VEGF206

Vascular endothelial growth factor-A (VEGF-A) mRNA undergoes alternative splicing events that generate several different homodimeric isoforms, e.g. VEGF121, VEGF145, VEGF165, VEGF189, and VEGF206. VEGF121 is a non-heparin-binding acidic protein, which is freely diffusible. The longer forms, VEGF189 or VEGF206, are highly basic proteins tightly bound to extracellular heparin-containing proteoglycans. VEGF165 has intermediate properties. VEGF165 was observed largely in Golgi apparatus-like structures. Immunogold labeling of cells expressing VEGF189 or VEGF206 revealed that the staining was localized to the subepithelial ECM. VEGF associated with the ECM was bioactive, because endothelial cells cultured on ECM derived from cells expressing VEGF189 or VEGF2O6 were markedly stimulated to proliferate. In addition, ECM-bound VEGF can be released into a soluble and bioactive form by heparin or plasmin. ECM-bound VEGF189 and VEGF206 have molecular masses consistent with the intact polypeptides. The ECM may represent an important source of VEGF and angiogenic potential. The isoforms VEGF145, VEGF165 and VEGF189 bind to heparin with high affinity, the affinity of VEGF206 is much weaker. All dimeric forms have similar biological activities but their bio­availability is very different. However so far there are only a few data about the biological activities of VEGF206.