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Updated: Sep 15, 2026

Study of the Actin Cytoskeleton in Live Endothelial Cells Expressing GFP-Actin
Published on: November 18, 2011
Rho GTPases and the regulation of endothelial permeability
Beata Wojciak-Stothard1, Anne J Ridley
1Ludwig Institute for Cancer Research, Royal Free and University College School of Medicine Branch, 91 Riding House Street, London W1W 7BS, UK. beata@ludwig.ucl.ac.uk
Abstract:
Endothelial permeability depends on the integrity of intercellular junctions as well as actomyosin-based cell contractility. Rho GTPases have been implicated in signalling by many vasoactive substances including thrombin, tumour necrosis factor alpha (TNF-alpha), bradykinin, histamine, lysophosphatidic acid (LPA), vascular endothelial growth factor (VEGF), and hepatocyte growth factor (HGF). Two Rho family GTPases, Rho and Rac, have emerged as key regulators acting antagonistically to regulate endothelial barrier function: Rho increases actomyosin contractility, which facilitates breakdown of intercellular junctions, whereas Rac stabilizes endothelial junctions and counteracts the effects of Rho. In this review, we present evidence for the opposing effects of these two regulatory proteins and discuss links between them and other key signalling molecules such as cyclic AMP (cAMP), cyclic GMP (cGMP), phosphatidylinositide 3-kinases (PI3Ks), mitogen-activated protein kinases (MAPKs), and protein kinases C (PKCs). We also discuss strategies for targeting Rho GTPase signalling in therapies for diseases involving altered endothelial permeability.
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