Recombinant Mouse VEGF 188 Protein

Vascular endothelial growth factor (VEGF or VEGF‑A), also known as vascular permeability factor (VPF), is a potent mediator of both angiogenesis and vasculogenesis in the fetus and adult (1‑3). It is a member of the PDGF family that is characterized by a cystine knot structure formed by eight conserved cysteine residues (4). Alternate splicing produces isoforms including 121, 145, 165, 183, 189, and 206 amino acid (aa) forms in humans, with 120, 164 and 188 aa isoforms found in mouse (1‑4). Mouse VEGF₁₈₈ shares 98% aa sequence identity with the appropriate isoform in rat, and 89% with human, bovine and canine VEGF. While isoforms VEGF₁₂₀ and VEGF₁₂₁ are freely diffusible, VEGF₁₈₈, VEGF₁₈₉ and VEGF₂₀₆ contain the highest number of basic aa, which bind heparin and tether these isoforms to the cell surface and extracellular matrix (3‑5). Expression of VEGF_188/189 is particularly high in the embryonic lung, where it is produced by type II alveolar epithelia (6). It is thought to be involved in lung, heart and liver vasculogenesis (5, 6). It is not sufficient for vasculogenesis during bone development, but may play a role in bone repair (5, 7). Tumor cell production of VEGF_188/189 correlates with poor prognosis (5). VEGF binds the type I transmembrane receptor tyrosine kinases VEGF R1 (also called Flt‑1) and VEGF R2 (Flk‑1/KDR) on endothelial cells (4). Although affinity is highest for binding to VEGF R1, VEGF R2 appears to be the primary mediator of VEGF angiogenic activity (3, 4). VEGF₁₈₈ binds VEGF R2 best when it is cleaved by uPA or plasmin into a 110‑111 aa form (4, 5). Human VEGF₁₆₅ and VEGF₁₈₉ also bind the semaphorin receptor Neuropilin‑1 (8, 9).