PUBLICATION

Syx, a RhoA Guanine Exchange Factor, Is Essential for Angiogenesis In Vivo

Authors
Garnaas, M.K., Moodie, K.L., Liu, M.L., Samant, G.V., Li, K., Marx, R., Baraban, J.M., Horowitz, A., and Ramchandran, R.
ID
ZDB-PUB-080902-29
Date
2008
Source
Circulation research   103(7): 710-716 (Journal)
Registered Authors
Garnaas, Maija, Ramchandran, Ramani
Keywords
vascular, zebrafish, PDZ, knockdown, intersomitic vessels
MeSH Terms
  • Intercellular Junctions/genetics
  • Intercellular Junctions/metabolism
  • Endothelial Cells/cytology
  • Endothelial Cells/metabolism
  • rhoA GTP-Binding Protein/genetics
  • rhoA GTP-Binding Protein/metabolism*
  • Zebrafish/embryology*
  • Zebrafish/genetics
  • Intercellular Signaling Peptides and Proteins/genetics
  • Intercellular Signaling Peptides and Proteins/metabolism
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
  • Mice
  • Microfilament Proteins/genetics
  • Microfilament Proteins/metabolism
  • Cell Movement/physiology
  • Neovascularization, Physiologic*
  • Guanine Nucleotide Exchange Factors/genetics
  • Guanine Nucleotide Exchange Factors/metabolism*
  • Animals
  • Vascular Endothelial Growth Factor A/genetics
  • Vascular Endothelial Growth Factor A/metabolism
PubMed
18757825 Full text @ Circ. Res.
Abstract
Rho GTPases play an important and versatile role in several biological processes. In this study, we identified the zebrafish ortholog of the mammalian Rho A guanine exchange factor, synectin-binding guanine exchange factor (Syx), and determined its in vivo function in the zebrafish and the mouse. We found that Syx is expressed specifically in the vasculature of these organisms. Loss-of-function studies in the zebrafish and mouse point to a specific role for Syx in angiogenic sprouting in the developing vascular bed. Importantly, vasculogenesis and angioblast differentiation steps were unaffected in syx knockdown zebrafish embryos, and the vascular sprouting defects were partially rescued by the mouse ortholog. Syx knockdown in vitro impairs vascular endothelial growth factor-A-induced endothelial cell migration and angiogenesis. We have also uncovered a potential mechanism of endothelial sprout guidance in which angiomotin, a component of endothelial cell junctions, plays an additive role with Syx in directing endothelial sprouts. These results identify Syx as an essential contributor to angiogenesis in vivo.
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