Neuropilin-1 regulates a new VEGF-induced gene, Phactr-1, which controls tubulogenesis and modulates lamellipodial dynamics in human endothelial cells

Cell Signal. 2012 Jan;24(1):214-23. doi: 10.1016/j.cellsig.2011.09.003. Epub 2011 Sep 10.


Recently, we identified a new Vascular Endothelial Growth Factor (VEGF)-A(165)-induced gene Phactr-1, (Phosphatase Actin Regulator-1). We reported that Phactr-1 gene silencing inhibited tube formation in human umbilical endothelial cells (HUVECs) indicating a key role for Phactr-1 in tubulogenesis in vitro. In this study, we investigated the role of Phactr-1 in several cellular processes related to angiogenesis. We found that neuropilin-1 (NRP-1) and VEGF-R1 depletion inhibited Phactr-1 mRNA expression while NRP-2 and VEGF-R2 depletion had no effect. We described a new interaction site of VEGF-A(165) to VEGF-R1 in peptides encoded by exons 7 and 8 of VEGF-A(165). The specific inhibition of VEGF-A(165) binding on NRP-1 and VEGF-R1 by ERTCRC and CDKPRR peptides decreased the Phactr-1 mRNA levels in HUVECs indicating that VEGF-A(165)-dependent regulation of Phactr-1 expression required both NRP-1 and VEGF-R1 receptors. In addition, upon VEGFA(165)-stimulation Phactr-1 promotes formation and maintenance of cellular tubes through NRP-1 and VEGFR1. Phactr-1 was previously identified as protein phosphatase 1 (PP1) α-interacting protein that possesses actin-binding domains. We showed that Phactr-1 depletion decreased PP1 activity, disrupted the fine-tuning of actin polymerization and impaired lamellipodial dynamics. Taken together our results strongly suggest that Phactr-1 is a key component in the angiogenic process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Binding, Competitive
  • Cell Culture Techniques
  • Cell Movement
  • Cells, Cultured
  • Endothelial Cells / metabolism
  • Endothelial Cells / physiology*
  • Gene Knockdown Techniques
  • Human Umbilical Vein Endothelial Cells / metabolism
  • Humans
  • Microfilament Proteins / genetics*
  • Microfilament Proteins / metabolism
  • Microtubules / metabolism*
  • Neovascularization, Pathologic / metabolism
  • Neuropilin-1 / genetics
  • Neuropilin-1 / metabolism*
  • Peptide Fragments / chemistry
  • Protein Binding
  • Pseudopodia / metabolism*
  • RNA Interference
  • Time-Lapse Imaging
  • Transcription, Genetic
  • Vascular Endothelial Growth Factor A / chemistry
  • Vascular Endothelial Growth Factor A / pharmacology
  • Vascular Endothelial Growth Factor A / physiology*
  • Vascular Endothelial Growth Factor Receptor-1 / chemistry
  • Vascular Endothelial Growth Factor Receptor-1 / genetics
  • Vascular Endothelial Growth Factor Receptor-1 / metabolism


  • Microfilament Proteins
  • PHACTR1 protein, human
  • Peptide Fragments
  • Vascular Endothelial Growth Factor A
  • Neuropilin-1
  • Vascular Endothelial Growth Factor Receptor-1