Tyrosine phosphorylation of the vascular endothelial-growth-factor receptor-2 (VEGFR-2) is modulated by Rho proteins

Related Experiment Video

Updated: Aug 8, 2026

RhoC GTPase Activation Assay
09:58

RhoC GTPase Activation Assay

Published on: August 23, 2010

D Gingras1, S Lamy, R Béliveau

  • 1Laboratoire de Médecine Moléculaire Hôpital Sainte-Justine-UQAM, C.P. 8888, Succ. Centre-ville, Montréal, Québec, Canada H3C 3P8.

The Biochemical Journal
|May 19, 2000
PubMed

Insights

Rho proteins, activated by cytotoxic necrotizing factor 1 (CNF1), increase tyrosine phosphorylation of vascular endothelial growth factor receptor-2 (VEGFR-2), suggesting a role in angiogenesis.

Area of Science:

  • Cellular Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Endothelial cell signaling is crucial for angiogenesis.
  • Rho proteins regulate various cellular processes, including cell growth and migration.
  • Tyrosine phosphorylation is a key post-translational modification in signal transduction.

Purpose of the Study:

  • To investigate the role of Rho proteins in regulating tyrosine phosphorylation of endothelial cell proteins.
  • To determine the effect of Rho-specific toxins on the vascular endothelial growth factor (VEGF) signaling pathway.
  • To elucidate the mechanism by which Rho proteins influence VEGF receptor-2 (VEGFR-2) activity.

Main Methods:

  • Incubation of endothelial cells with cytotoxic necrotizing factor 1 (CNF1) and C3 transferase.
  • Analysis of tyrosine phosphorylation levels of signaling intermediates using Western blotting.
  • Assessment of VEGFR-2 kinase activity and its association with downstream proteins.
  • Overexpression of dominant-active and dominant-inactive RhoA mutants.

Main Results:

  • CNF1 induced significant tyrosine phosphorylation of VEGF-mediated signaling intermediates, including focal adhesion kinase, paxillin, and phospholipase Cgamma1.
  • CNF1 treatment markedly increased tyrosine phosphorylation and kinase activity of VEGFR-2, promoting its association with downstream proteins.
  • These effects were dependent on RhoA function, as evidenced by inhibition with C3 transferase and effects of RhoA mutants.
  • CNF1 specifically affected VEGFR-2, with no impact on VEGFR-1 phosphotyrosine levels.

Conclusions:

  • Rho proteins play a significant role in regulating endothelial cell signaling pathways.
  • RhoA activation modulates VEGFR-2 tyrosine phosphorylation and kinase activity, impacting downstream signaling.
  • These findings suggest that Rho proteins are important regulators of angiogenesis through their control of VEGFR-2 activity.

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