title: A local VE-cadherin and Trio-based signaling complex stabilizes endothelial junctions through Rac1.
abstract: Endothelial cell-cell junctions maintain a restrictive barrier that is tightly regulated to allow dynamic responses to permeability-inducing angiogenic factors, as well as to inflammatory agents and adherent leukocytes. The ability of these stimuli to transiently remodel adherens junctions depends on Rho-GTPase-controlled cytoskeletal rearrangements. How the activity of Rho-GTPases is spatio-temporally controlled at endothelial adherens junctions by guanine-nucleotide exchange factors (GEFs) is incompletely understood. Here, we identify a crucial role for the Rho-GEF Trio in stabilizing junctions based around vascular endothelial (VE)-cadherin (also known as CDH5). Trio interacts with VE-cadherin and locally activates Rac1 at adherens junctions during the formation of nascent contacts, as assessed using a novel FRET-based Rac1 biosensor and biochemical assays. The Rac-GEF domain of Trio is responsible for the remodeling of junctional actin from radial into cortical actin bundles, a crucial step for junction stabilization. This promotes the formation of linear adherens junctions and increases endothelial monolayer resistance. Collectively, our data show the importance of spatio-temporal regulation of the actin cytoskeleton through Trio and Rac1 at VE-cadherin-based cell-cell junctions in the maintenance of the endothelial barrier.
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066 CX, The Netherlands.
authors.forename: Ilse
authors.initials: I
authors.lastname: Timmerman
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066 CX, The Netherlands.
authors.forename: Niels
authors.initials: N
authors.lastname: Heemskerk
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066 CX, The Netherlands.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Kroon
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066 CX, The Netherlands.
authors.forename: Antje
authors.initials: A
authors.lastname: Schaefer
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066 CX, The Netherlands.
authors.forename: Jos
authors.initials: J
authors.lastname: van Rijssel
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066 CX, The Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: Hoogenboezem
authors.affiliation: Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam 1098 XH, The Netherlands.
authors.forename: Jakobus
authors.initials: J
authors.lastname: van Unen
authors.affiliation: Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam 1098 XH, The Netherlands.
authors.forename: Joachim
authors.initials: J
authors.lastname: Goedhart
authors.affiliation: Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam 1098 XH, The Netherlands.
authors.forename: Theodorus W J
authors.initials: TW
authors.lastname: Gadella
authors.affiliation: Center for Cell Analysis and Modelling, University of Connecticut Health Center, Farmington, CT 06032, USA.
authors.forename: Taofei
authors.initials: T
authors.lastname: Yin
authors.affiliation: Center for Cell Analysis and Modelling, University of Connecticut Health Center, Farmington, CT 06032, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066 CX, The Netherlands.
authors.forename: Stephan
authors.initials: S
authors.lastname: Huveneers
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam 1066 CX, The Netherlands j.vanbuul@sanquin.nl.
authors.forename: Jaap D
authors.initials: JD
authors.lastname: van Buul
mesh_terms: D008841:Actin Cytoskeleton / Q000235:genetics / Q000378:metabolism; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002199:Capillary Permeability / Q000235:genetics; D042783:Endothelial Cells / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D007365:Intercellular Junctions / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D015820:Cadherins; D020558:GTP Phosphohydrolases; D020662:Guanine Nucleotide Exchange Factors; D017346:Protein Serine-Threonine Kinases; D020830:rac1 GTP-Binding Protein; D000099152:Cadherin 5; C107953:RAC1 protein, human; C099628:TRIO protein, human
keywords: Endothelium; GEF; Rac1; Trio; VE-cadherin