VEGF188

Rat Vascular Endothelial Growth Factor188 (VEGF188), a 20,07 kDa protein consisting of 188 amino acid residues, is produced as a homodimer. VEGF188 is a polypeptide growth factor and a member of the platelet-derived growth factor family. It is a specific mitogen for vascular endothelial cells and a strong angiogenic factor in vivo. Two high-affinity tyrosine kinase receptors for VEGF188 have been identified, VEGFR-1 (FLT-1), and VEGFR-2 (Flk-1) . Consistent with the endothelial cell-specific action of VEGF188, expression of both receptor genes has been found predominantly but not exclusively on endothelial cells. Expression of VEGFR-1 was also found on human monocytes, neutrophils (PMNs), bovine brain pericytes and villous and extravillous trophoblasts. In addition to its action as a mitogen it is a potent vascular permeability factor (VPF) in vivo and is also a chemo attractant for monocytes and endothelial cells. At least four different proteins are generated by differential splicing of the mouse VEGF gene: VEGF120, VEGF144, VEGF164 and VEGF188. The most abundant form is VEGF164. Whereas VEGF120, VEGF144 and VEGF164 are secreted proteins, VEGF188 is strongly cell-associated. In addition, the isoforms VEGF164 and VEGF188 bind to heparin with high affinity. All dimeric forms possess similar biological activities. A related protein of VEGF is placenta growth factor (PlGF) with about 53% homology and VEGF-B with similar biological activities. The full ORF of native rat VEGF188 (Ala27-Arg214) was cloned from total RNA of rat sinusoidal endothelial cells using standard protocols.