The heparin-binding domain confers diverse functions of VEGF-A in development and disease: a structure–function study

The longer splice isoforms of VEGF (vascular endothelial growth factor)-A, including VEGF_164(165), contain a highly basic HBD (heparin-binding domain). This domain allows these isoforms to interact with and localize to the HS (heparan sulfate)-rich extracellular matrix, and bind to the co-receptor Nrp-1 (neuropilin-1). Heparin-binding VEGF-A isoforms are critical for survival: mice engineered to express exclusively the non-heparin-binding VEGF₁₂₀ have diminished vascular branching during embryonic development and die from postnatal angiogenesis defects shortly after birth. Although it is thought that the HBD contributes to the diverse functions of VEGF-A in both physiological and pathological processes, little is known about the molecular features within this domain that enable these functions. In the present paper, we discuss the roles of the VEGF HBD in normal and disease conditions, with a particular focus on the VEGF_164(165) isoform.