparan Sulfate; D008222:Lymphokines; D008715:Methionine; D011505:Protein-Tyrosine Kinases; D012333:RNA, Messenger; D011975:Receptors, Mitogen; D040262:Receptors, Vascular Endothelial Growth Factor; D013498:Suramin; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C467484:VEGFA protein, human