title: Neuropilin-1-mediated vascular permeability factor/vascular endothelial growth factor-dependent endothelial cell migration.
abstract: Neuropilin-1 (NRP-1) has been found to be expressed by endothelial cells and tumor cells as an isoform-specific receptor for vascular permeability factor/vascular endothelial growth factor (VEGF). Previous studies were mainly focused on the extracellular domain of NRP-1 that can bind to VEGF165 and, thus, enables NRP-1 to act as a co-receptor for VEGF165, which enhances its binding to VEGFR-2 and its bioactivity. However, the exact functional roles and related signaling mechanisms of NRP-1 in angiogenesis are not well understood. In this study we constructed a chimeric receptor, EGNP-1, by fusing the extracellular domain of epidermal growth factor receptor to the transmembrane and intracellular domains of NRP-1 and transduced it into HUVECs with a retroviral expression vector. We observed that NRP-1/EGNP-1 mediates ligand-stimulated migration of human umbilical vein endothelial cells (HUVECs) but not proliferation. Our results show that NRP-1 alone can mediate HUVEC migration through its intracellular domain, and its C-terminal three amino acids (SEA-COOH) are essential for the process. We demonstrate that phosphatidylinositol 3-kinase inhibitor Ly294002 and the p85 dominant negative mutant can block NRP-1-mediated HUVEC migration. NRP-1-mediated migration can be significantly reduced by overexpression of the dominant negative mutant of RhoA (RhoA-19N). In addition, Gq family proteins and Gbetagamma subunits are also required for NRP-1-mediated HUVEC migration. These results show for the first time that NRP-1 can independently promote cell signaling in endothelial cells and also demonstrate the importance of last three amino acids of NRP-1 for its function.
mesh_terms: D001483:Base Sequence; D002455:Cell Division; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D017931:DNA Primers; D004730:Endothelium, Vascular / Q000166:cytology*; D006801:Humans; D039942:Neuropilin-1 / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology*
chemical_list: D017931:DNA Primers; D011993:Recombinant Fusion Proteins; D042461:Vascular Endothelial Growth Factor A; D039942:Neuropilin-1