The Amot/Patj/Syx signaling complex spatially controls RhoA GTPase activity in migrating endothelial cells

Blood. 2009 Jan 1;113(1):244-53. doi: 10.1182/blood-2008-04-153874. Epub 2008 Sep 29.


Controlled regulation of Rho GTPase activity is an essential component mediating growth factor-stimulated migration. We have previously shown that angiomotin (Amot), a membrane-associated scaffold protein, plays a critical role during vascular patterning and endothelial migration during embryogenesis. However, the signaling pathways by which Amot controls directional migration are not known. Here we have used peptide pull-down and yeast 2-hybrid (Y2H) screening to identify proteins that interact with the C-terminal PDZ-binding motifs of Amot and its related proteins AmotL1 and 2. We report that Amot and its related proteins bind to the RhoA GTPase exchange factor (RhoGEF) protein Syx. We show that Amot forms a ternary complex together with Patj (or its paralogue Mupp1) and Syx. Using FRET analysis, we provide evidence that Amot controls targeting of RhoA activity to lamellipodia in vitro. We also report that, similar to Amot, morpholino knockdown of Syx in zebrafish results in inhibition of migration of intersegmental arteries. Taken together, our results indicate that the directional migration of capillaries in the embryo is governed by the Amot:Patj/Mupp1:Syx signaling that controls local GTPase activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Aorta / cytology
  • Capillaries / cytology
  • Capillaries / embryology*
  • Capillaries / metabolism
  • Carrier Proteins / metabolism
  • Cell Line, Transformed
  • Cell Movement / physiology
  • Endothelial Cells / cytology
  • Endothelial Cells / physiology*
  • Guanine Nucleotide Exchange Factors / genetics
  • Guanine Nucleotide Exchange Factors / metabolism*
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / metabolism*
  • Kidney / cytology
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mice
  • Neovascularization, Physiologic / physiology
  • PDZ Domains / physiology
  • Rho Guanine Nucleotide Exchange Factors
  • Tight Junction Proteins
  • Zebrafish
  • Zebrafish Proteins / genetics
  • Zebrafish Proteins / metabolism
  • rhoA GTP-Binding Protein / metabolism*


  • AMOT protein, human
  • AMOTL1 protein, human
  • AMOTL2 protein, human
  • Carrier Proteins
  • Guanine Nucleotide Exchange Factors
  • Intercellular Signaling Peptides and Proteins
  • Membrane Proteins
  • PATJ protein, human
  • Rho Guanine Nucleotide Exchange Factors
  • Tight Junction Proteins
  • Zebrafish Proteins
  • plekhg5a protein, zebrafish
  • rhoA GTP-Binding Protein